Management of natural teak forest in Myanmar - Forest Department

Forest Department

Ministry of Forestry, Myanmar

ABSTRACT

The forest resources of Myanmar scientifically managed since 1856 have been decreasing due to population pressure and rising demands for forest lands and products. Forest cover assessed by Landsat images showed the country has 344,237 km² of forests, 50.9% of the total land area in 1989. Deforestation rate was 220,000 ha/year during 1975-1989. Forest inventories update forest resources information since 1981 at pre-investment, reconnaissance and management levels. Teak stand structures indicate that natural regeneration of teak is insufficient. Silvicultural treatments, e.g. improvement felling, thinning, etc., are to improve the natural regeneration of teak. British foresters once successfully treated natural stands but later abandoned due to its high cost. About 2,500 acres of teak plantation established by 1880 were damaged by bee-hole borer, and also observed soil depleting and erosion. However, block plantations started in early 1970s in degraded forests with cultural operations e.g. weeding, fire-protection, thinning when staffs and budgets available. Some Myanmar foresters suggest that, instead of making pure plantations in blocks, there should be only a gap or group planting using a wide spacing. Exploitation of natural teak forest has been controlled by yield fixation since 1858, using Brandis’ method of yield regulation; the annual allowable cut of teak for the present felling cycle is fixed at 178,750 trees. The Myanmar Timber Enterprise (MTE) manages teak extraction, milling and marketing. Since 1962, good quality teak logs were exported and small amount of 3 and 4 star logs were left for local use. Export policy now emphasizes to reduce teak log sale and to export more value added products. Remedial measures to conserve natural forests under the Myanmar Selection System are undertaken, using its advantages in timber exploitation, cultural operations, and the least disturbance on ecological and environmental conditions in forests. Adoption of proper land use policy, community fuelwood plantations by people’s participation are being planned.

Key words: Tectona grandis, Myanmar, natural forest, AAC, plantation, exports, trade, market.

INTRODUCTION

The forest resources of Myanmar, though scientifically managed since 1856, have been decreasing gradually both in extent and quality due to increased population pressure and consequent rising demands for the forest land and forest products.

Forest cover status in 1989

The Forest Department has, for the first time, assessed the potential forest area of the country in 1962 using the aerial photographs taken in the 1950’s. The forest cover status has been updated by using the information based on the satellite images in 1980, 1984 and 1990 respectively.

In 1990, under the National Forest Management and Inventory Project, the forest cover assessment was carried out using 44 frames of Landsat 5, Thematic Mapper false colour composite paper prints of 1:500,000 scale taken in the year 1989. The Landsat images were visually interpreted and aerial photographs, inventory data and local knowledge were used as ground truth.

According to 1989 appraisal, the forest cover of the country can be summarized as shown in Table 1 with the combined total of effective closed and degraded forests standing at 344,237 km² (85 million acres) or 50.9% of the total land area.

Table 1. Area of forest and land classes as determined by 1989 appraisal

Deforestation rate over the 14-year period between 1975 and 1989

The forest cover assessment has been carried out three times using Landsat images during the period of 1980 to 1990. The first assessment (or the 1975 Appraisal) was carried out in 1980 under the FAO/UNEP project using 1:1,000,000 scale Landsat MSS images taken during 1972-79. The second one (or the 1980 Appraisal) was made in 1984 under the National Forest Survey and Inventory Project using the same scale Landsat images taken during 1979-81. The third estimate (or the 1989 Appraisal) was done in 1990 under the same project using 1:500,000 scale Landsat TM images taken in the year 1989.

The rate of deforestation in the forest cover of Myanmar was estimated by comparison between the 1975 and 1989 appraisals as both of them had been guided and supervised by the same Myanmar forest officers. The forest cover status in 1975 and 1989, and its changes in 14 years are presented in Table 2.

Table 2. Rate of deforestation between 1975 and 1989

(Area in km²)

The above table indicates that the actual forest area has decreased over the 14-year period by 30,637 km² or at the rate of 220,000 ha annually. However, the physical transfer of forest land into non-forest uses over the same period was only about 2,110 km² in the 14 years or 15,000 ha annually.

MANAGEMENT OF NATURAL TEAK FORESTS

Forest inventories and growing stock

Forest inventories at national scale has been initiated since 1981 under the National Forest Survey and Inventory Project in order to have reliable and up-to-date information on the forest resources in Myanmar. Since then large scale forest inventories were carried out every year at three levels namely, pre-investment, reconnaissance and management levels with sampling intensity of about 0.1%, less than 0.1% and 0.5% respectively.

The sampling design for the pre-investment and management levels is the systematic sampling with plots located on a square grid of 3,300 × 3,300 yards, whereas a stratified random cluster sampling design was used for reconnaissance level inventory.

During the period of 1981-1989, the pre-investment inventory had covered about 9.55 million ha (23.60 million acres) and the reconnaissance inventory about 1.19 million ha (2.95 million acres) to make a total of about 10.74 million ha (26.55 million acres) which is approximately 31% of the total forest cover area of the country. Precision of the pre-investment inventories in two States and six Divisions ranges from 1.29% to 13.2% at the 95% probability level, whereas the precision of the reconnaissance inventories in two States, Chin and Rakhine States, are between 1.5% and 3.5%.

The following Table 3 shows the number of teak trees enumerated over the inventoried area of 9.55 million ha (23.60 million acres) carried out in two States and six Divisions during the period from 1981 to 1988.

Table 3. Growing stock of Teak in two States and six Divisions

According to the inventoried data for two States and six Divisions, the forest consists of 45.9 million teak trees, including 3.27 million trees of DBH 68 cm and over (GBH 7' 0” & over).

In the pre-investment inventory, there are about 480 tree species recorded, out of which teak composts of about 6.2% of the total. Table 4 indicates the composition percentage of teak among the other valuable species.

Table 4. Species composition of Teak

(Number of trees in million)

Stand structures of teak for six forest divisions

Based on actual growing stock of the inventoried data available in six forest divisions, stand structures of teak have been prepared and then compared with that of the growing stock derived from Meyer’s formula, Y = ke^-ßX with Y representing tree number and X the mid diameter of 1 foot class, the constants k and ß, stand for the relative stand density and percentage diminution in stem numbers.

The formula derived tree numbers indicate the desirable trend to aim at, which is next to impossible to achieve in practice in a mixed heterogeneous selection forest. However, the comparison of the curves have their own use as one can judge how far actual stand structure is deviating from the desirable trend and take corrective silvicultural measures.

The stand structures of teak constructed for the six divisions unanimously indicate that the actual stocking per acre of teak below 4' 0'' girth is less than the estimate made by Meyer’s method. This is clearly obvious that natural regeneration of teak is insufficient in all cases. In its girth classes between 4' 0'' and 7' 11'' the actual stock per acre is higher than that calculated by Meyer’s estimate, in all six divisions. This indicates a slight deviation from normal with the actual stocking higher than natural trend.

Silvicultural treatments in the Bago Yoma teak-bearing forests

The Bago Yoma is covered with a forest area of about 3.8 million acres (1.5 million ha), including evergreen, semi-evergreen, moist deciduous and dry bamboo forests, depending upon the extent of the rainfall, geology and soil. As it is the home of the good teak bearing forest in Myanmar, scientific management was introduced there since 1856 by Dr. Dietrich Brandis.

Various kinds of silvicultural treatments, such as improvement felling, natural regeneration felling, thinning in natural regeneration of teak (TNR), Nyaungbat felling, climber cutting, fire protection, etc., were carried out in order to improve the natural regeneration of teak and other valuable commercial species but only with limited funds.

Natural regeneration

In the natural forest, teak tree thrives best only if associated with bamboo and other species, and pure natural teak stands are rare and even where they are found, their condition is not satisfactory. Following the courses of nature, the British foresters had treated the natural stands with some success but later abandoned it due to its high cost. Some experiments show that natural regeneration is capable of restocking the forests more than double what it was 30 years ago if efficiently assisted and controlled with sufficient amount of funds.

From a study of the consolidated girdling statements, it was observed that, in some reserved forests of Bago Yoma, for every yield tree girdled, there is only 1 to 5 trees of 4 feet GBH and above left in the forest. As the norm at one time was that for every tree girdled there should be at least 15 trees of 4 feet GBH and above left in the forest, it indicates that natural regeneration of teak is deficient even in the good teak forests of Bago Yoma due to the lack of proper treatments in the old days.

Issues in artificial regeneration (plantation)

In those days, British foresters also attempted to establish plantation of teak and some valuable commercial species to compensate for the trees that had been extracted. After establishing about 2,500 acres of teak plantation up to the year 1880, the plantation policy had changed resulting from the findings that bee-hole borer was damaging in plantation than in natural forests, and pure teak is soil depleting and soil deteriorating with its big leaves inducing splash and sheet erosion where there is little or no undergrowth beneath it.

However, due to the population pressure and ever increasing demand of timber for domestic and foreign uses, block plantations were formed, starting from early 1970s, in the areas with degraded forests and poor stocking of teak and other valuable commercial species. Cultural operations such as weeding, fire-protection, thinning were done depending upon the available staffs and budgets allotted. Here also, sufficient funding is of utmost importance in order to apply proper cultural treatments to young plantations, since artificial means is rather risky in the long run and mistakes made are liable to be very costly, not only from the stand point of labour and money wasted but also from their disastrous effect on the productive capacity of the soil. Some foresters pointed out that block plantation of single species used to destroy or change the flora and fauna of the forest eternally or destroy the biodiversity or genetic pool of the forest.

Conclusions

Hence, where the natural regeneration is very scarce, some Myanmar foresters suggest that, instead of making pure plantations in blocks, there should be only a gap or group planting using a very wide spacing for teak (25' to 35') in the area with open canopy. Spots of grassland will be burnt and planted up and maintained by cultural operation up to two or more years until the plants become established.

Where the environmental conditions favour for the germination of teak seeds, improvement felling, Nyaungbat felling and climber cutting should be carried out and repeated both for inducing regeneration and for improving the already existing regeneration. In places where there are profuse regeneration of teak, thinning or even weeding may have to be carried out.

Annual allowable cut for future sustainable production

The exploitation of teak from natural forest has been controlled by yield fixation since 1858, using Brandis’ method of yield regulation. The growing stock of teak was determined by using the sampling method as well as 100% enumeration during girdling operation of teak. Table 5 shows the record of the actual cuts of teak against the prescribed cuts during the last 50 years since 1946.

Table 5. Actual cut of teak against its prescribed yield

(Number of trees)

The annual allowable cut (AAC) of teak for the present felling cycle is being fixed at 178,750 trees of DBH 68 cm and over and is valid up to the year 2000. The AAC of teak for the next cycle has to be revised based on the inventoried data using sampling method and 100% enumeration data of girdling operation carried out during the previous felling cycle. Since the forest area of two States and six Divisions were surveyed at pre-investment level, the AAC of teak for those areas could be estimated based on the inventoried data for the next felling cycle. Table 6 shows the estimated AAC of teak in comparison with the present AAC for the inventoried areas.

The future AAC is estimated by using data obtained from the inventoried areas and extrapolated for the Teak Selection Working Circle areas of the respective divisions. This table shows accessible and extensively extracted divisions (Bago, Magwe, Ayeyarwady, Yangon) are remarkably less than the present AAC, while the future AAC for the less accessible and lightly extracted divisions (Chin, Sagaing) are significantly increased.

Table 6. The present and future AAC of teak estimated in the inventoried areas

RESTOCKING OF TEAK BY MEANS OF ARTIFICIAL REGENERATION

Although there were plenty of teak trees in the natural forests in various densities, teak plantations were introduced in Bago Yoma forests as early as 1856 in order to ensure a permanent and sustained yield from them. But, as there were some opponents to the establishment of pure teak plantations, it was done only on a modest scale and in a compensatory way up to 1962. Starting from early 1970s block plantations were formed with a yearly increase in plantation acreage. Big scale planting programme was launched in 1980 with an initial target of about 40,000 acres (16,200 ha), stepped up by 10,000 acres per year to reach a final target of 80,000 acres (32,400 ha) annually. Table 7 shows the actual planting areas of teak and its annual rate during the period mentioned. Table 8 indicates the percentage of teak plantations among the other commercial species planted.

Table 7. Teak planting, 1896 - 1994

Table 8. Teak composition in forest plantation

UTILIZATION AND MARKETING OF TEAK

Teak extraction, milling and marketing are being managed by the Myanmar Timber Enterprise (MTE). The annual allowable cuts (AAC) of teak is around 0.34 million hoppus tons (0.6 million m³) whereas the actual cut has been around 0.28 million hoppus tons (0.5 million m³) on the average over 130 years. Table 9 shows the volume of teak log extracted from 1856 up to 1994.

Table 9. Teak logs extracted from 1856 to 1994

Since 1962, most of the good quality teak logs were exported and very small amount of 3 and 4 star logs were left for saw mills, due to the high demand of logs for the modernized wood industries in the developed countries, low outturn percentage of small sized timber and inferior quality of sawn timber produced by existing sawmills of Myanmar. Export of teak logs is shown in Table 10 in comparison with that of teak conversion in the last 5 years.

Table 10. Export of teak logs and teak conversion

The figures in Table 11 show the trend of the value/m³ of teak log and teak conversion in the year 1989-90 to 1993-94.

Table 11. Value of teak log and conversion

According to the above figures, the export of teak log is more favourable in terms of price due to low outturn percentage of small sized timber (as low as 30%). However, the export policy is now emphasizing to reduce the quantity of log sale year by year and to export more in teak conversion forms, and to promote the export market of value added teak products.

As teak is one of the best timber for all round utilization, it is highly demanded in both domestic and foreign markets. In Myanmar, teak will be substituted with other kinds of timber with more or less similar quality but with less cost for specific utilization as much as possible.

PROBLEMS AND REMEDIAL MEASURES

According to the forest cover assessment carried out in 1962, about 38.5 million ha (95 million acres) was still covered by the forests. The forest area was then reduced to 34.4 million ha (85 million acres) in 1989, due to various reasons as follows:

1. Encroachment in the forest land for agriculture, infrastructure, factories, and dwelling as the population increases;

2. Illicit cutting and logging of trees for commercial use;

3. Extension of pasture land for domestic animals;

4. Practicing of shifting cultivation; and

5. Excessive utilization of firewood and charcoal for daily cooking and warming.

At present, the extraction of timber concentrates only on a few species, about 40 out of 460 or so different kinds of species available in the forest. Creaming of the forest might lead to the devaluation of the forest in the long run through the decrease of valuable trees and their regeneration. The forest resource is decreasing yearly due to an increasing demand of timber and fuelwoods to meet the requirement of the growing population. There is a land use problem between agriculture and forestry, particularly the practice of shifting cultivation in the hilly region and permanent cultivation in thickly populated area.

The Forest Department, in line with the guide lines laid down by the Ministry of Forestry, is undertaking remedial measures to conserve the natural forest as mentioned below:

1. Extraction of timber is continuously being managed under the Myanmar Selection System which was introduced since 1856, as the system involves not only the exploitation of timber but also the application of cultural operations, such as improvement felling, climber cutting in favour of the better growth of established young valuable species and their natural regeneration.

2. Another reason in favour of the Myanmar Selection System is that it causes the least disturbance on the ecological and environmental conditions of the forest land.

3. It is being planned to adopt proper land use policy for the effective utilization of the State land for the most benefit of the people.

4. In order to conserve the natural forest with high value timber, the reservation of forest is planned to be increased from 15% of the total land area up to 30% year by year.

5. The natural forest is now being protected not only by the Forest Law but also with the people participation through education.

6. In order to decrease the production of fuelwood from the natural good forests, which is one of the main causes of deforestation, more community fuelwood plantations are being planned to be established by people’s participation.

7. In order to reduce the fuelwood utilization for cooking and industrial purposes, wood substitute fuel such as coal, agro-waste, forestry-waste is being introduced especially in the dry zone areas where the firewood problem is critical.

8. Instead of using the teak, the all round good timber, in all purposes, other kinds of timber with more or less similar quality will be substituted in specific utilization.

9. Extraction, processing and marketing of teak are being solely done by MTE and log export will be reduced year by year in favour of increasing the value-added product export, in order to have high value but for less timber, thus saving the forests.

REFERENCES

Ba Thwin and Saw Han. 1991. Management of Teak and Hardwoods stands for sustainable production. Forest Department, Yangon.

Forest Department. 1985. Annual Allowable Cut for Teak and non-Teak Hardwoods.

Forest Department. 1989. Forest situation in Myanmar.

Forest Resources Division. 1991. Forest Resources Data for all inventory areas in Myanmar (1981-1989).

Forest Resources Division. 1993. Forestry Fact Sheets.

Kyaw Tint and Htun Hla. 1991. Forest cover of Myanmar, the 1989 appraisal. Forest Department,Yangon.

Saw Kelvin Keh and Mya Aung. 1995. A critical review of the silvicultural treatments of the teak-bearing forests of the Bago Yoma with some suggested remedial treatments. Forestry Science Research Paper, Forest Department.

Saw Kelvin Keh and Shwe Kyaw. 1995. A general study of the growing stock of Teak (Tectona grandis) in the Bago Yoma; some suggested redress. Paper presented to the Teak Symposium, Forest Department.

Shwe Baw. 1995. Teak Marketing. (Paper presented to the Teak Symposium, FD.) Myanma Timber Enterprise.

Shwe Baw. 1995. Teak Marketing. (Paper presented to the Teak Symposium, FD.) Myanma Timber Enterprise.

ANNEX

Botanical names of some commercial tree species in Myanmar