فصلنامه پژوهشهای علوم و فناوری چوب و جنگل
سال بیست و دوم شماره 3 (پاییز 1394)

The aim of this study was the investigation of different light and irrigation treatments on growth indices and some morphological characteristics of ziziphus nummularia seedlings. In order to plant seeds completely randomized experimental design with two factors and 30 replicate were used. Irrigation factor at two levels (daily and every other day) and light factor at 3 level (full sun light، 75% light، 50% light). Samplings were performed at 3 times. Leaf number، leaf area، root length، shoot length and collar diameter were measured and root biomass، shoot biomass، total biomass، slenderness coefficient of seedlings، shoot root biomass ratio، net assimilation rate and relative growth rate were computed. Results showed that there are significant differences in some seedling characteristics in all sampling times، and 75% light and daily irrigation was determined as the best treatment. Also in the second time interval RGR and NAR had maximum amounts in 75% light and every other day irrigation. Results showed that the young seedlings of ziziphus nummularia have the best growth in midshade and enough moisture

Yearly hundreds fires occur in forests and rangelands and various regions of Iran. Identification of areas that susceptible to fires the most important step in reducing damages caused by fire and also forest and rangeland resources management and in general natural resources. The study area in this research is part of the Sardasht forests in West Azerbaijan province. In this research with extracting recorded information about occurred fires in Sardasht forests, location of occurring fires were identified and using 10 effective factors in fires in this region (Including: elevation, slope, aspect, land use/land cover, average annual precipitation, monthly average maximum temperature, population, distance from agricultural lands, distance from streams and distance from roads) forest fire risk in GIS using fuzzy weighted linear combination (FWLC) model evaluated and mapping of fire risk in five risk classes (very low to very high) were provided. For fuzzy modeling of value of each factor the fuzzy membership functions and for the weight to criteria Analytical Hierarchy Process are used.Fire risk map result showed that about 60 percent of the study area has a high fire risk. Also, after the integration of risk map with real fire areas, result showed that nearly 92 percent of the burned areas are located in high and very high risk classes.

In the paper industry, Twin roll press machines are utilized for recovering the dissolved materials resulting from the process of transforming wood into pulp and efficiency has a considerable role in wasting resources. The present research was performed for the purpose of showing the effective factors on efficiency by using a mathematical model based on the pattern of simulating the System Engineering Analysis. The Press function was analyzed according to the same principle. Research results show that in a fixed amount of production, the efficiency of washing the twin roll press has a direct relationship with the amount of fresh water and an indirect relationship with the dry percentage of diluted pulp (pulp consistency) in the related Press. The present research shows that the concentrated of soluble materials entering into the Presses has no effect on efficiency, but it is effective in the amount of recovered solution.

The pulp color reversion, at the end of bleaching, and non-totally consumption of peroxide are two problems in high-yield pulp bleaching. In this study, the effect of TAED, at the end phase of bleaching, on process and pulp properties was investigated. Hardwoods chemi-mechanical pulp (CMP) (85% yield), was bleached by mono-stage alkali peroxide process. Treatments comprising three different charges of peroxide (1.5, 2 and 3%) and alkali (sodium hydroxide) (1.12, 1.5 and 2.25) with and without using TAED at the end phase of bleaching i.e. the last 10 minutes. The results indicated that, the pulp brightness and bleaching selectivity increased by chemical charge rising, but with decreasing slope procedure. The chemical charge rising led to an increase in residual peroxide and filtrate COD load. TAED using, through reduction of alkali darkening reaction, caused to improve the brightness and selectivity, and reduce the COD load. Residual peroxide amounts of treatments, which have TAED treatment, were significantly decreased.

In this study, neutral sulfite semi-chemical pulping (NSSC) of the grain sorghum stalk (Sorghum bicolor) was investigated to produce fluting paper. The results showed that the highest screen yield (45.74%) was obtained using 30 min and 12% and the lowest screen yield (37.51%) attained at 90 min and 14%. Two cooking conditions were selected as optimum including 12%, 10% chemical charge and 30, 60 min cooking time according to the screen yield. The selected pulp freeness decreased to 400 ml. CSF by PFI-mill beater and then hand sheet made with grammage of 127 g/m2. Comparison of selected pulps strength including tear, tensile, and burst indices, RCT, CMT, and CCT carried out by normalization method. The result revealed that optimum NSSC pulping for grain sorghum stalk could be achieved by 10%, 60 min., and 170°C.

Understanding soil carbon fractions in relation to global warming is important for improving soil carbon management in natural forest ecosystems. Therefore, in this study we measured the contents of soil total organic carbon (SOC) in soil upper layers (0–20 cm) along a natural altitudinal transect (100–1400 m a.s.l.) in northern slope of Salaheddinkola forests, Nowshahr. Accordingly, vegetation data based on Braun-Blanquet method with some environmental properties were recorded in totally 77 plot with an area 400 m2 including seven classes of altitudinal gradient. Four ecosystem units were distinguished by using combined results of clustering (based on environmental data) and TWINSPAN (based on floristic data) as numerical classification analysis. Results analysis of variance showed that the amount of soil carbon sequestration had significant difference (0/05> P) in the four ecosystem units and third unit, which represents beech-hornbeam forests, to be allocated the largest amount of carbon sequestration (73/57 ton/ha), Because of the establishment of this unit in higher elevations and then high density of beech. Results of stepwise regression showed that nitrogen percentage, sand percentage and altitude were the most important factors affecting soil organic carbon content. Totally, the results of this study reiterate that the variability of soil carbon sequestration does not show a regular pattern along the altitudinal gradient and ecosystem units by exhibiting a proper distinction of environmental changes in habitat can be priority used in soil carbon stock variations study.

In order to establish in vitro proliferation of new hybrid poplar “Mofid”(Populus euphratica Oliv. × P.alba L.), shoots were collected from mature tree in Research nursery belongs to the department of Research Institute of Forests and Rangelands. Explants with single node were disinfected by different isolation treatment. Mercuric chloride with % 0.1 (W/V) concentrated solutions for 1 minute with 90% survival rate of explants appeared to be suitable disinfection treatments. The establishments of explants were taken in MS medium supplemented with 0.5 mg/l BA and 0.01 mg/l IBA. For evaluation of most affecting factors on in vitro proliferation, the experiment was conducted in a completely randomized design with 9 treatments including three media (MS,WPM and DKW) and three growth regulators hormones (BA+ 0.5 mg/l, 2ip +0.5 mg/l and BA+0.5 mg/l plus 2ip+0.5 mg/l) with three replication. Analysis of variance indicated that there is significant differences between media for maxillary shoot proliferation at α=0.5% level. Highest shoot proliferation (3.2 mean number of new induced shoots per explant) and shoot elongation (1.465 cm mean height of shoots) have been observed for DKW medium containing 0.5 mg/l 2iP plus 0.5 mg/l BA. Numerous micropropagation circles have been initiated by in vitro nodal segments of shoots. Roots were induced in DKW hormone free medium after two weeks. Acclimatization of rooted plantlets took place in polyethylene caps jam bottle, containing a light soil (Peat, hummus and sand in equal percentages) in growth chamber. Successfully acclimatized plantlets transferred to field.

Soil organic matter (SOM) has form only a small fraction of most forest soils (less than 12 percent), although it has an important impact on the physical, chemical and especially biological properties of soils. Organic carbon is accessible and decomposable carbon pool that could increase microbial biomass. By different way, organic carbon increase soil aggregation and porosity and finally forest production. The aim of this study was to investigate the relationship between soil properties including texture, porosity, SOM and microbial respiration with stand properties in order to find the most important relation between stand and soil. In this research, 30 sample plots in mixed Beech forest selected with 400 square meters area. Trees allometric characteristics with DBH greater than 20 cm were measured and some physical, chemical and biological soil properties determined by standard methods. Results showed Beech was the main stand species because of abundance and became more GBH. Tree crown area and GBH were the most important factors those affecting soil properties. A direct relationship was founded between trees crown area, SOM content and microbial respiration. Therefore we should pay special attention to the porosity and soil organic matter in the management of mixed beech stand to increase the stand volume and GBH. The results confirmed that changes in microbial respiration which is affected by soil sand variation in addition to SOM, therefore soil texture and sand content were more important in forest soil studies.

The purpose mangrove forests management the sustainable productivity of ecological services (ecological) plant coastal community based on investigation habitat scrutiny, the classification of plants and vegetative zones.In this research, In order to investigate and determine an appropriate inventory method for Qeshm Mangrove forests, considering inventory precision (confidence limit) and accuracy for canopy cover parameter per hectare and number per hectare a region with 632 ha area was selected in northwest of Qeshm island. An inventory grid with 200 × 500 m size was designed and established in the study area. Then, 60 control plots with 1 hectare area were laid out. Samplings carried out by diagonal transects with 50, 100, 150and 200m.Finally, the results of sampling by different lengths of transects were compared with control plots using analysis of variance and (E %)2 ×T criterion. The results of ANOVA showed that different lengths of transects had no significant differences (at confidence level of 95%) with control plots for estimation of species number per hectare and percentage crown cover parameters. Transects with 200m length had the most precision for estimating the above-mentioned parameters. Also, comparison of results for different lengths of transects with (E %)2 ×T criterion showed that transects with 100 m length are more appropriate for estimating the percentage crown cover and species number per hectare. It can be concluded that the transect 200 M the most precision and transect 100 M with (E %)2 ×T criterion is the most appropriate inventory method for these forests.

Wood-plastic Composite is one of the newest products in the world and has experienced huge growth in recent years. There is great potential for use of these products in various ways, so it is necessary to identify and evaluate the effective criteria on acceptance of this product among Iranian consumers. The methodology of research is descriptive analysis and after reviewing the literature and interviewing with industrial and academical experts, 10 effective criteria were identified and a questionnaire has designed in accordance with the principles of the LIKERT scale in order to determine the importance and priority of these indexes. The results show that the factors affecting the wood-plastic composites market doesn’t have equal importance in opinion of Iranian consumers. Among the properties of this product, moisture resistance usage range and customer satisfaction have more importance respectively. These criteria should be considered by manufacturers and suppliers in Iran. The most common reason of the acceptance of wood-plastic composites are moisture resistance properties and it can be replaced by other wood products because of good durability and Plasticity, however its high price compared with compact wood panels have to be considered.

In the present research, the effect of formaldehyde addition in sulfite pulping process and the refining revolutions on the strength and optical properties of rice straw pulp has been investigated. In order to achieve a final pulp kappa number of 12-13, cooking was done at 20% sodium sulfite in sulfite process and 18% sodium sulfite plus 4% formaldehyde in sulfite-formaldehyde process. The effect of refining revolution values on the pulp properties were investigated in the freeness levels of 500, 400, and 300 mL, CSF. Results indicated that, the addition of formaldehyde in sulfite process led to improve in delignification and increase in tensile and burst strengths. By the increasing of refining revolutions in all pulps, tensile and burst strengths were increased at slightly lower tear strength and optical properties.

This study was carried out to investigate the effect of treatment eastern cottonwood with nano-copper oxide on the surface roughness and contact angle. For this purpose, specimens with the dimensions of 50×50×2 mm (tangential × longitudinal× radial) were prepared from sapwood of eastern cottonwood followed by impregnating with nano copper oxide suspension (500, 1000, 1500 ppm). The obtained results showed that the most important roughness parameters exception Rv and Rvk significantly increased by treatment wooden samples using nano copper oxide. It is clearly verified this treatment amplified the surface roughness of wooden samples. The contact angles were also affected by treatment and had the same behavior as like surface roughness.

This study was carried out in the researching forest of the UPM University of Malaysia. In order to enrichment the forest artificially and in four different ways, make artificial gap in four 1 ha (100×100) plot. 9 micro plots 10m×10m made in 2 plots and 5 micro plots 10m×10m and 20m×20m in 2 other plots, totally 28 micro plots. In these micro plots was planted far from others in 2.5m×2.5m, seedlings of 3 species of Shorea assamica, Shorea platyclados, and Mersava anisoptera, (totally 812 seedlings). Species, number, diameter, length of stem with out branches, length, diameters of crown, survival percentage of seedlings and light intensity in each micro plot was recorded. The light intensity classified in 3 classes (Class 3: 17% - 23%, Class 2: 10% - 17%, and Class 1: 4% - 10%). Results showed that seedlings which are in Class 2 of light have more Height and Diameter growth and have more Chances of survival. M. anisoptera had the highest survival rate, and S. assamic had the less. M. anisoptera had the highest diameter growth and S. platyclados had the less. In Class 2 and 3 the diameter growth was more than in Class 1. S. platyclados had the highest growth rate in Class 2, and S. assamic had the fewer rates in Class 1. The S. platyclados had the highest crown diameter, and the S. assamica had the less. Crown diameter in Class 2 and 3 are the same and was the maximum rate, and in Class 1 had the minimum rate. M. anisoptera had maximum stem length and S. assamica had minimum and in different Light Classes had non-significant. Interaction between species and Light class had non-significant effect on height and diameter growth and had significant effect on crown diameter and stem length.