فصلنامه تحقیقات جنگل و صنوبر ایران
سال هفدهم شماره 2 (پیاپی 36، تابستان 1388)

Vegetative Enrichment of watersheds is one of the important objectives along with long term policies of the state for natural resources. Therefore, afforestation development needs the participation of people. Multipurpose tree planting helps to conserve soil and water and can be a suitable policy to enhance the participation of people. In order to determine the best species, 5 genotypes of almonds and a wild pistachio genotype were selected during the nursery phase and were planted as un-irrigated condition afforestation, on eastern, western, and southern aspects using randomized complete block design. Variables including mortality, collar diameter, seedling height and crown diameter were studied. Results showed that planting of two almonds genotypes (3 and 6) on western aspects considering their higher survival rate and growth attributes is recommended. Concerning the height survival rate and growth and the possibility of providing partial irrigation during summer periods, planting on southern aspects could also be recommended.

Volumes of 122 trees were measured using both regular and 3P volume remeasurement methods. The trees were selected according to sampling instruction out of 800 trees which have been marked in district one (Shourab) at Golband forest. Results indicated that the calculated volume by 3P method for industrial wood was 12% more and for fuel wood 15% less than the regular method, respectively. The reasons of such results could be firstly, because of considering broken logs with dbh>20 cm during harvesting operations as industrial volume in the 3P method. Secondly, because of measuring the logs with more than 6m length in regular method that is effective on industrial volume decrease. For promoting harvesting section, we can change some part of administrative regular remeasurement instruction. Therefore, besides respecting to scientific implementation of this method, improving of staff skills and forest and timber products should be taken into account.

This study was carried out in Carpino-Fagetum orientalis, Rusco-Fagetum orientalis, Fagetum oriental and Alno-Fagetum orientalis forest communities of Namkhaneh, Gorazbon and Chelir districts of Kheiroudkenar forest. The aim of the research was investigation on relationship between understory vegetation and soil condition and to determine the indicator species for predicting of specific site situation of Fagetum communities of the study area. Selective stratification sampling method was used to locate samples. One plot is sampled on each aspect in each community. Totally, 120 sample plots were selected in the Fagetum communities in the study area. The plot size was 400 m2 considering to minimal area method. At each sample plot, floristic list and an estimate of percent cover and abundance of each vascular plant in separate strata were recorded by using of Braun-Blanquet scale. At the center of sample plots, two soil samples were taken from 0-10 and 10-30 cm layers of mineral soil. The physical and chemical soil properties in each sample were analyzed. Two ordinations approach, DCA and CCA, were applied to determine the relationships between vegetation data and environmental variables. Results showed that the distribution of plant species is mainly associated with aspect, clay, total nitrogen, organic matter, phosphorous and exchangeable cations. Geranium robertianum, Mercurialis perennis and Ruscus hyrcanus indicate high soil fertility, while Festuca drymeia, Blechnum spicant and Epimedium pinnatum show low soil fertility. Carex remota, Sanicula europaea and Carex divulsa indicate a moderate soil fertility conditions.

This study aims in investigation on alteration of understory composition in Pine (Pinus eldarica Medw.) plantations with different ages. For this purpose, three Pine plantations in age of 8, 21 and 40 years were selected and sample plots were loud out in systematic-random method. Vegetation cover, density and frequency were studied for each species. Results showed that 47, 61 and 26 species were recorded for understory plants in 8, 21 and 40 years old plantations, respectively. Astragalus verus with Ecological Value (EV) of 33.36 was the dominant species in the 8-year old plantation, while Aegilops umbellulata with EV of 26.31 was the dominant species in the 21-year old plantation. In the 40-year old plantation, Trifolium stellatum was the dominant species with EV of 61.87. The Similarity Index showed the highest similarity between 8-year and 21-year old plantations. The highest Shanon and Simpson Index were computed in the 21-year old Pine plantation.

Poplar grows fast and can be used as row material in industry, pulp for paper, lumber and building products and as buffer strips to conserve plantation. Salinity has a major impact on plant growth and productivity. As tolerance of various poplar species to salinity is variable and imprecise, an experiment was conducted to evaluation different levels of sensitivity to salinity which consisting of factorial combination of 4 clones and 5 treatment {0.0 (control) 0.32%, 0.64%, 0.96% and 1.28%} of NaCl and CaCl2 with tree replications in a greenhouse in Shehid Fozveh Research Station of Esfahan Province from 1377 to 1379. Poplar clones include Populus nigra 63/135, P.deltoides 79/51, P. alba 44/9 and P. euramericana var. triplo. Salinity treatments were imposed by adding NaCl and CaCl2 (2:1molar ratio) to half concentration Hogland Nutrition solution that ranged from 0 to 1.28% m/v percent. Result of this experiment showed that number of leaf, dry weight of leaves, stems and roots were decreased with increasing salinity. With increasing salinity, amount of Na+, Ca²+, Cl- and K+ were increased. P.euramericana var. triplo and P.deltoides 79/51 growth had most reduction rate. P.alba 44/9 showed higher tolerance compare to the others.

Goal of this research was comparison of pure and mixed plantations of oak and companion species and introducing best treatment for rehabilitation of northern oak forests. This research was performed since 1994 with establishment of pure plantation of oak and mixed with maple, hornbeam, hackberry and Siberian elm in Chamestan Forest and Rangeland Research Station. The plot dimension was 25m×25m with planting distance of 1m×1m. The two lines of outer planting layers was omitted as buffer zone. Other trees were measured completely. The one way ANOVA and Tukey HSP tests were used for comparison of treatments. The study showed that better results for oak was achieved in mixed plantation with hornbeam (based on survival, diameter at breast height and H/D ratio) and Siberian elm (based on total height and pruning height), while the pure plantation and mixed with maple showed unsuitable results.

Fire in the Zagros forests disturbs some parts of these forests every year. Manna oak species (Quercus brantii) as the main species of these forests is stimulated by fire. In order to investigate post-fire resprouting of Quercus brantii, 133 sprout clumps were selected randomly in a burnt area of the Zagros forests in Kermanshah province. Some variables were recorded and classified as follows: dbh of the thickest sprouts in 4 classes, number of pre-fire sprouts in 5 classes, fire intensity in 5 classes and the number of post-fire sprouts. This study was conducted under completely randomized design with three replications for each class. Results showed that post-fire resprouting is positively related to the number of pre-fire sprouts and the fire intensity, whereas it is negatively related to the diameter of the thickest sprout. In general, the more pre-fire sprouts and more fire intensity as well as the smaller diameter size of pre-fire sprouts, would cause more post-fire sprouting in manna oak.

Visualization is one of the best methods to represent data from natural environments. In this research, the variation of the forest cover was visualized at a part of Zagros forests (741 hectare) using aerial photographs and satellite images. Geometric correction and relief displacement was done on 1997 aerial photographs. Aerial photographs of 1955 and 1969 were corrected by approximate image correction method using georefrenced images. Forest boundaries were determined on all of the images by visual interpretation techniques, However classification of 1997 aerial photographs and satellite image were done automatically using Maximum likelihood classifier. Aerial photographs of 1955 and 1969 were classified by dot grid. Shadow index was specified by determining the accurate canopy amount on 74 random trees and compare them with data deduction from images. Likewise, field data were collected using 141 circular 1200m sample plots in a systematic random grid (100m×300m). With preparation of essential data, visualizations were done on different scale in the 3DNature software. Results indicated the notable reduce of forest area (37%) since 50 years ago. Maximum amount of canopy drop (45%) have been occurred from 1955 to 1969. Canopy percent on forest region indicate ascending trend (+15%) from 1969 to 1997 and lightly descending trend from 1997 to 2003.

In order to amend usage effects of N fertilizer on Spruce seedlings and reduce its environmental compacts, an experiment was conducted during years 2005-2006 to investigate effects of N fertilizer application amount and time on growth of one and two year old seedlings of Spruce (Picea abies) in a nursery near Moscow city. The fertilizer application time was considered on account of phenological stages. The fertilizer amount and time treatments were applied simultaneously. The fertilizer amount treatments consisted of 0 (control), 40, 110 and 180 kg/ha. The fertilizer time treatments for two year seedlings consisted of tree and six phenological stages during 2005-2006 and for one year old seedlings consisted of four phenological stages in 2005. This trial was carried out under spilt plot in completely randomized block design with three replications in the nursery. Results showed that application of N fertilizer time treatments affected the seedlings height and diameter greater than the amount treatments. Interaction of fertilizing time and fertilizing amount treatment at first growth period on seedlings heights was significant (probability of 95%) at two fertilizing time treatments, including: 5.07.05 or interval between completing root system and stop of summer growth (difference between control and the other fertilizer amount treatments) and 23.08.05 or interval of forming lateral bud and beginning formation of apical bud (difference between both fertilizing levels of 110 and 40 kg/ha and in one side control and 180 kg/ha on the other side). From time point of view, most nutritive requirements of the two year old seedlings, were observed at phenological stages of intensive shoot growth and increment and bud development (G1-B2), indicating that minimum consumption of fertilizer in this period was able to leave equal or greater effect on seedling growth compared to maximum consumption at the other phenological stages.

Damping off is one of the prevalent diseases in forest nurseries, which makes sever damages to conifer seedlings every year. Damping off caused to changes in color and curvature of seedling into puteal and become to seedling mortality. This study was executed in order to identify the causes of damping off in conifer seedlings in the nurseries of Lakan in Guilan province. For this purpose, the infected seedlings were collected and transferred to the laboratory for further research. After isolation and purifying the morphologic characteristics, the macroscopic and microscopic characteristics of the pathogenic agents were studied. The detected isolated pathogens were: Rhizoctonia solani Kuhn, Pythium sp., Fusarium solani (Mart.) Sacc., F. oxysporum Schlecht, F. semitectum Berk. & Rav. and Fusarium sp. The all symptoms of pathogens distinguished were similar to the primary contaminated seedling. The obtained results showed that the abundant of Pythiium sp. was higher than the other patogens in Lakan nursery. We can mention that, this is the first report of the presence of Fusarium semitectum var. majus at the pine trees in the Guilan province in Iran.

Rapid early growth of poplars established from hardwood cuttings is critical to the success of Poplar cultivations. Without rapid growth, weed competition can significantly affect tree survival and productivity. The effects of cutting age and planting depth on early survival, growth and biomass of Populus deltoides clone 69/55 were studied in cold frame test in Guilan province. Results showed that early survival, aerial biomass, leaf and shoot dry weight, shoot number and length and finally root to shoot ratio (r/s) were significantly affected by cutting age. Planting depth only affected aerial biomass and shoot dry weight, however had no significant effect on the other variables. This study found that one year old cuttings planted about two third length deep, are preferable for vegetative propagation of Eastern cottonwood by cuttings.

This study attempted to investigate leaf area index in Quercus macranthera coppice stand. A forest of 278 hectares located at the northeast of Khalkhal was selected as the study region. The leaf area index was determined by direct method and by collecting all the leaves from the 60 coppice sprouts and measuring the mean leaf area and crown cover area of each coppice group. To determine the soil properties and its relation to the leaf area index, samples from the depth of 0 - 10 and 10 - 30 cm was selected. Physical (percent of clay, silt and sand) and chemical (amount of nitrogen, phosphorus, potassium, organic carbon and pH) properties of soil samples were determined in the laboratory. As a result, the leaf area index of oak species was 3.33 and the average dry weight of leaf was estimated to be 1864 kg/ha. No statically significant relations were observed between the phisiographical conditions and crown canopy density to the leaf area index. Considering the characteristics of the stand and soil, the aboveground biomass, diameter at breast height, tree height and the soil nitrogen showed the maximal correlation with the leaf area index.

In order to distinguish the Mondell pine species (Pinus eldarica) from its two natural generated morphotypes (i.e. Ball-shaped and Conical-shaped pines), qualitative alteration of peroxidase enzyme and the assessment of the enzyme activity were compared by use of polyacrylamide electrophoretic method on PAGE system. Furthermore, lignin contents of the needle and stem samples along with 13 macro morphological characteristics of individuals were compared with each other. Results showed that the isozyme pattern of three types of the studied pines, the activity of this enzyme and lignin contents were similar. Whereas, the morphological traits comparison, indicate clear differences in the pines. These, state that despite of obvious morphological differences and application of peroxidase enzyme in physiological changes, plant evolution studies, genetic consideration and identifying genus, species and subspecies but at least soluble portion is not suitable marker for distinction of these pines. The results of this study also, propose to use of molecular markers and cytogenetically studies in order to specify the cause of this occurrence.

This research was conducted to investigate on spatial structure and estimation of tree attributes in a forest plantation in the Caspian region of Iran. Field sampling was performed based on a 50m×125m systematic grid in a maple stand (Acer velutinum Boiss.) at age of 18 years using circular samples of 200m2 area. Overall, 96 sample plots were measured in 63 hectare and 14.25 hectare was inventoried as full census area, as well. Experimental variograms for forest stem basal area, stem density and tree height attributes were calculated and plotted using the geo-referenced inventory plots. The calculated variograms of basal area and height showed a high spatial autocorrelation, which fitted by spherical models. However, stem density showed a large amount of nugget effect. Based on variography results, optimal sampling distance for stem basal area and density obtained 165m and 350m, respectively. Estimations for basal area and height were made by ordinary block (15m×15m) kriging and cross-validation results showed that all the estimations are accurate. Furthermore, the estimated kriged mean of basal area showed no significant difference to the real mean in the full census area, while kriging in term of statistical precision was two times better than sampling. Therefore, geostatistics is able to capture and describe the spatial variability as well as estimates tree attributes (not stem density) in this kind of forest plantation, accurately.