CONSTRAINTS ON THE HARVEST OF LINE-PLANTED TIMBER TREES IN LOGGED AND ENRICHED DIPTEROCARP FOREST IN KALIMANTAN, INDONESIA

Where enrichment planting of timber trees results in high densities of planted and naturally-regenerated trees larger than the minimum cutting diameter, e.g. 40 cm diameter at breast height, harvest of all those trees would result in major residual stand damage. One proposed harvest strategy for enriched dipterocarp forest that we studied was to cut only planted trees and to fell them down the 3 m wide planting lines so as to protect the intervening 17-m wide strips of regenerating natural forest. Based on crown and bole characteristics of line-planted dipterocarp trees, felling down the planting line should be possible for 90% of the trees. When felled, the other 10% of the planted trees would cross at least one strip of natural forest. A bigger concern was that at the time of the planned harvest (25 years after planting), 31% of the planted trees would not quite have reached harvestable size. To avoid excessive stand damage and destruction of future crop trees, alternative harvest strategies are needed. For example, enriched stands could be harvested in two phases with modified shelterwood system. Alternatives to chainsaws and crawler tractors should also be considered such as feller bunchers or mobile crane cable yarders.