نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 رییس گروه تولیدی سازمان مدیریت و برنامه ریزی مازندران
2 دانشیار، گروه جنگل شناسی و اکولوژی جنگل
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Abstract
Background and Objective: Selective harvesting is an effective approach in sustainable forest management aimed at preserving species diversity and maintaining the ecological structure of forest stands. By focusing on the selective removal of mature and healthy trees, this method endeavors to minimize the damage inflicted on forest stands while sustaining ecosystem functions. Selective harvesting plays a significant role in forest biomass dynamics. This study was conducted to investigate the impact of selective harvesting on biomass changes in mixed hornbeam stands within an intervened forest.
Materials and Methods: The study was carried out within two series of forest plots: the first series comprised stands harvested by selective harvesting, and the second series consisted of unharvested control stands. Both were located in Dr. Bahramnia Educational and Research Forest at Shast Kalateh. Sampling followed a systematic random grid design covering an area of 300 by 400 meters. Seventy half-hectare sample plots were established across 24 parcels from both harvested and control stands. Comprehensive data on trees and deadwood were collected. Five biomass components were measured and calculated, including above-ground biomass, below-ground biomass, deadwood biomass, litter biomass, and soil organic carbon. Above-ground biomass was estimated using species-specific allometric equations. Below-ground biomass was determined through soil sampling and root separation. Litter biomass was quantified by collecting and weighing litterfall over a six-month period. Deadwood biomass was assessed by evaluating decay classes and species composition. Soil organic carbon biomass was calculated based on soil sampling and determination of organic matter content.
Results: The mean above-ground biomass in the harvested stand was 62 tons per hectare, compared to 54 tons per hectare in the control, with the difference being statistically insignificant. The below-ground biomass was 6.5 and 4.6 tons per hectare in the harvested and control stands, respectively, showing no significant difference. Deadwood biomass was measured at 21 tons per hectare in the harvested stand and 19 tons per hectare in the control stand, without significant variation. Litter biomass was equal at 1.2 tons per hectare in both stands. Soil organic carbon biomass averaged 84 tons per hectare in the harvested area and 83 tons per hectare in the control, with no statistically significant difference observed. Tree biomass, however, was significantly higher in the harvested series at 39 tons per hectare compared to 33 tons per hectare in the control.
Conclusion: Soil organic carbon biomass accounted for the largest proportion of total biomass, averaging 84 tons per hectare and contributing 57%. Above-ground biomass followed with 62 tons per hectare, constituting 25% of the total biomass. Of the five biomass components assessed, only tree biomass exhibited a significant difference between harvested and control stands, with greater values detected in harvested areas. Selective harvesting with controlled intensity can effectively maintain or increase biomass in forest ecosystems and is recommended as a sustainable management practice for natural forests.
کلیدواژهها [English]
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