Journal of Forest Ecosystems Researches
http://yujs.yu.ac.ir/jzfr
Journal of Forest Ecosystems Researches - Journal articles for year 2015, Volume 1, Number 2Yektaweb Collection - https://yektaweb.comen2015/3/10Investigation of Hawthorn and Maple's Stands Structures of Zagros Forest Using Nearest Neighbors Indices
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=41&sid=1&slc_lang=en
Considering the importance of forest structure and interaction among different tree species, this study conducted aimed to determine and compare spatial pattern, heterogeneity, and dimensions of Hawthorn and Maple trees with other neighbor trees. For determining Hawthorn and Maple trees structure, 30 individual of each trees were identified and studied. Based on the results, uniform angle index for Hawthorn and Maple trees were 0/744, and 0/733 respectively, which would propose a clumped pattern for these two species. Computed mingling index values for Hawthorn and Maple were 0/877 and 0/955 respectively that show a high tree species mixture. Also, the average of crown canopy differentiation and crown canopy dimension were 0/582 and 0/322 respectively, for Hawthorn tee and it was 0/42 and 0/656 respectively for Maple tree. Based on mean values, these results show that Hawthorn had high level of differentiation but was inferior in comparing to its neighbors whereas Maple has intermediate differentiation and is dominant to the other neighbors. The average distance to nearest neighbors for Hawthorn and Maple were calculated 7/374 and 6/278 respectively. The results of an absolute discrepancy algorithm (AD) showed a high differentiation of Hawthorn and Maple mixture in comparing to the other indices. It is concluded that maple is superior to hawthorn in dimension and because of low frequency of these two species, they hold high values of mingling indices.
babak pilehvarThe Effect of Water Stress on Gas Exchange in Two Iranian Oak Species (Quercus brantii) and Vyvl (Quercus libani)
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=38&sid=1&slc_lang=en
Drought is the major environmental stresses that it can have a negative impact on plant growth. The study of gas exchange under drought stress can help to identify factors affecting stress resistant. Due to this fact that Zagros forests has Mediterranean and dry climate, with the aim of this study was to assess the impact of drought on leaf gas exchange in two oak species (Quercus brantii and Quercus libani). Water stress consisted of four levels of water stress (100%, 70%, 50% and 30% FC) in the greenhouse situations. Those seedlings were intended for water stress weren’t irrigated to reach to the desired field capacity (70%, 50% and 30% of field capacity), but control seedlings were irrigated every day in order to soil water content at field capacity shall be kept 100%. Results showed that water stress treatment has a significant reduction of stomatal conductance, photosynthesis, conduct mesophilic, carbon dioxide emission, and transpiration. Also Quercus libani showed higher level of photosynthesis, water use efficiency and transpiration than Quercus branti. Overall, results in both species, showed stomatal and non-stomatal limitation would cause of photosynthesis reduction. Also, due to higher water efficiency and lower gas parameter variations, Quercus libani would gain better mechanism of waster stress and Quercus brantii would gain the use drought avoidance mechanism.Roghayeh Zolfaghari Modeling of Seed Germination of Platycladus orientalis in Response to The Interaction of Temperature and Water Potential
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=46&sid=1&slc_lang=en
Accessing to the data that could increase our knowledge associated with the response of seed to moisture content and temperature, is very important on exact time of planting decisions making. In this study Hydro-thermal-time modeling of Platycladus orientalis germination, one of the most planted trees in Iran forests, by applying 5 levels of water stress (0.-0.5, -1, -1.5, -2 MPa) and temperature treatments (10, 15, 20, 25, 30 ° C) was performed. The results showed that the optimum temperature (To) for germination is 23.12° C and basic temperature (Tb) for germination is 8.18 ° C. Meanwhile amount of the hydrotime constant (θH) for this species is 0.45. The outcomes indicated that the reduction in water potential and temperature germination is linearly reduced. Interaction of temperature and water potential factors affected significantly on time and percent germination value. A Hydro-thermal-time model was introduced for Platycladus orientalis L. in which its constant value was 105.1 MPa°C.d.Mehrdad ZarafsharAssessment of Needle Leaves and Broad Leaves Afforested Stands in Makhmalkooh Forest Park
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=36&sid=1&slc_lang=en
Assessment of the plantation is fundamental for managers to improve plantation quality and successful plantation in the future. This study aimed to assess and compares Makhmalkooh forest park plantation data due to 18 years old period. Sampling was performed in a randomized systematic design using 60 circular plots in a 50*150 m rectangular grid. Diameter at breast height, basal area, tree height and crown canopy were measured for each species in all plots, and then total volume and mean of growth increment based on age were computed. Results showed that Cupressus arizonica and Amygdalus scoparia had the highest value in density, heterogeneity in species composition, and crown canopy and Capressus sempervirens and Olea europea had the least one. The survival rate for all species were 78.5 percent and different plantation types showed significant difference in diameter, basal area, crown canopy and total volume. The most value in mean of diameter and height increment was assigned to Pinus brutia and Cupressus sempervirens and the least value were assigned to Olea europea and Amygdalus scoparia. The results showed that Cupressus arizonica and Pinus brutia are the best species for afforestation in this region.babk pilehvarModeling of Frequency Distribution of Tree’s Height in Uneven-Aged Stands in Dalab of Ilam
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=50&sid=1&slc_lang=en
The aim of this research, was to model the height frequency distribution of Quercus persica in Dalab forests of Ilam. In order to investigate the height frequency distribution of trees in the natural stands, 37 transect with fixed length (50m) selected and data were measure based on systematic random patterns with 100m×100m dimensions of network inventory. Finally, height of 209 trees of oak were measured and analyzed. Beta, Exponential, Gamma, Normal, Log-normal and Weibull probability distribution functions were fitted to the height distribution of oak trees. Characteristics of distribution function using the maximum likelihood estimation method was estimated. Empirical probability distribution and theoretical probability distribution was compared using Kolmogorov Smirnov and Chi square tests. The results of the Kolmogorov Smirnov test showed that Beta, Normal, Weibull, Gamma and Log-normal distributions were fitted to data better respectively but the Chi square test showed that Beta and Log-normal distributions had a good capability in explaining the trees height distribution. We concluded that Beta and Log-normal probability distributions can be used for those who want to simulate changes of forests.Mehrdad MirzaeiBiodiversity of Tree Species in Different Plot Size in Zagros Forests (Case study: Baniloan Area of Javanrood)
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=43&sid=1&slc_lang=en
One of the main factors affecting sustainable management in the forest ecosystem is the biodiversity conservation. For achieving this purpose, we need to estimate and determine the biodiversity. The efficiency of sampling depends to some extent on plot size in a study. Therefore, a study was conducted in the Zagros forest (Baniloan, Javanrood, Kermanshah) to assess the effect of plot size on the abundance and diversity of tree species. We measured the diversity indices e.g. (Shannon H), richness (Minhinick) and evenness (Sheldon) in our data. These indices were analyzed at 270 sampling points along 3 parallel transects which ran perpendicular to the slope. The distances between transects was 500 m. Each transect comprised 30 sampling points with 3 different sizes of plots (10m×10m-20m×20m and 30m×30m plots). Abundance and diversity of tree species, richness and evenness analyzed by ANOVA and Duncan. The results showed that abundance and diversity increased significantly by increasing the size of the plots. The maximum diversity was seen in 900m2 plot size. At 400 m2 plot, richness was higher than two other plot size. But evenness was not significantly affected by plot size.Shaieste GholamiStudy on Accuracy of Assessment of the Canopy Cover Density in a Pure Persian Oak Stand, by Using the Method of Terrestrial Photography
http://yujs.yu.ac.ir/jzfr/browse.php?a_id=47&sid=1&slc_lang=en
In order to study the accuracy of assessment of the canopy cover density of a pure Persian oak stand with mixed coppice and standard forms using terrestrial digital photography, 16 circular sample plots with an area of 4.9 in a grid with sizes of 25 m by 25 m, over as forest stand with an area of 1 ha, with was used. The method of vertical sighting with Same as Cajanus tube was considered as the method of control to record either present or absent of canopy cover in 195 systematic sample points in each of sample plots. 9 vertically terrestrial digital photographs that contained of an image in the centre of the sample plots, 8 images in line with the bout main and sub- main geographic directions were taken.
By calculation of the percentage of the canopy component of the forest stand using these methods, the results of the Kruscal–Wallis statistical test showed that there were not statistically significant differences between the different methods of estimation of the canopy cover component. In terms of the superiority of the bias indicator over the other methods, the method of 5 digital images in the main geographical directions, the method of 9 digital photographs and the method of 5 digital images in the four sub-directions were ranked from 1 to 3, respectively. The different methods of terrestrial digital photography would underestimate the canopy cover component in comparing with control method.
Alireza Salehi