Climate change impacts and vulnerability of the southern populations of Pinus nigra subsp. salzmannii

Abstract

The understanding of regional vulnerability to climate change in Mediterranean mountain forests is not well developed. Climate change impacts on tree growth should be strongly related to the steep environmental gradients of mountainous areas, where a temperature-induced upward shift of the lower elevation limit is expected, particularly amongst drought-sensitive species. Trees will adapt not only to changes in mean climate variables but also to increased extreme events such as prolonged drought. In this paper, we investigate the sub-regional temperature and precipitation trends and measure the basal area increment (BAI) in Pinus nigra subsp. salzmannii (Dunal) Franco. Significant differences related to altitudinal and latitudinal gradients and stand-age structure were found in response to long-term trends in climate dryness. Old trees growing at higher elevations showed similar extreme drought sensitivity but maintained almost steady BAI. Declining BAI found in trees at lower elevations and drier sites may imply a higher vulnerability to temperature-induced drought stress, suggesting an impending growth decline and an enhanced die-off risk. Our results illustrate how the effects of long-term warming and short-term drought on tree BAI are influenced by both site conditions and mean stand age in a drought-sensitive Mediterranean pine.

Drought-induced growth decline of Aleppo and maritime pine forests in south-eastern Spain.

“…Moreover, mortality and growth decline of several conifers throughout the Iberian Peninsula have been the subject of considerable study and debate (Camarero et al, 2004). In the Iberian Peninsula, relevant episodes of forest decline were detected in response to the 1980s and 1990s droughts, mostly affecting conifer forests in xeric sites from Mediterranean mountains (Lloret and Siscart, 1995;Peñuelas et al, 2001;Camarero et al, 2004;Linares and Tíscar, 2010). These studies focused on natural forests despite recent episodes causing a sharp growth decline and leading to massive defoliation events have been also described in pine afforestations (NavarroCerrillo et al, 2007).…”

“…However, southern pine populations may also show adaptive features to withstand the negative effects of drought on growth and hydraulic conductivity (McDowell et al, 2008). These adaptations should depend not only on the species' resistance or vulnerability to drought but also on local conditions such as soil water holding capacity which may modulate the effects of climatic stressors (Camarero et al, 2004;Macias et al, 2006;Linares and Tíscar, 2010).…”

Drought Influence over Radial Growth of Mexican Conifers Inhabiting Mesic and Xeric Sites

“…Some studies have argued that the radial growth of a tree species growing under xeric habitats is more affected by drought than those from mesic habitats [14]. Conversely, other studies have argued that species from xeric habitats are better adapted to withstand drought stress than species from mesic habitats [15]. This last idea implies that species in areas subjected to marked or prolonged seasonal water deficit (xeric habitats) may be less vulnerable to drought stress in terms of radial growth than species of wetter habitats (mesic habitats).…”

Predicting species dominance shifts across elevation gradients in mountain forests in Greece under a warmer and drier climate

“…Observational evidence of shifts in forest structure and function over the last century has started to accumulate and are frequently attributed to climatic changes. Tree growth changes related to temperature increase (Jump et al 2006;Linares and Tíscar 2010), decline in precipitation (Sarris et al 2011) and/or CO 2 fertilisation (Martínez-Editor: Will Steffen.…”