Since January 1998, the FOMISS Project (Forest Department Sarawak and GTZ) has cooperated with the private sector (Samling Strategic Corporation Sdn. Bhd.) to implement a trial Sustainable Forest Management System (SFMS) in a pilot area known as the FOMISS-Samling Pilot Area (FSPA) in Sarawak, Malaysia.
The SFMS incorporates optimum production and utilisation of forest products as one of the key Sustainable Forest Management (SFM) objectives. This includes the promotion of timber harvesting systems that are environmentally sound, economically feasible, and socially acceptable. Such harvesting systems have become commonly known as Reduced-Impact Logging, Low-Impact Logging, or Low-Impact Harvesting and are referred to generally as RIL systems.
Tractor skidding is the standard extraction method in the Mixed Hill Dipterocarp Forests of Sarawak. Due to the prevalence of red-yellow podsolic soils in this region, together with heavy rainfall and rugged terrain, Conventional Logging (CL) systems with tractors can cause substantial disturbance and damage to soils and forest stands (e.g., Abdulhadi et al., 1981, Nussbaum, 1995, Johns et al., 1996, Bertault & Sist, 1997, McNabb et al., 1997, Butaud, 1998). As a result, in recent years a variety of Codes of Practice or Guidelines for Reduced-Impact Logging (RIL) have been developed and implemented in many trial areas of tropical natural forests (e.g., Dykstra & Heinrich, 1994, Pinard & Putz, 1996, Jonathan & Rani, 1997, 1999, Elias, 1998, Sist et al., 1998, Armstrong & Inglis, 2000, Graaf, 2000, Hout, 1999, 2000, Pinard et al., 2000).
From various international seminars, workshops, roundtable discussions, and subsequent recommendations related to this issue, it can be concluded that there is now general agreement on the practices to be applied to reduce the impacts of ground-based timber harvesting on the environment.
Forest managers, while supporting in principle the move towards more environmentally friendly harvesting methods, are concerned about the economic implications of such RIL techniques. They claim that the overall costs of an implementation will not be offset by cost savings or additional revenues or attractive fiscal/private incentive packages, that enable them to cope with the additional financial burden arising from improved planning and monitoring as well as for implementation of RIL operations as part of an overall SFMS.
Several studies consider financial aspects of RIL (e.g., Elias, 1998, Barreto et al., 1998, Holmes et al., 1999, Hout, 1999). However, due to differences in timber, terrain and other conditions, these results are not directly transferable to the FSPA. For the purpose of an in-depth analysis of the economics of RIL, the FOMISS Project decided to undertake a financial analysis of RIL in comparison with conventional logging on the FSPA. The analysis was designed to evaluate the obvious economic values maintained or generated through the RIL system. These were addressed either quantitatively or qualitatively, depending on existing data and information.
Logging is the most important management intervention in a selective silvicultural management system. The impacts of logging include the direct effects of tree felling and associated damage to the residual stand where a large proportion of the remaining vegetation is killed or damaged. The removal of a significant number of mature trees reduces potential seed sources for the subsequent regeneration.
Logging modifies the physical environment through creating a complex mosaic of canopy gaps in a variety of sizes, shapes, and orientations. In larger gaps, an increase in incident sunlight will affect other key environment variables. Soil temperature will increase. This increase may lead to localised increases in air temperature through convection, resulting in reduced relative humidity and increased rates of evaporation. These effects combine and may lead to the rapid depletion of water in the upper layers of the soil during periods of reduced rainfall (Gardingen et al., 1998).
Direct effects of logging on the physical and biological characteristics of the soil environment include the removal of topsoil and associated nutrients, especially in areas used for skidtrails or log landings. Soils subjected to machine traffic may become compacted (the soil bulk density increases), affecting both seed germination and subsequent seedling growth. In addition, seed banks in the topsoil may be removed and the seed rain from the surrounding forest washed out. This results in the loss of potentially productive forest areas and leads to a significant disturbance to the catchment hydrology (Nussbaum, 1995, Nussbaum et al., 1995).
The effects of logging combine to influence ecological processes that control the establishment of seedlings and subsequent regeneration of the stand, and can significantly alter species composition and stand structure.
Changes in population structure greatly influence stand diversity and lead to genetic erosion. Among the disappearing species there might be potentially economic timber species (Abdulhadi et al., 1981). Since these modifications also affect the abundance of non-timber forest products and wildlife they decrease the overall value of forest resources and potentially reduce income for local communities.
Environmental changes also have a negative impact on the growth of the residual stand. In addition, weed species, which frequently overgrow the residual trees, may become dominant after logging. Climbing vines may also infest heavily logged forests and smother or inhibit the growth of regeneration (Abdulhadi et al., 1981).
Disturbance of the soil environment is often suggested as a contributing factor when dipterocarps fail to establish and regenerate following logging. Ingleby et al. (1998) demonstrated that the abundance of ectomycorrhizal fungi strongly decreased after logging. Dipterocarps appear to be highly dependent on their mycorrhiza, so the poor growth and survival of naturally regenerating dipterocarps in logged forests could thus, in part, result from the removal of host- or site-specific mycorrhizal fungi (Gardingen et al., 1998).
The alternation of stand structure can diminish the resilience of forest ecosystems. Logging also increases the likelihood of forest fires by increasing available fuel loads (CIFOR, 1999).
Degradation of tropical forests by careless, unplanned and uncontrolled harvesting practices has lead to growing awareness of the need to protect and maintain the long-term integrity and value of forest resources and the environmental services they provide. Efforts toward SFM have promoted the implementation of Reduced-Impact Logging techniques. RIL’s main objectives are to reduce soil disturbance, impacts on wildlife, and damage to residual trees (Sist, 2000).
The key elements of RIL are (Heinrich, 2000):
The effectiveness of RIL techniques in reducing damage and in optimising resource utilisation has been demonstrated by several studies. Table 1 summarises the benefits as well as the costs of RIL. Some aspects are difficult to quantify, because long-term experience with RIL in tropical forests does not exist. For example it seems obvious that training of harvesting crews will contribute to lower wear and tear of equipment and will improve work safety, but data to verify this assumption are not yet available.
|
Table 1. Key operational elements of Reduced-Impact Logging (RIL) and their costs and benefits. |
||
|
Operation |
Benefits |
Costs |
| Training |
|
|
| Harvest planning | ||
| Skidtrail alignment |
|
|
| Mapping of skidtrail alignment (SMT) |
|
|
| Tree marking (TMT) | ||
| Trees to be harvested |
|
|
| Potential crop trees |
|
|
| NTFP trees |
|
|
| Protected trees |
|
|
| Climber cutting |
|
|
| Data analysis, digitising (GIS Unit). |
|
|
| Review of Final Harvesting Map by verification, cross-checks |
|
|
| Harvesting operation | ||
| Skidtrail preparation |
|
|
| Log landing preparation |
|
|
| Tree felling & measurement |
|
|
| Log extraction | ||
|
Winching: long winch distance |
|
|
| Skidding |
|
|
| Post-harvesting operation | ||
| Installation of cross drains & sediment traps |
|
|
| Treatment of compacted areas |
|
|
| Damage assessment |
|
|
| Verification |
|
|
Source: Hammond et al., 2000; modified