An assessment of hollow logs and other logging residues from Deramakot Forest Reserve, Sabah, Malaysia

Sabah is in the process of implementing sustainable forest management practices in all its natural forest reserves. The management system model was developed by the Malaysian-German Sustainable Forest Management Project at the Forestry Department and tested in the Deramakot Forest Reserve. During logging operations it was observed that the number of hollow logs was very high. Although marked for harvesting, these hollow logs are usually not felled. The fellers test the trees by pushing the blade of the chain saw vertically into the stem. In some cases, a hollow stem is assumed, if a crown shows large defects like broken branches and a highly reduced number of leaves. The fellers and sawyers at the log landing cut off large parts of the top and lower portions of hollow logs. According to forest management plan for Deramakot, the annual allowable cut (AAC) is 20,000 m3. After a compartment is harvested, the compartment is closed for many years. If the amount of timber extracted from one compartment decreases considerably due to a high number of hollow trees, other compartment have to be opened earlier than planned. Thus, if a forest is to be managed sustainably, we must optimize the use of available resources and reduce the logging waste. A study on the utilization of hollow logs and other logging residues was initiated. First, it was evaluated how much timber can be extracted from trees regarded as hollow by the fellers. Secondly, the amount of timber which is considered as timber of low quality (hollow stem parts, top portions, big branches) was determined. At the same time it was tested whether the methods used for the detection of hollow stems are reliable. Some results of the study are : - A high percentage of logs presently considered as hollow and left in the forest still contains large amounts of usable timber. - The methods for determination of hollow logs or the extent of the hollow are not reliable and have to be improved. - In view of the improved processing techniques (e.g. finger jointing) the quality standards for logs suitable for log sales have to be changed. - The concept of logging residue utilisation has to be promoted. Education of forestry workers, field staff of the Forestry Department and of the license holders has to be started in order to change their attitude with regard to log quality. A different salary system for tree fellers has to be developed and implemented. They should be encouraged to extract as much timber as possible within the cutting limits and not discouraged as it is currently the case. - Recovery studies should be started to determine the amount of sawn timber produced from hollow log parts unsuitable for log sale and from other logging residues. - Feasibility studies (technical, economic), which cover the same area, should be started.