Influence of stand and site conditions on the quality of digital elevation models underlying New Zealand forests

New Zealand Journal of Forestry Science

Table 2 Mean range and summary statistics for variables used in analyses

Term	Mean	Range	R	P-value
Age (years)	13.7	0-38	−0.30	< 0.0001
Stand density –all (stems ha^-1)	872	17-11,183	−0.37	< 0.0001
Crop stand density (stems ha^-1)	434	0-2,283	−0.14	0.0048
Non-crop stand density (S_nc) – all (stems ha^-1)	438	0-10,833	−0.34	< 0.0001
S_nc : Diameter (D) > 250 mm (stems ha^-1)	7.1	0-483	−0.14	0.0058
S_nc : D > 275 mm (stems ha^-1)	5.2	0-433	−0.13	0.013
S_nc : D > 300 mm (stems ha^-1)	3.5	0-367	−0.12	0.025
S_nc : D > 350 mm (stems ha^-1)	1.9	0-267	−0.11	0.040
S_nc : D > 500 mm (stems ha^-1)	0.39	0-50	−0.11	0.036
S_nc : D > 750 mm (stems ha^-1)	0.09	0-17	−0.07	0.18
S_nc : D > 1000 mm (stems ha^-1)	0.04	0-17	−0.05	0.29
Aspect (º)	185	0-359	−0.01	0.80
Slope (º)	16.9	0.2-44.5	−0.23	< 0.0001
Incident pulse density (pulses m^-2)	3.84	2.27-10.38	−0.05	0.32

Shown are summary statistics describing the strength and significance of the relationship with the percentage of ground returns. Shown are the correlation coefficient (R) and P-value for simple linear correlations. The total number of plots used in analyses was 381.