Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

Table 2

Critical height ratio (CHR) model coefficients, correlation coefficients (𝑅²), and the proportion of subplots having at least one principal competitor (PC) aspen.

Site	Year	Stand age CHR determined (years)	Subsequent growth interval (years)^1	𝑛^2	CHR	𝑏0	Pr > |𝑡|	𝑏1	Pr >|𝑡|	𝑏2	Pr >|𝑡|	𝑅^2 (%)	% subplots with ≥1 PC aspen (%)
SBPSxc	2001	11	2	304	3.25	−0.343	<0.0001	−0.013	0.022	0.242	<0.0001	25.3	66
	2005	15	3	299	1.5	−0.006	0.875	−0.008	0.113	0.194	<0.0001	25.2	80
IDFdk3-A	2002	10	2	182	2.0	−0.409	<0.0001	0.003	0.834	0.411	<0.0001	15.7	30
	2006	14	3	181	1.25	0.194	<0.0001	−0.030	<0.0001	0.132	0.009	36.7	45
IDFdk3-B	1992	8	3	50	2.0	0.368	<0.0001	−0.022	<0.0001	—	—	44.3	92
	1999	15	5	59	1.25	0.186	0.0007	−0.026	0.015	—	—	13.4	78
IDFdk3-C	1992	12	3	49	1.25	0.395	<0.0001	−0.031	<0.0001	—	—	64.4	86
	1999	19	5	51	1.25	0.223	0.007	−0.083	0.0003	—	—	49.8	67
SBSdw1-A	1992	10	2	49	1.5	0.172	0.0009	−0.044	<0.0001	—	—	51.0	73
	1999	17	5	59	1.25	0.322	0.629	−0.458	0.015	—	—	69.8	73
SBSdw1-B	1992	11	2	47	1.0	0.194	0.002	−0.027	0.002	—	—	35.0	79
	1999	18	5	55	1.5	0.318	<0.0001	−0.136	<0.0001	—	—	40.8	65

¹Years of pine diameter growth subsequent to the determination of CHR.
²Number of lodgepole pine-centred subplots contributing to the analysis.