Biomass Modelling of Androstachys johnsonii Prain: A Comparison of Three Methods to Enforce Additivity

Table 6

Coefficients of regression for CON, SUR, and NSUR methods.

Tree component	Weight function	(±SE)	(±SE)	(±SE)	(±SE)	(±SE)
CON method
Roots		0.2522 (±0.6334)	0.0097 (±0.0002)^*
Stem wood		0.6616 (±1.1451)	0.0251 (±0.0004)^*
Stem bark		0.1895 (±0.3503)	0.0028 (±0.0001)^*
Crown		0.3033 (±1.5640)	0.0118 (±0.0006)^*
Total tree		1.4066 (±2.1984)	0.0494 (±0.0008)^*
SUR method
Roots		1.6513 (±2.3498)	0.1016 (±0.0040)^*	−0.4056 (±0.2584)
Stem wood		−3.8911 (±0.9553)^*	0.2106 (±0.0047)^*
Stem bark		0.1285 (±0.3260)	0.0014 (±0.0001)^*
Crown		−1.9730 (±1.5045)	0.1114 (±0.0044)^*
Total tree		−4.0843 (±3.1723)	0.3122 (±0.0068)^*	0.0014 (±0.0001)^*	0.1114 (±0.0044)^*	−0.4056 (±0.2584)
NSUR method
Roots		0.0075 (±0.0022)^*	1.0137 (±0.0326)^*
Stem wood		0.0131 (±0.0040)^*	1.7962 (±0.0549)^*	1.4113 (±0.1470)^*
Stem bark		0.0001 (±0.0011)	1.6545 (±0.1942)^*	1.7332 (±0.5460)^*
Crown		0.0407 (±0.0159)^*	2.2302 (±0.1343)^*	0.3146 (±0.1214)^*
Total tree

SE = standard error; “*” = significant at α ≥ 5%; “ ” = not significant at any probability level.