Forest temperature buffering in pure and mixed stands: A high-resolution temporal analysis with generalized additive models

• Published in: Forest ecology and management Vol. 583; p. 122582
• Main Authors: Steinparzer, Matthias, Gillerot, Loïc, Rewald, Boris, Godbold, Douglas L., Haluza, Daniela, Guo, Qiwen, Vospernik, Sonja
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2025; Elsevier
• Subjects: Acer platanoides; administrative management; air temperature; Austria; Carpinus betulus; ecosystems; Environmental Sciences; forest ecology; Forest microclimate; forests; GAM; humans; leaf area index; Microclimate modeling; Quercus robur; relative humidity; solar radiation; species; species diversity; summer; Temperature offset; Tilia cordata; Tree diversity; trees; urban forestry; wind speed; winter; Austria; Forest microclimate; Temperature offset; GAM; Microclimate modeling; Tree diversity; modélisation du microclimat; Microclimat forestier; décalage de température; diversité des arbres
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2025.122582

Forests foster buffered microclimates, but causal mechanisms have rarely been studied on longer timescales and in differently diverse stands. Here, we explore temperature regulation by a young experimental forest in Austria, focusing on four common colline broadleaf species (Acer platanoides L., Tilia cordata Mill., Quercus robur L., Carpinus betulus L.) in monocultures, two- and four-species mixed stands. Air temperature was monitored in 28 forest plots for two years and compared to open-field controls. Using generalized additive models (GAMs), we investigated direct temperature offsets and lags between open-field and sub-canopy temperatures, considering diurnal and seasonal changes, and causal factors such as global mean radiation, relative air humidity, wind, and leaf area index (LAI). Forests generally had a cooling effect during the summer and a warming effect in winter, where the cooling magnitude varied with species composition and environmental conditions. Specifically, Acer platanoides and Carpinus betulus demonstrated the highest cooling capacities, and Quercus robur the lowest. Mixed species stands exhibited higher temperature buffering effects relative to monospecific stands, suggesting that species diversity in forests can increase the ability to regulate microclimates. Solar radiation, relative air humidity, wind speed, and LAI all significantly influenced offsets. These findings are crucial for urban forestry and environmental planning, suggesting that careful selection of tree species can optimize temperature regulation, thereby improving human thermal comfort and ecosystem processes alike. •Temporal model predicted –6.0 °C for cooling and + 2.4 °C for warming effects.•Diurnal temperature offsets change in magnitude and direction throughout the year.•Species composition and diversity strongly influence forest temperature buffering.•The causal model predicted maximum cooling of –5.0 °C and + 1.5 °C for warming.•Solar radiation, humidity, wind speed and LAI are significant predictors.