Comparison of model forms for estimating stem taper and volume in the primary conifer species of the North American Acadian Region | Annals of Forest Science

EDPS Account

Volume 67 / No 3 (May 2010)

Ann. For. Sci., 67 3 (2010) 302

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Table VII

Estimated parameters and standard errors of the best two models for balsam fir, red spruce, and white pine.

		Balsam fir						Red spruce					White pine

	Estimate		std.	CAR	σ	R ²		Estimate	std.	CAR	σ	R ²		Estimate	std.	CAR	σ	R ²
Kozak (2004) Model 02	α ₀	0.911	0.015	0.718	0.827	0.984		0.940	0.017	0.743	0.861	0.983		1.057	0.025	0.840	2.416	0.982
	α ₁	1.026	0.007					0.998	0.006					0.991	0.010
	α ₂	–0.005	0.011					0.010	0.011					–0.031	0.014
	β ₁	0.368	0.006					0.508	0.005					0.372	0.006
	β ₂	–0.645	0.045					–0.636	0.038					–0.824	0.048
	β ₃	0.502	0.012					0.355	0.010					0.335	0.010
	β ₄	1.780	0.141					1.687	0.129					4.711	0.246
	β ₅	0.096	0.002					0.078	0.002					0.112	0.002
	β ₆	–0.487	0.013					–0.242	0.011					–0.556	0.017

Clark et al. (1991) I	β ₁	68.258	1.186	0.836	0.792	0.984		67.542	1.128	0.843	0.830	0.982		58.278	1.183	0.916	2.613	0.972
	β ₄	1.292	0.058					1.369	0.062					1.743	0.145
	β ₅	0.702	0.004					0.696	0.004					0.730	0.003
	β ₆	1.795	0.015					2.107	0.0170					2.534	0.026

Clark et al. (1991) II	β ₁	67.375	1.174	0.873	0.909	0.979		66.895	1.121	0.871	0.944	0.975		57.420	1.178	0.920	2.808	0.968
	β ₄	1.218	0.060					1.211	0.063					1.526	0.144
	β ₅	0.693	0.005					0.695	0.004					0.729	0.004
	β ₆	1.748	0.016					2.095	0.018					2.521	0.027

	θ ₁	0.8959	0.0024			0.998		0.8804	0.0027			0.997		0.8418	0.0023			0.997
	θ ₂	–0.8791	0.0156			0.998		–0.6849	0.0161			0.997		–0.6582	0.0315			0.997

Fang et al. (2000)	α ₀	0.000056	0.000002			0.9849		0.000053	0.000002			0.9894		0.000069	0.000003			0.9895
	α ₁	1.8731	0.0165					1.7869	0.0096					1.7630	0.0136
	α ₂	0.9637	0.0251					1.0995	0.0200					1.0352	0.0207

	p1	0.0299	0.0004	0.8476	0.5323	0.9815		0.0230	0.0004	0.8299	0.6938	0.9785		0.0360	0.0004	0.8962	1.7070	0.9769
	p2	0.5439	0.0033					0.6057	0.0027					0.5989	0.0032
	β ₁	0.0457	0.0006					0.0241	0.0010					0.0495	0.0004
	β ₂	0.0372	0.0001					0.0393	0.0001					0.0382	0.0001
	β ₃	0.0300	0.0001					0.0290	0.0001					0.0301	0.0001

std.: Standard error of estimated coefficients, CAR: estimated variance-covariance parameter, σ: estimated standard error of residuals.

Clark et al. (1991) I: upper stem diameters at 5.27 m were obtained by linear interpolation.

Clark et al. (1991) II: upper stem diameters at 5.27 m were predicted based on the regression form presented in Clark et al. (1991).