The Ecological, Economic and Social Effects of Eucalyptus^[5]

S. Shyam Sunder

Consultant

ABSTRACT

The expansion of eucalypt plantations has been matched by controversy about its use. This paper summarises a search of recent literature and reviews adverse allegations, advanced on ecological, economic and social grounds. The study shows that high water use continues to be a matter of concern, but the general conclusion is that while the water use of certain eucalypts is high, this conforms to the normal behaviour of other fast growing tree species. A few studies indicate that in lower rainfall years, the water use could be in excess of normal rainfall. Nutrient loss is a factor of management. In longer felling cycles the loss is made up by natural inflow; in short rotations with fast growth, fertiliser application is necessary. Eucalypts contribute positively to the environment in controlling desertification; afforesting denuded sites; and providing a land use for saline and alkaline soils of pH up to 8.5. In some areas eucalypts help save biodiversity by meeting fuel and small wood needs otherwise coming from natural forest. Economics are affected by the choice of species, provenances and management practices; great potential exists for increased yield through tree breeding. Plantations are managed economically for fuel, poles, timber and industrial wood; multiple use production in developing countries improves the economic returns. Social effects and controversies about the use of eucalypt are studied in detail. Allegations of social adverse effects are found to be exaggerated; possible social gains outweigh these.

Key words: Eucalyptus, eucalypt, ecological, economic, social effects, nutrient use, water use, fertilising, saline, alkaline lands, desertification, denuded sites, biodiversity, tree breeding, multiple use.

INTRODUCTION

This report is a contribution to updating FAO Forestry Paper 59, 'The Ecological Effects of Eucalyptus' with additional sections on economic and social aspects. No genus has evoked more respect or hate than Eucalyptus. The present paper is the continuation of the effort by the FAO to provide an unbiased view on Eucalyptus to decision makers, foresters, environmentalists and all people who grow trees.

Stephen Pyne, in his publication Burning Bush, stated that according to some authorities, Eucalyptus is less a genus than an alliance composed of three sub alliances, ten sub genera and over six hundred species. Hybrids are common, juvenile habits persist into adulthood and even "phantom species" have been identified. The plasticity of the genus is extraordinary. Its uses are equally diverse.

In 1985, when the FAO paper of Poore and Fries was published, eucalypt plantations covered 4 million ha outside its home. Today, eucalypts cover more than 6.5 million ha (416). By 2010, Brazil, Argentina, Indonesia, Chile, South Africa and Australia will have an estimated 9 million ha of eucalypt plantations (306). They are making vast strides.

In some of the developing countries, there have been controversies about eucalypts. These have since spread to a few developed countries as well. To begin with, arguments for and against were based on surmises, not backed by scientific evidence. If it was charged that the water level had dropped in one area due to the planting of eucalypts, it was rebutted that the fall in the ground water level was due to a greater discharge from bore wells than the recharge. If it was alleged that eucalypts poisoned the soil by some, this was rebutted by others.

Social Forestry was promoted with international aid in India with the stress on firewood, fruit, fodder and mulch species. Many farmers, backed by market forces, raised eucalypts and sold the wood to the highest bidder - industries. The blame for corrupting Social Forestry was levelled against eucalypts. Eucalypt was also criticised for what it was not - a producer of edible fruits or fodder. However, its extension has continued and fortunately, research has also caught up with it.

The Indian Statistical Institute, Bangalore, organised a national workshop on eucalypt in 1984. In the preface to the second edition of the proceedings of this workshop, published in 1988, the editors have made the following comments:

"The controversy on Eucalyptus culture, coupled with unwarranted publicity has rendered this innocent plant an object of hate. Well meaning individuals including many eminent men in literature, jurisprudence, medicine, social sciences etc., have of late started to voice their concern on the subject. Their concern is that Eucalyptus has a bad effect on the environment. "

Poore and Fries referred to the double standards used in passing judgement on forestry crops in comparison with agricultural crops. Most of the agricultural crops in any region are introduced species, and continuous cropping in agriculture requires the addition of fertilizer. Both of these basics are accepted. But, when it comes to forestry, eucalypt is decried as an exotic even in regions where it has been domiciled for over two centuries (96). It is cropped continuously in cycles of 4 to 6 years and then blamed for the consumption of nutrients. Pearl millet and maize consume more than 150% of the water used by wheat. Rice uses more than double the water used by pearl millet and maize (186). However, their water requirements are taken for granted. No one has decried rice on this ground. If water is available, it is cultivated; if it is not available, it is not. Yet, in the case of eucalypt, even when it has been proved that it is the most efficient consumer of water, producing biomass commensurate with the water consumed, it is labelled as an excessive consumer of water.

The economic and social aspects were only briefly touched upon in the earlier publication. Since then, many complaints on the social aspects of eucalypts have been made, particularly from the Southern state of Karnataka in India (32, 121). In this report these are therefore dealt with in greater detail.

ECOLOGICAL EFFECTS OF EUCALYPTUS

Introduction

The water cycle, interception loss, throughfall, stem flow and water use were covered in the publication of Poore and Fries. The general conclusion was that, while there is a difference in the yield of water from open plots and sites with trees, the behaviour of Eucalyptus spp. was not very different from forests of sal (Shorea robusta), pine and oak scrub. Studies since 1985 confirm the findings on interception loss, throughfall and stem flow and hence these are not discussed in this report. The conclusions on run off and water erosion were that most eucalypts are not good trees for erosion control. Papers published since 1985 generally deal with the use of eucalypts for soil erosion control because of its other advantages but the basics of its effectiveness in controlling erosion have not been dwelt upon. Hence, as the earlier findings remain valid, this issue is not discussed.^[6] In the present paper issues discussed under ecological aspects are: water use of eucalypts, nutrient use of eucalypts and eucalypts in shelter belts and agroforestry mixtures. These have remained as issues.

There are some positive aspects of Eucalyptus spp. benefitting the ecology of a locality or region, not covered in the earlier report. An analysis of the results of the studies in this field is included.

Water use of Eucalyptus

In the chapter on "Influence on the water cycle" Poore and Fries came to the following conclusions:

"The plantation of extensive forests of eucalypt in any deforested catchment will substantially decrease water yield from that catchment; the felling of such forests will increase it. The effect of eucalypt in reducing water yield is probably less than that of pine and greater than that of other broad leaved species; but all species of trees reduce water yield compared with scrub or grass.

The effects of eucalypt on run off, and therefore on erosion, vary greatly according to local conditions of climate, slope, and use of the ground vegetation and litter by local peoples. It is a function of the protection afforded to the soil by ground vegetation and litter, and differences between eucalypt and other trees depend upon the effect of the various tree species on these. Planting conditions, thinning etc. on steep and erodible slopes should favour ground vegetation and the accumulation of litter and the forest floor should be protected from fire and from the collection of litter. Terracing can compensate for poor ground cover."

The authors quoted excerpts from Lima and O'Loughlin (246) on water consumption and the recharge of aquifers by eucalypt as follows:

"Lateral spreading and depth of penetration of the root systems of the eucalypts vary with species, and this has to do with the intensity of water uptake. Withdrawing of soil moisture also depends on stand density and soil and environmental conditions. In alpine dry sclerophyll conditions, soil water regime does not differ between eucalypt forests, grassland and herb fields.

In regions of deeper soils and higher rainfall regimes, soil water deficit created by eucalypt forests seems to be in the region of 250 mm/yr. In comparison with crop or pasture land, this means that eucalypt forested lands would yield approximately 70 mm/yr less stream flow or ground water recharge. Comparative studies have shown that the overall soil water regime of eucalypt forests does not differ from that observed in pine plantations.

The effects on soil moisture reserves of eucalypt plantations apparently start to appear at the age of approximately 4-6 years, when the soil water deficit created by the plantations during the year is similar to the one observed in mature forest.

Transpiration rates differ among eucalypt species, varying apparently between 20 litres/tree/day to 40 litres. The evaporation rate from eucalypt forests in field conditions is more difficult to detect, but it appears to vary between 1.5 mm/day in winter to 6.0 mm/day in summer.

Some eucalypt species have not developed mechanisms for controlling higher rates of transpiration and are likely to suffer from drought stress, which limits their range of habitats. The majority of eucalypt species, however, do have some control of the rate of transpiration, which helps them to survive drought stress during part of every year, and which is apparently related to the rainfall regimes of their natural habitats.

Average catchment evapotranspiration of a well stocked eucalypt forest is probably around 1000 mm/yr for rainfall regimes above 1200 mm/yr. For drier regions, evapotranspiration also declines, perhaps reaching a value of 450 mm/yr when the rainfall regime is of the order of 500 mm/yr. For wetter regions, evapotranspiration increases, eventually reaching a value of 1500 mm/yr for tropical eucalypt forests of lower latitudes. Comparative studies have shown average annual evapotranspiration in pine plantations to be in the same order of magnitude as that observed in eucalypt forests.

Young, vigorous, dense regrowth of E. regnans forest was found to yield less water than mature forest. At the age of 21 years, the difference of water yield was found to be around 200 mm/yr, but catchment yields tend to equalise as the regrowth matures.

Thinning and selective cutting in mature eucalypt forest increased stream flow by an average value of approximately 400 mm/yr. The effect of clear felling on catchment yield is maximum during the second year after the cut."

Studies since 1985 generally support these findings but a few new aspects have emerged. There are species of eucalypt which thrive in moist conditions and these are used for drying up marshes. This is a positive quality and high use of water in these cases is accepted. It is the use of water in the lower rainfall zones by species like E. tereticornis and E. camaldulensis that is in question. In the cases in which they are found to utilise more water than accounted for by rain, do they 'mine' it or use water stored from years of higher rainfall?

Observations in Central India and in the foothill zone of the Himalayas indicate that, in regions in which large areas of E. tereticornis plantations have been raised, the level of water in wells falls until the plantations are about 6-8 years in age, the culmination of mean annual increment (MAI) and thereafter reverts to the earlier levels (38, 105). In the case of older plantations of E. globulus in the Nilgiris (India) no adverse effects have been noticed on the hydrological cycle (105).

The monthly evapotranspiration of an E. globulus plantation in Portugal, with an average yield of 8-12 m³/ha/yr worked on 10-12 years rotation, was the same as that of a natural open stand of cork oak (Quercus suber) with a developing understorey of shrubs. The regenerating coppice of eucalypt exceeded this only by 4 mm/month at the end of the drought cycle (9, 252).

The efficiency of water use of E. tereticornis as against that of species of other genera including fast growing species such as Albizia falcataria, Melia azadarach and Acacia auriculiformis has been proven (321, 416). While the earlier findings were that E. tereticornis used 0.48 mm-0.55 mm of water to produce one gram of dry matter under unrestricted supply of water, in rainfed conditions in Dehra Dun (India) only 0.122 mm of water was used, reconfirming its capacity to cut down water consumption under moisture stress. It has been found that the maximum consumption of water by E. tereticornis, in the Dehra Dun climate is during the rains (60%), followed by winter (26%) with the least during summer (14%), showing that the species adjusts its water use to the availability of water. These aspects have been summarised by Davidson (121).

The study of Dabral and Raturi at Dehra Dun concludes that over a period of 36 months water used was more than the rainfall received during the period "at the expense of the previously stored water" (117).

The findings of the research taken up by Calder, and his colleagues in Karnataka are interesting (90). The region has a dry tropical climate. At one site, the water use of a young E. tereticornis plantation was found to be no different from that of an indigenous dry deciduous forest. At two other sites, the annual water use of the eucalypt plantation and the indigenous forest was found to be equal to the rainfall. At yet another site, with deeper soil, water use of the eucalypt plantation was greater than the rainfall, that is 3,400 mm used against 2,100 mm received in the 3 years period of study. During these 3 years, rainfall was less than normal and yet at none of the sites was there any evidence of abstraction from the water table. The source of the extra water is unknown. One hypothesis is that, if roots penetrate successively deeper layers, water 'mined' would account for it. The other hypothesis, as suggested by Dabral and Raturi, is the use of water stored in the soil, from years with higher than average rainfall (117). The first suggests sustained growth, but at the cost of extra water. The second suggests non sustainable growth but with no negative impact on the local water table. Boden's work suggests the latter. Seven years old E. grandis plantations in three plots with MAI of 26, 16 and 6 tonnes per hectare per annum were studied by him. Tree vigour was found to be inversely proportional to soil water status (SWS). SWS under the largest trees was consistently and substantially drier than under the smaller trees. The least vigorous trees were, not withstanding their smaller crown and root system, growing marginally quicker than the largest trees. It is assumed that the latter have utilised available water resulting in a slowing down of their current growth (74). This interpretation conforms to the findings of Gurumurti and Rawat, who hold that the overall use of water by eucalypts is limited to the total rainfall regime of the area, in the absence of access to the water table (182). Chaturvedi also holds this view (105). This interpretation would explain the very wide variations in the coppice yield vis a vis the yield of seedling crop in different regions. The general conclusion in Australia has also been that there is an equilibrium between rainfall and evapotranspiration (241).

Nutrient use of Eucalyptus

One of the charges levelled against eucalypt is that it destroys the soil, rendering it unfit for any future economic use (229). This claim was unsupported by facts. As the best of agriculture fields in Australia are in earlier eucalypt forests, the charge would not stand to reason. This aspect was covered in detail by Poore and Fries. They analyzed the situation dividing the issues into the effect of eucalypts on soil quality with and without intercropping. The soil in unharvested stands of eucalypt was compared to that in natural forests of sal and pine. The comparisons were favourable to eucalypt. This is substantiated by the study of Kushalappa (236), discussed later.

The situation is different in the case of eucalypt plantations which are regularly harvested. In harvesting a eucalypt stand, a major portion of the stored nutrients in the above ground biomass is removed. In firewood-scarce regions, except for the roots below ground level, nothing else is left behind, In such a system there is bound to be a loss of nutrients, which will occur in any tree species, as in agriculture. The difference is only in the proportion of constituents that are reduced. If the felling cycle is long (at least longer than the culmination of MAI) and if branches, leaves and bark are left in situ, the natural inputs build up the nutrient chain sufficiently to maintain the production of wood over a number of rotations (38, 56, 235, 236). But in the case of short rotations, the loss has to be made up through the addition of fertilisers (38, 156, 160, 204, 290, 416, 441).

Studies since the publication of "The Ecological Effects of Eucalyptus" mainly deal with the extent of loss of each of the nutrients and the requirement to be made up. This depends on the species, climate and soil type (441). The addition of fertilisers has now become a regular feature of management in Argentina, Brazil, Portugal, Spain and South Africa. It is also practised in high density plantations in India (49, 222, 295, 369).

According to George and Misra (cited in 236), the better the growth, the higher the retention of nutrients in the biomass. Thus, while in the case of dry deciduous forests, the percentage of return of N,P,K of the annual uptake is 48, 77 and 81, in the case of E. tereticornis in the same region it is 46, 21 and 41 percent. A trend similar to that in dry deciduous forest was also observed in sal forests (394).

Kushalappa (235) has analyzed the nutrient status of a 12 yr old E. tereticornis plantation near Bangalore (India). According to this study, the inputs to the soil through weathering of the parent rock, litter, rain wash and root mortality more than make up for the loss of the nutrients due to harvesting, if the felling cycle is 12 years or more. In the computation, additions due to nitrogen fixing bacteria, and from the atmosphere (electric discharges) are not considered.

The recommendations made by Poore and Fries, based on a study by Raison and Crane continue to be valid. These are:

• Leaving nutrient rich biomass on the site; not harvesting root systems on most sites; removal of bark from tree trunks and its retention on the site;

• Use of conservative site preparation procedures, which minimise disturbance and loss of nutrients and organic matter from slash, litter layers and surface soil (factors of considerable importance according to Madeira (252) as well);

• Efficient use of fertilisers;

• The possible use of legumes (either intercropped or during a fallow period between rotations) to assist in the maintenance of soil organic matter and nitrogen.

The findings during the last 9 years would commend an addition:

• There may be ecological benefits if the felling cycle is longer than the culmination stage of MAI.

Eucalyptus in shelter belts and agroforestry mixtures

Poore and Fries, based on the work of Jensen, concluded that there was no evidence to suggest that the effects of eucalypts on the associated crop are different from any other kind of tree when planted in shelter belts or agroforestry. Evidence since then does not alter this conclusion.

Most of the research findings refer to decrease (or increase in rare cases) in agriculture output when agroforestry is practised. This is based on the border effect - loss of growth of agriculture crops in the strips adjacent to the rows of trees. The loss, except in case of trees casting heavy shade, is in the semiarid areas with deep water tables and not under irrigated conditions. The benefits of shelter, which would cover a bigger area, are not considered.

There are some differences in the yields of agricultural produce, depending on species, resulting from a competition between trees and agricultural crops for the same resources. Under rain fed conditions E. tereticornis and E. camaldulensis have fared better than some other species, e.g. Leucaena leucocephala, Morus alba and Grewia obtusa (221, 416). However, the evidence is not conclusive. In regions with a low water table, E. tereticornis has been found to be unsuitable (216, 416).

Eucalyptus spp. have been accepted as suitable for shelter belts and for mixture with agricultural crops in Columbia, Tunisia, Senegal, Nigeria, Cameroon, Pakistan, India, Bangladesh and China (32, 114, 161, 184, 197, 242, 288, 297, 310, 415, 416, 422, 455). This is based on the overall returns secured by the farmers. In the dry zone of Sahel, the limit of effective shelter extended to over 16 times the height of Eucalyptus camaldulensis trees, while Acacia nilotica, the other species used, provided shelter to a distance of 13 times its mean height (288). Shelter belts of E. microtheca (and Oxytenanthera abyssinica) in the dry Gezira zone in Sudan, established to protect irrigated crops, were expected to conserve water, which would help to increase the irrigated area by 6% (55).

An interesting agroforestry combination is the success of cardamom under E. grandis on slopes, reported from Sri Lanka (408). This was where the tea crop had proved to be uneconomical. In the higher altitude tea gardens in Kerala (India) similar results were obtained (pers. obs.).

Allelopathy and understorey

Most studies covering allelopathy are laboratory experiments with heavy concentrates. Willis (440), reviewing the experiments, concluded that, although there is evidence to support allelopathic effect of eucalypt on crops and undergrowth under certain conditions, the extrapolation of bioassay results on the effect of leachates and extracts on crop growth to field conditions is not necessarily valid, since the concentrations used in experiments may not correspond to the lower concentrations of leachate likely to occur under field conditions. This understanding would explain the differences in the results of experiments: in one case cowpea is found to be intolerant of E. citriodora, E. camaldulensis and E. grandis; in another its response to E. tereticornis was not different from that of other species (400).

The general finding is that decomposed litter is not inhibitory, whether it is of Acacia nilotica, Azadirachta indica, Populus deltoides or E. tereticornis (205).

The presence or absence of understorey is a factor of density of the stand and of the rainfall regime (30, 194). At the same age eucalypts could have more undergrowth or less as compared to Leucaena leucocephala depending on these factors (411). Generally, where site factors are favourable, there is a good growth of understorey in plantations of E. camaldulensis, E. tereticornis and E. brassiana (122). In the native forests of Australia, it is common to find 20 to 30 species of shrubs under eucalypt, and rather more in the early regeneration stages (320).

Positive impacts on the environment by Eucalyptus

In the controversy over Eucalyptus there has been a tendency for only the negative aspects of the genus to be highlighted. It may or may not be the best genus to meet some specific requirements, but its properties make its use appropriate in certain situations. Some of these are briefly discussed.

In the control of desertification there may be indigenous species which could be more effective; but most of these are usually difficult to establish. Furthermore, certain Eucalyptus species, by quickly producing firewood, would eliminate the causes which frequently may have lead to desertification. In the Sahelian zone, encroachment of the desert is mainly due to clearance of vegetation for firewood and charcoal (423). It is estimated that in sub Saharan Africa, 25 million ha of fast growing plantations are required to satisfy the demand for fuelwood and other rural requirements (366). Fast growing tree species, which can be established in harsh conditions and are not killed by fire, are the answer. Some species of Eucalyptus fulfil these criteria. In the arid region of Nigeria, where environmental degradation has resulted from serious deforestation and poor land use practices, silvi-pastoral systems with E. tereticornis, E. camaldulensis and E. citriodora (among other species) could ameliorate the condition (1). Eucalyptus spp. have also been used to fix sand dunes in Italy, Iran and Israel, in the last two countries by using harnessed flood water (120, 190, 327, 416).

The greatest positive contribution of eucalypts is perhaps in replacing indigenous species for firewood, thereby preventing further denudation of natural forests (20, 92, 140, 294). Nepal, which lost 22% of its natural forests between 1980 and 1985, is such an example; its major plantation programme with eucalypt quickly provided at least some of the important goods and services which had been lost (92). The percentage of loss of natural forests in the last decade may vary but this is a feature common to most of tropical Latin America, Africa and South Asia (268). Forests close to towns and cities have also been destroyed due to the same reason (80). Classic examples of halting this trend through the planting of Eucalyptus spp. are Addis Ababa, Lome and Antananarivo (51, 65, 309). In Kolar town in India, where eucalypt firewood was not in use earlier, it constituted 54% in 1989 (431). It is claimed that there is no biodiversity in eucalypt plantations (cited in 327) but these plantations may save biodiversity elsewhere by preventing the destruction of natural forests.

In badly eroded soils, ravines and lateritic areas, certain eucalypt species have given good results. The eucalypts are not always the best species for soil conservation or for planting at difficult sites, but their establishment is easy compared to most indigenous species. Hence their use in these plantations in Brazil and Central American countries, Nigeria, Ethiopia, Pakistan, India and Thailand, where the main species used are E. tereticornis, E. camaldulensis, E. robusta, E. microtheca, E. cloeziana, E. propinqua, E. punctata and E. globulus (36, 44, 80, 84, 146, 327, 381, 382, 384, 416). E. tereticornis was tried successfully in the badly degraded lateritic areas of West Bengal (India) only after trials with indigenous species had failed (411A). E. tereticornis, E. camaldulensis and E. trabutii have done well in coastal sands, while E. camaldulensis, E. microtheca and E. obtusa have given good results in brackish soils (120, 164, 327, 435). E. globulus has been used to reforest diseased indigenous forests of oak and chestnut in Spain (135).

Today there are 3 billion ha of saline and alkaline soils in the world (435). Increasing stream and land salinity is occurring due to poor irrigation practices. Some species of Eucalyptus are ideally suited for such degraded sites, providing a promising land use while ameliorating the situation (36, 52, 53, 61, 69, 79, 138, 163, 165, 201, 243, 258, 359, 379, 435).

Conclusions

There is need for further research on the water use of Eucalyptus.

The management practices which are suggested under "Nutrient use of Eucalypts" are of importance for sustainable returns from eucalypt plantations.

Eucalypts have a major role to play in shelter belts, particularly in harsh climatic conditions, and, to a lesser extent, in agroforestry systems.

The role of eucalypts in afforestation of difficult sites and in the amelioration of otherwise unusable soils will be of importance in the future.

Eucalypts can benefit the environment in many developing countries through the provision of fuelwood, which otherwise would be obtained by depletion of the natural forests.

ECONOMIC ASPECTS OF EUCALYPTUS

Introduction

The world's consumption of wood in 1989 was around 4,560 million m³, some of which was from non-sustainable, depleting sources. The projected consumption in 2010 will be about 6,860 million m³ (306 citing FAO, 1991). The increasing requirement must largely be met from plantations of fast growing species or there will be further loss of natural tree cover. Eucalypts will necessarily have a major role to play, particularly in the private sector.

A plantation crop is different from a natural forest and each has its place. Plantations raised for wood production are generally monocultures, as in agriculture, for ease of management and economy. Mixtures of species are used only if they benefit the main crop. Species selection is based on the objectives of raising the plantations, suitability to the climatic and edaphic conditions, investment and maintenance costs, returns and reduced chances of risks. Since five species of eucalypts today represent 50% of all plantations raised in the tropics, they must offer outstanding benefits.

In the social issues that have been raised in India, the profitability of eucalypt growing is itself sometimes a charge against it. Eucalypts can be raised economically for production of medicinal/perfumery oil or for honey. In the foreseeable future, eucalypts might be raised for producing methanol, industrial oil, or as a replacement for petroleum (209, 219, 416, 441). But today their use in plantations is limited to the production of firewood, poles, timber and as industrial raw material, mainly for the production of pulp and paper.

The economics of Eucalyptus is complicated. The eucalypts are sensitive to site quality and yield can vary in the order of 15:1 for any particular species within a region, depending on provenance and site. Within the same area, the yield difference between different species may be of the order of 4:1 while the difference in volume yield between provenances of the same species may be up to 8:1. Thus, depending on site, selection of species and their provenances, actual yields have varied from 1 m³/ha/yr to more than 50 m³/ha/yr. Added to this, correct fertilisation has helped in enhancing yield by a further 600% (27A and based on 124). With a water use of 750 mm per annum in a rainfall region of 800 mm in South India, the increment of E. tereticornis is 4.5 m³ ha/yr; in South Africa and Kenya, with a water use of 1500 mm in a rainfall region of 1800 mm, the increment of E. grandis is 45 m³/ha/yr; that is, with double the water use, ten times the yield is obtained, albeit with different species (90). Coppice yield is also variable. Whereas an increase of 70% in the first coppice rotation is commonly reported, in many regions it is less than the yield of the seedling crop. Contradictions contradicting other contradictions; that is Eucalyptus. Under favourable market conditions, given the necessary capital and proper management, eucalypt tree crops generate much more income than agricultural crops (181). Hence the 2.5 million ha of block plantations of Eucalyptus spp. in Gujarat, Haryana, Indian Punjab and Western U.P (in India) on either agricultural land or old fallow. The land value of sites suitable for eucalypt in the plateau belt of Ethiopia is higher than for those suited for agriculture.

Selection of species and provenances

Experience of a particular eucalypt species, provenance or hybrid growing on good quality sites in a country has sometimes been extrapolated to other sites with different climates or poor soils, with predictably disappointing results. In India, trials with E. camaldulensis are giving better results than eucalypt hybrid (E. tereticornis ?) commonly used in many regions (316). This is in spite of the eucalypt hybrid giving much better results than indigenous species in most trials. In the foot hill belt of Himalayas biomass production of eucalypt hybrid is around 57 t/ha at 5 years while sal (Shorea robusta) takes 22 years under similar climatic and edaphic conditions to produce this volume. In the semiarid parts of Central India, new provenances of E. tereticornis have given much higher yields than the local strains of eucalypt hybrid. In Bangladesh, it was observed that yield differences between species/provenances were more than 25 times on poor sites and 9 times on better sites. E. camaldulensis of Petford provenance has shown outstanding results everywhere in Bangladesh, and with proper management (spacing, fertilisation and weeding) economic returns are excellent even on barren land (122).

Based on experiments in different countries, Booth and Pryor have identified species suitable for different climatic regions of the world (77). In the foreseeable future it should be possible, with pooling of data, to have computerised species/provenance indications for all variations in climatic and edaphic factors.

Spacing

Spacing will depend on the objective of planting, soil type, soil moisture regime, inputs available, rate of growth, felling cycle and economics of thinning. In the main eucalypt planting countries, spacing varies from 2x2 m to 3x3 m. For the production of pulpwood and small posts, combinations of 2x2 m, 2x2.5 m and 2.5x2.5 m are adopted. In the case of production of logs and heavy posts, the spacings are 3x2.5 m, 3x3 m or 3.33x2.5 m. In developed countries where mechanical equipment is used for planting and weeding, the spacing is 3x3 m (254, 365).

Unfortunately, in farm forestry, farmers do not always follow the recommended silvicultural regime or think of long term sustainability. Hence in some regions, where there is demand for firewood, small sized poles and pulpwood, spacing has gone down to provide for 25,000 stems per ha with harvesting in 4 yr cycles (166, 169, 324, 432). Eucalyptus tereticornis wood of 6 years of age has been found to be better for pulping than that of 15 years (5, 416). High volume yield makes up for loss in diameter growth, high bark content and moisture. In the better managed farms, fertiliser and irrigation once a week in the first year and once every two weeks thereafter are provided and the returns are exceptionally high (295).

Dense planting at 3x1/3 m or 1x1 m without irrigation and fertiliser has also given good returns as long as market conditions are favourable, but once production overshoots demand, returns dwindle (416). It is then neither profitable nor sustainable. The lowest spacing suggested by Chaturvedi is 1.5x1.5 m on a felling cycle of five years (100).

In agroforestry under rain fed conditions, 6x1 m spacing has given the best results in Northern India (263).

Weeding and thinning

Some eucalypt species grow faster in the initial stage, while others put on more increment at a later stage. Short rotation eucalypts, raised outside Australia, belong to the former category. These species do not stand weed competition in the establishment stage and therefore weeding is obligatory (27A, 60). In the semiarid regions, clean weeding gives the best results (347).

As a rule, thinning is not done when the rotation is less than 10-12 years. In India, with rotations of 8-10 years, experience with eucalypt hybrid is that thinning improves neither diameter growth nor volume (106). In the longer rotation practices adopted in the Mediterranean countries and South Africa, the usual principles of thinning are applied: thinning should start early and be carried out at frequent intervals, the earliest thinning should be the heaviest and thinning should be ahead of the onset of competition (365).

It has been found that both in seedling and in coppice crops, thinning tends to reduce the total biomass increment, but it increases the volume of commercial wood (111). In South Africa, the experience has been that, while thinning reduces volume yield by 15%, it doubles the diameter increment.

Application of fertiliser

Organic matter and nutrient accumulation under eucalypts is low compared to tropical forests, but the soil nutrient status is well developed (similar to values for temperate forests) (280, 416). Thus, in good soils, with long rotations, where leaves, bark and branches are left on the site, eucalypt does not require fertilising. Such a practice has been successfully adopted in the jarrah (E. marginata) forests in Australia, where only P was considered to be liable to become a restricting factor after 3 or 4 rotations, i.e. after 300 years (407, 421).

In fertile soils, dry matter allocation is preferentially to leaf area development or production of above ground biomass (agb); while in non fertile soils, it is to the roots. In the latter category, addition of fertiliser will shift the preferential allocation. Some scientists have contended that growth increases with fertiliser addition may be more due to root development and structure than due to overall nutrient status (189). The problem has been to measure the capacity of the soils to supply nutrients (60).

There is very little response to fertilisers at sites where water is the limiting factor (131). At such sites, cultural practices to alleviate moisture stress are more important. The response to fertiliser will also be directly proportional to the water availability during the rotation (60).

Eucalypts respond dramatically to fertilising in short rotation systems in skeletal soils and other soils of low nutrient status in regions with good rainfall (50, 392). It is the relative addition of the limiting nutrient that determines growth. Hence responses to NPK and Ca and their combinations have produced different results in different soils (175, 277, 314, 315). Response to fertiliser is greater if applied early in the rotation. In South Africa, addition of superphosphate within 2 to 4 weeks of planting has given highly profitable results (361). In absolute terms the response to fertilisation is greater at sites with higher site index (60, 361, 369).

In good rainfall areas with severely truncated soils, the addition of urea and superphosphate resulted (with E. grandis) in a 9-fold increase in yield (380). In an E. diversicolor forest, the addition of 200 kg/ha of N and P each to 18 months old regrowth resulted in a doubling of the growth at the end of 5 years. C.P.E Cellulose Ltd. achieved 26-53% gains in solid volume (with bark) in a 79 months old eucalypt plantation in acidic soil in Brazil by applying 5-10 tonnes/ha of ash (306). In high density plantations in India, an individual dose of 10 g of NPK per plant followed by 1.2 tonnes of urea/ha every year has given highly profitable results (295). An overall assessment of fertilising eucalypt plantations in India showed that while the required dosage would increase the investment cost by about 32%, the increase in returns is orders of magnitude higher and would more than offset the costs (327).

An interesting study has revealed that it would be more economical to use harvesting residues for energy and invest in chemical fertilisers (169). This is however limiting the equation only to chemicals. In fertilising, special care has to be taken because any unutilized fertiliser could eventually pollute water supplies, as is observed in the case of agriculture (38).

In nitrogen deficient soils, the intercropping of leguminous shrubs provides considerable improvement (286).

Irrigation

In irrigation trials, the growth of Eucalyptus spp. has been slower than Prosopis juliflora and Cassia siamea (202, 203) and if volume biomass is the criterion, these are to be preferred. In semi-arid areas of Gujarat (India), where eucalypt hybrid is grown intensively, irrigation is provided once a week in the first year and once every two weeks thereafter (295). In areas with brackish water, returns from irrigated eucalypts are much higher than from agriculture (181). Trials with irrigation of municipal sewage water have also been successful (108, 404).

Economics of Eucalyptus as fuelwood

Firewood is the only source of fuel for cooking and heating for a large majority of the population in developing countries. In these countries more than 85% of the wood produced ends up as fuel, most of which is not paid for. In a plantation crop however, the programme should be economically viable.

In regions where firewood is scarce and where it has to be paid for, eucalypt fuelwood plantations have been economically successful. These are generally close to townships or in regions totally devoid of natural forests. In clay soils, returns from Prosopis juliflora may be better. The economics however, improves considerably, if, in addition, there is demand for pulpwood or poles/small timber, which is why eucalypts score over Prosopis juliflora. Multiple use provides better overall returns. Even in the case of plantations established by pulp based industries, branches, lops and tops are used for electricity generation (209, 233, 327, 416).

The use of eucalypts for firewood is remunerative where soils are unsuitable for sustainable agriculture, as in arid and semi-arid regions; where soils are heavily acidic; and in saline and alkaline areas. In India, Sri Lanka, Pakistan, Thailand and Fiji plantations of Eucalyptus spp. for firewood have been raised on a large scale in such areas (36, 181, 393, 435). Rotations have been as low as 4 years or as high as 40. Firewood is also obtained, in the form of thinnings, from the long rotation plantations raised for timber (43, 145, 301).

In Central American countries, 7 eucalypt species have been identified for firewood production. In New Zealand 4 species have been selected. This is on the basis of their potential commercial viability (291).

In many countries Eucalyptus spp. have been the obvious choice for production of charcoal, both for domestic use and in metallurgical/chemical industries (301). In Brazil, plantations of E. grandis, E. saligna, E. urophylla and E. deglupta are raised specifically for the production of charcoal for iron smelting (183). Activated carbon can also be commercially produced from some species of eucalypt (416).

Economics of Eucalyptus as poles

Poles of Eucalyptus spp. of different sizes are used in the construction of huts, for scaffolding, as mine props and in power and telecommunication lines. In the dry zone in India, it has been a common practice to collect small sized poles from natural forests and transport them over long distances for use in the construction of huts. Small sized poles of eucalypt hybrid are now meeting this demand at one quarter of the former cost without affecting the profitability for the grower. In West Bengal (India) sale as poles and firewood fetch 65% better returns than as pulpwood. In Ethiopia, dense planting and thinning produce poles (424). Coal mines in India, earlier using sal and Casuarina poles are now switching over to poles of Eucalyptus tereticornis (416). In some countries, large sized poles for power and telecommunication lines are raised on rotations of 30 years. In India the Bureau of Indian Standards has specified 3 grades of acceptability for poles. E. tereticornis falls between category I and II (416).

Eucalypt poles and logs have a tendency to split. Felling in the dormant season and air drying of debarked poles under shade reduces end splitting. Coating the ends with bitumen or using S-irons are also practised. In the case of poles for power and telecommunication lines, treatment with a creosote fuel oil mix is advocated to prevent rot (416).

Economics of Eucalyptus as pulpwood

Many species of eucalypts are ideal for production of pulp with suitable fibre quality, density, colour and homogeneity. Countries which have profited from this are Argentina, Brazil, Chile, Portugal and Spain, of which the first three countries will produce an estimated 58% of the market pulp in 1995 (306). By 2010, Argentina, Brazil, Chile, South Africa, Indonesia and Australia will have about 9 million ha of eucalypt plantations earmarked for pulp production (306). An encouraging factor concerning eucalypt is its suitability for pulp production at a very young age, when the rate of growth is the highest. The yield and strength properties of pulp in case of E. tereticornis are better at 6 years than at 15 (5, 14).

Species suitable for paper production (in admixture with long fibred pulp) are also ideal for rayon grade pulp.

Economics of Eucalyptus as timber

Many of the fast growing Eucalyptus species attain mechanical maturity by 15 years when, because of their rate of growth, they also reach lumber size suitable for saw milling (416). The fast rate of growth does not affect timber quality (255). In North India and parts of Nepal, E. tereticornis and E. camaldulensis attain the desired girth at 8 years as compared to 22 years taken by Dalbergia sissoo, a recognised timber species of the region. The traditional sal would take one hundred years to reach this size (92).

In the Chapter on Social Aspects of Eucalyptus in this paper, the comparable price difference between teak and eucalypt timber in India is dealt with. This difference is also true of eucalypts compared to local timbers in many other parts of the world. Thus, in Ecuador, Paraguay, Zambia, Madagascar, Israel, Pakistan, Sri Lanka and Bangladesh, Eucalyptus has now been accepted as timber (27A, 327, 416, 444). With reconditioning, at a cost which is a small fraction of the price of indigenous timber, eucalypts can be better than many recognised local timber species (327, 416). In Australia, small sized regrowth is gradually being recognised as a marketable commodity (228).

Suitable management practices with production of timber as the aim are formulated in Paraguay, South Africa, Sabah (Malaysia) and many other countries (259, 327, 416).

According to the standards prescribed by the Bureau of Indian Standards, out of 4 graded groups, timber of E. tereticornis falls in group II. Use has been found for it as pallets, packing cases and crates. Some of the inherent defective qualities of eucalypt have been reduced by the development of better seasoning and sawing practices (319, 384).

Economics of Eucalyptus for other industrial uses

In Israel, eucalypts are mainly grown for use in fibre and particle board production. Eucalypt wood is used for the same purposes in Argentina, Mexico and Spain. In Australia, hardboard production is predominantly from eucalypt. In Zambia, hardboards of E. grandis are considered to be better than those of most other species.

In India E. tereticornis has been found unsuitable for particle boards, but is good for fibre and cement bonded boards (416). E. tereticornis and E. citriodora are also used in the production of compressed wood. E. tereticornis raised in some regions, can be used directly for production of veneers, while in other cases it needs resin modifiers. Seasoned E. tereticornis has been successfully used for manufacturing furniture. It can be given a walnut or rosewood finish by appropriate treatment with ammonia vapour (94, 327, 416).

The value of eucalypts in this sector is in the context of reduced availability of timber from the natural forests.

Genetics and research on Eucalyptus

The greatest advantage of eucalypt is its high yield of wood, particularly under ideal conditions, even when these conditions may pose constraints to species of other genera. The next advantage is the possibility of produce inter-specific hybrids, for a specified product. It is estimated that, if 1% of the turn over of eucalypt wood based industries were to be invested in genetic improvement programmes, the overall yield could be increased by 20-40% (442).

Theoretical projections of potential gain in yield ranging from 17-154 % have been made, based on selection, cloning and combinations of breeding and clonal selection programmes. In clonal plantations in Congo, the MAI averaged 35 m³/ha/yr (after 6 years) compared with 20-25 m³/ha/yr from selected provenances and about 12 m³/ha/yr from unselected seed lots (306). Aracruz Florestal in Brazil, has increased the yield from 35 m³/ha/yr to 70 m³/ha/yr with a maximum yield of 100 m³/ha/yr on good sites with intensive management. Additionally, the bark content has been reduced from 18% to 12%. In Muak Lek Centre, Thailand, the increase in yield is from 16-22 m³/ha/yr to 45 m³/ha/yr. In the case of ITC Bhadra Chalam, India, the increase in yield is from 7 m³/ha/yr to 20 m³/ha/yr. CA Ltd. in Sao Paolo, Brazil and Associated Pulp and Paper Mills, Tasmania, have also achieved outstanding results. Cellulose Beira Industrial SA in Portugal expects production from plantations established after 1995 to be double the yield of dry kraft pulp achieved in plantations of 1985 (137, 306, 307, 377, 396, 399).

Most of the research in the private sector has been in the field of pulp production. This is however an indication of the possibilities with eucalypt for other end uses.

Conclusion

A subject of immediate importance is the classification, based on permutations and combinations of different climatic and edaphic factors, needed to identify the correct species and provenance for introduction in different parts of the world depending on the desired end use. Research in the field of increased production of firewood/timber is another priority issue.

SOCIAL ASPECTS OF EUCALYPTUS^[7]

Introduction

Kalpavriksha is a benevolent tree in Indian mythology, which yielded whatever was wished for. There were no environmental costs either. Unfortunately, mythology is of the past. Today, we have trees which yield fruits or nuts, fodder or mulch, timber or fuel and we have to make the choice; one product will be at the cost of the other. Species also have certain requirements in order to grow and these have to be met. No species is inherently good or bad. It depends on where, why and how it is grown. If the wrong choices are made, the species gets the blame.

In many countries in Latin America, Africa, and the Indian subcontinent, severe ecological degradation has taken place due to the uncontrolled clearance of vegetation both for agriculture and for use of wood as fuel. The traditional trees, which sustained the health, agricultural practices and rural economy, have ended up as firewood. Floods and physiological droughts are the consequences of this denudation. In many regions of the world, fuel wood, and not agricultural produce, is today the priority. The biomass part of the total energy consumption is 1% in developed countries and 39-43% in developing countries. If this were to be met from sustainable sources, fruit and fodder trees would reclothe the countryside. Cattle dung and agricultural waste, presently used as fuel, could instead benefit the agriculture fields.

Against the backdrop of depleted biomass resources, eucalypt has come to occupy the centre stage. The genus has a species for most climates and soils, permitting it to establish and grow faster than the indigenous species. It can be harvested repeatedly and is not browsed by the wandering cattle in search of fodder. Most Government supported programmes began in this context to produce firewood for the poor (113, 330A). But, in some countries, the wood produced from these programmes went to the forest industries instead.

When large scale cultivation was taken up in lands earlier under agriculture, several distortions resulted locally, such as a fall in the production of agricultural produce and a rise in unemployment. These issues have resulted in controversies.

Some hold the view that, if eucalypt is not grown to yield firewood and small timber, it would be impossible to reclothe the degraded countryside with trees to provide fruits, fodder and mulch (386). Others view eucalypts as benefitting only industries and the rich, at the cost of ecological degradation (98, 427). It could be argued that such a charge could apply to any tree species. However, since Eucalyptus spp. have been the main species used in most regions, the charge seems to secure validity. The situation in Karnataka State (India) illustrates this point, and is described in Annex 1. The reports on the use or misuse of eucalypts in one district of this State, in only one sector of the Social Forestry Programme (farm forestry), and the reported negative effects on the poorer sections of the population have been generalised to such an extent and spread around the world that they have resulted in changes in Government policies, in programmes funded by Aid agencies and in tree planting practices of the people. The following are some of the positive and negative social effects of the planting of Eucalyptus species.

Effect on food production

Between 1981 and 1988, 8.6 billion trees were planted by farmers in India. Eucalypts constituted 85% of these. Planting was undertaken both on uncultivated, privately owned, marginal land (of which there is an estimated 24 million ha in India) and on agricultural lands. In a cooperative venture in Maharastra State, covering 10,000 ha of eucalypt planting, half the area was found to have been under rainfed agriculture prior to the planting (377).

In the section on agroforestry above, the general conclusion arrived at is that in semi-arid areas where the water table is low, there is a reduction in the agricultural output over time. The border effect of trees, such eucalypts, also results in a fall of agricultural output.

Encroachment upon Government forests and other categories of Government lands for cultivation is a common feature in India, Sri Lanka, Burma, Nepal, Thailand, Indonesia and the Philippines. When the illegal settlers are removed, tree planting, often with eucalypts, is resorted to (395, 403A). The combined effect of all this could result in a significant fall in agricultural produce.

There are, however, positive aspects. In parts of Brazil, Cameroon, Nepal, India, Burma and Papua New Guinea, where afforestation is taken up in land earlier barren, the system of agri-silviculture or taungya is frequently adopted. This provides for raising agricultural crops during the first two or three years of the plantation (114).

The fall in agricultural production under agroforestry due to the border effect of trees has been the subject of several scientific studies. The actual losses have been computed. The increase in yield due to the shelter effect has, however, been referred to only in general terms. In the arid and semi-arid areas this can be considerable.

The availability of eucalypt for firewood, and the use of lops, tops and leaves, permits the diversion of cattle dung and agricultural waste, otherwise often used as fuel, to benefit agriculture.

With these different variables, it would be difficult to arrive at any general conclusion regarding the possible decrease in food production due to eucalypts. This has not been an issue, except in Karnataka.

An interesting finding in Kolar has been that with the income generated by Eucalyptus hybrid, several farmers have gone back to agriculture and vegetable farming after investing in bore wells (42, 313).

Loss of employment

Rain fed agricultural crops in the tropics require 150-180 man days of labour per year (and in limited areas where double cropping is possible, around 280-300 man days/yr) according to the University of Agricultural Sciences, Bangalore (pers. comm.). The requirement of labour for raising and tending of an Eucalyptus plantation on the other hand would be 350-400 man days in the year of establishment and about 40 man days per year thereafter according to the Forest Department of Karnataka (pers. comm.). Tree felling and debarking are done by skilled labour moving from site to site, rather than by local people. Thus, if eucalypt planting is taken up only in erstwhile agricultural areas, it results in loss of employment. Normally, eucalypt planting is taken up by farmers both on marginal agriculture lands (128) and on fallow lands and by the Forest Department (and industries) on land not previously under agriculture, and the loss in employment is thus not likely to be high.

A study from Kolar (42) has revealed that small farmers switching over to eucalypts have benefitted by the release of family labour otherwise committed to their unremunerative annual crop. The labour thus released earns more by hiring itself out within the village or by moving out. In Indonesia, concern has been expressed over the latter, since, while it may improve the economic situation, it could result in family ties being broken up (32).

In Ethiopia eucalypt plantations have been considered to be of great importance in providing opportunities for subsistence farmers to earn extra money in a way that is more flexible as regards working hours and can be adjusted to the needs of their rain fed crops (58). According to Rajan (327), dryland agriculture provides employment only for five months of the year to the family members of small and marginal farmers, while in the case of eucalypt plantations, it would provide them with some remunerative work during the off season.

It is difficult to arrive at any conclusion with regard to this important issue due to the lack of precise data. Conditions also vary considerably. In Portugal, it is estimated that while olive groves have an annual requirement of 199 man days per ha, vineyards require 128 days per ha and Eucalyptus globulus plantations require only four man days per ha annually (214). As against this, in Thailand, in the case of cassava being cultivated on former forest land, the labour requirement equalled that of tree planting with Eucalyptus camaldulensis (403A).

In sum, the only general conclusion is that tree farming normally requires less labour than agriculture, and if the former is to displace the latter, loss of employment is inevitable. But if the plantation programme is initiated on land otherwise unused, it results in generation of employment. In Minas Gerais, Brazil, it has been found that 6,000 ha of eucalypt plantation can generate employment for 1629 people (281).

Some countries have promoted eucalypt plantations in order to generate down stream employment. In the Solomon Islands, Eucalyptus deglupta plantations are raised mainly to promote employment in chip production and saw mill complexes (125).

In Kolar district, the small scale industries based on lops and tops of Eucalyptus hybrid have become a new source of employment (431).

Other issues affecting society

Firewood has always been regarded as a free good by the rural poor in developing countries. It is freely gathered from government forests and communal lands. As long as commercial sale of wood did not occur, such removals from communal areas were accepted by the community. With the conversion of the sites into plantations, restrictions come into force. Eucalypt plantations raised on communal land are reported to have caused problems of this type in some regions. This could occur with any development programme covering denuded communal lands and the solution lies in safe-guarding the interests of the poor, by regulating the conversion and building in components to benefit them. Once the plantation is established, leaf fall could serve to meet the some biomass needs - a social benefit, which however may be opposed to silvicultural needs.

A case has been made that in Karnataka eucalypts have helped landlords to circumvent land holding limitations. The Land Reforms Act is a State Act but is more or less uniformly applied all over India. Under this Act, an individual family cannot hold more than about 20 ha of rain fed agriculture land for personal cultivation. In the case of joint families with several members, the extent could be large.

The Karnataka State Act also provides for another limitation. Land left fallow for more than 3 years reverts to the Government. Thus, if families with land holdings larger than can be managed by them engage tenants, then the land would be lost to the tenants. If the land is left fallow, it would be lost to Government. It has been stated that eucalypt planting (tree planting comes under the definition of agriculture) has helped landlords circumvent both these restrictions (284, 338). This could have happened, but there is no indication of the extent of exploitation of the loopholes in any of the reports. It would also be illogical to blame eucalypt for this. The purpose could have been achieved also if seedlings of other species, which were available from the Forest Department free of charge, were used.

Widening the gap between the rich and the poor

It has been contended that the economic benefits accruing to landowners in the rural areas through cultivation of eucalypts has widened the gap between the rich and the poor, disrupting the social fabric. The rich have become richer (128). The following paper in this Proceedings, however, describes successful cooperative activities in eucalypt growing in Maharashtra State in India, involving even poor farmers.

Eucalyptus displaces indigenous species

Field bunds and homesteads have either remnant trees of pre-agricultural conversion period or indigenous fruit, oil seed or mulch yielding species, planted by the farmers. Their replacement, for economic reasons by Eucalyptus spp. or any other exotic is not a desirable change and neither are block plantations established in former indigenous forest.

Bias against Eucalyptus

There are regions in which the cultivation of Eucalyptus spp. could greatly benefit the people but unjustified fears of its negative aspects are dissuading such cultivation. In the poorer soils, at lower altitudes in Kenya where fuelwood stocks are being rapidly depleted, there is an urgent need to take up planting with fast growing species. E. tereticornis and E. camaldulensis have shown the most promise but farmers perceive these as a threat to agricultural crops. The reluctance is in spite of women in the drier parts having to walk 7 km a day to collect the day's need of firewood. Meanwhile, denudation continues (141). The same hesitation has curtailed the planting of eucalypts in Tanzania, in spite of the need being urgent (178). In the North-eastern region of Thailand, the natural forest cover has been reduced from 55.4% in 1962 to 14.8% in 1982 (294). Efforts to persuade farmers to plant E. camaldulensis have had little success (248). On the other hand, although farmers in the Dalocha region of Ethiopia have misapprehensions about the ill effects of eucalypt, they have taken to its planting with the realisation that their firewood and wood requirements cannot otherwise be met (436).

In many developing countries encroachment of the Government forests for agricultural cultivation is a common feature. This is countered by afforesting the area, after vacating the illegal settlers, and some of the most common species used are Eucalyptus spp. (395 403A).

While society at large suffers most in the long run from encroachments, particularly when these are in catchment areas, the human problem of the poor encroachers is highlighted and eucalypt is projected as a villainous species (98). The Headline in "The Nation", June 14, 1988 (Bangkok) (37) proclaimed "Eucalyptus planting sparks fiery protest - villagers attack forestry office". This was followed by a statement that resistance was growing against the Government's Eucalyptus planting policy. The material in the four columns of the report however reveals that the issue was not eucalypts but regularisation or otherwise of encroachment.

In Karnataka, for twenty years, all eucalypt from Government plantations went to the pulp industries. People hence believed that the species could benefit only the industries and, against this background, any tale about Eucalyptus was accepted. In the Amazon Region, while the concern should be over clearance of natural forests, E. deglupta, which is planted on a relatively small scale for the production of charcoal, gets the blame (144).

Social forestry: failures on poor sites

One of the well-intentioned programmes under the Social Forestry scheme in India is the allotment of small units (generally up to 0.5 ha) of Government land to identified landless poor families for raising tree crops. The right of the beneficiary is limited to the trees and their usufruct. Planting operations are subsidised. The preferred species is invariably eucalypt because of the anticipated early returns. If the site quality is reasonable, returns will be good. Generally however, sites are badly degraded and inputs poor, and returns will thus also be poor. In such cases, when expectation is high, disappointment after a period of waiting of 7 or 8 years, is abject. The failure is then ascribed to the species rather than to failure to match species to site.

Issues affecting growers

Fluctuation in prices of agricultural crops is common, but in many countries support prices are fixed by the Government and announced in advance. The benefit is even extended to crops like sugarcane. Where support is not provided, as in the case of vegetables, the fall in price is accepted as the element of risk involved in the enterprise. Not so with tree crops, which have long gestation periods.

In India, planting of eucalypts on farm lands started in the 1970's. Initially good money was made by the sale of small sized poles (for construction use in huts) and firewood. This led to plantings with close spacing, as close as 0.6x0.6 m in some regions. The result was early final felling, as Eucalyptus hybrid, planted at high density, showed poor response to thinning. When there is over production, there is a glut. Market imperfections have worsened the situation.

Commercial tree farming is of recent origin in India. There are no agencies to coordinate the sales or advise on the market prices for different products from the plantations. While the earlier regulations on tree felling and transport have been relaxed in most areas for the farm forestry species including eucalypts, middlemen exploit the ignorance of the farmers. The farmers thus receive barely 40-60% of the price and much less in the case of small farmers with small plantations (353, 355, 416).

Transport of small sized material over long distances is also not economical. Thus, in rural parts, in regions in which eucalypt plantations have been raised, the price of firewood has steadily declined since 1985. Many farmers have given up planting after uprooting the stumps in Indian Punjab, Haryana, Gujarat and Western U.P. In Gujarat, where 134 million seedlings were planted in 1984, only 12 million were planted in 1988. In Haryana, during the same years, the decline has been from 43 million to 4 million. Reduced planting is being attributed to ecological aspects by some. The real reason is the belied expectations and disenchantment of the farmers. Good returns are still secured where spacing is wide (3x2 m) coupled with a rotation of 9 years or more, to produce larger size material. Plantations near urban centres are profitable even with dense planting. In West Bengal and Karnataka, the prices still continue to be high because of the demand from pulp industries (101, 113, 212, 213, 353, 354).

In Brazil, integration of farmers raising plantations of E. grandis and E. alba has been successful (93). Group farming in West Bengal has helped the growers to secure reasonable prices (216, 374). In Maharashtra the first cooperative unit of farmers planned the production to meet the requirements of a proposed pulp unit. The assured market has permitted the release of excess material to trade in a profitable manner. Since then 22 cooperatives have been formed in the State (377).

Positive social aspects of Eucalyptus

Eucalypts for firewood, charcoal and poles. Socially, the greatest positive contribution of the eucalypt genus in the developing countries is in helping to meet the needs for fuel and for construction material for huts. In India, the first plantation of eucalypts to produce firewood was raised in grassy blanks in evergreen forests in Ootacamund in 1843. It was realised that the stunted forests in the valleys would otherwise be decimated. Today these valley forests still exist, at least partly because of these early plantations of Eucalyptus globulus.

The plantations of Eucalyptus spp. on the high plateaus of Ethiopia, which meet the firewood and charcoal needs of Addis Ababa, are of similar historical importance (327). Some countries which faced firewood deficit, such as Malawi, Botswana, Ecuador, Nigeria, Uganda and Mozambique, appreciated the fast growth of eucalypts for firewood production more than six decades ago (15, 18 260, 285). Planting on a large scale with eucalypt species for firewood, charcoal and poles now occurs in Argentina, Bangladesh, Bolivia, Brazil, Colombia, Ecuador, Ethiopia, Guatemala, India, Iran, Israel, Ivory Coast, Lesotho, Madagascar, Nepal, Pakistan, Paraguay, Portugal, Senegal, Somalia, Sri Lanka, Swaziland, Tanzania, Thailand, Turkey, Uruguay and Venezuela (27, 36, 184, 239, 284, 327, 416, 435).

The fall in prices of firewood and charcoal because of eucalypt plantations are reported from a few countries. If this has been a disincentive to the growers, it establishes that consumers have benefitted.

In rural parts of the tropics, fuelwood is a free good for the poor. Firewood, as a plantation product has to be paid for. But fallen leaves, bark, lops and tops are either free or are available at cheap rates. This is a common feature in all developing countries.

A study in West Bengal has shown that fallen material collected from plantations saves 2 hours per day per family in low income groups.

The availability of eucalypt poles, for use in construction and repair of huts, has been tremendously beneficial. In Gujarat, 27 million poles are used in the rural parts for this purpose (416). The material was earlier obtained from the forests at much higher prices.

The availability of sticks from the branches of felled eucalypt trees, for use as supports for plants of hybrid tomato and peas, has promoted cultivation of these crops in some areas (42, 313, 431).

Timber. The use of eucalypt as timber and small timber is new in Bangladesh, China, India, Pakistan and a few other countries. The scarcity of indigenous timber has lead to this trend. Eucalypt plantations have been raised for production of timber in Brazil, Chile, Colombia, Ecuador, Israel, Madagascar, Portugal, Senegal, South Africa, Spain, Turkey, USA, the former USSR and Uruguay (27A, 327, 416).

The quality of eucalypt timber depends on the species and on climatic factors. The comparative strength of E. tereticornis with a value of 100 for teak is: strength as a beam 75, stiffness as beam 70, shock resisting ability 115, shear 90, hardness 115 and weight 100. Its economic and social significance is that, while teak wood in India costs Rs. 22,500/- per m³, the cost of eucalypt timber is Rs. 1,100/- per m³.

Rural small scale industries. Rural small scale industries in developing countries, such as pottery, brick making, lime production, dyeing, smithy, jaggery making etc., have considerable socioeconomic effects. For most of these industries, firewood or charcoal are the only practical fuel alternatives, both from economic and technical points of view. Eucalypt firewood has provided relief to those units where indigenous firewood sources are depleted. In Thailand, the crisis faced by the tobacco industry, porcelain and ceramic industries, and the lime industry, due to falling supplies from natural forests is sought to be overcome by eucalypt (singly or with other species) from private plantations (318). In the Solomon Islands new sawmill complexes have been set up using eucalypt wood (125). Tea factories in Mozambique, Sri Lanka and South India largely depend on eucalypt firewood (389).

There is an interesting illustration from Karnataka. All along the sea coast there has been a large number of tile factories, for more than a century, producing "Mangalore Tiles". The forests in the mountainous region within 50 to 100 km provided the firewood. Now, with reduced extraction from the forests for environmental reasons and the total depletion of private firewood resources, the factories have been closing. This, in a belt receiving more than 2500 mm rainfall. (In the heavy rainfall zone, Eucalyptus hybrid failed due to attack by fungi, thus the Government brought in a ban on the cultivation of eucalypts in areas receiving more than 1,125 mm rainfall) . As against this, in Malur Taluk, in Kolar district, in a drought affected zone with no natural forests, new small tile manufacturing units have been springing up. There are presently 42 of these and the fuel used is the lops and tops of Eucalyptus hybrid (431).

Honey and oil. The potential offered by eucalypt, particularly for production of honey and oil, has been little utilised in most countries where eucalypts have been introduced. Many species of eucalypt flower over long periods in the year, including in the dry season after the harvest of agricultural crops. Several of these species are rich in both nectar and pollen. In Australia, apiaries based on eucalypts are well established and honey exported from the country is highly valued. In Algeria, China, Congo, South Africa, Swaziland, Togo and Tunisia, honey production based on eucalypts is being taken up at an increasing scale. Production and consumption of honey have considerable significance in rural areas (57, 76, 82, 151, 250, 305, 329, 416, 445). The very short rotations adopted in some countries are however not conducive to honey production.

Extraction of oil from the leaves of E. globulus and E. citriodora is a cottage industry in some parts of India, providing continuous employment to the people (416).

Provision of raw material for industries. Paper and, to a lesser extent, rayon play a major role in a country's social well being. Rayon, mixed with cotton, is a cheap enough fabric for even the poorest, if its lasting qualities are considered (327). Eucalypts play a prominent role in the production of both paper and rayon. Whereas one hectare of cotton crop under rain fed conditions yields around 175 kg of floss, the same area under Eucalyptus hybrid produces 1,250 kg of rayon. Eucalypts could thus help to release some areas presently under cotton to cereals and pulses (386).

Environmental benefits. Eucalypt trees, planted in open tracts, provide shade to people, crops and cattle in the arid regions of the southern Sahara belt. In many countries in arid and semiarid regions, eucalypt is raised as an avenue tree. In the desert areas of Israel and Iran, "oases" of greenery with eucalypts have been formed by harnessing flash floods (1, 44, 197, 226).

Conclusion

Social and economic problems arising from insensitive plantation establishment or unwise management are real, but many of those that have been highlighted in the literature and the press appear to be exaggerated and to ignore the benefits of the genus. In most developing countries in the tropics, ecological degradation - due to clearance of trees for agriculture on marginal lands and for meeting firewood needs - contribute to environmental degradation. This has been abetted by a lack of land use policy. Eucalypts offer the scope to ameliorate the situation.

In promoting the social forestry programmes, it was a mistake not to have considered the influence of market forces and thus to have raised expectations.

Information on market prices and the most economic mix of end products for each region would assist the growers. In countries facing acute firewood shortage, price support could be useful. Disincentives in the form of Government regulations on tree felling and transport hampers tree planting.

There is insufficient data on the combined effects of shelter belts and border effects of trees. Similarly, data on the overall effect of tree farming on employment is sketchy.

The potential of eucalypts for promotion of apiculture has remained unexplored.

GENERAL RECOMMENDATIONS

Most controversies on the subject of Eucalyptus are due to a lack of dissemination of data and information about the ecological aspects of species of the genus Eucalyptus. Both the positive and the negative ecological aspects of the genus and its general advantages and disadvantages should be made known widely. International organisations should condemn unscientific publications based on misrepresentations, which cause damage to tree planting programmes and thus to human development and wellbeing.

In community areas, the introduction of eucalypt should be done only with the concurrence of the people. Particular attention should be paid to the needs of land-less people, whose former access to the areas involved might be curtailed by the planting programme.

If there are indigenous species which serve the same purpose of planting well, these should be preferred.

The genetic quality of the eucalypt planting material made available to people for the production of firewood and timber requires improvement. The correct package of management practices aimed at sustainable production should also be made available.

Imperfections in marketing and restrictive government regulations should be removed and the forming of co-operatives of growers should be encouraged.

Further research needs to be carried out in the following fields:

- Identification of suitable species and provenances for afforesting degraded sites including alkaline and saline soils. Data should not only refer to climate and soil factors, but also to the objectives of plantation establishment. All species of comparable advantages should be included;

- The combined effects of eucalypts on agricultural crops with regard to competition for water and nutrients by border trees and trees used in agroforestry systems, and the beneficial effects of shelter belts;

- The water use of eucalypts;

- The overall effect of establishment of eucalypt plantations on employment;

Annex 1

Social Forestry and Eucalyptus, Kolar District, Karnataka.

Karnataka, located in South-west India has a land area of 19.2 million ha, of which 56% is under agriculture and barely 15% has tree cover. Except for the mountainous region in the West, where rainfall is high and there is good forest cover, the state is semi-arid and almost totally devoid of tree growth. Against an estimated requirement of 11 million tonnes of firewood, used as fuel in the rural areas, production is barely 5 million tonnes. This has resulted in decimation of the tree cover over vast regions.

During the 1950's and early 1960's, when the population was less than half of what it is today and forest resources were plentiful, the establishment of forest industries was encouraged. The State thus has three paper mills (two in the Government sector) and a rayon producing unit. These companies entered into contracts with the Government for the supply of eucalypt wood (and bamboo) covering periods of about 30 years. The contracts did not provide a price escalation clause and hence, by the 1970's, these rates were considerably lower than the then prevalent market rates. All eucalypt plantations raised under Government programmes to promote pulp production were committed to industries.

In 1975, the Government started providing incentives to promote private tree planting, in the form of free distribution of seedlings on a small scale, in order to bridge the huge gap which now existed between the supply and demand of fuelwood; and in 1981, a major Social Forestry Programme was taken up to promote tree planting on Government lands outside the reserve forests as well as on private lands, with the aim of benefitting the local community and the rural poor.

Private tree planting in the form of wood lots has long been the practice in three districts of the State, namely, Bangalore, Kolar and Tumkur. The Casuarina and Eucalyptus plantations were first intended to meet the firewood and pole needs of the State Headquarters, Bangalore. Eucalypts were introduced in India, for the first time, during the 1790's, at Nandi Hills in the Kolar district. In fact, for the local people, eucalypt hybrid is as indigenous as tamarind or cashew, also exotics to India.

The availability of free seedlings from a large number of rural nurseries prompted a spurt in planting activity particularly in these three districts, with Eucalyptus hybrid.

Meanwhile, the paper and pulp industries in the State were facing a deficit of 0.25 million tons per annum. They therefore began to buy eucalypt wood from the farm forestry sector. This was the situation when the first report, "Social, Economic and Ecological Impact of Social Forestry in Kolar" by Vandana Shiva, Sharatchandra and Bandyopdyay was published in 1981 (425).

The report explained that the paper and pulp industries in the State were very heavily subsidised and that the Government, unable to meet the entire wood requirement, promoted Social Forestry through free supply of seedlings to farmers. It asserted that Eucalyptus hybrid was useful only as an industrial raw material and was good neither for firewood nor timber. The programme was said to only benefit the rich farmers who could divert their rain fed ragi (an inferior millet) area to the more economic Eucalyptus hybrid. The report contains a graph showing a sharp decline in ragi production between 1977 and 1981, and a doubling of its price, with a devastating effect on the poor. The report said that the reduced amount of labour needed in tree farming, especially on land earlier under agriculture, resulted in widespread unemployment. This forced people to enter Government forests and steal wood for subsequent sale as a means of livelihood. The report claimed forest guards killed some of these people.

The other issues touched upon were ecological. The report indicated that the planting of eucalypt had resulted in the lowering of the water table, affecting agriculture in the entire region. It stated that eucalypt was destroying the soil irreversibly. The report received much publicity throughout the country causing a hatred for the Eucalyptus genus itself. In international journals, this report was cited as an authoritative document (48, 88, 121, 206, 395). News items appeared daily, with personal views of people who had experienced or seen the evil effects of Eucalyptus spp. Floods and droughts were now blamed on eucalypt. The eucalypt was considered a Satan.

In early 1981, however, well before the publication of the report, the Government had in fact amended the Forest Act to give it the power to revise the rates earlier contracted with the forest based industries. With this, the rate of Rs. 24/- per tonne of standing Eucalyptus was enhanced, first to Rs. 205/- and then to Rs. 264/- retrospectively. The amendment also gave the Government the power to revise the rate once every two years (386). The present rate to industries, at site, is Rs. 614/- with bark, inclusive of taxes, 307% higher than the rate charged to the general public (94). Cultivation of Eucalyptus spp. by the farmers under Social Forestry was not a feature confined to Karnataka alone. It was taken up much earlier and on a larger scale in Gujarat, where there are no pulp industries. It had also caught on in Uttar Pradesh, Punjab and Haryana.

So far as the free supply of eucalypt seedlings is concerned, the fact is that seedlings of all species were free (386). The deficit faced by the pulp industries then was 0.25 million tons against a deficit of 6 million tons of firewood.

The yields of ragi quoted in the report, and the area under the crop, were selective. 1980-81 was a severe drought year resulting in a drastic fall in the production of ragi as it fluctuates with the annual rainfall. The yield of ragi in subsequent years has been higher, comparable to the production in years before the Social Forestry programme was started.

The increase in the price of ragi over a period of eight years was less than in the case of rice, which was not affected by the Social Forestry programme. The price of ragi increased from Rs.1.00 per kg in 1979 to Rs. 2.10 in 1986 as compared to the price of rice which rose from Rs. 2.25 to Rs. 5.00 during the same period (386).

The killing by the Forest Guards referred to in the report was an incident which took place in a teak and rosewood forest 350 km away from Kolar and the ragi area. It was reportedly in a skirmish with smugglers in a good forest belt. There was no Social Forestry Programme there (386).

Studies conducted by others, individuals and institutions alike, have established that cultivation of Eucalyptus hybrid in the Kolar District was not related to the economic status of the farmers (42, 128, 130, 313, 329, 395). Eucalypt growing was profitable, and the small farmer also wanted to reap the benefits. Eucalyptus hybrid was seen as an economic shield against the not too dependable monsoon-influenced annual crops (42, 313).

The Government again amended the Forest Act in 1984. Under this amendment, eucalypt plantations raised after 1974 were reserved exclusively for the supply of firewood and poles to the local people. This amendment received no publicity (386).

In 1983 one political party called for uprooting eucalypts in the State. This was carried out in two villages in a symbolic manner, with wide spread publicity (317). The press described it as destruction of eucalypt by the irate farmers of Tumkur district. In some papers on eucalypts published thereafter, the reported number of seedlings destroyed began to increase. In an article in 1986 the number of seedlings destroyed was noted as lakhs (one lakh is one tenth of a million) (430). In a report in 1991, it was indicated as millions (430). In the very same villages planting of Eucalyptus hybrid by farmers has continued. The demand for Eucalyptus seedlings placed with the Forest Department by farmers of Tumkur district for planting in the 1993 rainy season was 2.4 million (41).

A second report entitled "Ecological Audit of Eucalyptus Cultivation" was published in 1984 (426). This report also quoted the ragi production figures of 1980 although the yield in 1981 was more than 900% higher than the figure from 1980 the report had used.

The report then moved on to other aspects and stated that Eucalyptus hybrid was promoted only because of its suitability for pulp production, and that the fast rate of growth, which encouraged its use, was a myth. According to the report there were a large number of indigenous species which grew faster. The report cited the rates of growth of several of these species including teak but these quoted rates were from good forests receiving three to eight times the rainfall of the drought prone Kolar district (386).

By citing selectively from different documents, it was been argued that eucalypts do not grow in Australia in areas receiving a rainfall lower than 700 mm, and hence, if grown as exotic in areas receiving less than 700 mm rainfall, they would lead to desertification. Transpiration rates of different species in different regions and different types of forests were quoted which stated that eucalypts use 1,136-5,526 mm/year, while in the case of mixed forest it was 140 mm/year.

The same authors have subsequently published other papers, expressing similar views, supported by some other documents (427, 428, 429, 430).

In Karnataka, the Economic and Planning Council, the highest advisory body of the Government, held a workshop in September 1983 on the social and ecological aspects of eucalypts, in which opponents of the eucalypts participated. This was followed by a National Seminar on Eucalyptus in January 1984 and next by two workshops organised by the Planning Commission of India in May 1984 and by the Indian Statistical Institute in June 1984 respectively.

The main findings of the first workshop were as follows:

... if planted in (poor) agricultural land or degraded land as envisaged in the government plans, then the run off and soil loss will decrease ... in such category lands with a planting density of about 3,000 plants per ha, it withdraws the nutrients from lower levels and deposit them on the surface improving the nutrient status of the top soil ... undergrowth can occur provided the planting densities are low ... Typically, there are other reasons for the absence of undergrowth such as excessive grazing, fires, fuelwood collection and soil erosion ... regarding water consumption there are two measures:

i. Grams of biomass produced per litre of water consumed; and

ii. Litres of water consumed per ha.

The first criterion helps one to decide on the tree species to be adopted and the second facilitates a selection between different alternative uses of water ... if the decision is to plant trees then Eucalyptus hybrid is a good choice ... however one has to look at the total water balance ... it is a fact that Eucalyptus hybrid does not serve as fodder which is why it is not browsed. Hence, Eucalyptus hybrid can be useful only in a fuelwood plantation ... it has been asserted Eucalyptus hybrid leaves do not decay. This is unlikely and in fact farmers use the leaves for composting ... all the socio-economic arguments for and against eucalypts vs. food would be applicable to any other tree crop. Many of these would also be applicable to commercial crops like sugarcane, cotton, etc. ... ragi production fluctuates drastically depending upon the seasonal conditions ... the impact of eucalypts planting on food grain production is negligible ... with tree planting (and particular with Eucalyptus hybrid) income levels of cultivators increase ... it also leads to substantial down stream employment ... much greater research is needed on each of these issues.

Government policies began to change as criticism of eucalypts persisted in India. The National Forest Policy of India (1988) disowned the responsibility of reserve forests to meet the needs of forest based industries, a primary issue in the earlier policy of 1952. An embargo was placed on the introduction of any exotic species in forestry until ecologists, scientists and foresters were satisfied, after long term trials, that it had no deleterious effects. In Karnataka, where eucalypt constituted 47% of seedlings raised by the Forest Department in 1983-84, this figure was reduced to 24% in 1987-88 (70). It is now limited to 20% (41). Since 1990, eucalypt planting by the Forest Department in Karnataka can only be done on degraded, barren areas receiving a rainfall of between 500 mm and 750 mm (232). The Government has reacted to criticism, whether justified or not.

This description of the Eucalyptus debate in Karnataka State illustrates the power of public opinion on Governments, and the need to inform the public, their representatives and the Government fully and fairly on environmental, social and economic issues arising from all forestry development programmes, and those involving plantations of the eucalypts in particular.

Annex 2

Extract from "Socioeconomic attributes of trees and tree planting practices"

The following Conclusions are extracted from Chapter 3, "What can we learn from the great eucalyptus debate?" in "Socioeconomic attributes of trees and tree planting practices" by J.B. Raintree, 1991. Community Forestry Note 9. FAO, Rome.

"In summary then, the most important lessons we can draw from the eucalyptus controversy for a constructive change in the way we design tree growing interventions would appear to be:

1)There is need for greater openness and imagination in the use of a systematic client-oriented approach to the design of tree planting interventions based on a much expanded repertoire of tree growing practices and the recognition that what we are dealing with are always the attributes of a particular species in the context of a particular technology intended for a particular user within a particular socioeconomic setting in support of a particular development strategy. There is no use in blaming a tree for human errors at other levels of the decision making process.

2)In order to secure the benefits of tree growing to all potential beneficiaries it is crucial to transcend the narrow focus on primary production systems to discover and develop the full range of secondary processing, marketing, extension support and other infrastructural arrangements which collectively constitute the necessary and sufficient preconditions of rural development, particularly where landlessness is prevalent and population threatens to exceed the human carrying capacity of primary production systems.

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