CROWN DENSITY ASSESSMENTS, CONTROL SURVEYS AND REPRODUCIBILITY

摘要

This study aims to evaluate the quality of crown density data, based on independent, pairwise tree assessments. The data originates form monitoring of forest health (crown condition) in Norway; 250 plots, comprising 12 000 individual trees of Norway spruce, ahve been reassessed by a single observer during 1990=-95. Of the trees, 2300 were controleld more than twice, providing the possibility of evaluating the quality of assessed temporal changes of crown density. True errors (standard deviation) are estimated to be about 10/100 for single trees and 5/100 for plot means, while the real standard deviation of the differences were slightly higher.