Predicting stand age in managed forests using National Forest Inventory field data and airborne laser scanning

Forest Ecosystems

Table 4 Independent variables of the first stand age model. Sqrt refers to square root

	Estimate	Standard error	t-value	P-value
Intercept	2.331	0.133	17.570	< 2e–16
f_p90	0.058	0.008	7.741	3.45e–14
f_b05	0.030	0.005	5.566	3.71e–08
f_b10	−0.023	0.005	−4.253	2.40e–05
l_avg	0.426	0.066	6.483	1.70e–10
sqrt (l_max)	0.226	0.047	4.763	2.32e–06
Leica60	−0.193	0.025	−7.719	4.07e–14
mineral	−1.244	0.141	−8.803	< 2e–16
sqrt (l_max × other)	−0.129	0.008	−16.353	< 2e–16
sqrt (l_max_ × mineral)	0.240	0.037	6.550	1.12e–10
sqrt (l_max_ × low)	0.115	0.018	6.430	2.36e–10
l_avg × site1	−0.412	0.066	−6.247	7.29e–10
l_avg × site2	−0.431	0.065	−6.633	6.59e–11
l_avg × site3	−0.404	0.065	−6.230	8.04e–10
l_avg × site4	−0.361	0.065	−5.546	4.15e–08
l_avg × site5	−0.321	0.069	−4.643	4.11e–06