Nitrogen addition to the canopy of Castanopsis chinensis (Sprengel) Hance promoted xylem formation in a subtropical forest in China

Table 3 Effect of N on xylem ring width and growth rate during early growth season (February to May in 2015 and February to April in 2016) and late growth season (June to December in 2015 and May to December in 2016). T represents the effect of N addition; D represents the effect of DOY; T × D represents the interaction effect of N addition and DOY. DOY represents the day of year

	Phase	Effect	Year 2015		Year 2016
	Phase	Effect	F	P	F	P
Xylem width	Early	T	44.550	< 0.001	15.781	< 0.001
		D	525.331	< 0.001	589.182	< 0.001
		T × D	61.742	< 0.001	17.190	< 0.001
	Late	T	0.615	0.433	3.061	0.082
		D	1635.723	< 0.001	1286.332	< 0.001
		T × D	0.051	0.821	3.281	0.074
Growth rate	Early	T	54.012	< 0.001	14.862	< 0.001
		D	1137.091	< 0.001	1401.469	< 0.001
		T × D	37.500	< 0.001	3.922	0.048
	Late	T	0.043	0.836	1.683	0.195
		D	2850.324	< 0.001	1955.191	< 0.001
		T × D	0.181	0.671	0.000	0.995

ISSN: 1297-966X