Iranian Journal of Forest and Poplar Research
Year:2011 | Volume:18 | Issue:4 (42)|Papers Count:17

In this research, several ecological characteristics of Pyrus glabra Boiss. Were studied. Distribution area of wild pear was drawn on a topographic map, and altitudinal range of horizontal and vertical distribution was determined. This species is mostly distributed on altitudes above 2000 m. Thirteen sample plots, each 1000m2 were selected considering aspect, land form and altitudinal classes. In each sample plot, various variables such as species, diameter at breast height, tree height, crown cover, origin (standard or coppice), age class, number of sprouts, associated species and forest type were measured or recorded. A soil profile was dug in each sample plot in order to study physico–chemical properties of soil. Data were tested with Principal Component Analysis (PCA). The average number of trees per plot was 8, from which 73 percent were of coppice origin. The mean diameter of breast height was 14 cm and the average of tree crown area was 11m2. The minimum and maximum height of trees were 2m and 7.8m, respectively, while the mean height was 4.6m. The western aspects contained the highest number of trees per plot, while the eastern vallies showed the highest values for diameter at breast height, trunk height, crown area, and total height. The depth of bed rock and the percent of sand and gravel were limiting factors in the soil of the studied area. The soil fertility is sufficient for plant growth in most cases and could be regarded as moderate fertile forest soils. Land form and soil fertility are the most important factors for distribution of wild pear in the studied area.

Dead tree, which consisting of both standing dead tree and material that has fallen to the ground, is a dynamic resource in forest ecosystem. In order to investigate on falling and dynamic model of snags (standing dead trees) in a mixed beech forest, this research was carried out in compartments No. 112 and 214 in Kheyroud forest, north of Iran. 215 dead trees were measured and then 64 dead trees were randomly selected for analyzing. According to the results, hornbeam snags in a natural forest showed higher breaking height in comparison to beech snags. Investigation on snag dynamic showed that snag falling is higher on steep slopes; however, there is no significant difference between slope gradient and snag falling. Increasing in decay class, caused increasing in sang falling. Also effect of dead wood size, decay stage (quality of dead wood), slop and species were analyzed. Results showed that slop and species have no significant effect on the sang falling, while the effect of deadwood size and decay stage on sang falling is significant.

Establishment of germplasm collection project was performed with planting of 64 Populus deltoides, P. euramericana, P. nigra and P. alba clones in Safrabaste Poplar Research Station in 1983. Five seedlings of each clone were planted in 5m×5m. This study conducted on seven P. deltoids clones. Phenological characteristics (flushing, flowering, seed bearing and leaf fall) were recorded every year up to the end of the study at 2005. Results showed that P.d. 69/55 and P.d. 73/51 were both the earliest and latest clones in flowering and seed bearing, while P.d. 69/55 was the earliest and P.d. 72/51 was the latest clones in flushing. Results of poplar clones growth showed that P.d. 73/51 and P.d.72/51 clones with 40.7 cm and 26.4 cm had the maximum and minimum DBH, respectively. Also P.d. 73/51 and P.d.72/51 clones with 28.7 m and 25.6 m had the maximum and minimum height growth, respectively. The P.d.73/51 and P.d.72/51 clones had the highest and lowest wood production with 32.07 and 13.01 m3ha-1yr-1, respectively.

In order to study the relation among trees and shrubs diversity to altitude, slope gradient, aspects and distance from roads and villages factors, a case study was done in the protected forests of Ghalajeh in Kermanshah province in Zagros region. Crown diameter of trees was measured in two directions (north-south and east-west) in 114 sample plots with dimension of 60m×60m in a 450m×200m sampling grid. The location of plots was registered using GPS. Then the crown cover percent in each sample plot was computed. Some biodiversity indices including Simpson and Shannon-Winner for species diversity, Margalef for richness and Simpson and Smith-Wilson for evenness were applied in each plot. Digital values of altitude, slope gradient, aspects and distance from roads and villages were extracted for each plot. The correlation analysis between crown cover and mentioned factor was done by Duncan statistical test. Results showed that crown cover and species diversity were low around of villages and roads. Results of correlation analysis were also showed that altitude, slope and aspect have significant correlation by diversity, so by increasing the altitude, the species diversity and richness are increased. Results showed that in the northern slopes and 25-60 percent slop category, the crown cover and species diversity were maximum.

One of the oldest traditional usages of forests is cutting the branches for fodder production. In Iran in some regions of northern Zagros some species specially Lebanon oak (Quercus libani Oliv.) is used to provide fodder. For this reason each family normally has a forest region to meet cattle's fodder and fuel wood by cutting tree branches. Since trees could record this phenomenon in their tree rings, in this study we tried to investigate the tree rings by using of Dendrochronology to understand the effect of human activity like cutting branches on tree rings formation. According to this idea, two stands of oak forests that located in regions near the village and regions that located in low human interruption (holly places like cemeteries) have been selected. Twenty thick and healthy trees were selected from each region and samples were taken in the shape of disks and increment cores. After preparing samples surface, ring width of the trees were measured by binocular and LINTAB measurement table with 0.01 mm precision. Cross dating have been done using TSAP software. Growth curves of trees in interrupted region showed significant growth reduction in comparison with growth curves of trees in preserved region. In addition, this type of usage of forests will change the normal growth form of the trees and will increase the negative pointer years as an index of the radial growth reduction in interrupted region. It looks that the severity of this traditional way of cutting branches is increased during the last 100 years.

Forest fires, as an ecological risk, whether with human or natural origin, have profound effects on land cover, land use, production, local economies, global trace gas emissions, and health. Identification of factors affecting the existence of forest fire as well as its zonation in the given watershed is one of the basic tools for forest fire control and fighting actions. The aim of this research is to develop the forest fire risk map based on vegetation, physiographic and climatic factors, human, distance to rivers and roads, in a part of Paveh forests. For this purpose, digitally diffusion forest fires map with field checks using GPS were prepared, initially. Then affecting factors were binary compared using Analytical Hierarchy Process (AHP) method by indicating the weight of each factor as indicator for their effects in occurrence of forest fire. Accordingly, the forest fire zonation risk map was prepared using weighted information layers and weighted coefficient of each factor. Five categories of forest fire risk, including very high to very low, were derived, automatically. The mapping result of the study area was found to be in strong agreement with actual fire-affected sites. The results indicate that the 90% of burned areas are located in high risk class.

Oriental beech (Fagus orientalis Lipsky) seed storing is unavoidable, due to long-time cycle of mass seed production (sometimes up to 8 years) and demand for restoration of its non-regenerated gaps in northern forests of Iran. In this research, F. orientalis seeds with moisture content (MC) of 30% and 7% were stored during 11 months in refrigerator (4ºC). By terazolium test, it was revealed that viability of both seed types started to decline after month 3. At the end of the month 11, the viability of seeds with 30% and 7% MC was 51% and 76%, respectively. It is concluded that, the fresh and dry seeds of F. orientalis can be stored near to 1 year in mountain forests of north of Iran and then sown in nursery or sown/broadcasted (with soil scarification) in forest. In order to inhibit the decay, fresh seed is better to be soaked with fungicide at once collection.

In order to have a better recognition of plant communities, studying the spatial pattern of them is necessary to understand many of the issues in forest ecology and management. This study was conducted in Bayangan in Kermanshah province, as a part of Zagros forests. Sampling methods including fixed area plots and distance methods, such as T-square and Compound sampling, were used to investigate the spatial pattern of Manna Oak trees (Quercus brantii Lindl.). A grid of 100 m×100 m was applied and then 50 sample plots were established. The grid intersections were applied as the center of sample plots and the beginning of distance sampling techniques. Dispersal indicators such as Green, Morisita, Standardized Morisita, Johnson and Zimmer, TF, TN, Hopkins and C were used to analyze the spatial pattern. All of the applied indicators showed a clumped pattern for Quercus brantii. Among the distance indicators, TF, TN and C, presented better results than the other indices.

Importance of Non-Wood Forest Products (NWFPs) in providing food, medicine, hygienic and industrial materials has caused to harvesting of more amount of them annually. These products are entered in the local, national, and international markets and therefore, the local people gain high income through selling them. Therefore, identifying and measuring of NWFPs is one of research priorities in Iran. This study was carried out to collect necessary data for estimation the amount of produced fruit of two important species in Arasbaran forests: Cornelian cherry (Cornus mas) and Hazelnut (Corylus avellana) for economic studies. Transect sampling was used to estimate the annual products of the fruits. A number of trees were selected in systematic random manner. Characteristics such as weight of fruit, crown height, crown diameter and, the number of sprout at each tree were measured to investigate on correlation between these characteristics and the relations among them. In the next step, suitable model was fitted in order to estimate the amount of fruit production. PROC CORR and GLM of SAS 9.1 software were used for statistical analysis. Finally, the fruit amounts of cornelian cherry and hazelnut were estimated as 914 kg and 395 kg per hectare, respectively.

Wood production in vast areas is one of the main strategies to protect and preserve the limited forest areas of the country that requires large nursery seedling production. Therefore, it is essential to determine variables influencing the amount and quality of seedlings production. Several variables including age and quality of parent trees, cutting dimension and appropriate place of cutting have an impact on seedlings quality and quantity. This study aims to determine the appropriate place of cutting of shoots and young branches of poplar species. For this purpose, cuttings were prepared from five poplar clones (two species of P.×euramericana, one clone of P.deltoides, one clone of P. nigra and one clone of P.alba) with three locations (lower, middle and upper part of annual shoots) and were planted in a factorial randomized block design with three replications. Parameters including survival, seedling collar diameter, height of seedlings and number of shoots per cutting were measured in two successive years. The results of this study indicate that, 1) all studied species and clones present different characteristics and capabilities of seedling production; 2) cutting position causes significant differences in the rate of survival, collar diameter and seedling height; 3) difference of parameters is more obvious between cuttings prepared from upper part of shoots and lower and medium parts of shoots.

In order to study the relation between ground cover vegetation including shrubs and bushes, and natural regeneration of wild pistachio (Pistacia atlantica), a research project was carried out in 4 ha in a protected area in wild pistachio experimental forest of Fars province. Statistical analysis using T-test showed that fencing of the area within studied 5 years had no significant impact on establishment of natural regeneration of wild pistachio. The regression between number of shrubs such as Amygdalus scoparia, A. lycioides and A. ebornea and the number of natural regeneration (seedlings) of wild pistachio was computed as y=5.8207x0.6499 (R2=0.755). Therefore, we can conclude that improvement of shrubs and bushes could be an effective alternative for rehabilitation of degraded wild pistachio forests.

The effects of acorn size, fencing and protection treatments (treeshelter and mulch) were investigated on seedling establishment of Chestnut-leaved oak (Quercus castaneifolia) in first growing season. For this purpose, a degraded forest in 750 m above sea level was selected in Loveh forest (Golestan province-Iran). Then, 1728 sound and ripe acorns were selected from a seed lot, collected from six parent trees located in adjacent to the examination area. Using a split-split plot design, the effects of 3 acorn size classes: small (diameter<15mm), medium (diameter between 15 and 17mm) and large (diameter>17mm), 2 fencing levels (fenced and open), and 4 protection treatments (control, mulch, treeshelter, and treeshelter with mulch) were engaged for measuring the seedlings emergence, establishment percent, total length, and survival rate. At the end of the first growing season, seedlings originated from the large seeds had higher emergence percent, establishment percent, total length and survival rate. Fencing promoted establishment percent about twofold, and treeshelter, singly or with mulch, increased establishment percent, total length and survival. From this investigation, it can be deduced that large seeds in seed sowing can improve seedling establishment chance, provided that suitable methods of collection, sterilization and storage of seed lots are applied. Likewise, treeshelter, singly or along with mulch can improve establishment percent, total length and survival rate, however, with constructing a suitable fence around the plantation area, treeshelter and mulch treatments can be ignored.

Measurements of stemflow (SF) were conducted during the 2009 summer season in pure and natural oriental beech (Fagus orientalis Lipsky) and oak (Quercus castaneifolia C.A.M) forests located in the Kheyrud Forest Research Station of Tehran University. Measurements were made inside two plots of beech and oak forests with areas of 0.56, 0.12 ha, respectively. SF was collected from six beech and oak trees with different diameters by the spiral-type SF collection collars installed at diameter at breast height. Gross rainfall (GR) was collected by means of three manual collectors placed in a neighboring open area from the study plots. All the measurements were performed on a rainfall event basis. During the study period, 10 events were recorded with cumulative GR of 257 mm. The cumulative SF depths for beech forest was 8.1 mm, whilst for oak forest was 0.7 mm. At the event scale, the averages intercepted rainfall by the stemflow in beech and oak forests, i.e. SF/GR, were 2.6%, 0.2%, respectively. A strong positive correlation was observed between [(SF/GR)/GR] (R2=0.93) in the beech forest, while a weak positive correlation was observed in the oak forest (R2=0.43). Averages bark roughness indices calculated by the number of bark furrows and furrows depths were measured 2.10 and 0.50 for oak and beech trees, respectively. Although the study indicated that GR allocated to SF is not a remarkable amount in both oak and beech forests, the SF volume in the beech trees is higher than that of oak which was found to be highly correlated with higher bark water storage capacity as well as higher bark roughness of the oak trees.

For vegetative propagation of Populus caspica an examination was carried out as randomized completely blocks design in Koludeh nursery, Amol, north of Iran. For this purpose 3-bud cuttings, with stock plants provided from stem of 1-year sapling, 1-year sprout of tetard, 1-year branch of tree, and plantation methods of cuttings with 3 buds under ground and 2 buds under ground, were sown in plastic pods filled with loamy-sand soil. Results revealed that cuttings with 3 buds under ground germinated two weeks later than cuttings with 2 buds under ground. Cuttings with stem of 1-year sapling and 1-year branch of tree produced greater germination (60%-62%) and production efficiency (46%-48%), but lower survival 60%-77%), height growth and collar diameter growth compared to cuttings with 1-year sprout of tetard. Cuttings with 2 buds under ground created higher germination rate and lower survival rate than those with 3 buds under ground; however, production efficiency as well as height growth and collar diameter growth was similar in both treatments. From this investigation it can be deduced that stem of 1-year sapling as well as 1-year sprout of tetard is favored for vegetative propagation of Populus caspica. This is while that, 3-bud cuttings either as 1 bud on ground or 3 buds under ground do not change production efficiency, statistically.