Modelling growing space of four valuable broadleaved tree species in southern China

We present management tools for growing four valuable broadleaved tree species, indigenous to subtropical southern China. Crown diameter (CD) of the species studied can be predicted very well by using a model that is solely a linear function of diameter at breast height (DBH). The addition of tree age (AGE) and yield class (YC) to this model did not significantly improve its predictive capacity. We used species-specific crown diameter models to calculate the amount of growing space and subsequently stand density that each species needs to achieve desired stem radial growth rates. Furthermore we used this information to calculate a “distance factor”, a rule of thumb that roughly estimates the distance between two neighboring trees needed to achieve a desired future target diameter. These tools facilitate the planning of thinning regimes by using crown diameter models combined with annual radial growth rates to calculate the number of crop trees per hectare required to reach a desired target stem diameter.