Abstract:

Tree volume estimate of forest stand or sample plot by using the current one-way tree volume table is significantly biased, and on the other hand, the workload for measuring heights of sample trees in field is rather heavy if two-way tree volume table is directly used. To Dealing with counter this problem existed in practice, a new approach is presented in this paper that two-way tree volume table can be employed directly to estimate the volume of forest stand or sample plot based on the establishment of a variable relative height curve model. By using this approach, the precision of volume estimate is almost as high as that by using tree height curve, but in this case, it is not necessary to measure heights of sample trees, so the workload in field is reduced evidently. The general form of variable relative tree height curve model presented in this paper is: RH_i, =[1-e^{-f₁(${\bar D}$)})]^{-f₂(${\bar D}$)}*[1-e^{-f₁(${\bar D}$)*RD_f}]^{-f₂(${\bar D}$)}.

Key words: Relative tree height curve model, Variable parameter, Tree volume estimation