Phenology of Photosynthesis in Winter‐Dormant Temperate and Boreal Forests: Long‐Term Observations From Flux Towers and Quantitative Evaluation of Phenology Models

作者：D. R. Bowling, Christina Schädel, Kenneth R. Smith, Andrew D. Richardson, Michael Bahn, M. Altaf Arain, Andrej Varlagin, Andrew P. Ouimette, J. M. Frank, Alan Barr, Ivan Mammarella, Ladislav Šigut, Vanessa N. Foord, Sean P. Burns, Leonardo Montagnani, M. E. Litvak, J. William Munger, Hiroki Ikawa, David Y. Hollinger, Peter D. Blanken, Masahito Ueyama, Gioṙgio Matteucci, Christian Bernhofer, Gil Bohrer, Hiroki Iwata, Andreas Ibrom, Kim Pilegaard, David L. Spittlehouse, Hideki Kobayashi, Ankur R. Desai, Ralf M. Staebler, T. Andrew Black · 发表于：Journal of Geophysical Research Biogeosciences · 年份：2024 · DOI：10.1029/2023jg007839 · 被引用次数：27 · 研究领域：Plant Water Relations and Carbon Dynamics、Plant responses to elevated CO2、Remote Sensing in Agriculture

Abstract We examined the seasonality of photosynthesis in 46 evergreen needleleaf (evergreen needleleaf forests (ENF)) and deciduous broadleaf (deciduous broadleaf forests (DBF)) forests across North America and Eurasia. We quantified the onset and end (Start GPP and End GPP ) of photosynthesis in spring and autumn based on the response of net ecosystem exchange of CO 2 to sunlight. To test the hypothesis that snowmelt is required for photosynthesis to begin, these were compared with end of snowmelt derived from soil temperature. ENF forests achieved 10% of summer photosynthetic capacity ∼3 weeks before end of snowmelt, while DBF forests achieved that capacity ∼4 weeks afterward. DBF forests increased photosynthetic capacity in spring faster (1.95% d −1 ) than ENF (1.10% d −1 ), and their active season length (End GPP –Start GPP ) was ∼50 days shorter. We hypothesized that warming has influenced timing of the photosynthesis season. We found minimal evidence for long‐term change in Start GPP , End GPP , or air temperature, but their interannual anomalies were significantly correlated. Warmer weather was associated with earlier Start GPP (1.3–2.5 days °C −1 ) or later End GPP (1.5–1.8 days °C −1 , depending on forest type and month). Finally, we tested whether existing phenological models could predict Start GPP and End GPP . For ENF forests, air temperature‐ and daylength‐based models provided best predictions for Start GPP , while a chilling‐degree‐day model was best for End ...