Relationship between canopy depth and other dimensions of coastal Pinus thunbergii Parlat. forests in Japan

The relationship between canopy depth and other dimensions of coastal Pinus thunbergii Parlat. forests was analyzed from data for 29 stands using a mathematical model describing canopy depth. The model was derived from the relationship between mean diameter at breast height (D) and mean tree height (H). Maximum mean tree height (H(max)), which was calculated as H(max) = AD(B) where A and B are parameters, approximated the upper 95 percentile of H for a given D. Maximum canopy depth (L(cmax)) was calculated as L(cmax) = H(max) - H(B), where H(B) is mean clear length. Relative maximum canopy depth (R(cmax); defined as L(cmax)/H(max)) was approximated as 1/R(cmax) = 1/(aS(R) (b)) + 1, where a and b are parameters. The term S(R) was defined as N(-1/2)/H, where N is stand density (trees m(-2)). From these equations, the canopy depth (L(c))was derived as L(c) = H - H(max)/(aS(R) (b) + 1), because L(c) = H - H(B). From these relationships a diagram showing possible points of regulation of canopy depth was developed.