F. Hatami, Research Expert of Forest Research Division
Research Institute of Forests and Rangelands
The destruction of a significant area of Zagros forests of Iran has mainly been due to climate change, the spread of pests and diseases, and excessive utilization, leading to drying of trees and oak decline, particularly affecting the Brent’s oak species (Quercus brantii Lindl.). Numerous studies, both within Iran and internationally, have investigated oak decline, yielding valuable insights into this phenomenon. However, there has been a notable absence of dendrochronological research, which is crucial for understanding the temporal trends in changes affecting tree species.
Trees can record historical events in their growth rings, enabling the study of tree ring growth, also known as tree chronology, to investigate trends over time. In examining the decline of Brent’s oak, having access to climatic data from the region, along with a history of natural events such as pest outbreaks, diseases, fires, and other incidents, can enhance the accuracy and certainty in identifying the key factors contributing to this crisis.
To address the increasing decline of Brent’s oak in the central and southern Zagros forests, a research project was initiated to conduct dendrochronological studies in Chaharmahal and Bakhtiari province, focusing on the oak decline in this province (Figure 1). The objective of this research is to determine the onset of oak decline, examine the growth patterns of Brent’s oak, and evaluate the sensitivity of both declined and healthy trees. Ultimately, the study aims to identify the factors contributing to decline, with a particular emphasize on the role of climate. Following preliminary analyses and field surveys, sample trees were selected and cores were collected for dendrochronological analysis. The findings, which will be published in the future, are expected to enhance our understanding of oak decline and provide valuable chronological and climatic data for the forests of Chaharmahal and Bakhtiari provinces.
Figure 1. Oak forests affected by the phenomenon of oak decline in Lordegan city, Chaharmahal and Bakhtiari province
(photo by F. Hatami, spring 2024)
