Environmental control of daily stem radius increment in the montane conifer Cedrus libani

Aylin Güney,Özdemir Şentürk,Manfred Küppers,Serkan Gülsoy,Armin Niessner

doi:10.1007/s11676-019-00983-0

Abstract

Growth response of conifers is species- specific and depends on site and climate conditions. Studies on daily radial stem growth use different analytical approaches to determine species reactions to environmental conditions. These results contribute to improve forecasts of tree growth under a changing climate. During 2013 and 2014, radial stem growth of 33 mature Cedrus libani individuals growing under different climatic conditions in Turkey and Germany was monitored hourly using high precision point dendrometers. Stem radius increments (SRI) were extracted from dendrometer readings. The annual course of SRI showed site-specific patterns with mean daily values ranging between 9.9 and 29.3 µm over the growing season. Correlation and principal component analyses indicated that humidity and low temperatures during the growing season favored SRI. Multiple regression analyses demonstrated that precipitation and relative air humidity were the most important factors influencing daily SRI. Climate-growth relationships were further evaluated using the regression tree method. Precipitation was the most significant factor on daily SRI for all sites. The close coupling of SRI to relative air humidity and precipitation underlines the importance of stem water status for radial stem growth of C. libani which is native to regions with summer drought. It further explains the superior growth of C. libani in Germany.

Highlights

Temperatures and the frequency of drought are expected to increase, especially in semi-arid and arid areas like the Mediterranean region (Stocker 2014)
During 2013 and 2014, radial stem growth of 33 mature Cedrus libani individuals growing under different climatic conditions in Turkey and Germany was monitored hourly using high precision point dendrometers
stem radius increment (SRI) were extracted from dendrometer records for the growing seasons 2013 and 2014 (Fig. 2)

Summary

Introduction

Temperatures and the frequency of drought are expected to increase, especially in semi-arid and arid areas like the Mediterranean region (Stocker 2014). Changing climatic conditions might affect tree growth in a positive or negative way, and influence forest productivity and species distribution (Ciais et al 2005; Deslauriers et al 2007b). Karst, is susceptible to summer droughts and it is widely accepted that, in the near future in Germany, the species ability to fulfill ecological functions will decrease (Kolling et al 2009; Milad et al 2011). It is important to understand how stem growth dynamics (i.e., ring formation), may be affected by environmental conditions and a changing climate (Bouriaud et al 2005; Rathgeber et al 2011). Automatic point or band dendrometers under high resolution are commonly used to measure variations in stem radius (Herzog et al 1995; Deslauriers et al 2007b). Information from dendrometer measurements allows for the investigation of the influence of site conditions and

Methods

Results

Discussion

Conclusion