TY  - JOUR
AU  - Wang, Yanfang
AU  - Wei, Liang
AU  - Zhong, Liheng
AU  - Yu, Xizi
AU  - Huang, Pengtao
AU  - Wang, Fang
AU  - Marshall, John D.
PY  - 2025
TI  - Adding a storage pool improves 3-PG tree-ring simulations
JO  - Forest Ecosystems
SN  - 2095-6355
VL  - 14
IS  - 2
AB  - Tree rings provide long-term records of tree growth and climate changes, which makes them ideal benchmarks for forest modeling. Tree-ring information has greatly improved the reliability of 3-PG, which is one of the most commonly used process-based forest growth models. Here, we strengthen 3-PG's ability to simulate tree-ring width and stable carbon isotopes (δ13C) by enhancing its descriptions of tree physiology. The major upgrade was adding a carbon storage pool for tree-ring formation using stored carbohydrates. We also incorporated previous modifications (replacing the age modifier with a height modifier) of 3-PG and tested their efficacy in improving tree-ring simulations. We ran the model based on two grand fir (Abies grandis) stands. The updated model greatly improved the simulations for both tree-ring widths and δ13C. The results represent one of the best tree-ring δ13C simulations, which accurately captured the amplitude in annual variations of δ13C. The correlations (R2) between simulations and observations reached 0.50 and 0.73 ​at two stands, respectively. The new model also greatly improved the simulations of raw tree-ring widths and detrended ring-width index (RWI). Because of better descriptions of tree physiology and more accurate simulations of tree rings than the previous model version, the updated 3-PG should provide more reliable simulations than previous 3-PG versions when tree-ring information is used as a benchmark in future studies.
UR  - https://doi.org/10.1016/j.fecs.2025.100384
DO  - 10.1016/j.fecs.2025.100384