Intra- and Inter-Annual Growth Patterns of a Mixed Pine-Oak Forest under Mediterranean Climate

Elisabet Martínez-Sancho,Cristina Valeriano,Margarita I Popkova,Emilia Gutiérrez,Isabel Dorado-Liñán,Vladimir V Shishov,Montse Ribas

doi:10.3390/f12121746

Abstract

Temperature and precipitation variability throughout the year control the intra-annual dynamics of tree-ring formation. Physiological adaptation of trees to climate change is among the key issues to better understand and predict future forest performance and composition. In this study, we investigated the species’ coexistence and performance of Scots pine and pubescent oak growing in a mixed sub-Mediterranean forest in the northeast of the Iberian Peninsula. We assessed intra-annual cumulative growth patterns derived from band dendrometers during four consecutive growing seasons and long-term changes in basal area increment for the period 1950–2014. Our results revealed that Scots pine followed an intra-annual bimodal growth pattern. Scots pine growth was mainly limited by water availability at intra-annual, interannual and decadal time scales, which resulted in a negative long-term growth trend. Conversely, oak displayed a unimodal growth pattern, which was less climatically constrained. A significant increase in basal area of oak denotes an overall better potential acclimation to prevailing climatic conditions at the expenses of a higher risk of physiological failure during extreme climate events.

Highlights

Climate change is altering forest ecosystems at various time and spatial scales, modifying their composition, structure and functioning [1]
We evaluated the phenology of secondary growth during four consecutive growing periods and assess the intra-annual and inter-annual growth dynamics and climatic drivers
Our objectives were (1) to assess the phenological differences in annual treegirth dynamics between both species, (2) to identify the specific-species intra-annual growth patterns aiming at providing insights of differential use of resources, (3) to characterise long-term growth trends as a proxy of tree performance, and (4) to identify growth climatic drivers at intra- and inter-annual level

Summary

Introduction

Climate change is altering forest ecosystems at various time and spatial scales, modifying their composition, structure and functioning [1]. Drought is one of the most hazardous consequences of climate change in Mediterranean ecosystems, since water availability is already scarce, during summer [4]. This situation could be further aggravated during the 21st century since projected changes in climate point to a mean temperature increase coupled to larger precipitation variability as well as more frequent, persistent climate extreme events in the area [5,6]. Drought-induced tree mortality is expected to occur more frequently in the Mediterranean region, as has been previously reported [7,8,9]. Vegetation shifts may occur in both latitudinal and altitudinal transitions between Mediterranean and temperate climate zones [10,11,12,13]

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Conclusion