The phenology of leaf quality and its within‐canopy variation is essential for accurate modeling of photosynthesis in tropical evergreen forests

• DOI: 10.1111/gcb.13725
• Publication Date: 2017-04-18T11:53:15Z
• Authors: Jin Wu; Shawn P. Serbin; Xiangtao Xu; Loren P. Albert; Min Chen; Ran Meng; Scott R. Saleska; Alistair Rogers
• Keywords: Seasonality; Photosynthetic capacity; Evergreen forest

Abstract Leaf quantity (i.e., canopy leaf area index, LAI), quality per‐area photosynthetic capacity), and longevity all influence the seasonality of tropical evergreen forests. However, these components phenology are poorly represented in most terrestrial biosphere models (TBMs). Here, we explored alternative options for representation effects TBMs that employ Farquahar, von Caemmerer & Berry (FvCB) CO 2 assimilation. We developed a two‐fraction (sun shade), two‐layer (upper lower) photosynthesis model to evaluate different modeling approaches assessed three phenological variations quantity, quality, within‐canopy variation longevity). Our was driven by prescribed derived from ground‐based measurements within an Amazonian forest. Modeled not sensitive but highly its vertical distribution canopy, with markedly more sensitivity upper quality. This is because light absorption canopies near maximal entire year, implying seasonal changes LAI have little impact on total absorption; has greater effect sunlit leaves than limited, shade foliage abundant canopy. leaf, model, which accounted components, able simulate seasonality, explaining ~90% average eddy covariance‐derived work identifies parsimonious approach representing forest utilize FvCB assimilation highlights importance incorporating realistic mechanisms seek improve projection future carbon dynamics