Two new methods applied to crown width additive models: a case study for three tree species in Northeastern China

Key message

The non-linear seemingly unrelated regression mixed-effects model (NSURMEM) and generalized additive model (GAM) were applied for the first time in crown width (CW) additive models of larch (Larix gmelinii Rupr.), birch (Betula platyphylla Suk.), and poplar (Populus davidiana Dode). The crown radii in four directions (CR) exhibited different growth trends and responded differently to tree size and competition variables. In the absence of calibration, GAM was more accurate than NSURMEM for CR and CW predictions.

Keywords
Crown radii; Crown growth patterns; Larix gmelinii Rupr.; Betula platyphylla Suk.; Populus davidiana Dode; Natural secondary forests

Publication
Wang, J., Jiang, L., Xin, S. et al. Two new methods applied to crown width additive models: a case study for three tree species in Northeastern China. Annals of Forest Science 80, 11 (2023). https://doi.org/10.1186/s13595-022-01165-5

Data and/or Code availability
The data used in the current study can be obtained from the corresponding author with reasonable requirements.

Handling Editor
John M. Lhotka