فصلنامه جنگل و فرآورده های چوب
سال هفتاد و پنجم شماره 4 (زمستان 1401)

The aim of this study was to investigate some soil properties that were affected by management including logging, tourism and forest reserve in Guilan province, Iran. In each of the studied area, five transects with a length of 200 meters, perpendicular to the road, were selected and soil samples at 10, 50, 100, 150, and 200-meters distances from the road were gathered. In each transect, five samples of 25 m2 were selected. Measured soil properties were consisted of bulk density, porosity, pH, organic carbon, and microbial respiration. The results showed that with increasing distance from the road, the mean of bulk density in the area of logging, tourism and forest reserve decreased from 1.64 to 1.10, 1.33 to 1.07 and 1.11 to 1.08 gr/cm3, respectively, and mean of pH decreased from 6.96 to 5.48, 6.57 to 5.48 and 4.88 to 4.56, respectively. The highest and lowest levels of organic carbon and rate of microbial respiration were observed in the control and logging areas, respectively. The results of analysis of variance showed that there is a significant difference between all soil properties in the sampled areas and different road distances. Mean comparison also showed that there was a significant difference between the mean of soil properties in the control area with the logging and tourism areas. The results of this study showed that the type of management of natural areas may have different destructive effects on soil properties.

This study was conducted to investigate the effect of degradation due to traditional forest exploitation on runoff and sediment following the change of some soil characteristics in the Zagros vegetation area in Manesht and Qalarang protected areas in the north of Ilam. Based on the objectives of the study, the treatments of degraded forest, intact forest (control) and agricultural lands in the region were considered in three slopes (15, 25 and 35%) and each in three replications. In this study, runoff and sediment due to rainfall were considered. Analysis of variance test was used to investigate the effect of vegetation cover on runoff and sediment, Duncan's test was used to compare means, and Pearson's correlation method was used to determine the significance and extent of each variable measured in the soil on runoff and sediment. The results showed that with increasing the slope, the amount of water infiltration in the soil decreases and as a result, more runoff and sediment is produced. The results showed that the amount of runoff, sediment and runoff coefficient in degraded forest lands is higher than the treatment of intact forest (control) and agricultural lands. In degraded forest lands, the amount of runoff is 5.43 mm and sediment is 0.3671 tons per hectare and in untouched forest lands (control), the amount of runoff is 0.33 mm and sediment is 0.0019 tons per hectare, respectively, and in agricultural lands, the amount of runoff, and sediment were calculated as 22. 0.00 mm and 0.004 t / ha, respectively. The results of correlation coefficient showed that the parameters of acidity, clay percentage, silt percentage had a positive correlation and sand percentage had a negative correlation with runoff and acidity parameters, silt percentage had a positive correlation and sand percentage had a negative correlation with sediment content. According to the results of this study, it can be concluded that eliminating or changing the use of vegetation, especially forest cover reduces the amount of soil permeability and thus increases the amount of soil runoff and sediment. Therefore, by preserving, rehabilitating and developing forest trees and shrubs, as well as preventing the change of use of these lands to agriculture, especially in sloping forest lands, runoff and sediment production can be prevented.

Quantification of forest structure is one of the most important factors in sustainable management. The aim of this study was to compare the survey method and the effect of area and shape of sample plots in quantifying the structure of oak forests in the middle Zagros. To that end, an area of 30ha in the forests of Qhale-Gol Khorramabad was identified and a complete inventory was conducted. The data were entered into the geographic information system (GIS) environment in the form of information layers, and then, based on the objectives of the research, a regular random grid with specific dimensions of 100x100m and with an intensity of 10%, 25 sample plots (circle and square shape) were taken. In addition, to investigate the effect of the area of the sample plots on the structural characteristics of the forest, square plots of 25, 50, 75 and 100 were randomly taken with an intensity of 10%. According to the Mann-Whitney test, the shape of the sample plots had no significant effect on the results, and the dominance and differentiation indices in all methods had the same results. However, the area of the plots and their distribution had an effect on the results of the two indices of Mingling and Uniform angle. For the Mingling of 50 to 100 are plots and according to the Uniform angle index, 12 and 25 are plots had a significant difference from the average of the society. Nevertheless, no apparent difference was observed in the range of values and classes of any of the structural indices. according to this, all examined methods and sample plots have an excellent ability to describe the structure. In the case of more sensitive indicators such as Uniform angle and Mingling, the error can be reduced by applying corrective methods such as changing the number of neighbors.

The arid and semi-arid areas in the south of Varamin city are one of the areas that are prioritized for the implementation of tourism development and conservation programs due to soil erosion conditions, excess livestock grazing and destruction of pastures and vegetation. Therefore, the purpose of this research is a comprehensive evaluation of the ecological conditions to evaluate the environmental potential of recreation in this area. For this purpose, first, soil and vegetation samples were taken from sample plots from all three areas of Dolat Abad, Shokar Abad and Fakhr Abad in Varamin, and the required data and maps were prepared. Soil samples were collected and important soil parameters were determined in each sample and maps of these parameters were prepared. Then, the evaluation of the environmental potential of tourism was done by the method of intersecting ecological maps. For this purpose, the mapping of ecological factors, including slope, aspect, height, density of vegetation, precipitation, and temperature, as well as soil texture, was done. They were classified and coded according to the degree of desirability for wide recreation and then superimposed, and finally, the 1st and 2nd grade capacity classes and the unfavorable classes were created from the combination of these layers. In terms of totality and summation of ecological factors affecting the potential of tourism, Shakarabad region has more potential than the other two regions of Fakhrabad and Daulatabad. In general, what has caused the difference and superiority of tourism in Shakarabad region compared with the other two regions is the soil factor, which has caused the development of tourism in Shakarabad region to be higher than the other two regions. Another important factor is the land use and the proximity of this area to the desert protected area, which itself provides a high potential in the Shakarabad region for the development of outdoor recreation. The results of this research showed that by combining the multi-criteria evaluation method and the geographic information system and considering all the ecological factors, the real potential of outdoor recreation in forest areas and reserves can be determined.

The aim of this study was to investigate changes process of vegetative characteristics of mangrove seedlings over time and determination of chlorophyll content in different concentrations of desalination sewage. After collecting propagules from 30 healthy mother trees and planting them, propagules were irrigated with water treatments of 0, 1, 2, 3, 5, 10 and 20% concentration of desalination sewage. Then vegetative characteristics of seedlings were measured every two weeks in different treatments and analyzed using repeated measure model. The amount of chlorophyll a and b were measured by Arnon method and compared using ANOVA. The results showed that changes in height growth, length and radial growth of leaf of mangrove seedlings had significant differences over time. Gradient of height growth and length growth of leaf was sharp at the beginning and then trend increased gradually. Radial leaf growth was slowly increasing with increasing time and was almost zero at the end of the period. The average of height growth, length and radial growth of leaf decreased at high amount of concentration of desalination sewage. The amount of chlorophyll a (5.37mg/g), b (1.30 mg/g) and total chlorophyll (6.67 mg/g) were the highest in the 0% treatment. According to the results, growth slows down over time with increasing age, and at high concentrations, this decline becomes more intense. Therefore, it was recommended that suitable management programs should be used in using of desalination set and sewage removing in order to minimize mangrove forest damages.

In this research, beech and hornbeam chips were chosen randomly from the chips pile of Mazandaran Wood and Paper Industries and cooked under CMP conditions and pulps were prepared at the yield of 85%. The CMP pulps were separately bleached with hydrogen peroxide and sodium dithionite and 60 gr/m2 hand sheet were made. Then, a solution of 0.5 percent of DTPA was sprayed over a number of hand sheets. Then, their optical characteristics were measured and compared using TAPPI Standard test methods. The results of this study explored that following H2O2 bleaching brightness and greenness increased and opacity, absorption coefficient, K/S ratio and a* factor decreased. After complementally bleaching with sodium dithionite, the most part of optical properties improved. Following DTPA solution spraying on the surface of hand sheets, brightness, opacity and greenness improved and absorption coefficient, K/S ratio and a* factor decreased.  Among the different treatments, DTPA spray has a great effect in stability of brightness and increasing it durability against optical deterioration. Also, the complementally bleaching pattern in improving the optical properties of the paper obtained from hornbeam CMP pulp was more noticeable than that of beech.

Today, paper is being increasingly used in the packaging industry all over the world due to environmental issues, recyclability and printability. Accordingly, researchers and producers are seeking for solutions to solve the disadvantages of paper used for packaging food products. The coating is a method of enhancing the barrier and mechanical properties of paper. Also, to preserve food against microbial agents, antibacterial substances are used in the composition of coating materials. In the present study, starch, cellulose nanofiber, starch-zinc nanooxide, and cellulose nanofiber-zinc nanooxide were used as coating treatments. The results showed that using cellulose nanofiber and starch with zinc nanooxide will result in improved mechanical and barrier properties of paper. Burst strength, air permeability, and water vapor transmission rate (WVTR) showed the best results after coating the papers with cellulose nanofiber-zinc nanooxide compound. Tear strength showed the best result after coating the paper with cellulose nanofiber. The coated papers by starch and the coated papers by cellulose nanofiber-zinc nanooxide compound showed the highest and lowest water absorption, respectively. Adding zinc nanooxide to the coating material resulted in improved antimicrobial and antipathogenic against Escherichia coli and Staphylococcus aureus bacteria properties of the paper. According to the results, paper coated with a combination of cellulose nanofibers and zinc nanooxide was selected as the best treatment.

In this study, efficient hybrid hydrogels as drug delivery platforms were synthesized using Kraft lignin, a biopolymer obtained from the alkaline paper industry, chitosan and glutaraldehyde as a crosslinker. The ratio of lignin was an important variable factor of this study and its effect on morphology and mechanical properties were studied. The characteristics such as compressive property, swelling capacity, drug release, degradation time, and SEM imaging of the hydrogels of chitosan and chitosan/ lignin with different amount of lignin were investigated. Also, paracetamol drug was selected as a drug model. The results showed that the glutaraldehyde crosslinker can effectively create a crosslinked structure, so that the durability and stability of the hydrogels in the desired conditions is up to 15 days for the pure chitosan sample and 11 days for the lignin chitosan sample, respectively. Although the shortest shelf life (5 days) corresponds to the highest amount of lignin, which was a shorter period of time, but it gives enough time for the drug to be completely released. The results showed that although the hydrogel structure is weakened by increasing the percentage of lignin, the drug was released faster with the increasing of lignin, which can be considered as a factor for changing the release rate of drug according to the intended application. The highest amount of release was observed in hydrogels with the highest amount of lignin, so that in the first two hours, its amount was about six times higher than that of pure chitosan hydrogel.