New Zealand Journal of Forestry (1965) 10(1): 43–61
©New Zealand Institute of Forestry
Crown Depth of Radiata Pine in Relation to Sand Density and Height
An analysis of crown depth data from permanent sample plots showed that the increase in crown depth with lower stocking was linear when plotted over the average spacing between trees. For all data combined, crown depth increased by 1.6 ft for every foot increase in average spacing. This was a great deal less than indicated by previous studies, and shows that earlier predictions of crown depth to be achieved under more drastic thinning regimes may have been over-optimistic.
Site had a significant effect on crown depth, but differences in the rate of increase from close to wide spacing were not significant. There were strong indications, however, that crown depth varies not only with stand density, but also with the height of the stand, particularly in young stands. This would mean that a progressive rise of green crown level in young stands is no guarantee that the stand has reached a maximum crown depth characteristic for a given density.
A number of factors are considered, which may account for this finding. It is concluded that, to obtain a reliable estimate of crown depth under different thinning regimes, both stand density and stand height have to be taken into consideration.