Climate has a larger effect than stand basal area on wood density in Pinus ponderosa var. scopulorum in the southwestern USA

Table 2 Significance of fixed effects terms and model fit statistics. The sample height × GSL interaction, PDSI, and pre-1962 values were significant at < 0.0001 for all models, so for clarity, they are not included in the table

Model	GSL	Year	Sample height	R²-adj^a	RMSE	\|%E\|^b
Basal area increment	< 0.000	< 0.000	< 0.000	0.50	9.10	41.46
Ring density	0.142	0.051	< 0.000	0.49	46.72	7.82
LW proportion	0.019	< 0.000	< 0.000	0.13	0.072	37.50
EW density	0.281	< 0.000	< 0.000	0.49	43.93	7.91
LW density	0.087	0.331	0.425	0.20	94.23	10.14
Maximum density	0.083	0.002	0.649	0.22	94.37	9.57

^aPercent variation in the response that is explained by the fixed effects of the predictors
^bMean absolute percent error

ISSN: 1297-966X