Iranian Journal of Forest and Poplar Research
Year:2007 | Volume:15 | Issue:1 (27)|Papers Count:11

In order to investigate the adaptation of Juniperus species, two plantations of Eastern Red cedar that were 10 years old (with 5285 m2 area) and at spacing of 2x2.5m and 22 years old (with 1600 m2 area) and at spacing of 4x4m were chosen in Chamestan experimental station in Mazandaran province. In 2003, data for survival, d.b.h, height and quality were collected. Results could be summarized as following:1- 10 years old trees showed generally 66.8 % survival, 4.3m in height, 6.2cm in d.b.h. Mean  annual height and diameter increment were 43cm and 6.2 mm, respectively. The highest mortality rate (21.4%) was recorded in the third year of plantation. The highest rate of annual height growth (78 cm) was recorded in the 5th year and the highest rate of annual diameters increment (10 mm) in the 10th year after plantation.2- 22 years old trees showed 98% survival, 7.28m in height and 18.6cm in d.b.h. Mean annual height and diameter increment were 33cm and 8.5mm, respectively. Stem quality in two plantations showed that 90% of trees have quality of first grade. In general, Eastern Red Cedar could be introduced as promised species for plantation in suitable areas.

Physical characteristics and the best method for germination of Pistacia atlantica and P.khinjuk seeds were studied in a Complete Randomized Block Design, with 4 treatments and 4 replications. The seeds of P. atlantica collected from Firoozabad and Neyriz while those of P. khinjuk seeds were from Mamasanie in Fars province. The treatments were cooling, acid, acid + cooling and control. The studied factors were weight, size, moisture content, germination and healthiness of seeds. Results showed that the weight of 1000 seeds of P.atlantica from Firoozabad and Neyriz and P.khinjuk from Mamasani were 314.8 g, 243.211 g, and 87.038 g, respectively. The means of size (length, width and thickness) of P.atlantica from Firoozabad was 9.3, 7.0, 5.5 mm, respectively. The size of Neyriz seeds was 9.0, 6.2, 5.3 mm and that of P.khinjuk from Mamasani was 6.9, 5.7, 4.6 mm. The maximum and minimum rate of germination in Firoozabad seeds were 76% and 20% related to acid+ cooling and control treatments. In seeds of Neyriz the mentioned rates were 65.5% and 38.5% related to cooling and acid treatments. The P.khinjuk seed lot collected from Mamasani showed no germination.

This research was conducted on north and south aspects in plantation site of Wild Almond (Amygdalus scoparia Spach) in Mishan region at Chaharmahal and Bakhtiari province. At the first step, 50 shrubs of A. scoparia were selected randomly in each aspect. After that, quantitative characteristics such as height, collar diameter, crown diameter and number of coppice sprouts were measured. The results indicated that the mean height, collar diameter, crown diameter and number of coppice sprouts in north aspect was significantly more than those in south aspect. The results of this research might help the foresters to establish a more desirable plantation with wild almond on the degraded forests.

T-square sampling method is one of the distance sampling methods for estimating the plant density and canopy cover. For plant density measurements, three formulas, of Diggle and Byth have been used. In this study, applicability of these formulas regarding to accuracy of estimate for density and canopy cover of Zagross Oak (Quercus brmztii) forests in research and educational Forest of Qasr-e Shirin (Kermanshah province) were examined. At first, 50 hectares of the forest area was selected and the inventory of the population was carried out. Then, 50 systematic random sampling points for T-square sampling method in this area were measured and recorded. The results show that none of the formulas could provide an acceptable estimate based on ±10% accepted accuracy; even though, the Byth formula has more accuracy level for density and crown coverage for this kind of forests.

The worth of forest areas and increasing demand of wood in the country has lead our attention to increase wood production. Therefore short rotation system for intensive wood production is strongly recommended. Chainsaw is usually used in addition to labor for cutting and harvesting the low diameter stem which is a hard and uneconomic task. Due to intensive wood production under short rotation method, a special professional machine is required for harvesting low diameter trees of poplar stands. The exotic harvesting machines are used for harvesting very low diameter trees, which are not proper to use in Iran. For this reasons, a harvesting machine was designed, manufactured and attached to a garden tractor and driven by P.T.O shaft. The machine had three round knives for cutting trees up to 12.5 cm diameter. The machine power was determined according to the power required to cut the poplar stems. The rotational torque of P.T.O. shaft transmitted to the knives by two pulleys and a gearbox that designed according to the rotational speed and torque. Other parts such as bearings and seals were selected according to DIN standard. After designing and manufacturing the parts, the machine was produced and its efficiency and productivity was evaluated. The elementary assessments show that this machine is suitable for cutting woods in intensive poplar plantations of short rotation system (2, 3 and 4 years) and its operation and application is more comfortable, quicker and more safe than the chainsaw machine.

Mixed beech forests (Fagus orientalis) are the most important forests with the highest degree of naturalness in Hyrcanian forest of Iran. These forests commonly dominate by shade tolerance species with irregular and uneven-aged stand stmcture. The aim of this study is to analyze the stand structure and spatial pattern in order to identify specific structural patterns. We studied the stand structure and spatial pattern of trees in mixed beech forest in the Shastkolate Educational Forest to examine the coexistence strategies of different species. Data was collected from a 16.9 ha permanent plot on a 406x416m quadrate area. We measured all trees exceeded than 7.5cm in diameter at breast height on permanent plot. The six main species were divided into two groups based on density and stand structure. Group A had higher density than group B, as well as reverse J shaped DBH distribution of Jive standing trees. Species in group A have clump spatial distribution pattern in all layers. However, clump intensity is more than in understory and size of patch clump was smaller in this group. This situation for group A may explaining by having numerous coppice, sucker and patch regeneration in the understory layer. Middlestory and understory stems of the six major tree species were patchily distributed throughout the plot. However, for Alder (Alnus subeordata) and Maple (Aeer velutinum) common pattern in canopy layer was complete spatial randomness. The distributions of beech trees were negatively associated with other species. These results suggest species differences in favorable canopy condition.

The objective of this study was to find out the restrictions of seedling production of Lablally pine (Pinus taeda L.) in nursery (2003-2005). The statistical analysis of seedlings qualitative and quantitative parameters (collar diameter, height, survival and quality degree) showed that there were significant differences between sowing dates of autumn and spring. In respect to mean collar diameter, the autumn sowing date was better than the spring sowing date but respect to mean height of Lablally pine (Pinus taeda L.) there was not significant differences between sowing dates of autumn and spring. Also in respect to survival and quality, the spring sowing date was better than the autumn sowing date (P<0.01). Continuous investigation of seedling for two years showed that only a few seedlings had suitable growth at the end of the second year (almost %7). According to lab tests, there are not any evidence of pests or diseases on the dead seedling, so physical and chemical soil test was performed and the results showed that high pH and lack of the micorhiza were the soil factors which had negative effects on the seedlings survival and growth.

Soil microorganisms are important components of forest ecosystems. The term plant growth promoting rhizobacteria (PGPR) is used to describe non-symbiotic soil bacteria, which have potential to colonize plant root and stimulate growth. The aim of study was assessment the effects of Aeer velutinum seeds inoculation with PSBs. Five isolated bacterial strains (including Pasturella, Aeintobaeillus, Pseudomonas, Alealigense and Enerobaeter) were cultured separately in liquid Seperb medium at 25°C. Bacterial cells were isolated by centrifuge and resuspended in phosphate buffer saline (pH= 7.2) to a density of 3x108 cfu per ml. Seeds of Aeer velutinum were sowed in plastic pots and inoculated with bacterial suspension. Control seeds received sterile phosphate buffer saline. After seven months, seedlings were harvested. Shoot height, root length and their dry matter, available phosphorous in soil and seedlings were determined by standard methods. Results indicated the positive effect of PSBs on seedling emergence of Aeer velutinum. Inoculated seedlings had more developed root system than those of controls. In conclusion, results indicated the stimulatory effect of PSBs on seedling emergence and their growth. According to results, it seemed inoculation of a mixed inoculums will be more effective in stimulating of growth.