3D canopy models reveal how forests adapt to drought and heat

Using advanced 3D canopy reconstruction combined with high-resolution physiological measurements, researchers quantified how light penetration, stomatal conductance, and chlorophyll content drive carbon absorption under stress. Results reveal that thinning improves canopy light availability and boosts carbon uptake, even under drought, while reduced rainfall suppresses photosynthetic performance.

Extreme climate events—particularly droughts and heat waves—are increasingly undermining forest productivity and carbon sequestration. Conifer plantations, which play a major role in global carbon storage, face particular risks as shifts in precipitation and rising temperatures alter canopy dynamics and physiological processes. While thinning is recognized as a useful management tool to reduce competition and enhance resilience, its combined effects with drought stress are poorly understood. At the same time, breakthroughs in remote sensing technologies such as UAV-based LiDAR and 3D modeling now allow unprecedented insights into canopy structure and function. Based on these challenges, this study investigates how canopy phenotypes regulate photosynthesis and carbon gain under climate extremes.

A study (DOI: 10.1016/j.plaphe.2025.100070) published in Plant Phenomics on 13 June 2025 by Xiaomei Sun’s team, Chinese Academy of Forestry, underscores the role of canopy architecture in regulating forest carbon dynamics and highlight new approaches for climate-adaptive forest management.

Using high-resolution phenotyping, the team developed a specialized 3D canopy reconstruction algorithm for Larix kaempferi, integrating physiological measurements such as gas exchange, chlorophyll content, and stomatal conductance. The models were validated against measured photosynthetic rates, daytime net canopy photosynthesis, and leaf–branch tilt angles, demonstrating strong accuracy. Microclimate parameters including air temperature, relative humidity, and soil moisture were quantified under thinning (Thn) and control (CK) treatments, while vertical patterns of intercepted photosynthetically active radiation (PAR) and stomatal conductance were mapped across canopy depth. Photosynthetic capacity was further assessed with a canopy productivity model to estimate Pmax and Fv/Fm, corrected for diurnal light inhibition via a suppression factor. Results showed that thinning increased canopy light penetration from 15% to 22% (95% CI: +5% to +8%), leading to an 18% rise in carbon absorption under drought, while rainfall reduction (RP) decreased PAR by 12%, stomatal conductance by 20%, and chlorophyll content by 8%. The combined Thn+RP treatment raised carbon absorption by 25%, though water limitations constrained its long-term benefit. Sensitivity analyses indicated A_leaf had the strongest effect on PAR interception, while R_canopy and K exerted smaller influences. Thinning also raised under-canopy temperature by 1.5 °C, reduced humidity by 6.8%, and increased surface soil moisture by 3.4%. Vertical analyses revealed S-shaped PAR–depth relationships, with Thn improving light penetration into deeper canopy layers, whereas Thn+RP redistributed radiation instead of simply reducing it. Spatial simulations of carbon gain showed thinning generally enhanced canopy productivity, although water scarcity under RP moderated these benefits. The study highlights strong links between canopy structure, chlorophyll, and nitrogen content, demonstrating how 3D phenotyping can capture complex photosynthetic dynamics more effectively than traditional field methods.

The findings carry significant implications for climate-smart forestry. Thinning emerges as an effective strategy to optimize light availability, reduce competition, and enhance forest carbon sequestration, particularly under moderate drought stress. Beyond forestry practice, the study demonstrates how high-throughput phenotyping and digital canopy reconstruction can transform ecosystem modeling. By accurately simulating canopy processes, managers can better predict forest responses to climate extremes and design interventions that balance productivity with resilience. These tools may also inform carbon accounting frameworks, biodiversity conservation, and plantation management strategies worldwide, especially as forests face intensifying pressures from climate change.

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References

DOI

10.1016/j.plaphe.2025.100070

Original URL

https://doi.org/10.1016/j.plaphe.2025.100070

Funding information

This work is supported by the Fundamental Research Funds of CAF (CAFYBB2023QA001), State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100 Shaanxi, P.R. China (F2010121002-202429), The National Key Research and Development Program of China (2023YFD2200801), National Natural Science Foundation of China (General Program) (32371862).

About Plant Phenomics

Plant Phenomics is dedicated to publishing novel research that will advance all aspects of plant phenotyping from the cell to the plant population levels using innovative combinations of sensor systems and data analytics. Plant Phenomics aims also to connect phenomics to other science domains, such as genomics, genetics, physiology, molecular biology, bioinformatics, statistics, mathematics, and computer sciences. Plant Phenomics should thus contribute to advance plant sciences and agriculture/forestry/horticulture by addressing key scientific challenges in the area of plant phenomics.