Processing small trees
Tree specimens below 7 cm in diameter are recorded in a circle with a 3 m radius during forest inventory. Records are classified into three height groups along with information on species, average diameter by tree species and whether apical bud browsing damage is observed on the small tree. Average diameter is interpreted to mean an estimate of the diameter at the midpoint of average tree height.
When it processes data, the Field Map software extrapolates the values measured inside the circle with the 3 m radius to the 500 m2 area, and then projects that to a hectare (multiplies by 20), and to the area represented by the sample tree (with a five-year data set the latter comes to 400 ha).
Number/hectare values for tree species groups are calculated as follows: analytical statistics concerning separate territorial units project the parameters of a small tree to sampling plots with at least one small tree.
Additional statistics can be prepared on the basis of size group, tree species, browsing damage and other parameters, such as grouping according to stock below standard/free standing.
Wood volume calculations rely on cubic capacity derived from average diameter and the average height associated with each height group.
Taking tally of small trees