Sapwood Area Related to Tree Size, Tree Age, and Leaf Area Index in Cedrus libani

Aylin Güney

doi:10.30516/bilgesci.389609

Abstract

Sapwood includes the water conducting part of the stem which transports water and minerals from roots to leaves. Studies using sap flow gauges have to determine the area of the sapwood in order to scale measured sap flow densities to the tree or stand level. The aim of this study was to investigate the relationship between sapwood area at breast height and other tree parameters which are easy to measure of the montane Mediterranean conifer Cedrus libani, including a total number of 92 study trees of different size and age. The study was conducted at four different stands situated between 1000 and 2000 m altitude in the Elmalı Cedar Research Forest of Antalya, SW-Turkey. Sapwood area of the sample trees was determined by extracting two tree cores from opposite directions of the stem using an increment borer and by visually assessing the wet part of the core. Parameters measured besides sapwood area were diameter at breast height, stem radius without bark, sapwood depth, tree basal area, tree height, tree age, and projected crown area. Furthermore, at each stand, leaf area index (LAI) was determined using hemispherical photographs of the forest canopy. The most significant relationship was found between stem radius without bark and sapwood area (R2: 0.94) followed by tree basal area and sapwood area (R2: 0.90). Although it was the second best predictor, tree basal area should be used to estimate sapwood area when estimating stand transpiration since it can be measured faster and without giving damage to the tree. Mean sapwood area and mean site-specific LAI showed a significant positive correlation. The findings of this study can be used in ecophysiological studies when transpiration rates of C. libani are measured using sap flow gauges.

Highlights

Sapwood is the living and water conducting portion of the stem which transports water and minerals from roots to leaves, and where to a lesser extent energy reserves are stored (Matyssek et al, 2010)
Sapwood area was positively related to Tree basal area (TBA) and diameter at breast height (DBH) using non-linear and linear regression, respectively (Figure 1)
Regarding the values obtained from all study trees, TBA was the best predictor for sapwood area explaining 90% of the variation

Summary

Introduction

Sapwood is the living and water conducting portion of the stem which transports water and minerals from roots to leaves, and where to a lesser extent energy reserves are stored (Matyssek et al, 2010). In the industrial context (e.g. lumber production), it is important to know about physical and technological properties of the sapwood because they differ from those of the heartwood (Longuetaud et al, 2006). In ecophysiological studies sapwood is an important parameter when measuring sap flow rates and transpiration of single trees or whole stands (Gebauer et al, 2008; Motzer et al, 2005; Phillips et al, 1996; Wullschleger et al, 2004). The amount of sapwood area to leaf area (or leaf biomass) is an indicator about the water conducting capacity of the sapwood in relation to transpiration demand, and about the photosynthetic production relative to respiratory costs (Longuetaud et al, 2006; Mäkelä et al, 1995; Rodriguez‐ Calcerrada et al, 2015). Bilge International Journal of Science and Technology Research, 2 (1): 83-91

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