Elevation versus species effects in climate-growth relations in the Central Italian Alps
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To estimate the effects of a warmer and drier future climate on mountain forests, we analyzed the climate response of radial growth of five different conifer species along elevation transects between 1070 m and the forest line near 2400 m above sea level within an inner-alpine dry valley in the LTSER area Matsch|Mazia in Northern Italy. For additional information in growth processes and tree hydraulics automatic dendrometer measurements were used. As expected, we generally observed positive growth responses to temperature near the forest line and to precipitation at low elevation. However, water availability and extremely dry years surprisingly affected growth of Larix decidua and Picea abies up to 1800 m. On the other hand, Pinus nigra and Pinus sylvestris did not show a significant precipitation response at the lowest site, where their growth rate was constantly low. Near the forest line Pinus cembra benefited less from warming in the last 40 years than L. decidua, dendrometer measurements revealed that its growth was strictly limited by vapor pressure deficit. Overall, site elevation determined tree growth patterns, but within the same elevation species-specific differences were found, especially between L. decidua and the pine species, with P. abies in-between. Our results should contribute to a sustainable adaption of mountain forest management in the Alps to future climate conditions.