Northern Forests Of Iran Research Articles

Characteristics of coarse woody debris in successional stages of natural beech (Fagus orientalis) forests of Northern Iran

Coarse woody debris (CWD) is an important structural and functional component in forests in Northern Iran. In this study we determine the temporal patterns of CWD in Kheyroud Forests by examining the CWD volume in different decay classes and size classes along a chronosequence of secondary forest succession. The volume of CWD followed the general “U-shaped” temporal trend: the highest in the late successional forest (51.25 m<sup>3</sup>.ha<sup>–1</sup>), lowest in the middle successional forest (25.95 m<sup>3</sup>.ha<sup>–1</sup>) and intermediate in the early successional forest (37.05 m<sup>3</sup>.ha<sup>–1</sup>). The late successional forest had a larger amount of logs, snags and stumps than the other two forests. In contrast, the snag volume did not differ between the late and middle successional forest. CWD in decay classes III and V was greater in the late successional forest than that in the other two forests, while CWD in decay classes II and I did not differ among the three successional forests. CWD in class II and I was significantly higher in the early successional forest than that in the middle successional forest. In the early and middle successional forests, CWD in early decay class was dominated by <I>Carpinus betulus</I> L. followed by <I>Fagus orientalis</I> Lipsky. In the late successional forest, CWD in early decay class was dominated by <I>Fagus orientalis</I> while CWD in the late decay class was dominated by <I>Carpinus betulus</I>. While forest succession had a large influence on the amount of CWD in different decay classes, it had no effect on CWD distribution among the different size classes. Our results suggest that both anthropogenic and natural disturbances have had a long-term effect on the distribution of CWD among three forests.

A model for removal of speckle noise in SAR images (ALOS PALSAR)

Speckle noise is primarily due to the phase fluctuations of the electromagnetic return signals. Since inherent spatial-correlation characteristics of speckle in synthetic aperture radar (SAR) images are not exploited in existing multiplicative models for speckle noise, a speckle noise model is proposed here that provides a new framework for modelling and reducing the speckle noise. Both quantitative and qualitative criteria, including speckle reduction and texture preservation, are used to evaluate the performance of the proposed filter; one PALSAR (new Japanese sensor) image and a JERS-1 image are employed in the evaluation. The results showed that the proposed filter is slightly better than commonly used filters such as the Kuan, gamma, enhanced Lee, and enhanced Frost filters. The proposed filter can be used in different applications, including mapping and forestry biomass estimation. Furthermore, one of the benefits of the proposed filter is that it is independent of the threshold, which is required in most commonly used filters. The proposed filter was tested with SAR images of different sites in the northern forests of Iran.

Physical Soil Properties and Slope Treatments Effects on Hydraulic Excavator Productivity for Forest Road Construction

Effects of moisture, porosity and soil bulk density properties, grubbing time and terrain side slopes on pc 220 komatsu hydraulic excavator productivity were investigated in Miana forests road construction project which located in the northern forest of Iran. Soil moisture and porosity determined by samples were taken from undisturbed soil. The elements of daily works were measured with a digital stop watch and video camera in 14 observations (days). The road length and cross section profiles after each 20 m were selected to estimate earthworks volume. Results showed that the mean production rates for the pc 220 komatsu excavators were 60.13 m3 h(-1) and earthwork 14.76 m h(-1) when the mean depth of excavation or cutting was 4.27 m3 m(-1), respectively. There was no significant effects (p = 0.5288) from the slope classes' treatments on productivity, whereas grubbing time, soil moisture, bulk density and porosity had significantly affected on excavator earthworks volume (p < 0.0001). Clear difference was showed between the earthwork length by slope classes (p = 0.0060). Grubbing time (p = 0.2180), soil moisture (p = 0.1622), bulk density (p = 0.2490) and porosity (p = 0.2159) had no significant effect on the excavator earthworks length.

The late-Holocene vegetation history of the Central Caspian (Hyrcanian) forests of northern Iran

Pollen analysis of the peat in a small mire on the northern slope of the Alborz Mountains (550 m a.s.l.) in the Central Caspian forests of Iran reveals changes in forest and wetland vegetation during the last millennium. A forest, principally of Alnus and Carpinus occurred over almost the whole period. Quercus, Ulmus and Parrotia were less common, while Fagus, Pterocarya, Acer and Diospyros fluctuated as a probable result of human interference and/or climatic change. Two phases of clay deposition in the mire can be dated to the `Mediaeval Climatic Anomaly' (AD 1100) and the beginning of the `Little Ice Age' (AD 1560—1600). Although human activity seems to have persisted in the region during the whole of the past millennium, increased NAP values point to intensified human interference since the beginning of the nineteenth century.

Deforestation and the Development of the Iranian Wood Industry

The raw materials of Iran's plywood industry are procured from the northern forests of Iran, and development of the plywood industry is intensively related to the situation of these forests. Previous research has indicated that the future development and location of plywood units in Iran will be highly dependent on the northern forests of Mazandaran & Gilan provinces, which have the second and fifth priorities among thirty provinces in this regard (Azizi, Memariani, 2004). Annual and per capita deforestation is a key factor in development planning, and the structure and operations of all sections of the wood industry, including plywood, needs to take account of this. In this research, we have estimated the number of plywood units required over an extended future period, taking into account annual deforestation, durability of the forests and per capita deforestation, using case study and exponential smoothing methods. The results have shown that the plywood industry will need to establish new plants, area of the forests will decrease by half, and per capita deforestation will increase in the coming decade.

Site demands and life habitat of Maple "Acer velutinum Boiss." in northern forests of Iran

Site demands and life habitat of Maple "Acer velutinum Boiss." in northern forests of Iran

Review of Environmental Toxicants: Human Exposures and Their Health Effects, by Morton Lippmann, Van Nostrand Reinhold/Chapman and Hall, New York/London, 1992 and Waste And Pollution: The Problem For Britain, by Kenneth Mellanby

Municipal solid waste landfills are known as one of the main greenhouse gas resources in the world. One solution to mitigate greenhouse gas emissions from these resources is to install biogas recovery systems. In this regard, determining the appropriate period to install biogas systems becomes important. Meanwhile, methane generation and global warming potential of landfill are important and should be considered as the main indices for determining the appropriate period of biogas production from landfills. Saravan landfill, a black spot, is located in the forests of Northern Iran. In this study, a hybrid landfill gas emissions modeling (LandGEM) and life cycle assessment (LCA) were employed to determine the appropriate period to install biogas recovery project in Saravan landfill in order to capture methane and reduce global warming. The results demonstrated that for the studied period of 140 years, the maximum amount of methane generation will be achieved in 2019 which is equal to 17948 Mg. The LandGEM + LCA results indicated that for a period of 30 years (from 2018 to 2047), the methane generation will be reached to 47% of the total methane emissions from this landfill. Meanwhile, the global warming potential for the same period is equal 47% of the total global warming potential of the landfill. Therefore, it is concluded that the period of 2018–2047 is an appropriate period to install biogas plant in terms of energy generation and mitigation of global warming.

Relationship between insect herbivory and environmental variables in forests of northern Iran

Abstract. Hajizadeh G, Jalilvand H, Kavosi MR, Varandi HB. 2016. Relationship between insect herbivory and environmental variables in forests of northern Iran. Nusantara Bioscience 8: 155-160. This research aimed to recognize the relationship between the intensity of insect herbivory and environmental variables (stand structure, and physical and chemical properties of soil and litter) in Hyrcanian forests, northern Iran. Three forest types (Pinus brutia, Parrotia persica-Carpinus betulus, and Fagus orientalis), which covered the elevational gradient of the study region, were selected. In each forest type, three random plots (20×20m) at 100m intervals were sampled. The dominant polyphagous species, Ennomos quercinaria (Hufnagel, 1767), belonging to Geometridae family was identified. The forest types experiencing the lowest and highest defoliation intensity were P. brutia (12±2.08) and F. orientalis (57.67±5.36), respectively. The intensity of insect herbivory was significantly correlated with various structural parameters [forest type, elevation, diameter at breast height (DBH), tree density, tree cutting and canopy opening (%)], physical and chemical properties of the soil [clay, pH, and potassium (K)], and litter properties [depth and total nitrogen (N)]. The study illustrates a way to monitor geometrid population dynamics across environmental gradients in terms of their population density, degree of polyphagy and distribution; such results could be useful for developing appropriate management plans for these economically important insects.