Analyzing the heterogeneity of the stand structure in the understory initiation developmental phase in the Hyrcanian forests

Document Type : Research Paper

Authors

1 Department of Forest Science and Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Iran.

2 Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Iran.

10.22059/jfwp.2024.371286.1280

Abstract

Investigating forest structure is an important and necessary topic, especially in line with the goals of close-to-nature silviculture. This research aimed to quantitatively analyze the complexity of stand structure during the transformational phase of understory formation in the oriental beech (Fagus orientalis Lipsky) forests of Kheyrud, Nowshahr. After field inspections, three one-hectare sample plots in the transformational phase of understory formation were selected, and a full inventory of all stand parameters, including tree diameter at breast height, natural regeneration, size and distribution of gaps, and deadwood, was carried out. To analyze the structural complexity in forest stands, the structure complexity indices, Cox coefficient, coefficient of variation, and Gini coefficient of tree diameter were used. According to the research results, in this evolutionary phase, the highest frequency is in small diameter classes, while the lowest frequency is in large trees. The distribution curve of trees forms a decreasing exponential with a steep slope in small diameter classes. The average deadwood volume was 30 m³, and the average gap factor of crown coverage was 6.4%. Additionally, the mean Gini coefficient and diameter change coefficient were 0.7 and 6, respectively. These values, along with the Cox coefficient, indicate optimal complexity in the stand structure during this phase. In the understory, the average abundance was 306 stems per hectare, with beech being the most abundant species. Based on these results, to maintain heterogeneity in the managed forests while preserving large trees in the stand, it is suggested to implement operations to increase the complexity of the forest stand structure and perform thinning from below.

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Main Subjects


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