ForestTemp - Sub-canopy microclimate temperatures of European forests

Ecological research heavily relies on coarse-gridded climate data based on standardised temperature measurements recorded at 2 m height in free-air. However, many organisms experience environmental conditions that differ substantially from those captured by these macroclimatic temperature grids. In forests the tree canopy functions as a thermal insulator, affecting biological and ecological processes. To improve the assessment of climatic conditions and climate change-related impacts on forest biodiversity and functioning, temperature grids reflecting forest microclimates are thus urgently needed. Combining more than 1,200 time series of in situ near-surface forest temperatures with topographical, biological and macroclimatic variables in a machine learning model, we predicted the mean monthly offset between sub-canopy temperature at 15 cm above the surface and free-air temperature over the period 2000-2020 at a spatial resolution of 25 m across Europe. This offset was used to evaluate the difference between micro- and macroclimate across space and seasons and finally enabled us to calculate mean annual and monthly temperatures for European forest understories. We found that sub-canopy air temperatures differ substantially from free-air temperatures, being on average 2.1°C (standard deviation ± 1.6°C) lower in summer and 2.0°C higher (± 0.7°C) in winter across Europe. The provided forest sub-canopy temperature maps will enable future research to more accurately model below-canopy biology and species distributions.

HAESEN Stef;  LEMBRECHTS Jonas;  DE FRENNE Pieter;  LENOIR Jonathan;  AALTO Juha;  ASHCROFT Michael B.;  KOPECKY Martin;  LUOTO Miska;  MACLEAN Ilya;  NIJS Ivan;  NIITTYNEN Pekka;  VAN DEN HOOGEN Johan;  ARRIGA Nicola;  BRUNA Josef;  BUCHMANN Nina;  CILIAK Marek;  COLLALTI Alessio;  DE LOMBAERDE Emiel;  DESCOMBES Patrice;  GHARUN Mana;  GODED BALLARIN Ignacio;  GOVAERT Sanne;  GREISER Caroline;  GRELLE Achim;  GRUENING Carsten;  HEDEROVA Lucia;  HYLANDER Kristoffer;  KREYLING Jurgen;  KRUIJT B.;  MACEK Martin;  MALIS Frantisek;  MAN Matej;  MANCA Giovanni;  MATULA Radim;  MEEUSSEN Camille;  MERINERO Sonia;  MINERBI Stefano;  MONTAGNANI Leonardo;  MUFFLER Lena;  OGAYA Romà;  PENUELAS J.;  PLICHTA Roman;  PORTILLO ESTRADA Miguel;  SCHMEDDES Jonas;  SHEKHAR Ankit;  SPICHER Fabien;  UJHÁZYOVÁ Mariana;  VANGANSBEKE Pieter;  WEIGEL Robert;  WILD Jan;  ZELLWEGER Florian;  VAN MEERBEEK Koenraad; 

2022-04-11

WILEY

JRC123998

1354-1013 (online),   

https://onlinelibrary.wiley.com/doi/10.1111/gcb.15892,    https://publications.jrc.ec.europa.eu/repository/handle/JRC123998,   

10.1111/gcb.15892,