小陇山林区主要树种胸径与树高异速生长关系OA

As a crucial functional area for water conservation and biodiversity conservation in the western section of the Qinling Mountains,the Xiaolong Mountain Forest Area plays an indispensable role in regional sustainable forest management due to the growth patterns of its tree species.Taking the major tree species in this forest area-Quercus aliena,Ulmus davidiana,Pinus armandii,and Pinus tabuliformis-as research objects,this study analyzed disc diameter data at different heights of harvested trees during forest management from 2008 to 2010.Linear,power,and quadratic polynomial functions were em-ployed to fit the allometric growth relationship between tree height and diameter at breast height(DBH),while the varia-tion of the mechanical design principles of tree trunks with DBH was explored.The results showed that allometric growth re-lationships existed between tree height(H)and DBH(D)at different growth and development stages of trees.Additional-ly,the variation trends of the height-diameter ratio with DBH were basically consistent across all tree species,all confor-ming to the power curve fitting law.As DBH increased continuously,the relative growth rate of tree height to DBH gradual-ly stabilized.Overall,the mechanical design principle of tree wood in the Xiaolong Mountain Forest Area exhibited stress autocorrelation.However,the variation patterns of the allometric growth exponent(α)differed significantly among tree species with increasing DBH,reflecting the specificity of growth strategies for different species.Except for U.davidiana,the relative diameter at 0.4H(relative height)of the other three species was significantly positively correlated with tree height,which could serve as a reliable indicator for predicting the potential future growth capacity of tree height.For decid-uous broad-leaved tree species,the relative diameter at the top of the trunk showed a negative correlation with tree height,whereas evergreen coniferous tree species mostly exhibited a positive correlation-this difference can be used for intuitive judgment of the tree height growth potential.Furthermore,deciduous broad-leaved tree species had a relatively thicker bark compared to evergreen coniferous tree species.