Babak Pilehvar, Zahra Mirazadi, Vahid Alijani, Hamzeh Jafari Sarabi,
Volume 1, Issue 2 (3-2015)
Abstract
Considering the importance of forest structure and interaction among different tree species, this study conducted aimed to determine and compare spatial pattern, heterogeneity, and dimensions of Hawthorn and Maple trees with other neighbor trees. For determining Hawthorn and Maple trees structure, 30 individual of each trees were identified and studied. Based on the results, uniform angle index for Hawthorn and Maple trees were 0/744, and 0/733 respectively, which would propose a clumped pattern for these two species. Computed mingling index values for Hawthorn and Maple were 0/877 and 0/955 respectively that show a high tree species mixture. Also, the average of crown canopy differentiation and crown canopy dimension were 0/582 and 0/322 respectively, for Hawthorn tee and it was 0/42 and 0/656 respectively for Maple tree. Based on mean values, these results show that Hawthorn had high level of differentiation but was inferior in comparing to its neighbors whereas Maple has intermediate differentiation and is dominant to the other neighbors. The average distance to nearest neighbors for Hawthorn and Maple were calculated 7/374 and 6/278 respectively. The results of an absolute discrepancy algorithm (AD) showed a high differentiation of Hawthorn and Maple mixture in comparing to the other indices. It is concluded that maple is superior to hawthorn in dimension and because of low frequency of these two species, they hold high values of mingling indices.
Hashem Habashi, Ali Shahrdami, Ramin Rahmani, Fatemeh Rafiee Jazi,
Volume 4, Issue 2 (9-2025)
Abstract
Background and objectives: The Hyrcanian forests play a crucial role in carbon storage, soil and water conservation, and climate change mitigation. Previous studies on the silvicultural management of these forests have mainly focused on estimating stand volume and structural characteristics, while the impacts of different management regimes—particularly the shelterwood system—on aboveground biomass, as a key indicator of carbon sequestration, remain unclear. The main objective of this study was to quantify and analyze the effects of shelterwood management treatments on tree quantitative characteristics and aboveground biomass in the beech (Fagus orientalis Lipsky) forests of Kelardasht, northern Iran.
Materials and methods: The research was conducted in Compartment 5 of the Kelardasht forest management plan. Five management treatments were selected: control, shelterwood, partial shelterwood, shelterwood with improvement cutting, and unmanaged (outside the management plan). In each treatment, five 0.5-hectare plots were randomly established. Diameter at breast height (DBH), total height, and stem height were measured, and tree volume was calculated. Aboveground biomass was estimated using tree volume, wood specific gravity, and FAO expansion factors. Data were analyzed using one-way ANOVA and independent t-tests.
Results: Mean DBH and total height were significantly higher in unmanaged treatments (control and outside the management plan) than in managed ones. The control treatment had the highest aboveground biomass (613.58 t ha⁻¹), whereas the complete shelterwood treatment had the lowest (272.56 t ha⁻¹), representing a 56% reduction compared to the control. The partial shelterwood and shelterwood with improvement cutting treatments had mean values of 417.13 and 273.61 t ha⁻¹, respectively. These patterns were consistent with structural indices such as stand volume and total height; even-aged stands resulting from complete shelterwood had lower biomass, while uneven-aged structures in partial shelterwood and control treatments performed better.
Conclusion: The findings suggest that the partial shelterwood method is a suitable option for the mid-elevation forests of Kelardasht, as it combines considerable economic benefits with biomass levels closest to the control treatment, while maintaining the advantages of uneven-aged forest structures. For the first time, this study demonstrates that prolonging the shelterwood regeneration period can lead to the formation of natural, uneven-aged stands that exhibit features of sustainable forests, with important implications for enhancing carbon sequestration in these valuable Hyrcanian ecosystems.
