Testing Aleppo pine seed sources response to climate change by using trial sites reflecting future conditions

Abstract

Large-scale biogeographical shifts in forest tree distributions are predicted in response to the altered precipitation and temperature regimes associated with climate change. Adaptive forest management to climate change experienced in either stable or rapidly changing environments must consider this fact when carrying out reforestation programs or specifically assisted population migration for conservation purposes. The aim of this study was to compare field performance of eleven seed sources of Aleppo pine outplanted in core and marginal habitats and to assess their phenotypic plasticity for further screening under specific conditions in particular reforestation areas. We hypothesize that current marginal habitat due to low temperature is shifting toward conditions found on the core habitat and that current core habitat will shift toward warmer and drier marginal habitat. Our study reproduced real conditions of reforestation in potential future climatic conditions. Results suggest that it is difficult to predict Aleppo pine provenances' performance in different natural sites from their performance at a single location, even though 'Levante interior' and 'La Mancha' seed sources showed the best overall response among sites. On a site basis, provenances were matched in groups according to their survival and growth responses. Seedlings grown from local seed sources or seed orchards performed better on the core habitat. However, as conditions shifted to marginal habitats, seedlings from climatically similar regions performed better than local sources at least in the short term; our findings suggest that new plantations in areas already affected by global change could be better adapted if they use alternative seed sources.