Iranian Journal of Forest and Poplar Research
Year:2012 | Volume:19 | Issue:4 (46)|Papers Count:19

For maintaining of Zagros forests role in wild life, water and soil conservation, the suitable solutions and methods for assessing the existing conditions and planning for management of this forests should be given. This study was carried out in forest regions around Ilam city (Karzan region) in a forest area of 86 ha with coppice and seed origin. At first, a 100 percent forest inventory was implemented. The coordinates of each tree on the ground was recorded and their quantitative attributes (crown diameter, DBH of seed origin trees) were measured. Using Arcview software in GIS environment the eight cells sample plots for different inventory networks namely 100 m×100 m, 100 m×200 m and 200 m×200 m were simulated and statistical analysis were done. The mean value of trees density per hectare for all three networks were calculated and compared with their real data (100 percent inventory) by t-test (a=0.05).Results showed that there is no significant difference between mean values in three inventory networks and the real mean value.

The purpose of this research is the possibility to recognize of trees canopy die back using Quickbird satellite images and mapping of its distribution in district one from Shastkolate forest, North-west of Iran. After geometric quality and radiometric evaluation of data, geometric correction of panchromatic image was carried out with 45 ground control points and RMSE of 0.65 at X axis direction and 0.78 at Y axis direction. Moreover, the multi-spectral images were registered with georeferenced panchromatic image with 60 ground control points and RMSE of 0.19 at X axis direction and 0.25 at Y axis direction. Using ratioing, principal component analysis and creation of suitable vegetation indices, some artificial bands were created and used as suitable bands for image analysis. In order to prepare the training area and to evaluate classification accuracy, sample ground truth were provided by recording the died back trees using DGPS on a 500 m×100 m systematic network and 360 sample plots with 1000 m² area. After selection of training area and suitable bands collection, data were classified with supervised method by using maximum likelihood and density slicing. Results of the classification accuracy evaluation on 4 main bands and also 7 selective bands by maximum likelihood algorithm and vegetation indexes by density slicing algorithm showed that overall accuracy amount and Kappa coefficient for 2 forest classes and died back for 4 main bands and 7 best selected bands by maximum likelihood algorithm were 77%, 0.56, 83% and 0.685, respectively. In addition, overall accuracy amount and Kappa coefficient for density slicing of NDVI and TNDVI vegetation indexes were 51%, 0.16, 56% and 0.19, respectively. Results showed that recognition of died back trees using Quickbird satellite image was not completely possible due to reflection of shrub and under storey plants, adjacent trees crowns and low ratio of reflection of dried branches in compare to rest green crown, which are registered as digital value of pixels.

Hornbeam is the most frequent species in forests of northern Iran. This paper aims to study the relationship between gap size and some quantitative and qualitative characteristics of hornbeam seedlings. For this purpose Khanikan district in Korkrood forest was selected in northern Iran. Four sizes of gap were selected based on silvicultural definitions including: area with less than 200 m², 200 to 500 m², 500 to 1000 m², and larger than 1000 m² and in each gap, 4 subplots each 2 m² were laid out. The current study was made in 2 phases: 1) study on light intensity using fish-eye camera, and 2) quantitative (including collar diameter and height) and qualitative characteristics of hornbeam seedlings. The obtained result showed that the intensity of light changed between 2 and 70 percent in different gaps and different locations of the gaps. The number of hornbeam seedlings increased with a relative increase in the light intensity initially and then decreased. Collar diameter and height of seedlings didn’t show significant differences among different light intensities. The number of seedlings was reduced significantly in the gaps larger than 500 m2. The best qualitative condition and the maximum number of hornbeam seedlings were observed in the gaps smaller than 200 m2.

In this study, wood yield of five poplar clones with Turkish origin were investigated in Karadj. Seventy five young trees (one year old seedling) from each clone were planted in a randomized complete block design on March 1996 in Alborz Research Center at Karadj. Diameter at breast height and height of trees were measured at the end of each growing season. Total volume, volume increment and annual current volume were calculated for each clone. Among the studied clones, Populus nigra 62.154 had the highest diameter and height with 20.5 cm and 14.67 m, respectively. The clone P.nigra 62.154 with 26.85 m³/ha/y showed the maximum annual volume increment, while Populus nigra 62.127 showed the lowest annual volume increment with 18.71 m3/ha/y. There was no significant difference among studied clones in term of volume increment. The results indicated that the maximum yield growth was obtained in the period of 2003 to 2006, in which 68.22 to 75.51 percent of total growth has been occurred.

First phase of research project for establishment and adaptation of different poplar species and clones in northern Iran was started on 1992 and lasts for 15 years. The studied species include Populus deltoides 77.51, P.d.69.55, Populus euramericana I-214, P.e.45.51, P. simonii, P. trichocarpa and the native maple (Acer velutinum) as control species. seedlings were prepared in the Safrabasteh research station and then planted with three replications in 2 ha research area at Siahkal in Guilan province. Each plot contained 25 trees with 4 m×4 m spacing. Results showed that P.e.45.51 and P. trichocarpa had the least mortality rate and the maximum diameter, height and volume, whereas the native maple (control species) showed the minimum diameter, height and volume. The mean annual volume increment of P.e.45.51 was calculated to 5.7 m3/ha/y in contrast to Acer velutinum with 0.53 m3/ha/y. Among the poplars, P. simonii was the weakest species and produced 0.65 m3 wood in hectare and year.

Nowadays, severe destruction in Zagros forests is obvious because of environmental and socioeconomical problems. In this context, the role of landuse planning in the optimal management of the resources is very important. In this research, landuse planning map was prepared for Sarab Darrehshar catchment in Ilam province, by system analysis method. For this purpose, the maps of slop, aspect and elevation were integrated and then the map of primary ecological units prepared. By integration of this map with maps of soil, plant typology and canopy, the final units map was obtained. Then, this map data and other ecological data driven from other maps, were collected in a table called as region ecological characteristics table. Prioritization of landuse in this study was performed by the modified quantitative and objective method. In the next step, landuse planning map with 18 types of different combination of consistent landuses was performed using ecological models of Iran, ecological capability evaluation model in Zagros forest (prepared in this research) considering socio-economical information of the area. Results indicated that the smallest area belonged to landuse of rural development with 36.7 ha and the largest areas belonged to watershed management, conservation and forestry with 3136, 2853 and 2288 ha, respectively. Areas of 1, 2, 3 and 4 of the quality degrees of forest landuse, were zero, 473, 1085 and 730 ha, respectively. Comparison of current map and landuse planning map revealed that a basic revision on kind and degree of the current activities in the studied catchment is needed.

This investigation was carried out in three distribution regions of Mountain Almond using typology maps in Qom province, central Iran. In each region, three landforms including slope, valley and ridge with four geographical aspects (north, east, south and west) were selected and physico-chemical soil properties, as well as some qualitative and quantitative characteristics of almonds were studied. Results showed that the maximum density of almond was found on slopes, whereas the maximum height, crown diameter, annual height increment and canopy cover were measured in valleys. Geographical aspect showed an important role on characteristics of almond, hence the maximum density of this species was observed on south and east aspects. In addition, the highest presence of almond was obvious on sites with light soils (moderate texture). Principle Component Analysis (PCA) indicated that potassium, phosphorus and lime showed the highest positive relation with both vectors (one and two), while the soil texture parameters (clay, sand and loam) showed negative relation with the second vector.

In this trial, 24 Poplar clones (10 clones of Populus deltoides, P. euramericana and P. alba as wide crown species and 14 clones of P. nigra as narrow crown clones) were studied in Sanandaj, western Iran during 2001-2008. Planting of cuttings were accomplished on early March of 2000 and transplanting of saplings and planting were conducted on early April of 2001 with spacing of 4 m×4 m for Wide Crown Clones (WCC) and 3 m×3 m for Narrow Crown Clones (NCC) in 2 separated experiments with 3 replications. Each plot contained 25 saplings that were planted as 5×5 rows (9 saplings as main and 16 for buffer effect). In each year, some morphological traits were evaluated. Results showed that in terms of diameter at breast height (D), tree height (H) and wood volume per hectare (V) there were significant differences among years and also between WCC and NCC groups (P£0.01). Although growth traits of tree diameter and volume during the period increased, but increasing rates in different years were different. Based on the mean comparisons of the years, there were no significant differences between the two consecutive years of growth (e.g., 2005 and 2006 etc.) in terms of the D and V traits in the NCC and WCC, but each year took place in a specific group for H in both NCC and WCC. P.a. Saghez in terms of D and V traits was different from others among WCC, but all clones of the NCC behaved almost the same from viewpoint of growth procedure. The growth rate of WCC was more than NCC, indicating the growth rate (diameter, height and volume) of WCC were higher than NCC. Based on the results and graphs of diameter (D) and wood volume (V) in both WCC and NCC, two stages of the rapid growth vs. three stages of slow growth were observed. This point indicates that the rates of diameter (D) and wood volume (V) growths are a periodic process in poplars (Populus spp.). In other words, diameter and volume growth traits had a periodic mode over the time. The phenomenon is a practical result to determine the time of cutting and harvesting of poplar trees. By calculating the growth years of trees, farmers can harvest them at the end of the rapid growth year and don’t need to remain the trees in the farm in the slow growth year. This reduces the costs of farm maintenance.

Estimation of biomass has many applications in forestry practices and researches. Randomized Branch Sampling (RBS) is one of the methods, which is used for estimating tree biomass. In this research, RBS method was introduced and the accuracy of biomass estimation was tested for total and crown biomass of 5 trees in the plantations of two species including Mulberry (Morus alba) and Black Locust (Robinia pseudoacacia). The plantations are located in Mobarake Steel Complex area in the semi-arid regions of Esfahan province in Iran. Actual biomass was measured by weighting all tree components and estimated biomass was calculated by RBS method. Actual and estimated biomass was compared by paired t –test. Results showed that there is no significant difference between crown and total amount of actual and estimated biomass for both species. Relative bias varied between 3.3 to 7.6 percent. Although results of this research by cutting 5 trees seem to be Preliminary, this research showed that RBS method can be considered as an accurate method for estimating tree biomass.

The current research is the first step on integral investigations for selection and production of appropriate seedlings and clones for development of poplar plantations. Diameter, height, survival and homogeneity of 70 clones of native and exotic poplar species were studied in an experimental nursery in central Iran, Markazi province in frame of randomized complete blocks design with 3 replications. Results indicated that P.x. interamericana from hybrid groups, P. trichocarpa 044.62 from section Tachamahaca, P.a. 44.9 from section leuce, P.e. I-154, P.n. 63.135, P.e. 476, P.n. 62.140, P.n. 62.197 and P.e. triplo from section Aigerios showed the maximum values of the studied parameters. P. ciliata from section leucoides and P. euphratica from section Turanga showed the weakest values.

Recently, local farmers prefer to convert their paddy field to poplar plantation in the Guilan province. The aim of this research was economically evaluation of poplar plantation compare to paddy field in the Guilan province. In order to fulfill this project, cost and revenue data of plantation and paddy field has been collected via questionnaire. Net profit has been calculated for plantation and paddy field during 8 years. Revenue obtained from final harvesting has discounted from plantation and annual cost, and then the result was compared with annual net profit of paddy field per hectare. The results indicated that annual net profit of plantation is almost two times more than paddy field.

Phenology describes the phenomena that happen periodically in the life of living creatures. The differences between the appearance of this phenomena result in phenology behavioral patterns. The phonological studies are important for many applications such as typology in silviculture, afforestation, natural regeneration, livestock grazing planning, and species selection for park designing and decorating. Detecting changes in phenology of plant species receives more attention due to undergoing current climate changes studies. According to the literature, there are two main methods for registering phonological events including descriptive and remote sensing approaches. In this paper the advantages and disadvantages of these methods are discussed, and a new quantitative method based on the leaves and fruits colours changes is proposed. A case study on Olea europaea L. was used to describe the quantitative methods. In the proposed quantitative method, imaging of the plant parts (Leaf and fruit) was done in every other week intervals. Using smudge tools in Photoshop software, the colour of each part of the plant were uniformed and their RGB digits were assessed. Then the percentage of each colour channels was determined and their diagrams of changes during the time were analyzed. This method results in an exact determination of the plant transformation. The studied method analyzes image series of plant parts to detect color changes; hence, it provides a base to study of phenological changes in a quantitative manner. By detecting the RGB digital number, it is easy to report the exact color and it provides a comparable bases. Descriptive method is the most common way for phenology studies. In this method, viewpoints of the observer extremely affect the result and may cause misreporting during an observation or recording. The remote sensing method is more appropriate to be used in large scales environmental condition monitoring programs and also for vegetation responses to universal continental changes. This method is not suitable for small scales studies. The RGB based reporting system can be useful in other field of studies such as pedology, geology, horticulture and so on.

Urban forests with various ecological and environmental benefits are one of the most important ecosystems, therefore, study of ecological parameters in urban forests is essential. In this research, one of the oldest urban forests of Sanandaj city, Taileh, with area of 1.7 ha was selected. Direct method (leaf gathering from the crown) and 100% inventory method was used to estimate leaf biomass and leaf area index (LAI) of Celtis caucasica, which was the main species. Firstly, different quantitative variables such as diameter at breast height, collar diameter, tree height, crown length and small and large diameter of crown were measured. In addition, the leaves of one fourth of the tree crown were picked off and after weighting, their dry weight were measured in laboratory. Gravimetric method was applied for calculating LAI, in which the relationship between leaf area and it`s dry weight used to estimate the total area of whole tree leaves. Allometric equations were calculated for estimation of leaf biomass and LAI. Based on the results, the mean values of leaf biomass, Specific Leaf Area (SLA) and LAI were 37 kg, 103.5 cm2/gr and 3.7 for C. Caucasica, respectively. The compound variable, DBH2×H, was the most effective factor to estimate the leaf biomass (R2=0.69), but in LAI equation, the root of DBH had the main role (R2=0.72).

Juniperus excelsa has wider distribution than other species of Juniperus in Iran. In most of habitats, different individuals have rough conditions especially in soil. One of the major problems is the lack of regeneration which can face the life and future of these habitats with challenge. The biological properties that are most useful for detecting the deterioration of soil quality are those that can be most closely related to nutrient cycles, including soil respiration, microbial biomass, nitrogen mineralization capacity and the activities of soil enzymes. In particular, enzyme activities are especially significant in soil quality assessments because of their major contribution to the soil ability to degrade organic matter. This research was carried out to study the interaction of soil enzyme activity and regeneration of Juniperus in Chaharbagh habitat in Golestan province of Iran. Sampling was done from 0-10 and 10-20 cm depths of soil under trees with and without regeneration. The activity of acid and alkaline phosphatase, dehydrogenase, urease and microbial biomass enzymes has been measured using reaction with substrate and by means of spectrophotometer. Results showed that activity of these enzymes and microbial biomass was significantly more in 0-10 cm than 10-20 cm depth because of more oxygen, suitable dispersion of roots and adequate nutrients. Existence of some microorganisms in upper depths has accelerated mineralizing nutrients. Regenerations uses these suitable nutrients. After formation of regenerations, their interaction on microorganisms have caused more permanency. This desired condition has preserved both microorganisms and regenerations.

Competition is a fundamental ecological process driving succession in a forest and affects on forest stand structure. Understanding competition among tree species is especially important when management goal is to mimic the dynamics of natural ecosystems. Three 1-ha stem-mapped plots were established at three developmental stages of initial, optimal and decay in an intact natural, unmanaged and uneven-aged beech (Fagus orientalis Lipsky) forest in the Kelardasht region, in the north of Iran. Diameter of all trees with dbh greater than 7.5 cm were recorded. All of the measured trees were assigned into four diameter size classes as small, medium, large, and extra large timbers. Spatial associations among tree size classes were analyzed using bivariate Ripley’s K-function. Results showed that association patterns (i.e., attraction and repulsion) varied among different size classes across different development stages, likely influenced by shade-tolerance characteristics, seed dispersal limitation and intra-specific competition of beech trees. This study highlighted the application of bivariate Ripley’s K-function and the importance of competition in understanding stand dynamics of beech forests across development stages. The information derived from these untouched stands could be useful as a key reference for developing management programs, silvicultural interventions, plantations and reforestation programs as well as giving us insight into competitive processes to enable better modeling of beech stands dynamics.