. 2016 Apr 1;7:418. doi: 10.3389/fpls.2016.00418

Table 3.

Statistical parameters of the tested factors affecting xylogenesis (number of cambium cells or tracheids in different development stages) in Scots pine (P. sylvestris) and black pine (P. nigra) trees showing different defoliation levels after drought-induced dieback.

Species	Effects	No. cambial cells			No. radially-enlarging tracheids			No. wall-thickening tracheids			No. mature tracheids
		5 days	10 days	15 days	5 days	10 days	15 days	5 days	10 days	15 days	5 days	10 days	15 days
Scots pine (Pinus sylvestris)	Tree		0.12			0.22			0.28			0.09
	Defoliation		−0.17			−0.57			−0.14			−2.17
	Time	0.02	0.01	0.03	−0.29	−0.28	−0.34	0.01	0.06	0.07	0.21	0.28	0.26
	Mean temperature	0.04	0.31	0.63	0.58	−0.26	−0.89	0.11	0.24	0.44	0.19	0.16	0.15
	Relative humidity	0.06	0.01	0.05	0.28	0.06	−0.01	0.23	0.18	0.20	0.18	0.15	0.14
	Radiation	0.04	0.21	0.33	−0.01	0.44	0.48	−0.03	0.16	0.18	−0.16	−0.13	−0.09
	Precipitation (P)	0.04	0.08	0.12	0.05	0.22	0.28	0.01	0.06	0.05	0.10	0.14	0.10
	Water balance	−0.05	−0.05	−0.11	−0.04	−0.20	−0.27	−0.24	−0.07	−0.03	−0.08	−0.20	−0.09
	$R_{adj}^{2}$ (%)	29.61	28.54	33.60	38.97	39.60	45.95	44.51	41.20	45.62	34.45	33.89	34.14
Black pine (Pinus nigra)	Tree		0.03			0.17			0.03			0.06
	Defoliation		−0.55			−0.78			−1.15			−5.16
	Time	0.04	0.02	0.02	−0.24	−0.25	−0.27	0.06	0.20	0.21	0.22	0.23	0.27
	Mean temperature	0.07	0.06	0.02	0.58	−0.04	−0.94	0.04	0.72	0.84	0.14	0.12	0.10
	Relative humidity	0.03	0.05	0.01	0.24	0.04	0.06	0.01	0.03	0.04	0.12	0.04	0.11
	Radiation	0.04	0.20	0.32	−0.01	0.52	0.53	0.05	0.01	0.03	−0.10	−0.08	−0.03
	Precipitation (P)	0.01	0.01	0.03	0.01	0.20	0.27	0.04	0.08	0.04	0.03	0.07	0.20
	Water balance	−0.01	−0.04	−0.02	−0.05	−0.19	−0.22	−0.15	−0.22	−0.29	−0.05	−0.08	−0.14
	$R_{adj}^{2}$ (%)	29.81	28.70	32.24	41.26	37.45	46.38	38.70	42.76	48.33	46.82	45.72	45.99

The last line of each model gives the adjusted R² ( $R_{adj}^{2}$ ), which measures the proportion of variance of the dependent variable explained by the model. All models were evaluated for 5-, 10-, and 15-day long intervals. Bold values indicate significant effects (P < 0.05).