Journal of Forest and Wood Products
Year:2017 | Volume:70 | Issue:1 |Papers Count:22

Understanding the underlying processes in spatial pattern of trees is an important goal in forest ecology. The first step in characterizing these spatial patterns is to use appropriate summary statistics.This study was aimed to compare four univariate second-order summary statistics (Ripley' sK-, L -, pair correlation and O -ring functions) in spatial pattern analysis of Christ's thorn jujube trees (Ziziphus spina-christi) in Fars province. All individual trees with height more than 1 m were mapped in a 200´200 m2 plot. Two other point patterns were also generated with similar density and different spatial distributions from the true pattern. The observed pattern of trees showed no spatial heterogeneity as compared to homogeneous Poisson process. The results showed that K - and L -functions did not reveal the clustering of Christ's thorn jujube trees in different spatial scales as shown by pair correlation function andO -ring statistic because of their cumulative structure. The range of dispersion resulted from K - and L -functions (20 m) did not conform the results of pair correlation function and O -ring statistic (11m). Comparison of mean squared error also showed that O -ring function had the least amount compared to pair correlation, L - and K -functions in all three plots. In general, pair correlation function and O -ring statistic were more precise and efficient than K - and L -functions in analyzing the pattern of Christ's thorn jujube trees in this study.

The production of good quality seedlings and increased performance are essential to the success of any plantation program. In order to develop a mechanism to evaluate the quality of nursery seedlings prior to planting in the field, production of good quality seedlings in nursery has important role in successful reforestation projects. Seedling sizes and nutrition status are two important factors in good quality seedlings. For these reasons, in this study nutrient concentration and content of nitrogen, phosphorous, calcium and potassium in roots and leaves of graded Oak seedlings (small, medium and large) sampled in two-stage sampling at the end of the first growing season (early September 2010 and late February 2011) were measured. The aim of this study is to know different levels of these nutrients in graded seedlings. The results showed there was not significant difference between nutrients in leaves and roots of graded seedlings in September and February, respectively. But higher seedlings had higher nutrient concentration rather than the smaller ones in February thanks to having more ability for absorption of nutrients. The content of nutrients in big and medium seedlings is more than small-sized ones.

This study was conducted to investigate the devastating impact of Mistletoe (Viscum album L.) on asymmetry index and leaf characteristics of Ironwood (Parrotia persica DC.) in Tamishan Forest, Noor, Iran. For this purpose, 20 Ironwood trees were selected inside and outside of the forest. The results showed that the highest and lowest values of leaf area and specific leaf area were observed in healthy and infected trees, respectively, both inside and outside of the forest. Stomatal characteristics of diameter, area and density also varied depending on location of trees and branch types (healthy or infected). Analysis of variance (ANOVA) indicated that the effect of left or right sides of leaves (sides) and trees were significant, while the interaction between side´trees was not significant. The difference between left and right sides of leaves were also significantly affected by location of trees and branches types. Generally, this study showed that the presence of mistletoe influenced the asymmetry index and have been caused to changes in the morphology of the infected trees. Finally, due to nutrition importance of Viscum album for animal to prevent from death of host trees, mechanical removing of Viscum album from host trees with high density is recommended.

Vegetation enhances the soil resistance against instability and erosion through increasing the soil cohesion. The main effect of vegetation in stability improvement is soil reinforcement by roots. The amount of reinforcement depends on distribution and strength of roots. The aim of this study was to assess the quantity of these two parameters of Persian oak roots and also comparing the tensile strength and reinforcement effect of roots in winter and summer seasons. Damage survey method was used to assess the distribution of roots. The diameters of all roots in trenches were measured by a digital caliper. Some root specimens were randomly selected from five tree samples and their tensile strengths were measured using a standard Instron. The range of root diameter and corresponding force and tensile strength were 0.1-5.5 mm, 1.3-411.3 N and 0.93-1217.39 MPa, respectively. Maximum and minimum root densities were in 0-10 and 50 cm soil horizons. The maximum reinforcement effect was belong to winter and 0-10 cm horizon. Minimum and maximum reinforcement effects for winter season were 0.0001 and 3.37 and 0.0004 and 2.87 MPa for summer.

Rhizophora mucronata forest stands are among the unique mangrove association in the coastline of southern Iran. These stands along with Avicennia marina constitute the only mixed mangrove forest in Sirik site. Despite the long-standing presence of Rhizophora mucronata among mangrove forests of Iran, few studies have been done about its habitat conditions. Understanding these conditions and their comparison with the environmental characteristics of adjacent habitats, could help to identify the leading factors in presence of Rhizophora mucronata only in Sirik habitat. For this purpose, based on the same experiences in Iran and other countries, 14 effective indices on distribution of R. mucronata were recognize and mapped. Such indices as tidal zone, temperature properties, annual rainfall, climate, seawater salinity, soil acidity, wave, substrate, and slope of habitat are among the indices considered in this study. The prepared maps were exported into GIS software. Then, 5% of each map in Sirik, Jask and Minab habitats was randomly selected for exploring the Pearson correlation coefficient and normality test via Kolmogrov-Smirnov test by using Minitab 16 software. The environmental conditions of the mentioned habitats were compared by using independent t-test. The results showed that there are significant difference between fluctuation of temperature, wave height, average maximum flooding level, water salinity and pH of soil in Sirik habitat (with R.mucronata species) and Jask and Minab (without R. mucronata species).

Predicting the volume of standing trees precisely is the basis of growth rate, amount of allowable harvesting, aboveground biomass carbon sequestration, and the foundation of optimal management according to the sustainable development. New technology of artificial intelligence including artificial neural network (ANN) was applied for modelling and predicting the commercial volume of measured trees in district 3 of Glandroud forests. The data of renewed volume table was acquired from bureau of natural resources and watershed management of Mazandaran province, Nowshahr. Diameter and total height of 150 fallen trees were used as inputs to develop the stage-wise modeling by feed forward back-propagation (FFBP). Two non-linear functions, Logsig and Tansig, were applied as transfer functions. Each function with the same topology showed the different outputs having different accuracies. After initial weighting and training algorithm, transfer functions of neurons had different rotation for decreasing the errors. After each trial, which led to various topology functions, the result showed that the model including diameter and total height with transfer function of Logsig, topology of one hidden layer and fifteen neurons, was the best model to predict the volume of trees in this study. The mentioned model provided the considerable accuracy with the highest coefficient of determination (R2=0.99), the least mean squared error of test (MSE) and the least average deviation (AD=0.158).

Frankia symbiosis with Alnusglutinosa improves the growth and nutrition of the host plant.Therefore, the establishment of high N2-fixing activities, active nodule-forming populations of Frankia in soil is desirable. In this study, seedlings of A. glutinosa were inoculated with Frankia isolated from twenty-five root nodules ofA. glutinosa in different sites of Guilan province, northern Iran. The seedlings were grown in pots filled with sterilized sand in a green-house. The seedling growth, N2-fixation and nodulation were measured 10 weeks after inoculation. The Inoculated seedling had higher dry weight of shoots, roots and nodules, and nutrients content compared to control. The N2-fixing activity varied from 0.017 to 0.337 mg N mg-1 nodules. The greatest N2-fixing capacity was observed in seedlings inoculated with AG6 Frankia crushed nodules compared with other treatments. There was a significant positive correlation coefficient between nodule dry weight, plant biomass and nutrients contents, that resulted of microbial inoculation effects. The results revealed that introduced Frankia could improve the growth and N2-fixation of A. glutinosa. Thus, selection true sources of inoculums that have a considerable influence to A. glutinosa and optimizing the sustainable production of these inoculums are needed. We concluded that AG6 had a superior effect on A. glutinosa seedlings and can be used for future studies.

This study aims to quantify the economic opportunity cost of conservation to coastal communities adjacent to mangrove forests in the southern coasts of Iran (Qeshm Island). The main commercial use of the Hara forests in this area is restricted to fishing, tourist boating trips, and limited leaves cutting.We applied a choice modeling (CM) approach to measure the value of a reduction of access under hypothetical scenarios in which local users would receive monetary compensation for lessening or forgoing mangrove forest utilization. Data were collected from the rural households living in the villages adjacent to mangrove forests and then analyzed by using conditional logit model. The results showed that the existence of a willingness to accept compensation for increases in environmental risk is associated with conservation program. Local communities are willing to accept a lower compensation when the aim of protection is to lessen the Hara cutting and fishing amount relative to recreational opportunities banning. The estimated mean WTA was 235000 IRR/hsld/day. The results also showed that there is a heterogeneity in the individual’s preferences, which attributed to factors including income, age, family size, job and experience of participation in the environmental projects.

Many species used in forestation could survive even in severe conditions, but considering the growth and economic efficiency is also important. Eucalyptus species are important sources for the production of wood, paper, fuel, and oils that are commonly used for planting the forests in the tropics. The purpose of this study was to evaluate the growth of adaptable species and cultivars, industrial and fast growing eucalyptus, for planting in inefficient lands of dry areas in Ilam province. For this purpose, the vegetative growth of eight species and varieties of eucalyptus including E. camaldulensis (from four origins), E. sargentii, E. microtheca, E. melliodora and E. saligna were investigated in a five-year period.in a randomized complete block design with three replicates in Mohsenab research station of Mehran, Ilam. The data analysis was performed using ANOVA and Duncan's multiple range tests in SAS software. The results indicated that there is a significant difference between species and cultivars in terms of indicators of height, trunk diameter, and canopy.E. camaldulensis is superior regarding to vegetative growth index in this study compared to other species. Three varieties of this species has an annual production of between two to five cubic meters per hectare, Shafarood variety has shown annual yield of more than 35 m per ha.

Estimation and mapping of forest resources is a prerequisite for sustainable forest management. Site productivity is a key indicator of forest ecosystem services like wood production, carbon sequestration, etc. It allows foresters to forecast growth and production and hence select the most suitable tree species for a site. Due to the extent of Hyrcanian forests and mountainous areas in these forests that are sometimes difficult to access, it seems necessary to find suitable methods for mapping the quantitative parameters in these forests. In this study, site form index which is the most reliable criterion for evaluating the site productivity of mixed and uneven stands was used. This study aims at mapping beech forest site productivity by using ordinary kriging and inverse distance weighted in research forest of Tarbiat Modares University. For this purpose, 123 0.1 ha circular sample plots were laid out in beech dominated stands. The height and diameter of beech trees with DBH³7.5 cm within each plot was recorded. The cross validation results showed that by using criteria such as mean error (OK=-0.036, IDW=-0.192), mean absolute error (OK=1.598, IDW=1.749), root mean square error (OK=2.053, IDW=2.223), relative mean error (OK=0.104, IDW=0.553) and relative root mean square error (OK=5.906, IDW=6.393), Kriging had significant advantage over IDW method and showed high estimation accuracy. Therefore, the methods can be applied to similar uneven-aged beech stands in the north of Iran.

Field capacity and permanent wilting pointare used to calculate the amount of available water and generally the amount of water required by plants. Determination of these parameters usually takes much time and on the other hand there is not enough equipment for their analysis in all of the laboratories. Therefore, estimating of some soil physical and chemical properties can provide useful information to obtain the ability of hold moisture by soils. In this study, soil samples from area of Gysvm in Guilan province were taken and transferred to the laboratory and, particle size distribution, organic matter content, pH, particle density, bulk density, FC and PWP were measured. The correlation of FC and PWP with other soil properties was analyzed by using the univariate multiple regressions. The results showed that FC had significant and strong relationship with organic matter and the amount of sand (r=0.8, p<0.01 and p<0.05). In addition, PWP showed significant relationship with silt and organic matter r=0.57, p<0.05). In general, the results showed that for estimation of FC and PWP in this area or similar places, the other soil characteristics, which can be evaluated easier, can be used.

Analyzing spatial patterns of individuals within life stages and spatial associations between different life stages is essential for understanding the spatial and temporal dynamics of plant populations. This research was conducted to study the spatial patterns and spatial association of Juniper trees (Juniperus polycarpos C. Koch) at different life stages in Juniper forests of Layen, Northeast of Iran. Data collection was done using four one- hectare square sample plots randomly selected, which fully mapped. Spatial patterns and spatial association of different life stages (juvenile, premature and mature; based on crown diameter) were then analyzed using O - ring univariate and bivariate statistics, respectively. Results showed that the general spatial patterns of the trees in total and in every life stage was clumped at least up to 25 m, while after that tends to random distribution at larger scales. Spatial association analyses revealed that there was no significant intra-specific competition among life stages namely, the spatial association was positive (attraction) or independence. It is concluded that clump patterns are due to heavy fruit and dispersal limitation of Juniper trees and harsh environmental condition of the study area.

The use of tree species in phytoremediation is valuable, but it is necessary to have more detailed knowledge on the physiological mechanism and potential of different species. Thus, in this research, the ability of the purification of two species (Cupressus arizonica and Platycladus orientalis) in the seedlings stage in response to lead contamination were evaluated. In this regard, two species of annual seedlings during the growing season in contaminated substrate which were grown in the soil of lead concentrations of 0, 100, 200, 300, 400 and 500 ppm. The end of the experiment time, different variables such as gas exchange, growth and physiological parameters were studied in two species on the all treatments. The statistical analysis indicated that the rate of photosynthesis and physiological parameters of both species were affected by the negative effects of lead contamination, but this weakness in plant metabolism didn’t led to seedling mortality any two species. The negative effects of lead contamination on the growth and biomass of C. arizonica were less in any indication of more resistance of this species. Therefore, it can be concluded that each species has different mechanism in response to lead contamination but C. arizonica is more resistant in comparing to C. arizonica. Surely, studies, particularly in higher concentrations and in longer period for the final confirmation of these findings are necessary.

The aim of this study was to evaluate the effect of chemical modification of cellulose nanofibers (CNF) on physical, mechanical and fungal biodegradation of plasticized starch (PS) bio-composites.Composites were produced using corn starch, glycerol / water as softener and 10% (based on dry weight of both) the original and modified cellulose nanofibers as reinforcement. Successful acetylation of cellulose nanofibers process was conducted using acetic anhydride and pyridine as the catalyst.Water absorption, water vapor permeability, mechanical, dynamic mechanical properties and furthermore, fungal biodegradation of composites were investigated. The results showed that addition of CNF and acetylated cellulose nanofibers (ACNF), resulted in improved mechanical properties of the PS composite and have a significant positive effect on its water absorption. Dynamic mechanical analysis (DMA) showed that the storage modulus significantly improved by addition of cellulose nanofibers. Weight loss measurement was used to evaluate the fungal biodegradation of the nanocomposite under various conditions. Obtained results revealed that the effect of addition of both (CNF& ACNF) on the weight loss was significant and increased the bio-degradation period of plasticized starch composite, especially in PS/ACNF nano-composite.

Cationic starch has been widely used with various mineral nanoparticles such as nanosilica, in wet-end of papermaking. This study was aimed to study the effect of cationic starch with different degrees of substitution (DS: 0.018 and 0.045) in nanoparticle containing system with nanosilica, in recycled OCC pulp. In this respect, initially, to study the shape and dimensions of nanosilica sol particles, atomic force microscopy (AFM) and transmission electron microscopy (TEM) was used; thereby the average size of nanosilica sols were measured less than 50 nm. Moreover, in order to study the papermaking process parameters, the results revealed that high DS cationic starch (0.045) resulted more effective interactions with silica nanoparticles, so that, an increase in drainability of the furnish from 300 ml CSF for blank sample to about 560 ml CSF, was observed. In addition, as the internal bonding strength of paper can be a proper indicator of the starch performance, the effect of cationic starch DS was more prominent in the case of this strength index; such that, following application of high DS cationic starch, the internal bonding strength was raised more than twice as much. On the other hand, generally, although, due to electro-kinetics of cationic starch adsorption, reversing the charge of the whole paper-making system can be as a limiting factor for application of high DS cationic starch, but, in OCC recycling production lines, application of high DS cationic starch was much more effective.

This study was carried out to make cellulose Nano fiber reinforced Kraft liner paper from rice straw. In this regard, P.deltoides clone 69-55 as a fast growth and high yield biomass species was selected for pulp production. Variable factors of Kraft pulping process including sulfidity, active alkali, temperature and time were applied in three levels and liquor to wood ratio of 4: 1. Optimum conditions of Kraft cooking were found as 23% sulfidity, 18% active alkali, 170 °C, and 180 min. cooking temperature and time, respectively. The pulping yield and kappa number of control pulp were measured as 53.94% and 17.2, respectively. Then, the pulp was refined to achieve freeness degree of 333 ml. CSF. Nano-cellulose fiber of rice straw was added to improve the strength of control kraft pulp. The nanofibers at 5, 10 and 15% loadings were mixed with pulp suspension and 60 g/m2 handsheets were manufactured by means of a laboratory hand sheet maker. It was found that all the strength characteristics of prepared papers were improved by addition of nanofibers in different levels.Tensile, burst, and tear indices increased up to 26.31%, 20.08%, and 10.07%, respectively by addition of 15% cellulose nanofibers to the control pulp suspension. Moreover, bending stiffness and RCT improved to 24.48%, and 52.38%, respectively. The overall results indicated that incorporation of cellulose nanofibers had a positive effect on kraft liner pulp produced from P.deltoides.

In this study, the effect of mixing method and nanoclay content on the physical, mechanical and morphological properties of wood plastic composite (WPC) were evaluated. Wood plastic composites were produced from recycled polyethylenes (low and high density) mixture, nanoclay and wood flour.The matrix and wood flour content were 60 wt% (LDPE 34% & HDPE 26%) and 40 wt%, respectively. Also, nanoclay was added in two levels 0 and 3 wt%. Simultaneous mixing and premixing method were used to manufacture the samples. The melt premixing samples exhibited superior physical and mechanical properties compared to the samples made by simultaneous mixing method. The composites containing nanoclay exhibited higher water absorption and lower strength properties. The results also indicated nanoclay agglomeration and poor distribution in the polymer matrix. Compared with the simultaneous mixing method, better distribution has been found for nanoclay particles in the samples made from the premixing method.

Different factors influence on the properties of wood composite panels. Evaluating all of these factors not only increases waste of time and energy but also decreases accuracy in estimation of influence value of selected factors in manufacturing panels in order to obtain optimum point of different properties of wood composite panels. Hence, application of a new statistical method is necessary for determination of model estimating production´s optimum point. This study was aimed to evaluate the artificial neural networks performance to model the physical properties of the particleboard made of canola stalks particles. The physical properties of the particleboard were modeled and estimated using different weight ratios of melamine formaldehyde to urea formaldehyde, canola stalks to poplar particles and mat moisture content through MLP, RBFN and ANFIS artificial neural networks. The results showed that MLP neural network has better performance than RBFN and ANFIS neural networks to estimate the physical properties of the particleboard. The results also showed that the artificial intelligence models have a proper precision and ability to predict the particleboard's physical properties. The results of the sensitivity analysis also showed that for estimating TS2 and WA24, the most important parameter was mat moisture content with a positive effect on the modeling, and melamine formaldehyde to urea formaldehyde ratio was also the most effective parameter for estimating TS24 and WA2.