2024-03-29T09:12:20Zhttps://www.tdx.cat/oai/requestoai:www.tdx.cat:10803/1329912017-09-03T09:40:51Zcom_10803_1col_10803_35851
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Ecologia forestal
Ecología forestal
Forest ecology
Dendroclimatologia
Dendroclimatología
Dendroclimatology
Canvis climàtics
Cambios climáticos
Climatic changes
Boscos
Bosques
Forests
Ecologia de les muntanyes
Ecología de montañas
Mountain ecology
Long-term growth and functioning of high-elevation Pinus uncinata forests and trees inferred through dendroecology = Creixement i funcionament a llarg termini de boscos i individus de Pinus uncinata inferits mitjançant dendroecologia
[Barcelona] :
Universitat de Barcelona,
2014
Accés lliure
http://hdl.handle.net/10803/132991
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Galván Candela, Juan Diego,
autor
1 recurs en línia (278 pàgines)
Tesi realitzada a l'Institut Pirenaic d'Ecologia (CSIC)
Tesi
Doctorat
Universitat de Barcelona. Facultat de Biologia
2014
Universitat de Barcelona. Facultat de Biologia
Tesis i dissertacions electròniques
Camarero Martínez, Jesús Julio,
supervisor acadèmic
Gutiérrez Merino, Emilia,
supervisor acadèmic
TDX
Iberian Pinus uncinata tree-growth variability and its responses to climate are analyzed by means of dendrochonological methods from an individual- to a population-level scale across its distribution area in the Iberian Peninsula. This multiple approach provides new knowledge about the site-tree-climate interactions at an individual scale, and about the species performance at a population scale.
Age-related changes in sapwood area were the main drivers of BAI in mountain P. uncinata forests. Thus, any potential climate-induced effect on BAI will be mainly driven by sapwood production, which is mediated by tree age and altitude. Because slow-growing high-elevation trees get older than fast-growing low-elevation trees, we expect differential age-mediated BAI responses along the altitudinal gradient.
Climate plays a secondary role in controlling TRWi variability among coexisting trees even in these high-elevation environments. Actually, altitude plays a major role affecting P. uncinata TRWi responses to climate at the site and tree scales. This suggests that the altitude-mediated decrease in air temperatures is the major driver of TRWi at both the site and tree levels determining the maximum elevation of the tree growth form.
These results also stress that both (a) a tree-scale approach to quantify growth-index responses to climate and (b) a detailed characterization of the potential drivers of those individual tree responses are requisites for applying an individual-based framework in dendroecology.
Following a population-based approach, a weakness of the theoretically temperature-sensitive TRW proxy to capture recent warming trends is observed. Instead, summer drought is increasingly influencing TRW along the 20th century, which agrees with observations from Iberian mountain forests.
Rising temperatures might have led to an increase in drought stress of Pyrenean and Iberian high-elevation forests as has been observed in other Mediterranean similar ecosystems. We may be attending how a physiological threshold in terms of optimal temperature for growth is surpassed, reinforcing the role of drought as a plausible growth-limiting factor of Iberian high-elevation forests during the last decades.
The intricate topography and diverse climate of the Mediterranean Basin produce varied and often opposite trend signs in dendrochronological proxies like TRW or BAI even between neighbouring sites, during the last decades. In spite of this local complexity, our findings reveal a pattern acting at synoptic scales where tree growth across the Mediterranean Basin is limited by drought or low water availability during the growing season.
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