Abstract
Vegetation phenology, i.e., seasonal biological events such as leaf-out and leaf-fall, regulates local climate through biophysical processes like evapotranspiration (ET) and albedo. However, the net surface temperature impact of these processes—whether ET cooling or albedo-induced warming predominates—and how the dominance changes across phenological transitions and regions remains poorly understood. Here, we investigated the effects of vegetation foliage on daytime land surface temperature (LST) following six phenological transitions, spanning from the start of season to end of season, in deciduous and mixed forests across the mid- to high-latitude Northern Hemisphere during 2013–2021 using multiple satellite products and ground observations. We quantified vegetation effect as the difference between observed LST and LST estimates from the Annual Temperature Cycle (ATC) model, representing a no-foliage scenario. We found that vegetation-induced cooling consistently outweighs warming following all phenological transitions except for the end of the season. Cooling intensity increased with vegetation greenness, ranging from 1.0 ± 0.5 °C (mean ± 0.15 SD) in 59% of forests after the start of the season (SOS) to 6.1 ± 0.8 °C in 89% of forests following the onset of maturity, before declining toward the end of the season. Over half of the regions experiencing cooling showed intensification of surface cooling with climate warming, suggesting an amplified vegetation-mediated cooling under future climate change. The findings provide a more precise understanding of the role of vegetation in modulating climate at the intraseasonal scale, highlighting the importance of integrating phenological impacts into climate adaptation strategies and Earth system modeling.
| Original language | English |
|---|---|
| Article number | e2501844122 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 122 |
| Issue number | 37 |
| DOIs | |
| State | Published - Sep 16 2025 |
Funding
Y.L. and A.W. are funded by the State Key Laboratory of Forest Ecology and Conservation, the National Key Research and Development Program (2022YFF1300501) on forest ecological product supply in Northeast China (2022–2026), and the Liaoning Province Science and Technology Attack Special Project (2023JH1/10400001) on desertification management at the southern edge of the Horqin Sandy Land (2023–2026). A.D.R. acknowledges support from NSF awards 1832210 and 2224545, A.M. funding by the Bavarian State Ministry of Science and the Arts (bayklif project). J.M is supported by the Oak Ridge National Laboratory (ORNL) Reducing Uncertainties in Biogeochemical Interactions through Synthesis and Computing Scientific Focus Area project and the Terrestrial Ecosystem Science Scientific Focus Area project funded through the Earth and Environmental Systems Sciences Division of the Biological and Environmental Research Office in the Department of Energy Office of Science. ORNL is supported by the DOE Office of Science under Contract No. DE-AC05-00OR22725. J.D. is supported by NSF NRT fellowship (award 1829075) and NASA FINESST fellowship (award 80NSSC23K0138). Ground phenology data used in this study was provided by the PhenoCam Network, which has been supported by the NSF, the Long-Term Agroecosystem Research (LTAR) network which is supported by the United States Department of Agriculture (USDA), the U.S. Department of Energy, the U.S. Geological Survey, the Northeastern States Research Cooperative, and the USA National Phenology Network. We thank the PhenoCam Network collaborators, including site PIs and technicians, for publicly sharing the data that were used in this paper. We acknowledge the AmeriFlux sites for their data records. Funding for AmeriFlux data resources was provided by the U.S. Department of Energy’s Office of Science. site PIs and technicians, for publicly sharing the data that were used in this paper. We acknowledge the AmeriFlux sites for their data records. Funding for AmeriFlux data resources was provided by the U.S. Department of Energy’s Office of Science. Bavarian State Ministry of Science and the Arts (bayklif project). J.M is supported by the Oak Ridge National Laboratory (ORNL) Reducing Uncertainties in Biogeochemical Interactions through Synthesis and Computing Scientific Focus Area project and the Terrestrial Ecosystem Science Scientific Focus Area project funded through the Earth and Environmental Systems Sciences Division of the Biological and Environmental Research Office in the Department of Energy Office of Science. ORNL is supported by the DOE Office of Science under Contract No. DE-AC05-00OR22725. J.D. is supported by NSF NRT fellowship (award 1829075) and NASA FINESST fellowship (award 80NSSC23K0138). Ground phenology data used in this study was provided by the PhenoCam Network, which has been supported by the NSF, the Long-Term Agroecosystem Research (LTAR) network which is supported by the United States Department of Agriculture (USDA), the U.S. Department of Energy, the U.S. Geological Survey, the Northeastern States Research Cooperative, and the USA National Phenology Network. We thank the PhenoCam Network collaborators, including ACKNOWLEDGMENTS. Y.L. and A.W. are funded by the State Key Laboratory of Forest Ecology and Conservation, the National Key Research and Development Program (2022YFF1300501) on forest ecological product supply in Northeast China (2022–2026), and the Liaoning Province Science and Technology Attack Special Project (2023JH1/10400001) on desertification management at the southern edge of the Horqin Sandy Land (2023–2026). A.D.R. acknowledges support from NSF awards 1832210 and 2224545, A.M. funding by the
Keywords
- albedo
- climate feedback
- evapotranspiration
- vegetation phenology