29 research outputs found
A Comparative Study of Soil Carbon Sequestration between a Deteriorated Rangeland and Pinus eldarica and Fraxinus rotundifolia Stands
No full textTehran 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
Economic Analysis of Residual Tree Damage Following Selective Logging in a Caspian Hardwood Forest
No full text 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
Coarse woody debris variability due to human accessibility to forest
No full textOriginally published in Forests (MDPI):
Behjou FK, Lo Monaco A*, Tavankar F, Venanzi R, Nikooy M, Picchio R (2018) Coarse woody debris variability as result of human accessibility to forest. Forests 9(9): article number 509 (open access)
Corresponding author: Angela Lo Monaco, [email protected]
DOI: 10.3390/f9090509
The article can be dowloaded at: https://www.mdpi.com/1999-4907/9/9/509
Abstract: Coarse woody debris (CWD) plays an important role in supporting biodiversity and
assisting ecological processes. Sometimes local people intervene modifying the expected distribution
of CWD components, harvested as fuel wood. The effect of the human accessibility (HA) on the
volume and characteristics of CWD (snag, downed log and stump) was investigated in the natural
uneven-age mixed hardwood stands of the Hyrcanian forests of Iran to quantify the impact on CWD.
The HA was classified into three classes (easy, medium and difficult) on the basis of slope class,
slope direction to the nearest road and road type. As expected, a negative relationship between
the degree of accessibility was found with respect to the main qualitative and quantitative indices
referring to CWD. The results showed that the volume of CWD decreased with an increase in
human accessibility class (HAC), thus the mean volume of CWD in the difficult, medium and easy
accessibility classes were 14.87 m3 ha1, 8.84 m3 ha1 and 4.03 m3 ha1, respectively. The decrease in
CWD volume was more associated with the decreasing volume of small diameter of low decayed
downed logs. The ratio of snag volume to standing volume, the ratio of downed log volume to the
volume of trees and the ratio of CWD volume to standing volume increased with a decrease in HAC,
while the ratio of downed log volume to snag volume decreased with a decrease in HAC. No selective
behaviour on the botanical species of CWD was recorded. For ecological forest management, the effect
of HAC on CWD should be considered. A constant supply of snags and downed logs must be
preserved to assure a high level of biodiversity. To balance social needs and biodiversity requirements,
an increased level of CWD retention might be needed in areas with easy accessibility. The obtained
results may be useful when ecological and socio-economical needs have to be taken into consideration
in future policy-making decisions.
Keywords: snag; downed log; stump; forest road; uneven-agemixed hardwood stands; Hyrcanian forest
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
Assessing the state of forest health in Oriental beech (Fagus orientalis L.) dominated forests in Iran
No full textWe assessed landscape-scale forest health in northern Iran based on the Forest Health Monitoring (FHM) method. Using five plot clusters, we collected, analyzed, and reported information on the four key selected indicators (i.e., tree biodiversity, crown condition, natural regeneration, and deadwood) in FHM. To obtain a numerical value of forest health to make the indicators operational we used an analytical networking process to assess the contribution of each indicator to forest health. The results demonstrated that tree species diversity and species evenness were high (Shannon–Wiener index= 2.11; Simpson index= 0.8; Pielou index= 0.76), but species richness was at an intermediate level in the forest (Margalef index= 2.81). In terms of crown condition, with an average crown diameter of 7.1 m, the results of crown dieback classification showed that the most-healthy class had the highest frequency with 65.2% in the study area. The mean density of natural regeneration was 273 individuals ha-1 and 80% of which were represented by healthy seedlings. Total deadwood was 44.12 m3 ha-1 and was formed by 168 individuals per ha-1. A great contribution to the total deadwood in number (89%) falling in the lower DBH class (<50 cm), representing 51% by volume. From the point of wood decay, Class 1 (least decomposed) had the most numerous and the most significant volume of deadwood. The assessment results of FHM show that the major indicator influencing forest health is tree diversity which contributes 61%. The remaining three indicators include crown condition, natural regeneration, and deadwood contributing 21.7%, 13%, and 4.4%, respectively. It must be highlighted that forest health monitoring information in temperate Hyrcanian forests is currently not available, and therefore, this paper presents the first experimental study carried out. The findings of this study are required to assess the state of current health and identify trends that will be used in the decision-making process for better management of the forests
Residual Trees Response to Selective Cutting Operations in Caspian Forests
No full textDamages to residual trees caused by felling operation were assessed in the stands of a Caspian hardwood forest. Following the felling operation, a fi eld survey was done to collect data of all residual trees (species, DBH, height) and of tree wounds (size class, location, intensity of damage). Different harvesting intensities were studied, and treatments were replicated three times. The results showed that the treatment with the medium and high harvest intensity was found to cause the highest percentage of damage and the largest stem wounds. It is concluded that harvesting intensity should be limited to 3 trees/ha during each harvesting operation to reduce the extent of tree damage and thus future fi nancial loss
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
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