Why Models Underestimate West African Tropical Forest Primary Productivity

Overview

Journal Nat Commun

Specialty Biology

Date 2024 Nov 6

PMID 39505869

Authors

Huanyuan Zhang-Zheng

Xiongjie Deng

Jesus Aguirre-Gutierrez

Benjamin D Stocker

Eleanor Thomson

Ruijie Ding

Stephen Adu-Bredu

Akwasi Duah-Gyamfi

Agne Gvozdevaite

Sam Moore

Imma Oliveras Menor

I Colin Prentice

Yadvinder Malhi

Affiliations

Soon will be listed here.

Abstract

Tropical forests dominate terrestrial photosynthesis, yet there are major contradictions in our understanding due to a lack of field studies, especially outside the tropical Americas. A recent field study indicated that West African forests have among the highest forests gross primary productivity (GPP) yet observed, contradicting models that rank them lower than Amazonian forests. Here, we show possible reasons for this data-model mismatch. We found that biometric GPP measurements are on average 56.3% higher than multiple global GPP products at the study sites. The underestimation of GPP largely disappears when a standard photosynthesis model is informed by local field-measured values of (a) fractional absorbed photosynthetic radiation (fAPAR), and (b) photosynthetic traits. Remote sensing products systematically underestimate fAPAR (33.9% on average at study sites) due to cloud contamination issues. The study highlights the potential widespread underestimation of tropical forests GPP and carbon cycling and hints at the ways forward for model and input data improvement.

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