Table 2
Variable exponent specifications, AIC,
ΔAIC and AIC weights for the three best models for stem taper (Eq. 8)
Model
AIC
ΔAIC
AIC weights
1. x
ijk β ¼ β
0 þ β
1
h
H þ β
2 log
h
H
À Á
þ β
3 D þ β
4 alt
þ β
5 BA
þ β
6 twin
þ β
7 psum
þ β
8 W
626,303.9
0
0.227
2. x
ijk β ¼ β
0 þ β
1
h
H þ β
2 log
h
H
À Á
þ β
3 D þ β
5 BA
þ β
6 twin
þ β
7 psum
þ β
8 W þ β
9 tsum
626,304.8
0.913
0.144
3. x
ijk β ¼ β
0 þ β
1
h
H þ β
2 log
h
H
À Á
þ β
3 D þ β
4 alt
þ β
10 SD
þ β
5 BA
þ β
6 twin
þ β
7 psum
þ β
10 W
626,304.9
1.038
0.135
h height within the tree,
H total tree height,
D diameter at breast height,
alt altitude,
BA stand basal area,
twin mean winter temperatures,
psum summer
precipitations,
W average wind speed,
tsum mean summer precipitations,
SD stand density
Understanding the Factors Influencing Stem Form with Modelling Tools
309