A Survey of Ciidae (Coleoptera, Tenebrionoidea) of the Hyrcanian Forest (Iran) with New Faunistic Records

Assessment and management of environmental impacts of forest harvesting activities, one of the main reasons is that its importance is increasing day by day. Skidding operations could lead to an increase in detrimental soil disturbance and soil surface compaction that reduced forest soil fertilities. The aim of this study was to investigate and quantify of forest soil compaction following the skidding operations with wheeled cable skidder. This study was carried out in compartment no. 311 and 319 in Gorazbon district in Kheyrud forest in Hyrcanian forest. This study was conducted in a completely randomized factorial design and changes in soil bulk density and porosity with the skidder traffic intensity such as low intensity (less than 3 passes), moderate (3 to 7 passes) and very large (more than 7 passes) and two depths of 0-10 and 10-20 cm of soil were measured. The results showed that with the increase of machine traffic, soil bulk density was increased but the largest percentage increase was observed in initial passes (less than 3 times). Soil bulk density at the depth 0-10 and 10-20 cm, was more than the control area by 21.2 and 6.5 percent, respectively. Soil porosity percentage at wheel rut was decreased comparing to the control area and this reduction in the 0-10 cm depth was greater than 10-20 cm soil depth. The most of the porosity reduction were occurred in the low intensity traffic and increase in skidder traffic has shown less effect on reducing soil porosity.

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Effect of Oriental beech root reinforcement on slope stability (Hyrcanian Forest, Iran)

Journal of Forest Science ◽

10.17221/93/2013-jfs ◽

2014 ◽

Vol 60 (No. 4) ◽

pp. 166-173 ◽

Cited By ~ 5

Author(s):

E. Abdi

Keyword(s):

Tensile Strength ◽

Slope Stability ◽

Root Distribution ◽

Factor Of Safety ◽

Power Relationship ◽

Strength Increase ◽

Hyrcanian Forest ◽

Reinforcement Effect ◽

Root Reinforcement ◽

Oriental Beech

Vegetation significantly affects hillslope mechanical properties related to shallow landslides and slope stability. The objective of this study was to investigate and quantify the effect of Oriental beech root reinforcement on slope stability. A part of Hyrcanian forest in northern Iran was selected for the study area. To do the research, the Wu model (WM) was used and data related to the distribution and tensile strength of Oriental beech roots were collected. Root distribution was assessed using the concept of the root area ratio and trenching method. Laboratory tensile tests were conducted on fresh roots for strength characteristics. The factor of safety was calculated for two different soil thicknesses (1 and 2 m) and slope gradients between 10 and 45°. The results showed that the root distribution generally decreased with increasing soil depth and the mean root strength value was 38.23 ± 1.19 MPa for 0.35–5.60 mm diameter range. The results verified a power relationship between tensile strength and root diameter. The reinforcement effect (C<sub>r</sub>) decreased with depth and the strongest reinforcement effect was in the second soil layer (10–20 cm) which showed a shear strength increase of 1.47 kPa. The increased factor of safety due to the presence of roots in one- and two-metre soil thicknesses was 27–44% and 15–26%, respectively. The improvement effect of roots was increased with increasing slope gradient and shallower soil thicknesses.    

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