The Optimum Standard Angle of the Uniform Angle Index

The paper was to improve the theory of the uniform angle index,a measure for describing spatial forest structure.The standard angle,which implied absolute regularity of the spatial distribution of the neighboring trees around a reference tree,was an important factor influencing the efficiency of the uniform angle index for describing the spatial distribution of a forest.Based on theoretical arguments,and 100 simulation stands of one ha including (1 000) trees each,a standard angle of 72° was found to be optimal,producing a uniform angle index-mean value of 0.5 in Poisson distributed tree populations.