Objective An age-independent theoretical growth equation was constructed to predict the dominant height of Pinus massoniana plantation when the age was unknown or not an effective influence factor.

MethodsBased on the four theoretical growth equations of Hossfeld IV, Lundqvist-Kolf, Richards and Schumacher, an age-independent dominant height model of Pinus massoniana was constructed by using the difference form of hidden age factors, and the free parameters were expressed as a function of site index.

ResultsAmong the four basic theoretical growth models, the age-related dominant growth model of Pinus massoniana plantation established by Richards model performed the best. The fitting accuracy of age-independent models was higher than that of age-related models, and the age-independent dominant growth model of Pinus massoniana plantation established by Richards model and Korf model performed the best. When the site index was introduced to the model, the fitting accuracy of Hossfeld model improved most obviously, and when k was set as a variable parameter, the age-independent dominant high growth model was the best.

Conclusion When the forest of different age or age is difficult to obtain, the theoretical growth model independent of age can predict the growth of dominant height. After the functional relationship between site index and free parameters is replaced in the model, the accuracy of the model is improved and the model can be better applied to predict stand growth.