6. Biomass of trees Because of the difficulty of deter- mining the biomass (or volume) of trees in the wild, Canadian forestry ecology researchers chose a sample of 25 trees in a BC forest, from each of three different species, then measured each tree's diameter (at chest height), and estimated its height via a special viewing instrument (and basic Pythagorean math for triangles). Later these trees were chopped down and the biomass of each was determined by a precise method