Climate Change Projections for Bioclimatic Distribution of Castanea sativa in Portugal

The chestnut tree is an important forestry species worldwide, as well a valuable food resource. Over recent years, Portugal has shown increasing trend in area, increases production, hinting at the socioeconomic relevance of this agro-forestry species. In study, bioclimatic indices are applied to analyse spatial distribution trees mainland Portugal, namely growing degree days (GDD; 1900–2400 °C), annual mean temperature (AMT; 8–15 summer with maximum below 32 °C (NTX), and precipitation (PRE; 600–1600 mm). These assessed for baseline (IBERIA01, 1989–2005) future climates (EURO-CORDEX: 2021–2040, 2041–2060, 2061–2080) under two forcing pathways (RCP4.5 RCP8.5), also taking into account land cover. For baseline, GDD showed only 10% suitability cultivation southern whereas much higher values found north country, altitudes (50–90%). AMT, elevation areas northern show almost 100% suitability. Concerning NTX, reduces from west (100–90%) east (40%). Regarding PRE, heterogeneous throughout territory, 50%. A new Chestnut Suitability Index (CSI) was then computed, which incorporates information four previous indices. CSI reveals ranging 100 75% north, while central 25 climates, progressive reduction found, particularly RCP8.5 long-term period. Changes conditions may restrict narrow area country. reductions have socio-economic ecological implications management