1,720,971 research outputs found
Economic Analysis of Residual Tree Damage Following Selective Logging in a Caspian Hardwood Forest
Full text link This study evaluated the logging damage to residual trees following logging operations by opportunity and replacement cost approaches. A total density of 5.1 trees/ha and 17.3m3/ha of wood were harvested. On average, 9.8 trees were damaged for every tree extracted including 8 trees killed or severely damaged. The results of showed that selective cutting can damage residual trees US$47369.25. The results of this study also suggest that logging practices need to be accompanied by close supervision of field personnel and post logging site inspections to be implemented properly
Recreational activities impact on the amount and characteristics of woody debris in the Fandoghlou forests, Northwestern Iran
No full textAbstract
In this research, the volume and composition of woody debris (WD) were inventoried by line intersect sampling (LIS) in recreational and conservative parts of Fandoughlou forests in Northwestern Iran. Based on the pre-study qualitative assessments of WD properties, 60 transects in conserved part including 60 ha tract and 60 transects in recreational part including 60 ha and 60 transects were set up for WD survey. In each area, a systematic series of sampling points was located in the inventory of WD. At each sampling point, we performed line-intersect sampling (LIS) with a line length of 100 m with random orientation of sample lines. Estimates of the total volume of WD across recreational and conservative parts of the forest ranged from 0.70 m3 ha-1 to 1.49 m3 ha-1. The results of independent t-test indicated that the amount of CWD and FWD in conserved part is significantly higher than CWD and FWD in recreational part (t4, 0.05 = 4.26, p = 0.013; t4, 0.05 = 2.69, p = 0.05). The number of tree species of CWD composition was higher in conserved area, more than 5 species including (hazel, beech, hornbeam, oak, maple, and other species). In the conserved part, CWD in highly-decayed classes accounted for 75% of total CWD volumes, but in the recreational division, CWD in the early decayed classes accounted for 79% of total WD volumes. Our results suggest preserving the current conserved forests and maintaining the structural and functional integrity of WD.</jats:p
Effects of Forest Logging Systems on the River Flow Regime Indices Using Graphical Techniques: A Case Study in a Small Natural Forest
No full textThis study aims to investigate the impact of forest exploitation methods on monthly discharge and hydrological indices of river flow using graphical methods in a forested watershed in North Iran. To achieve this, 10 hydrological index changes related to river flow regime influenced by the Shelterwood/clear cutting, Femel cutting, and the Near Nature approach forest cutting methods were assessed. According to the results, it can be stated that the Shelterwood/clear cutting method influenced monthly flow indices by increasing the coefficient of variations and intensifying runoff production, while the Femel cutting and the Near Nature approach methods contributed to regulating the flow regime and sustaining river flow. The influence of various tree-cutting techniques on river flow values and fluctuations is more evident during the wettest months compared to low-water months. The period of Shelterwood/clear cutting disrupted the natural correlation between precipitation and runoff production. Furthermore, the shift from Shelterwood/clear cutting to Femel cutting and the Near Nature approach progressively diminished the slope of the curve, indicating a reduction in monthly runoff at both measurement stations. In conclusion, opting for an appropriate method, such as the Near Nature approach, is preferable from both ecological and hydrological perspectives when managing forest areas in the study region and similar conditions involving comparable topography, climate, soil, and forest stands. The index-based coupled with graphical methodology employed appropriately demonstrates the influence of logging techniques on monthly flow patterns, which provides valuable insights into evaluating the repercussions of alternative management interventions on river flow dynamics
Selective logging and damage to unharvested trees in a hyrcanian forest of Iran
No full textSelective logging in mature hardwood stands of Caspian forests often causes physical damage to residual trees through felling and skidding operations, resulting in a decline in bole quality and subsequent loss of tree value. This study evaluated the logging damage to residual trees following logging operations. A total density of 5.1 trees/ha and 17.3 m3/ha of wood were harvested. On average, 9.8 trees were damaged for every tree extracted, including 8 trees destroyed or severely damaged. The most common types of damage included uprooted stems, stem wounds to the cambial layer, and bark scrapes. Damage to trees sustained along skid trails was found to be significantly more than the damage that incurred within logging gaps and winching areas. The results of this study suggest that logging practices also need to be accompanied by close supervision of field personnel and post-logging site inspections to be implemented properly
Effects of tree diameter and some working conditions on residual stump height following selective logging - Short Communication
No full textImpact of logging intensity on stem density, basal area and biodiversity indices five years after logging in a Caspian hardwood forest
No full textA Comparative Study of Soil Carbon Sequestration between a Deteriorated Rangeland and Pinus eldarica and Fraxinus rotundifolia Stands
Full text linkTehran as the capital city of Iran is one of the most populous cities that overpopulation and industrial improvement there have caused the great diffusion of greenhouse gases. However, forestation in deteriorated rangelands of this city can have a high potential to decrease the density of atmospheric CO2. This research was done in two stands of Pinus eldarica and Fraxinus rotundifolia and the adjacent deteriorated rangeland as control (blank), in Chitgar forest park of Tehran and soil carbon sequestration content was measured. In addition, the relationship between soil organic carbon (SOC) and some physicochemical factors of soil was determined. Results indicated that Pinus eldarica and Fraxinus rotundifolia stands caused the increment of soil carbon sequestration around 46.18 and 37.2 tons per hectare, respectively in comparison with adjacent deteriorated rangeland. The content of SOC in two mentioned stands was more in the first layer than that of the second layer but it was opposite in blank (control). The result of stepwise regression showed that sand was the most important factor, affecting SOC. According to the results of correlation analysis, there was a positive significant relationship between SOC and % silt and % sand and a negative significant relation between SOC and %clay and %gravel. The economic values of carbon sequestration increment in mentioned stands were calculated to be 13.9 and 2.5 million dollars, respectively. Our study showed that forestation is an effective land-use option to restore deteriorated lands of this area and have a high potential to alleviate global warming and climate change
Evaluation of Ardabil City Carrying Capacity Using DPSIR Method and ELECTRE Model
Full text link In the modern view, argument about urban carrying capacity and spaces utilized due to urban development throughout the world has been considered. The increase in size and number of the cities, human activities such as land use change, high consumption of resources and emission of pollutants have left negative impacts on the function and structure of the urban ecosystems and have caused many problems for the circulation of materials and energy. The present study, by applied method and with the aim of studying carrying capacity of Ardebil City using the components of driving force, pressure, state, impact and response with multi-criteria decision model ELECTRE to prioritize the four- Regions districts of the Ardabil City by effective indicators in the form of 5 components discussed in the DPSIR method has been done. Collected information first, classified and categorized by DPSIR method, then by the means of utilizing Expert Choice weighted and ultimately by the implementation of ELECTRE model, the four- Regions districts of Ardabil City in terms of the presented indicators were prioritized. The results obtained from DPSIR method showed that, among the four- Regions districts of Ardabil City, driving force coefficient and then responding with 0/40 and 0/35 ratio have the greatest impact on the carrying capacity of the region. Also, the results of the prioritization of the ELECTRE model exhibit that regions 2 and 3 use the maximum capacity of the area according to the components used in DPSIR, and regions 1 and 4 are in the next priority
Effects of Management on the Amount and Characteristics of Woody Debris in Mixed Stands of Caspian Forests
No full textWoody debris (WD), including coarse woody debris (CWD) and fine woody debris (FWD), is an essential structural and functional component of forest ecosystems. This study was carried out in Caspian hardwood forest sites. In this study, the volume and composition of WD were inventoried by line intersect sampling and fixed area plot sampling in unmanaged and managed forests on 6 compartments (3 managed and 3 unmanaged). Estimates of the total volume of WD in managed and unmanaged forests ranged from 11.9 m3.ha-1 to 25.82 m3.ha-1, respectively. The results of independent t tests indicated that the amount of CWD in the unmanaged forests was significantly higher than CWD in the managed ones (t22, 0.05 = 2.64, P = 0.015). Also, the results of independent t tests indicated that the amount of FWD in the managed forests was significantly higher than FWD in unmanaged forests (t4, 0.05 = 5.07, P = 0.007). In the unmanaged forests, WD in decay classes 3, 4, and 5 accounted for 77% of the total WD volume, but in the managed forests, WD in decay classes 1 and 2 accounted for 87% of the total WD volume. The results suggest preserving the current unmanaged forests (protected forests) and maintaining the structural and functional integrity of woody debris
Soil physical properties degrade further on skid trails in the year following operations
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