forestSAS (version 1.0.1)

uniform.angle: A forest spatial structure index characterizing tree spatial distribution patterns

Description

The uniform angle index (UAI) is used to characterize the spatial distribution of a forest community or of individual tree species within that community.By gradually comparing the included 4 angles with the standard angle (72).

Usage

uniform.angle(x, para)

Arguments

x

Moving clockwise around reference tree,4 angle were obtained among adjacent neighbours

para

standard angle (72)

Value

Result will retrun five values,0,0.25,0.5,0.75,1,which means none, one, two, three, or four angles are smaller than 72, respectively.

References

Zhao ZH, Hui GY, Hu YB, Wang HX, Zhang GQ, and von Gadow K. 2014. Testing the significance of different tree spatial distribution patterns based on the uniform angle index. Canadian Journal of Forest Research 44:1419-1425.

Examples

# NOT RUN {
angle1<-c(80,80,80,80)
angle2<-c(80,80,80,70)
angle3<-c(80,80,60,70)
angle4<-c(80,50,60,70)
angle5<-c(40,50,60,70)

uai1<-uniform.angle(angle1,para=72)
uai1
uai2<-uniform.angle(angle2,para=72)
uai2
uai3<-uniform.angle(angle3,para=72)
uai3
uai4<-uniform.angle(angle4,para=72)
uai4
uai5<-uniform.angle(angle5,para=72)
uai5
# }