Response of Pinus sylvestris L. to recent climatic events in the French Mediterranean region

Abstract

Exceptional climatic events from 2003 to 2005 (scorching heat and drought) affected the whole of the vegetation in the French Mediterranean region and in particular the Scots pine (Pinus sylvestris L.), one of the most important forest tree species in this area. To understand its response to these extreme conditions, we investigated its radial growth, branch length growth, architectural development and reproduction for the period 1995-2005, and linked these variables to climatic parameters. We used four plots situated in southeastern France and presenting different levels of site quality and potential forest productivity. The results show that: (1) the climatic episode 2003-2005 was highly detrimental to the growth (bole and branches), crown development, and cone production but favored the production of male flowers; (2) these variables depend on climatic factors of both the current and previous years; (3) the 2003 scorching heat impact was strong but was mainly apparent from 2004; it was part of a 6-year-long unfavorable cycle beginning in 2000, characterized by high minimum and maximum temperatures and very dry springs; (4) in spite of a significant effect of site quality, the Scots pine's response to extreme climatic conditions was homogeneous in the French Mediterranean area; and (5) the stress induced by poor site conditions generally resulted in the same consequences for tree growth, architecture, and reproduction as in unfavorable climatic conditions.

Fingerprints of extreme climate events in Pinus sylvestris tree rings from Bulgaria

“…In contrast, in years when precipitation was abnormally low and temperatures were higher than usual, most trees formed narrow rings. Our findings are in line with recent detailed intra-annual studies of P. sylvestris tree-ring formation Oberhuber and Gruber 2010;Eilmann et al 2011), which confirmed previous conclusions (Antonova et al 1995;Rigling et al 2001; Eilmann et al Thabeet et al 2009) that drought stress hinders cell production in P. sylvestris and thus may have profound effects on tree-ring width. The effect of moisture deficiency on tree-ring width in our study sites was most pronounced during several known drought periods-namely in 1917-1919, 1945-1948 and 1984-1994.…”

“…Water shortage and stress are known to strongly influence cell metabolism and division and thus have an impact on tree-ring formation (Whitmore and Zahner 1967;Antonova et al 1995). In analogy with studies of tree-ring formation in coniferous species at sites with similar ecological conditions, we expect that latewood cell production at our sites starts in July, and cell wall thickening and lignification continues into October (Gindl et al 2001;Camarero et al 1998;Rigling et al 2001;Eilmann et al 2011), but may be terminated earlier due to dry conditions (Thabeet et al 2009;Gruber et al 2010;Eilmann et al 2011). Thus, droughts in July and August may considerably influence the stages of latewood cell production and development.…”

Climate Change Impact on Tree Architectural Development and Leaf Area

“…Recent studies on tree architectural development and primary growth suggested that the long lasting impact of repeated droughts on tree crown development could be one of the causes of these delayed effects [12][13][14].…”

An improved species distribution model for Scots pine and downy oak under future climate change in the NW Italian Alps

“…The aims of this work were (1) to detect drivers of current pine and oak occurrence in a mountain region of the southwestern Alps, by fitting species distribution models (SDM) on climate, soil, land use, stand structure, and disturbance-related predictors; (2) to apply the models using future (2080) scenarios, in order to assess if and where vegetation shifts are likely to occur under climate and management changes; and (3) to compare the effects of the Europe-wide drought events of (Thabeet et al 2010 on Scots pine vitality against SDM predictions in 2080, in order to assess the potential role of extreme drought response as an early warning of future vegetation changes.…”