Stem Volume and Taper Functions

Abstract

Direct measurement of the wood volume in a tree stem is a difficult and time-consuming process, particularly if the tree is standing. For many forest species around the world, functions have been developed that allow estimation of the volume in all of the stem or that much of it which is large enough to be merchantable. These ‘volume’ functions require measurement only of the diameter at breast height over bark and total height of the tree and, sometimes also, the degree of taper of the stem determined by diameter measurement at two heights. More recently, functions have been developed widely across the world that allow estimation of the stem diameter at any height up a tree stem, again, usually from measurement only of diameter at breast height over bark and total height of the tree. Whilst rather more complex mathematically than volume functions, these ‘taper’ functions allow estimation both of the total wood volume in a tree stem and of the dimensions of the individual logs that might be cut from the stem as required by the market that the forest is supplying. This chapter describes these functions and their application.