Forests contribute an enormous carbon flux to terrestrial ecosystems. Thus, accurate estimation and prediction of forest dynamics both play an important role in understanding the carbon cycle in the background of global change. Process- based ecological models have been often considered effective tools for evaluating forest dynamics at multiple scales.

Previously, the Global Change Ecology Group at Wuhan Botanical Garden has developed an individual tree- based carbon model, FORCCHN2 (Forest Ecosystem Carbon Budget Model for China version 2.0), by integrating non- structural carbohydrate (NSC) pools to couple tree growth and phenology. The model was tested in a temperate forest in central Massachusetts, USA (Harvard Forest), and it was able to predict realistic and stable carbon dynamics.

In this paper, this research group presented a dynamic- link library (DLL) package aimed to provide a flexible and user- friendly interface for implementing the newest version of FORCCHN2.

The FORCCHN2 has been tested at 78 flux sites and applied in predicting the spatial distribution of mean gross primary productivity, aboveground and belowground autotrophic respiration, soil heterotrophic respiration, net primary productivity, and net ecosystem productivity of the Northern Hemisphere forests (1980- 2016).

The assessment indicated that FORCCHN2 was able to satisfactorily predict carbon dynamics in hemispheric- scale forests, and provided an open- access dataset of carbon outputs across Northern Hemisphere (https://doi.org/10.6084/m9.fifigshare.18318722.v1).

With the potential applications of FORCCHN2 in many researches, there is plenty of scope for this model in the study of forest ecology, climate change, and carbon estimations.

This work was supported by the National Natural Science Foundation of China, which has been published in Geoscientific Model Development entitled " FORCCHN V2.0: an individual- based model for predicting multiscale forest carbon dynamics”.

The spatial distribution of mean GPP (gross primary productivity), aboveground and belowground autotrophic respiration, soil heterotrophic respiration, NPP (net primary productivity), and NEP (net ecosystem productivity) predicted by FORCCHN2 for forest ecosystems of the Northern Hemisphere during 1980-2016. (Image by FANG Jing)

Schematic representation of FORCCHN2. LAI is leaf area index, NSC is non-structural carbohydrates, C is carbon, and N is nitrogen (Image by FANG Jing)