A tree distance-dependent growth and yield model for naturally regenerated pure uneven-aged maritime pine stands in central inland of Portugal

Table 1 Summary statistics for the data collected at the tree level in sample plots of 1,000 m² and concentric sub-sample plots of 500 m² in the first year of measurements

Tree variable	Symbol (units)	n	Min.	Max.	Mean	Std. dev.
Sample plots—1,000 m²
Diameter (dbh)	d (cm)	2,619	5.0	41.4	17.9	7.9
Height	h (m)	2,619	2.5	21.9	12.2	3.9
Crown width	cw (m)	2,619	0.6	8.1	2.5	1.0
Height to the crown	hc (m)	2,619	0.3	17.7	6.8	2.7
Crown ratio	cr	2,619	0.08	0.93	0.45	0.1
Sub-sample plots—500 m²
Age	t (years)	314	16	64	42	10.0
Diameter increment	id5 (cm year⁻¹)	314	0.1	1.6	0.5	0.2
Total volume	v (m³)	314	0.0024	1.2183	0.1770	0.2
Bole diameter	d _h (cm)	2,353	0.0	57.0	11.4	9.1
Bole height	h _d (m)	2,353	0.1	20.6	5.8	4.7
Merchantable volume	v _m (m³)	2,353	0.0001	1.2183	0.1355	0.3

ISSN: 1297-966X