Influence of Climate on Radial Growth of Black Pine on the Mountain Regions of Southwestern Turkey.

Mehmet Doğan,Nesibe Köse

doi:10.3390/plants8080276

Mehmet Doğan, Nesibe Köse

Open Access

https://doi.org/10.3390/plants8080276

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Abstract

In this study, we identified the most important climate factors affecting the radial growth of black pine at different elevations of the mountain regions of Southwestern Turkey (Sandıras Mountain, Muğla/Turkey). We used four black pine tree-ring chronologies, which represent upper and lower distribution limits of black pine forest on the South and North slopes of Sandıras Mountain. The relationships between tree-ring width and climate were identified using response function analysis. We performed hierarchical cluster analysis to classify the response functions into meaningful groups. Black pine trees in the mountain regions of Southwestern Turkey responded positively to a warmer temperature and high precipitation at the beginning of the growing season. As high summer temperatures exacerbated drought, radial growth was affected negatively. Hierarchical cluster analysis made clear that elevation differences, rather than aspect, was the main factor responsible for the formation of the clusters. Due to the mountainous terrain of the study area, the changing climatic conditions (air temperature and precipitation) affected the tree-ring widths differently depending on elevation.

Highlights

Tree-rings have been used to determine the effect of environmental factors on tree growth because year-by-year changes in environmental factors cause variations in tree-ring widths
Response function coefficients related to precipitation were significantly positive only in May for CIU chronology, obtained from the upper limit of black pine forest at north slope of the mountain
The effect of precipitation on AGA chronology, obtained from the lower limit of black pine forest at south slope of the mountain, was positive and significant in May and June, while the effect of mean temperature was significantly positive in February and March, and significantly negative in June

Summary

Introduction

Tree-rings have been used to determine the effect of environmental factors on tree growth because year-by-year changes in environmental factors cause variations in tree-ring widths. The spatial distribution of air temperature and precipitation are geographically highly variable due to the continentality, distance to the sea, altitude and orographic/topographic characteristics [17,18]. For this reason, depending on physical geography properties, especially elevation and aspect in mountainous areas, air temperature and precipitation change within a very short distance, which causes the annual ring growth of trees distributed at different elevations and slopes to be different. Mazza et al [13] analyzed the climate–growth relationships of silver fir along an altitudinal gradient in Central Italy Their results emphasized different growth responses along

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