Journal of Forest and Wood Products
Year:2019 | Volume:71 | Issue:4|Papers Count:8

Knowing the effects of forest harvesting on water losses and the occurrence of devastating floods is necessary in the management of forest watersheds. In the curent research, the effect of forest utilization was studied on the runoff and loss of water by using the SWAT model in the Kheyrud forest watershed. For this purpose, calibrating and validating of the model were firstly done by putting the 20 percent exploitation from each sub-basin into use and repeating the simulations of the SWAT model. The rate of monthly flow changes was obtained and then evaluated by using the indices % F and f. The % F index makes use of sub-region area parameter in monthly discharge analysis. The calibration and validation of the SWAT model were performed using SUFI2 algorithm in SWAT-CUP software and error evaluation criteria, respectively. The results of calibration and validation of the SWAT model showed the acceptable capability of simulation for this model. The implementation of 20 percent showed that increasing the exploitation percent of forest trees in sub-basins 3, 4, and 5 resulted in increasing the monthly discharge, while the implementation of 20 percent in sub-basins 1 and 2 presented no tangible effect on the increase of the watershed’ s monthly discharge. In fact, sub-basins situated in the middle of the Kheyrud watershed, especially sub-basins 4 and 5, due to the concurrency of the sub-basin discharge at the outlet point of the catchment, accompanied with the proper physiographic conditions providing a condition for the watershed to have a greater monthly discharge. These results can be useful in managing forest exploitation and selecting the most suitable utilization places.

In order to study the diversity of macro-morphological traits of leaves and seeds in three populations of Betula in Iran, a total of 1800 leaves and seeds from 90 trees were measured in three sites of the taxon of this genus. 25 macro-morphological traits of leaves and seeds were used. Quantitative data were analyzed via one-way analysis of variance and nesting statistical design. Duncan's test was used for multiple comparisons of means. Cluster analysis was applied to compare and categorize the habitats and principal component analysis (PCA) was used to determine the most important traits in separating the three habitats. Multivariate analysis results indicated that leaf length, petiole length, the distance of the widest base of the leaf to leaf spot, the distance between the second and third veins, the average distance between the veins, petiole length, leaf length, leaf width in 0. 9 part of the leaf length, number of teeth between the second and third veins and the tip of the leaf, seed length, length and width of seed wings were the most important variables in grouping the populations. The results of cluster analysis showed that different clusters contain different populations. The plasticity was used to determine if the environment was effective on the traits or not. The results showed that the traits that are recognized as the main traits in the differentiation of these habitats are also less affected by the environment in terms of plasticity; and these traits are more influenced by genetics. Therefore, these traits can be used to identify the different populations of this genus in these three habitats as suitable attributes in completing the identification keys provided for the birch.

The aim of this research was to pick out the most relevant allometric equations to estimating aboveground biomass of Paulownia Fortunei species in Dr. Bahramnia Forestry Plan. Totally, 16 Paulownia Fortunei trees were cut, and then they were transformed and weighted. After that, to determine the coefficient of dryness this species, some samples were taken from the different parts of trunk, branches, leaves and fruits. The samples were dried in Oven at 110 ° C for 48 hours (for trunk and main branches) and 70 ° C for 48 hours (for other sections). Using 29 allometric equations, the relationship between aboveground biomass as dependent variable and D. B. H, height and dry wood density as independent variables were analyzed. The results indicated that among the various models, Model No. 21 was used using combination of two variables of diameter at breast height and height as independent variables with an explanation coefficient of 0. 947 and the mean square error of 26. 77% of the best fit. The results showed that the model number 21 that used combination of diameter at breast height and tree height as independent variables were the best prediction for aboveground biomass of Paulownia Fortunei species, with R2 0. 947 and RMSE%-26. 07%. The result was not improved by adding dry density as other independent variable along with diameter at the breasts and height trees. In sum, among the all investigated independent variables, the variable of diameter of the breasts height showed the most fit on total biomass of Paulownia Fortunei species.

Due to the importance of Mediterranean cypress in seedling production and forestation practices in dry and semi dry environments of the country, this research was carried out with the aim of investigating the response of Mediterranean cypress seedlings to moisture changes and nitrogen nutrition of the soil. For this purpose, 270 healthy and uniform seedlings of Cupressus horizontalis L. were prepared and examined under 6 soil moisture contents (100, 75, 50, 25, 15 and 10 percent of field capacity) and 3 levels of urea fertilizers, including control, low and high concentrations, respectively with 0, 75 and 150 mg/kg urea by using a two-way factorial experiment with 3 replicates based on randomized complete block design for 5 months (from May to November). The results showed that more than 82. 2% of seedlings survived up to 25% field capacity (FC) in control (no fertilizer) treatment. Survival of seedlings in 15% and 10% FC under the effect of urea fertilizer, especially under HN treatment, was gained 100% and 66. 7%, respectively. Regardless of urea, reduction of soil moisture content particularly in 50% and 25% FC decreased significantly the characteristics of stem length growth, biomass of different parts, quality index (QI) and physiological properties (photosynthetic area, relative water content and total chlorophyll) of seedlings. However, increase of urea fertilizer increased the survival, biomass of different parts of seedlings, physiological properties, WUE, total chlorophyll, and QI of seedlings. Therefore, it is suggested that in order to produce C. horizontalis seedlings, soil moisture content should not drop under 50% FC; Otherwise, the use of urea fertilizer is necessary with the aim of improving the growth, quality and water use efficiency of seedlings.

One of the considerable procedure to supply the lignocellulose material for the industries is the expansion of agroforestry in appropriate points of Iran. Due to ecological adaptability and fast growth of Maple among the existing native species at the northern forests of the country, it could be considered as a reasonable species in agroforestry. The purpose of this study was to investigate the characteristics of pulp made from Maple using monoethanol amine, monoethanol amine/ anthraquinone, soda, and soda/ anthraquinone processes and evaluation of their properties. The treatments were used in three levels of Monoethanol amine concentration (50, 75 and 100 wt%) in monoethanol amine pulping, alkalinity (22, 24 and 26 wt%) in soda pulping, and time (180, 240 and 300 min) under the constant temperature at 165 ˚ C. The anthraquinone was added to the monoethanol amine and soda process as a chemical additive in two levels of concentration (0, 0. 1wt%). The optimal cooking of monoethanolamine/anthraquinone, soda/anthraquinone, and soda processes lead up to 67. 93, 50. 97and 52. 36 % of total yield, and 27. 7, 19. 1 and 29. 23 of Kappa number respectively. The results showed that the highest amount of tensile index (61. 36 Nm/g), Burst index (3. 341 kPam2/g), tear index (6. 382 mN. m2/g) and brightness (20. 81 %) belonged to soda, monoethanol amine/anthraquinone, and soda pulps respectively. According to the results of this study, the soda process had significant effects on the Maple samples in comparison with the monoethanol amine process. Due to high energy consumption and more time for delignification, the Monoethanol amine process is not applicable to wooden resources.

The purpose of this study was to investigate the effect of urea as additive on reduction of formaldehyde emission and internal bonding strength (IB) improvement. Experimental boards were made using wood particles and urea formaldehyde adhesive. Pressure (25. 26 kg/cm2), temperature (200 ˚ C) and press time (7 minutes) were considered as constant factors. The wood particles with urea formaldehyde resin were pressed in three levels (8, 9 and 10 wt%) and urea additive at five levels (0, 3, 6, 9 and 12 wt%). Urea powder as additive was added in the two forms: to the particles and to resin solution. Test specimens for formaldehyde emission and IB were prepared from experimental boards following standers AS/NZS 4266. 16 and EN 326-1, respectively. Formaldehyde emission was determined according to the Japanese standard desiccator method. In this study, the concentration of the formaldehyde gas reached the E2 class. The results showed that the reduction of urea formaldehyde resin decreases the release of formaldehyde from particleboard. In addition, the results illustrated that by decreasing the percentage of the urea additive in particleboard, both formaldehyde releasing also the formaldehyde emission ere reduces. Furthermore, IB was increased (higher than standard) by adding urea powder to resin solution. The presence of urea at the surface of the wood chips prevents the formation of good connections between adhesive and wood particles.

The aim of this study was to investigate the effect of the primary material of urea formaldehyde adhesive on the physical and mechanical properties of the medium density boards. In this study, two types of urea formaldehyde adhesive based on formalin and urea formaldehyde condensates were used. The adhesives made with both primary materials had low molar ratio of formaldehyde to urea (grade E1). The effect of press factor on the four levels (8, 8. 2, 8. 4, 8. 6 s/mm) and the amount of adhesive at four levels (9, 9. 5, 10, 10. 5) percent on the physical properties such as thickness swelling and mechanical properties including flexural modulus, elastic modulus and internal bonding of the resulted boards of two different types of adhesives were studied. The results showed that the resulting boards with formalin-based urea formaldehyde adhesive had the highest flexural strength, elastic modulus and internal bonding, and also the least percentage of thickness swelling compared to the boards made with the urea formaldehyde-based adhesive. By increasing the press factor, the boards made with formalin-based adhesive compared to the adhesive based on the formaldehyde condensate had the same performance in lower consumption percentage. The use of formalin, despite the high quality of the resulting boards, requires a special maintenance requirement in the industry, in comparison to the urea-based adhesive based boards, due to high temperature instability.

Dissolving pulp, generally producing from wood and cotton linter and is determined as high α-cellulose which is widely used by numerus cellulosic products like microcelluloses, nanocelluloses and various cellulose derivatives. Huge attempts have been focused on non-woods as pulping raw materials, due to limitations of the resources of wood and cotton. Extreme exploitation of biomass via extraction and conversion of unsuitable components respect to a special application (non-cellulosic materials in dissolving pulp) is biorefinery purpose. Toward biorefinery approach, in this study Kenaf (Hibiscus cannabinus) stalk pre-hydrolyzed by hot water and the optimum residence time (40min) at 160 oC was selected based on the stalk yield loss (27 wt%) and then subjected to soda-anthraquinone pulping at different alkaline and time levels. Concerning optimum purity and brightness, the pulped biomass under 22 wt% alkalinity at 90 min with 17. 8 kappa NO and pulping yield of 65. 9 wt% was followed by AD1EpD2P bleaching sequences based on kappa factors of 0. 3, 0. 4 and 0. 45. Pre-hydrolyze treatment revealed that the yield and acidity reduced due to hemicelluloses removal that were increased by longer times which is valuable respected to the biorefinery approach and α-cellulose requirements. Bleaching Kappa factor of 0. 45 resulted in: kappa NO. 1, yield 30. 6 wt% (based on the kenaf stalk), α-cellulose 94. 1 wt%, viscosity 6. 4 cP, ash content 0. 51%, DP 1670, and brightness 80. 9 respectively. Kappa factor increment led to yield (-2. 2%) and ash (-0. 25%) loss, together with increase in viscosity (+2%), brightness (+4. 3%) and degree of polymerization (+360). Therefore, kenaf stalk could be used as a proper non woody feedstock for α-cellulose production.