Diverse responses of forest growth to drought time‐scales in theNorthernHemisphere

Abstract

Biosketchs: Sergio M. Vicente-Serrano is a climatologist focused in the development of methods and tools to improve drought quantification and monitoring, and the analysis of hydrological, agricultural and ecological impacts of drought. J. Julio Camarero is a dendroecologist and plant ecologist interested on the analyses of growth and regeneration patterns of woody plants in response to global change. César Azorín-Molina is a climatologist interested in the study of extreme weather events and their impacts. He is expert in atmospheric circulation processes from local to regional scales. 2 AbstractAim: To identify the main spatio-temporal patterns of tree growth responses to drought time-scales at a hemispheric scale using a climate drought index and tree-ring records, and to determine if those patterns are driven by different climate and forest features.Location: Northern hemisphere. Methods:We used a large-scale dendrochronological dataset of tree-ring width series from 1657 sites and a time-dependent drought index which incorporates information on precipitation and temperature variability (SPEI, Standardized Precipitation-Evapotranspiration Index). Correlation analysis was used to quantify how tree growth responds to different drought time-scales. The variety in the correlations was summarized by using a Principal Component Analysis (PCA) and the contribution of the various environmental factors was estimated using predictive discriminant analysis (PDA). Results:The period from the water shortage to the impact on tree growth differs noticeably among forest types and tree families. There is a gradient in the growth responses to droughts including: (i)forests not responding at all to drought such as those located in cold and very humid areas; (ii)forests located in semi-arid areas characterised by responses to long-term droughts; (iii) forests responding to mid-to long-term droughts subjected to sub-humid conditions; and (iv) forests dominating humid sites which respond to short-term droughts. Main conclusion:Forests located under semi-arid and sub-humid conditions tend to respond to longer time-scales than those located in more humid areas. The characteristic time-scale at which forest growth mainly responds to drought is a proxy of drought vulnerability, reflecting the tree resistance to cope with water deficits of different duration and severity.

How do climate and topography influence the greening of the forest‐tundra ecotone in northern Québec? A dendrochronological analysis ofBetula glandulosa

“…; Martin‐Benito, Beeckman & Canellas ; Mendivelso et al . ; Vicente‐Serrano, Camarero & Azorin‐Molina ; data downloaded from the Global SPEI data base: http://sac.csic.es/spei/database.html). Based on the climate data of the Climatic Research Unit of the University of East Anglia, the SPEI is calculated as the monthly difference between precipitation and potential evapotranspiration (see Vicente‐Serrano, Begueria & Lopez‐Moreno for more details) and has a spatial resolution of 0.5° of latitude and longitude.…”

Drought Variability and Land Degradation in Semiarid Regions: Assessment Using Remote Sensing Data and Drought Indices (1982–2011)

“…Thus, Stephenson [96] showed that the evapotranspiration deficit is a better metric than precipitation for explaining the current distribution of vegetation communities at the global scale. Moreover, the SPEI is computed on different time scales, enabling identification of the most suitable time scale to detect the varied response times of vegetation communities to water deficits [30,97]. This approach is undoubtedly preferable to identifying drought impacts on vegetation activity and growth based on annual precipitation, and has usually been used in studies analyzing the influence of climate on the NDVI in semiarid regions [98][99][100].…”

Análisis comparativo de índices de sequía en Andalucía para el periodo 1901-2012

“…Los valores que toma el SPEI para la determinación de episodios secos son los mismos que el SPI (Tabla 1). Este índice ha sido ampliamente aceptado y utilizado en estudios de sequía a muy diversas escalas (Vicente-Serrano et al, 2014a;Manatsa et al, 2015;Naumann et al, 2015;Blauhut et al, 2015;Stagge et al, 2015aStagge et al, , 2015bDas et al, 2016;Rhee and Cho, 2016;Yang et al, 2016).…”