Relationships Between Climatic Variables and Tree-Ring Width of Silver Fir (Abies alba Mill.) in Kozara National Park (Bosnia and Herzegovina)

Jelena Subotić,Goran Trbić,Tatjana Popov,Zoran Maunaga,Vojislav Dukić,Danijela Petrović

doi:10.15177/seefor.20-05

Abstract

Silver fir (Abies alba Mill.) is the most common conifer species in Bosnia and Herzegovina. The paper describes the development of a silver fir master tree-ring chronology from Kozara National Park and analyzes the influence of the climate conditions on tree-ring widths. The knowledge concerning the effect of climate on cambium activity and, as a result, on tree growth is of great importance for silviculture, which is particularly complex in terms of deterioration of health condition. Four sites were selected for sampling at Kozara National Park. At each sampling site, 15 dominant trees were drilled with Pressler’s increment borer at breast height. The development of chronology included three steps: i) cross-dating of a series of tree-ring width and checking of their quality using the COFECHA program, ii) data standardization in the ARSTAN program, and iii) master chronology development. Correlation analysis was performed in order to determine the links between tree-ring width and climate (primarily temperature and precipitation). In the 88-year-long master chronology, pointer years analysis identified five positive and nine negative years. Correlation analysis revealed that precipitation had stronger and more significant impact on silver fir radial growth, particularly at the beginning of the growing season, in April and May (r=0.175 and r=0.318, respectively), and in the crucial July−September period (r in the range of 0.143−0.222). The highest negative correlation coefficient with temperature was determined for September of the previous year (r=-0.282) and then for summer months (July and August) of the current year (r=-0.184 and r=-0.272, respectively). In addition, statistically significant correlation between radial growth and the Forestry Aridity Index was determined (r=-0.390). The results of tree-ring width climate analysis obtained in this study are in accordance with other studies carried out in Bosnia and Herzegovina and in the surrounding area.

Highlights

Silver fir (Abies alba Mill.) grows naturally in central and southern Europe
Study Area The study area covers the area of Kozara National Park, which encompasses the central part of the eponymous mountain, located in the north-western part of Bosnia and Herzegovina (Figure 1)
Based on core samples extracted from 58 trees at four sites in the broader Mrakovica area, the first silver fir master chronology for this area was built

Summary

Introduction

In Bosnia and Herzegovina, fir is found in mixed beech and fir forests, beech, fir and spruce forests and very rarely in pure fir forests. The most significant forests in Bosnia and Herzegovina are the community of beech-fir (Abieti fagetum) forests (Stefanović 1977, Stefanović et al 1983, Beus 1984). According to the National Forest Inventory, silver fir is the most common conifer species in Bosnia and Herzegovina. Beech and fir (with spruce) forests, i.e. forests with fir (pure and mixed), cover 599,000 ha or 28% of the total forest area (high and coppice forests). The highest stock of wood and the highest increment for high forests in Bosnia and Herzegovina were determined in these forests with fir (Čabaravdić et al 2016)

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