1- Master’s degree in Forestry, Faculty of Desertology, Semnan University, Semnan, Iran.
2- Faculty of Natural Resources, Semnan University, Semnan, Iran , mojtabaamiri@semnan.ac.ir
3- Faculty of Natural Resources, Semnan University, Semnan, Iran.
4- Forest Research Division, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran.
Abstract: (687 Views)
Aims: In this study, the response of individual trees and the stand structure to windstorm damage were investigated in a mixed broad-leaf forest stands located in Darabkola Forest, Sari, northern Iran. A field survey was conducted over an area of 2612 ha of the given stands.
Material & Methods: A full inventory was performed for all trees with diameter at breast height≥ 10cm and all damaged (i.e., snapped, snags, branch loss, broken trunk or uprooted) trees were identified within the study area. Tree height was measured using Laser Distance Meter for trees more than 10 m high and a Clinometer for all trees <10m. The percentage of trees damaged was the dependent variable; but, independent variables included number, mean height (m), total basal area (m2) and volume trees (m3). Independent t-test was performed to compare the mean of trees based on diameter classes. Also, the affection of height on susceptibility to windstorm effects was tested by comparing mean trees height within each class.
Findings: The number of the damaged trees varied with species, ranging from 0.04 % (2 individuals) in Tilia begonifolia Stev to 53.7 % (2709 individuals) in Fagus orientalis L. Among the damaged trees 5054 recorded, 2231 (44.20 %) had been snapped and 787 (15.6 %) uprooted, and 2028 (40.20 %) were snags. Among the species, Fagus orientalis L. (47.7 %), Alnus subcordata C. A. Mey. (19.7 %) and Carpinus betulus L. (18.8 %) were most susceptible to uprooting, whereas Populus caspica Bornm, Quercus castaneifolia C. A. Mey. and Ulmus glabra Huds. were the least susceptible to uprooting. The species differed significantly in their susceptibility to snapping. Trees ≥60cm dbh were more likely to be snapped (78 %) or snags (69 %), whereas trees <60 cm dbh were more presumably to be uprooted (50 %). Also, about one third (33 %) of total trees larger than 60 cm (D.B.H) have showed distinct effects and individual trees >20 m were more commonly uprooted. The number of snapped trees, snags and uprooted trees had a sharp increase in trees taller than 20m.
Conclusion: Our finding showed that Oriental beech and Common hornbeam to be species that were most susceptible to both being snapped and snagged, whereas Caucasian alder had the most uprooting damage among the other species. Overall, features like species, D.B.H, height and height to diameter ratio (H/D.B.H), were intensively related with the type and severity of windstorm damage. The findings showed that windstorms cause substantial structural effects in mixed stands of beech and hornbeam.
Article Type:
Original Research |
Subject:
Forest Ecology and Management Received: 2023/04/20 | Accepted: 2023/07/4 | Published: 2023/09/19
* Corresponding Author Address: Faculty of Natural Resources, Semnan University, Semnan, Iran |