At present, less than five percent of the total area of productive tropical forests is considered to be under active management. Despite some attempts, in a number of countries, to design and promote sustainable environmentally sound harvesting methods, their application has still not taken place in the majority of operations.
While deforestation (clearing of forests for changing the use of the land) is caused to a very large extent by all forms of horizontal expansion of agriculture and ranching, degradation of tropical forests is often due to careless harvesting of forest products in excess of their regenerative capacity. This is particularly the case of timber harvesting of rainforests in the humid tropics and of fuelwood collection in dry areas.
Considerable efforts are needed to introduce and disseminate ecologically sound logging methods to reduce environmental impact and to increase the future productivity of the stands.
To assist tropical countries in this respect, FAO has started to implement a programme of environmentally sound forest harvesting to sustain tropical high forests. Four items of interest are reported below:
(i) a timely publication entitled: Manual on Harvesting Technologies to Sustain Tropical High Forests (FAO) Forestry Paper Series, will go to press with the following contents:
(a) review of the literature related to timber harvesting in the tropics with a comprehensive bibliography;(b) summary of information on the current utilization of tropical high forests for timber production;
(c) review of the problems related to harvesting of timber from tropical high forests;
(d) evaluation of harvesting technologies capable of promoting sustainable utilization;
(e) general guidelines on sustainable harvesting, serving as a base to formulate national codes of harvesting practices.
(ii) Environmental Impact Studies on Controlled Harvesting Operations:
Studies are being carried out to fill the gaps in existing information on the environmental impact of felling, wood extraction, transport and road development on the various components of the forest ecosystem. Different levels of technology, intensity and complexity of forest utilization are being studied in tropical high forests throughout the tropical regions.
(iii) Further studies are being undertaken to generate more precise information on the amount of wood residues in timber harvesting and processing in the tropics and to create awareness within forestry institutions and industrial companies for appropriate decisions. In early 1993 results will be published in: Study on Wood Residues from Timber Harvesting and Primary Processing: A Global Assessment for Tropical Forests.
Based on ten country studies and on other data available, a model has been developed to estimate production and potential utilization of wood residues in all tropical countries. One of the main findings suggests that in the late 1980s total volume of wood felled for timber production amounted to 466 million m3 annually, of which about half remained as unutilized forest residues (see table below). Reducing the rate of forest residues in the tropics to the same level as in temperate forests, would result in a reduction of wood volume to be felled by one third; thus the area affected by harvesting could be reduced substantially.
(iv) Based on the results of the programme so far, an International Conference on Environment and Sustainable Forest Harvesting is planned. Its main objective will be to define ways and means to integrate the findings of these and other studies into harvesting operations in tropical countries.
Further information can be obtained from the Forest Harvesting and Transport Branch, Forest Products Division, FAO Forestry Department, Via delle Terme di Caracalla, 00100 Rome, Italy. Tel. +39 (6) 57974727 - Fax. +39 (6) 57975137.
