A. Haara et al., THE K-NEAREST-NEIGHBOR METHOD FOR ESTIMATING BASAL-AREA DIAMETER DISTRIBUTION, Scandinavian journal of forest research, 12(2), 1997, pp. 200-208
The purpose of this study was to examine the use of the non-parametric
k-nearest-neighbour method in estimating the basal-area diameter dist
ribution. Distance-weighted nearest-neighbour estimation was based on
the similarities of known stand characteristics, e.g. basal area and b
asal area median diameter, between the target stand and reference stan
ds. The weights for the reference stands were determined using similar
ity distances. These similarity distance functions were determined by
tree species using standardized stand variables. The material of this
study consisted of 553 forest stands located in eastern Finland. The a
ccuracy of the k-nearest-neighbour method was compared with the Weibul
l distribution by tree species, using current stand volume characteris
tics and those that should exist after IO yrs' simulation time. The We
ibull-based method tn;as, in most cases, more accurate than the neares
t-neighbour method, but the results were also quite good for the k-nea
rest-neighbour method. Both methods were negligibly biased across the
whole material. However, at the extremes of the volume distribution cl
ear underestimates were obtained when using the XI-nearest-neighbour m
ethod.