نشریه علوم و فنون منابع طبیعی
سال سوم شماره 3 (پاییز 1387)

The White Poplar species is one of the important and native trees in the northern forests of Iran. This species can be seen in the lands with suitable humity and along the riversides as the mono – base or in group with other species and as the pure or mixed with other species such as Alder and Ash. Unfortunately, due to the destructicn and too much use, this species is at the risk of demolition. Due to the importance of this species and saying that regeneration will ensure its existence , so this study was condueted on its natural regeneraticn. This study aimed at specifying the area of the White Poplar in the riversides of Chalous. A study on the regeneration or lack of regeneration and statistical analysis of some characteristics of the cut species such as height, quality, regeneration stages, etc. was made. This research was done on this species in the riversides of Chalous by the 100% statistical sampling . The total area of the White Poplar along the riversides equals to 24833 m2 . About 289 White Poplars with the average diameter of 45 cm and height of 19 m were counted in this study . These trees are seen in the riversides ranging from the Chalous bridge to Marzanabad. 350 White Poplars with the average height of 140 cm were counted in this study which had poor regeneration due to their base trees. The cause of diminishing the number of this species was the demolition of its natural environment along the Chalous riversides due to the natural and unnatural elements , especially the human , animal factors , and the overflowing of rivers . The studies showed that 98% of White Poplar seedlings had non – genus origins, and this was due to its high capability in non-genus reproduction and most of pines. 79% of White Poplar seedlings of this area had a good quality and most regeneration of White Poplar , about 56%, is in the seedling stage. Finally, the study on regeneration of the White Poplar in the riversides of Chalous in comparison with areas such as Ezydeh, Nour, Safrabasteh showed that the regeneration did not have appropriate quality and quantity .

Information about the structure of the urban forest such as the compoition of species and the density of canopy cover is prerequisite for planning, designing and managing of the urban vegetation on a local and regional scale. So in this syudy, different methods of inventory, including 100% inventory with 15 meters transect and aerial photos (with 1:8000 scale) and IKONOS images (with 1 meter spatial resolution) were compared in order to find the optimum and most appropriate method in estimating the canopy cover of street trees in one kilometer in Shahrivar 1386. In 100% inventory considered as the basis for comparing with other methods, the canopy cover of trees is estimated in every 15 meters transect. The results of paired t-tests analysis showed that there were not significant differences between the 100% inventory, aerial photos (df=38, t=0.709, and p=0.48) and IKONOS images (df=38, t=0.887, and p=0.38). The results of regression analysis also indicated that the aerial photos (R2=0.87), and IKONOS images (R2=0.62) were suitable for estimating the canopy cover of street trees. The expenses spent in 100% inventory for estimating the canopy cover of street trees were respectively 6.5 and 34 times greater than those spent in estimating that with the aerial photos and IKONOS images as the expenses spent in the aerial photos were also 5 times more than those in the IKONOS images. Therefore, based on the results of the study, we can suggest that the satellite images with high spatial resolution such as IKONOS and Quickbirds images with lower times and expenses can be used for estimating the total canopy cover of street trees, and the better management of them in metropolises and to be aware of changes in these valuable resources in short periods of time.

In this paper, at first an attempt was made to estimate the amount of consumption of the total and per capita of each of the printing, writing papers and newsprint and to determine the amount of the internal and export products in the consumption balance by using the information and data regarding the production, export, and import during the past decade. Then based on the idea that the amount of consumption of the kinds f paper products under the study was a function of both the per capita of the produats in question and the population in different years, the linear regression analysis was used to survey the population growth and per capita consumption in the past (the years between 1373-1382 (1994-2003) and to estimate the total consumption during the years 1384-1390 (2006-2011) as well as the year 1400 (2021). Finally, based on the estimation of the amount of consumption (demand), each of the papers under the study during the predicted times and based on the observation of the most important projects in practice for the production of paper and cardboard which will be produced during the few years in the future, the amount of shortage for the purpose of meeting the full demand which must be satisfied through the import will be determined. The results of study show that the newspaper consumption for the year 1390 (2011) will pass the 150,000 tons, and it will reach to 250,000 tons in 1400 (2021) for per year which will cause the shortage for satisfuing the full demand in 1400 (2021) to reach to 194,000 tons per year. Iran will be obliged to meet more than 78% of its needs through import. Regarding the writing and printing papers, the studies show that the consumption of the said papers will exceed 415,000 tons in year 1400 (2021). It can also be expected that by beginning the projects undertaken regarding the papers in question, Iran will attain self-sufficiency by the year 1390. Of course, attaining this important target is possible when the said factories start their activities in due time, and this seems to be optimistic.

In this study, the woods of the imported Aspen, Beech and Horn Beam were randomly selected from the Mazandaran Wood and Paper industries (MWPI) from which standard chips were prepared and then the pure CMP pulp by 85% yield was produced. Then the biometrical properties of fiber, the chemical components of wood flour and CMP pulp, the decreased percentage of the chemical components and hand-sheet properties were measured and analyzed statistically. The results showed that the imported Aspen has shorter fiber length, more fiber diameter and lumen and smaller cell wall thickness than the Beech and Horn Beam .The imported Aspen wood has the least Klason lignin and the most Holocellulose from the chemical component point of view. Also, the hand-sheet properties of the CMP pulp of the samples under the study indicated that the tear strength and burst strength of papers obtained from the Beech and Horn Beam were smaller than the imported Aspen.

In this study, three healthy planted maple wood trees were randomly selected from the Chamestan area in Noor, and then they were cut down. The speciments were studied to measure their physical and biometrical properties (in the longitudinal and radial directions) according to the D143 standard regulation of ASTM (1990). The properties such as special density, percentage of moisture content, average annual growth, fiber length and dimensions, and biometric ratios were measured. The results showed that the special dry density decreased, and the ratio of moisture increased, and the dimensional chang also decreased in the longitudinal direction of trees from the bottom to the up, and there were no significant differences in the properties of these three heights. Also the means of each of these properties were 54% gr/cm3, 56%, 12.85% and 13.23% respectivly. The average fiber length, biometric ratios, Rankles and flexibility were 870.26 microns, 38.01, 90.01 and 55% respectively.

Among the few species in Iran-Turani forests, Eucalyptus is considered as the most important species in the Sistan and Baloochastan region, and it is of much use and application in the wood industry. The easy plantation, the growth rate and other advantages caused this species to spread to different parts of the world and to be planted in many countries. In order to examine the properties of Eucalyptus Cameldulensis wood, six healthy trees, of two age groups of 14 and 20, were sampled from the Agricultural Research Center of Zabol and their physical properties and fiber length were measured using the standard ASTMD143 and Franklin method respectively. The results showed that an increase in the age of trees would increase the oven dry density, volume swelling, volume shrinkage and fiber length of wood species of Eucalyptus.

Absenthium, a plant of the compositae family, is a grass which is static and has the height between 40-60 cm and even one meter which grows naturally in the heights of up to 2000 meters. In this study, the flowering twigs of Absenthium were collected from the natural vegetatives in Kojur area of Nowshahr in three time intervals: in the morning (at 6 a.m.), at noon (at 12), and in the afternoon (at 20 p.m.) in khordard, 1387, and then the samples were dried under the shade condition. Then the essential oil was distilled and collected in two different time intervals (two hours and four hours) by the Klonger apparatus and then was injected into GC and GC-mass for the analysis. Based on the dry weight of the plant, the output of the essential oil samples obtained in the morning, at noon and in the afternoon were 0.97%, 1.17%, and 1.12% after two hours, and 0.92%, 1.02%, 0.97% after 4 hours respectively. This shows that the amount of essential oil in the afternoon sample was greater than the other samples. Of the 20 extracted compounds, ß-Thujone, 1,8 Cineole, ß -Pinene, ∂- Phellanderene were the main ones after 2 hours, and 2-Ethyl, 4-Methyl, 1- Phenil, 1,3 Pentadien, Nuciferol , 7-Ethyl, 1,4 Dimethylazulene and Germacrene D were indentified as the major components after 4 hours.

Determining the number of shrub plants per unit area of rangeland for the right management and substantial development of rangelands is an important and essential issue. The distance methods are used to estimate the density of wood shrub plants. This study was conducted in order to compare the efficiency of distance methods from the accuracy, precision and time points of view. This study was done on the regular shrub species of semi-steppe area of Chapar Ghoime in the north-east of Gonbad Kavous. Three one-hectare areas of shrublands of Atriplex Lentiformis were selected for the study. Four 100m transects were located on each of the 1-hectare areas, and 20 sampling points with 5 meters distance from each other were specified on the length of each transect. The methods for comparing the density were: point-center quarter, random pairs, the nearest neighbours and closest individuals. The number of shrubs in each one-hectare area was precisely counted, and the samples were selected as the control ones. The standard deviation and multiple Duncan test were used to compare the methods with the control method from the precision viewpoint, and to compare the methods from the accuracy point of view, the relative difference of each method with the control method was used. The analytic hierachy method was used to determine the most efficient distance method of estimating the density. The results showed that the nearest neighbours, the fastest and most correct methods, and the closest individuals were the most precise distance methods of estimating the density of this species. The most effective method of estimating the density in the research and study projects was the method of the closest individual.