BUSCADOR RECOLECTA

Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/388312

Droughts impact forests by influencing various processes such as canopy greenness, tree growth, and reproduction, but most studies have only examined a few of these processes. More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics. Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species, many of which exhibit masting. We assessed how greenness, evaluated using the normalized difference vegetation index (NDVI), tree radial growth, and seed or cone production responded to drought in five tree species (three conifers: silver fir (Abies alba), Scots pine (Pinus sylvestris), and stone pine (Pinus pinea); two broadleaves: European beech (Fagus sylvatica) and holm oak (Quercus ilex) inhabiting sites with different aridity. We correlated these data with the standardized precipitation evapotranspiration index (SPEI) using the climate window analysis (climwin) package, which identifies the most relevant climate window. Drought constrained growth more than greenness and seed or cone production. Dry conditions led to high seed or cone production in species found in cool, moist sites (silver fir, beech, and Scots pine). We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine, which showed lagged growth−cone negative correlations. However, in the seasonally dry holm oak forests, severe droughts constrained both growth and acorn production, leading to a positive correlation between these variables. Drought impacts on greenness, growth, seed, and cone production depended on species phenology and site aridity. A negative correlation between growth and reproduction does not necessarily indicate trade-offs, as both may be influenced by similar climatic factors., We thank all the people who helped collect field data on seed or fruit production. This research was funded by the Science and Innovation Ministry of Spain (projects AGL 2012-33465, AGL 2016-76463-P, PID 2021-123675OB-C43, and TED 2021-129770B-C21). ARC acknowledges support by Margarita Salas postdoctoral fellowship (reference RCMS-22-G1T6IW-17-NLHJ80) of the Universidad Politécnica de Madrid. We thank several colleagues for their help during field sampling. The authors gratefully acknowledge the Universidad Politécnica de Madrid (www.upm.es) for providing computing resources on Magerit Supercomputer (www.cesvima.upm.es)., Peer reviewed