Journal of Forest and Wood Products
Year:2020 | Volume:73 | Issue:2|Papers Count:11

Sawing process as the primary conversion of woodwork is one of the most important indicators to evaluate the efficiency of wood processing companies. In today's Iranian wood industry, poplar species play an important role in supplying primary material. Increasing efficiency with optimizing the important factors like wooden species, machines and operators is necessary. The province of Ardebil, especially Khalkhal, is one of the important centers for poplar timber production. There are a large number of small and large workshops in the wood industry, from which 60 workshops were selected. In this descriptive study, survey analysis of effective indicators on the sawmill yields is based on the comparison of analysis using SPSS software. For this purpose, Friedman test was used to rank the effective indices of sawmills in Khalkhal area. According to the results, the manpower with the average rating of 4. 05, the quality of timber with an average rating of 3. 93, management with an average rating of 2. 87, the quality of log with the average rating of 2. 62, and the quality of machinery with the average rating was 1. 53 were, respectively, the most important factors. Also, Chi-square test showed that training of manpower affects the sawmill efficiency of poplar logs in workshops. Efficiency of poplar sawmills equals 71% that shows the importance of this indicator.

In this study, the effects of using nan-oalumina (aluminum oxide) in combination with melamine formaldehyde resin on the mechanical properties of special impregnated decorative paper was investigated. Melamine formaldehyde resin was treated with 1% (w/w) functionalized nano-silica with 20 nm particle dimensions in addition to functionalized nano-alumina with 20 and 50 nm particle dimensions at 3 weight levels of 0. 5, 1 and 5% (w/w) and then, they were used to laminate the base papers. Papers were first impregnated with urea formaldehyde resin and air dried; then, they were laminated with melamine formaldehyde resin mixed with the desired nanoparticles using a painting hair brush. Characteristics of final prepared specimens including resistance to the wearing, cigarette burns, staining, cracking and impacting were evaluated. The results showed that the resistance to wearing and cracking properties of the laminated papers improved by using nanoalumina, and the addition of finer nano-alumina in melamine formaldehyde resin for coatings of special impregnation papers resulted in a greater improvement in wear and crack resistance indices. Nano-alumina did not have a statistically significant effect on improving cigarette burning resistance, although qualitative comparisons indicated improved cigarette burn resistance with nano-alumina 50 nm and the use of higher percentage of nano-alumina also statistically improved cigarette burning resistance. All in all, nano-alumina with finer and more functional dimensions can be recommended for melamine decorative paper.

This study was done to replace the imported long-fiber chemical pulp (LFCP) by adding nano lignocellulose fiber (NLCF) and dual composition of nano-cationic starch (CS) and nano-cationic polyacrylamide (CPAM) for preparing durable paper made from waste lint recycling combing machine. For this purpose, 5% unbleached NLCF and 1% CS or 0. 1% CPAM were mixed to waste lint pulp (WLP) as the control. The LFCP was added to the WLP in three amounts of 10%, 20%, and 30%. Also, CS and CPAM at three levels were used separately in WLP. Handsheets were made from 13 types of pulp compositions in grammage of 90 g/m2 and their physical, mechanical and optical properties were measured according to the relevant standards. Based on the results, addition of 1% CS to the control pulp (except for the paper yellowness) could be a good substitution for the LFCP. Also, the addition of NLCF resulted in a significantly decrease of handsheet’ s brightness and an increase of handsheet’ s yellowness. Furthermore, double fold endurance and softness of handsheets decreased compared with the LFCP, which might be due to the accumulation of NLCF on the surface of the paper according to SEM images. The addition of 0. 05% CPAM except for double fold endurance could improve the paper properties compared with using LFCP in WLP. Nano-particle dispersion somewhat improved using dual composition systems and the addition of nano-CS revealed that the paper strength improved compared with using NLCF alone and nano-CPAM.

In this study, the possibility of using superchrome and Fantachrome coatings on beech and poplar surface was investigated. Initially, samples were cut into 2×10×10 cm dimensions and after coating with superchrome and fantachrome paints, pull-off and cross-cut adhesion, contact angle and gloss tests were performed on their surface. The properties of coated surface was investigated by light microscopy. According to the results, the contact angle of the coated samples with superchrome and fantachrome significantly increased compared with the control sample in both beech and poplar species. The highest and the lowest amounts of pull-off adhesion strength of superchrome and fantachrome coatings were in fantachrome-coated beech and superchrome-coated poplar, respectively. Also, the results of cross cut adhesion test confirmed the results of pull-off test. After coating, the gloss content of the specimens significantly increased and the highest gloss was related to fantachrome coatings on beech and poplar samples, 141. 8 and 141. 7 gloss units (GU), respectively. In addition, the results of microscopic examination showed that the primary primer of the coating penetrated the wood texture by 4 microns but the surface chrome coating was 11 microns thick on the wood surface.

The aim of this study was to investigate the mechanical properties of foamed, reinforced and light weighted natural fiber/polypropylene nanocomposites using spherical carbon nanoparticles for use in the automotive industry. For this purpose, bagasse flour at constant level of 40%, azodicarbonamide foaming agent at 0, 2 and 4% levels, spherical carbon nanoparticles at four levels, namely 0, 0. 25, 0. 5 and 1% were selected as study variables. Polypropylene as polymeric matrix, and polypropylated maleic anhydride coupling agent (4% constant value) were considered for different nanocomposite compositions. The mixing of materials was performed using an internal mixing machine and then by hot and cold two-step press. Test specimens for density, impact strength, flexural and tensile tests were fabricated using standard molds. The ultrastructure of the nanocomposites was also studied using SEM microscopic images. Results showed that by increasing the amount of foaming agent, the density of the product decreased significantly, but had a negative effect on mechanical strengths except impact strength. Impact strength of lightweight nanocomposites had higher values than that of control samples. It was also found that increasing the amount of carbon nanoparticles was able to compensate for the decrease in other resistances in lightweight nanocomposites and increase their quantities. Ultrastructural examination of the samples also showed that in the presence of carbon nanoparticles, bagasse particles were better dispersed inside the polymer and a better bonding between them and the polymer occurred. Also, the presence of a foaming agent increases the pores and decreases the density.

Forest reserves are a shrinking pattern of biosphere reserves in which unique and rare or endangered species grow naturally. Juniper genus is one of the few indigenous conifers of Iran with habitats in large areas of the country. However, nowadays, despite its importance, there is a declining trend that is particularly critical in areas without control and management. The purpose of the study was to investigate and quantify the inter-specific competition of juniper trees (Juniperus excelsa) with the main associated species, namely pistachio (Pistacia atlantica) and maple (Acer monspessulanum), in Kandirigh forest reserve in Ardabil Province of north-west of Iran. For this purpose, full census inventory was taken in a protected area of 13. 2 hectares, and variables of DBH, total height and crown diameter and spatial coordinates of all tree species were recorded. Then, the bivariate O-ring statistic and mark correlation function (MCF) were used to evaluate the competition between the junipers with pistachio and maple. Bivariate O-ring statistic showed that most of the interactions of these three species are independent or, ultimately, at small scales are attractions. Univariate and bivariate mark correlations function also showed that the interested variables of DBH, total height and crown diameter were spatially independent. All of this is due to the lack of significant competition between juniper trees and the associated species in this forest reserve. Thus, pistachio and maple can be introduced as associated species for the reforestation and enrichment of the other juniper habitats with similar conditions.

In order to access the most suitable poplar clones for the purpose of expanding wood farming activities in the lowland areas of Guilan province, twelve different poplar clones from euramericana, deltoides and hybrid poplars were studied in nursery (annual seedlings) and poplar plantation (three-year-old trees). This study was carried out in a Randomized Complete Block Design with three replications at Fakhr Abad research station in 2019. Survival percentage, diameter and height of one-year-old seedlings in nursery as well as survival percentage, diameter at breast height and height of three-yearold trees in poplar plantation were measured at the end of the growing season. Analysis of variance of data obtained from survival percentage, diameter and height of different studied poplar clones showed that there was no significant difference between survival rate of three-year-old trees and diameter of one-year-old seedlings, but there was a significant difference between survival rate and height of oneyear-old seedlings and diameter and height of three-year-old trees. Thus P. deltoides Marquette, P. deltoides 92/258, P. eur. Blanc de poitou and P. deltoides 92/160 clones in a group with the highest and P. x. 87m. 119 had the lowest survival rate, and P. deltoides Marquette and P. deltoides 92/258 clones had the highest and lowest height growth in nursery, respectively. Also, the study of diameter at breast height and height of three-year-old trees showed that P. deltoides 92/258 and P. eur. I-Sieres had the highest and the lowest diameters, respectively. P. eur. Blanc de poitou clone was not competitive with other clones in height.

Protective measures are needed to reduce the negative impacts of soil compaction. Water diversions are one of the management tools to reduce the negative impacts of ground skidding and helping soil recovery. In this research, the effects of constructed water bar were studied on the process of soil physical properties recovery in skid trail in west of Guilan. Seven years after logging completion and conservation of skid trail by constructed water bar, changes in soil physical properties were evaluated in two slope classes and three traffic classes in 40 m2 sample plots at wheel tracks and between them. Control samples were selected within 30 m from the edge of the skid trail. Soil samples were collected using a cylinder to a depth of 10 cm. Soil penetration resistance and rut depth were measured by analog hand-held soil penetrometer and rut 5 meter leveling rod, respectively. Influence of slope and traffic changes on soil physical properties was investigated in two treatments, three replications, and 72 samples. The results showed that the slope of the skid trail, traffic intensity and their interaction have significant effective on bulk density, total porosity, penetration resistance and rut depth. Mean bulk density, total porosity and penetration resistance in slope below 10% and low traffic treatment were not significantly different from control area. Overall, the results of study indicated that after log skidding, water bar construction had positive effects on soil physical properties of low slope and traffic trails.

This study was conducted to assess the effect of soil physical and chemical properties on diversity and structure of tree cover in oak forests with an area of 275 hectares in Qamyshlh city of Marivan Kordestan, Iran. For this purpose, a total of 90 samples, each 10 yards, randomly laid out on a regular gird network were selected and in the center of each plot, soil samples were taken at the depth of 0-30 cm. Results revealed that the average diameter of trees had a significant positive correlation with phosphorus, potassium, organic matter and carbon to nitrogen ratio in the soil. The results also showed that there is no significant relationship between the most measured soil characteristics and richness, evenness and diversity indicators. However, soil pH with Pirlo and Simpson indexes and phosphorus with Margalef index had a significant negative relationship. Correlation between the percentage of tree species and soil characteristics showed that among the studied species, Q. branti were more sensitive to changes in soil properties compared with other species. However, the analyses of ordination methods showed that there is no direct relationship between species distribution and soil properties. In addition to the soil effects, due to the proximity of the forest land to rural residential areas, it can be said that the most influential factor in shaping the composition, diversity, and structure of Qamyshlh tree species are human factors.

Determination of the spatial pattern of trees is one of the important structural parameters of the forest for identifying changes in forest communities and it's monitoring in recent years. On the one hand, extracting this structural parameter using satellite data has a significant impact on reducing cost of inventory and makes it easy to evaluate forests of forest managers. In this study, the spatial pattern of trees in the natural forest of Farim of Mazandaran province was determined by using SPOT7 satellite data. Thus, some tree`s characteristics such as species, diameter at breast height, the diameter of canopies, gaps and the position of each tree were measured in 12 plot with area about one ha (100 m x 100 m). On the other hand, after radiometric and geometric corrections of satellite data, the tree`s canopy and gaps were classified, using the object-based method, and tree position per plot also was determined by canopy gravity center. Then, the spatial distribution pattern of the trees and structure, distinguished and extracted by field inventory and satellite data was compared by O-ring function. The results showed that the overall accuracy of canopy and gaps extracted from satellite data by objectbased classification was about 91% and kappa coefficient equaled 0. 7. The spatial pattern of trees were random except of the small radius and similar to the pattern of trees in-ground inventory. In total, results showed that SPOT-7 data and the object-based classification have an acceptable potential for determining the spatial pattern of forest stands.

Plant distribution in forest ecosystems is not accidental and influenced by various factors. This study was done to investigate the structure, physiognomy and site requirements of Mediterranean cypress species (Cupressus sempervirens var. horizontalis) in order to achieve the basic structure, physiognomy and site requirements information of this species relative to soil and physiographic factors in Eshkevar, Rahimabad, Rudsar. For this purpose, 25 circular plots, each one with 1000-m2, were located according to random sampling. In each plot, type of tree and shrub species were designated; then, diameter at breast height (DBH) of trees more than 7. 5 cm was measured. In each plot, soil sample were taken from 0 to 10 cm depth. The results indicated that stand structure was uneven-aged. Physiognomy studies showed that in tree, shrub, and herbaceous layers, broad-leaved and need-leaved trees, deciduous shrubs, and forbs were, respectively, dominance life forms. Between environmental factors, aspect and soil textures were effective on diameter, height and individual number of Mediterranean cypress. Number of species had a positive and negative correlation with sand percentage and aspect, respectively.