فصلنامه جنگل و فرآورده های چوب
سال هفتاد و چهارم شماره 2 (تابستان 1400)

Forest natural attractions provide great potential for attracting tourists. The ecotourism recreational planning is necessary to prevent forest degradation and alleviate the pressure of forest-dweller communities on forest areas. It has a significant role in enhancing the cultural, social, and economic aspects of society as well as the protection of natural resources to achieve sustainable development. To achieve correct planning, it is necessary to assess the ecological capability of forest areas, align with the socio-economic capability to develop an accurate model. This study aimed to design an ecotourism environmental model for Hyrcanian forests located in the north of Iran. To develop the model, a set of ecological and socio-economic criteria along with relevant sub-criteria were identified through the literature review, then a questionnaire was designed to priority the set of criteria and sub-criteria based on the expert’s opinions. The entropy technique has been used to priority criteria, and fuzzy logic approach along with expert experiences applied to classify the sub-criteria. The results showed that 7 ecological criteria, 7 socio-economic criteria, 40 ecological sub-criteria, and 44 socio-economic sub-criteria, were effective on ecotourism based on expert’s opinions. The most important ecological and socio-economic criteria were water resources, vegetation, tourist attractions, and human historical and cultural aspects of forests, respectively, which the geological criteria were the less important criteria amongst others. Thus, the ecotourism environmental model was developed by a combination of the ecological capability model and socio-economic capability model for Hyrcanian forests.

Todays, analyzing the effects of earthquakes on tree growth became possible by using dendrochronological methods. This study is done by the aim of investigating the effects of the severe Roudbar-Manjil earthquake in 1990 on the growth of Cupressus semperviren trees in Rudbar county. For this purpose, after obtaining a license to cut down eight Cupressus trees in Roudbar city, the trees were randomly selected; cut down and eight discs were taken from their diameter at breast height. Also, in order to investigate the effects of climatic factors, 30 years (1983-2012) temperature and precipitation data of the region were received from Manjil synoptic station. Preparation of images of research disks slices with 2mm thickness were done using, medical radiology device and comparative dating, estimation of reliability components, chronological analysis of data, plotting and correlation between growth and climatic factors were performed using Mini-Viewer, ARSTAN, Excel and Spss software's. In addition, release and suppressed growth of trees in the five year after earthquake period were calculated, using growth change equations. The results showed that there was no correlation between tree growth and temperature factor (r = 0.21); While the correlation of precipitation factor with tree growth during 30 years was positive (r = 0.809) and during the years (1991 to 2000) was negative (r = - 0.72). Therefore, the growth changes of this species, which increased in the first five years after the earthquake and decreased in the second five years, can be related to the effects of the earthquake on trees. On the other hand, Cupressus semperviren was recognized as an earthquake-resistant species because the growth of suppression in the studied disks did not show a significant difference with the release growth.

In this study, the rate of seedling emergence from direct seeding of Brant`s oak (Quercus brantii Lindl.) and wild pistachio (Pistacia atlantica Desf.) in Dalab forests of Ilam in two altitude and five regeneration establishment positions during two years 2018-2019 was examined. For this, six sites were selected at an altitude of 1400 and 1550 m above sea level with the same aspects. In each site, a transect was implemented perpendicular to the slope, and on it regeneration establishment positions including “under tree crown”, “under shrub”, ‘under bushes”, “next to the rock” and bare spaces, observing three replicates were established. At each regeneration establishment position 12 holes were dug. In the dug holes, the seeds of the mentioned species were planted in the winter of 2017. The number of green holes and the number of emerged seedlings were counted during the spring and summer of 2018 and 2019 years. The results showed that the effect of sampling year, sampling season, altitude, regeneration establishment position and interaction effect of altitude and regeneration establishment position on the percentage of green holes is significant. The percentage of green holes decreased in the second year compared to the first year and in summer compared to spring. The highest percentage of seedling emergence was at lower altitudes and under tree crowns. The performance of Stones and bushes was better than shrubs which ranked after tree crowns. It was concluded that if seed sowing is done according to the natural pattern of regeneration, successful results can be hoped for.

Various engineering measures, such as mulching, have been applied to skid trails to suppress the negative effects of surface runoff and flood hazards. However, study on the effectiveness of such treatments to restore soil properties is scarce. In this study, the effect of organic mulches including leaf litter, rice straw and sawdust on the recovery of physical properties of compacted soil of skid trails (i.e., soil bulk density, porosity, resistance to penetration and soil texture) was evaluated and tested two years after skidding operations compared to untreated trails and undisturbed (control) area. The results showed that the treatment of leaf litter mulch, rice straw and sawdust had a significant effect on the recovery of soil bulk density, porosity and soil penetration resistance, but had no significant effect on soil texture. The results showed that litter mulch has the greatest effect on the recovery of soil physical characteristics compared to straw and sawdust mulch. However, for two years, the soil texture was not affected by the type and amount of mulch. Also, in the surface depth, the effects of mulch are more significant. We can conclude that the applying different organic mulches increased levels of each mulch moderately ameliorated soil physical properties, after mechanized operations over a two-year period, compared to the untreated treatment; however, the values of soil properties were still lower than those in the undisturbed (control) area, indicating that two years is not long enough to restore the soil properties to pre-harvest levels in the study area.

The activity of fungal and enzymes are important for soil quality in forest ecosystems. Altitudes above sea level (a.s.l.) are important for their impacts on biological and non-biological characteristics of soil by effecting distribution of fungal communities and their enzymatic activities. The aim of this study was to investigate fungi diversity and soil enzyme activities in relation to soil quality index (SQI) along an altitudinal gradient (0, 500, 1000, 1500, 2000 and 2500 m a.s.l.) in Vaz watershed- Mazandaran province. In each elevation level, nine 400 m2 plots were investigated for tree cover and soil characteristics. The soil physical, chemical, and enzymatic properties were measured by conventional laboratory technique. To profile fungal community, ITS region was PCR amplified using barcoded primers and sequenced using next-generation sequencing technologies. Our results showed that the highest SQI and leucine aminopeptidase activities were observed at the lowest elevation level with the highest soil microbial respiration, nitrogen and temperature. The highest percentage of ectomycorrhizal and yeasts fungi, as well as the highest activates of arylsulfatase and acid phosphatase enzymes were associated with middle SQI in 1500 m altitude level with a high correlation with soil carbon concentration. The lowest SQI, along with the activity of saprotrophic fungus and β-glucosidase and cellobiohydrolase enzymes was noted in higher elevations. It can be concluded that with increasing elevation, SQI is decreased due to a reduced ectomycorrhizal fungi population and decreased activities of carbon/nitrogen-dependent enzymes in the absence of coexisting tree species.

Achieving sustainable forest management at different levels depends on basic information measurement to understand the use of this data correctly. The height of trees is one of the most important components of forest measurement that it forms the body of many forestry research works. Therefore, much effort is being made to measure it faster and more accurately. Nowadays, smartphones have a variety of technologies for measuring the height of trees. In this research, the researcher tried to evaluate the efficiency of height measurement technology based on augmented of additional reality by carefully checking the height of some trees. For this purpose, the number of 75 coniferous trees in the Faculty of Agriculture and Natural Resources of Lorestan University was randomly selected and their height was measured by using the trupulse 360 (reference tool) and Augmented reality technology available in both iPhone 8 and Samsung S 8 smartphones. Paired comparisons of data were performed by using paired t-test and the correlation between data, the mean square error and the relative mean square error was measured too. By using the height measurement application, the highest correlation and the lowest RMSE value for iPhone8 were obtained, 0.989, 0.285 m and 4/97% respectively. By using the popular and current technology-based application, the RMSE was estimated to be 0.354 meters and 8/56% for the iPhone and 0.377 meters and 14/5% for the Samsung Galaxy. It seems the technologies in the new smartphones have this ability to replace the traditional tree height measurement tools.

Persian walnut (Juglans regia L.) is an economically important species cultivated worldwide for its wood and nuts. Walnut has high genetic diversity due to sexual reproduction and cross-pollination. In this study, the Genetic diversity of walnut was investigated from the wood production viewpoint. In 1999, the walnut seeds of straight and good quality trunk mother trees of three regions including Karaj (10 seeds), Baft (22 seeds) and Isfahan (22 seeds) were planted in the Forests and Rangelands Research Institute, Iran. During 1996 and 1997, the vegetative traits of 17-18 years old walnut trees, including collar diameter at 30 cm height, stem shape quality, tree height, canopy area, diameter at breast height, wood volume production and mean annual height growth were studied. Analysis of variance of studied traits indicated that there was a significant difference between regions in stem shape, canopy area and diameter at breast height. Study of different regions showed that the trees with Baft origin had higher height (3.27 m), canopy area (7.47 m2) and mean annual height growth (17.77 cm) than other Regions. However trees with Karaj origin had higher diameter at breast height (9.37 cm). The UPGMA dendrogram grouped genotypes into two groups. Genotypes of group 1 had higher wood production; however genotypes of group 2 showed higher wood quality. The results indicate considerable genetic variation among genotypes that can be useful in walnut breeding programs.

The phenomenon of oak decline is one of the most important current problems in the Zagros forests. Lack of nutrients and differences in nutrient uptake between healthy Brant`s oak (Quercus brantii Lindl.) and trees affected by decline is one of the main causes of dryness of these trees. Tree nutrition can be considered as a management strategy to solve this problem and stop the decay of oak trees. Nutrient spraying is one of the common methods of plant nutrition that meets the needs of the plant in a short time. In this research, the similar trees of two forms (coppice and seed-origin) were selected in the Monj area of Chaharmahal and Bakhtiari province. In each form, trees were divided into three levels of health (Healthy, dieback and crown drought up to 50%). Five similar trees by dimension were selected in each level of health (totally 30 trees). Before and after nutrient spraying, the quality characteristics of the trees were recorded and a mixed sample of leaves was prepared from them. Nutrient spraying were done at full time of leaves from early June to July with an interval of 10 days in three shifts. The results showed that the amount of micronutrients elements in the leaves of trees at the beginning of the growing season was significantly higher than the end of the season. Among the micronutrients elements, the amount of boron in the leaves of healthy trees was more than decaying trees. Qualitative evaluation of trees showed that the progression of dieback has stopped in most of the studied trees. Feeding of decaying trees and increasing the possibility of nutrient uptake from the soil can be effective in stopping the decay of trees.

Kenaf is one of the most successful industrial plants for cultivation in Iran due to its unique properties for papermaking. The present research was conducted in order to supply virgin fiber for corrugated board to compensate shortage of wood in Iran. Harvest age is one of the important technical-economic aspects, so sampling was done from Cuban type of kenaf at three harvest ages of 5, 6 and 7 months and biomass was determined at 7 months of age. Soda-anthraquinone (AQ) pulping trials of kenaf core was carried out by 18 combination using 14% and 16% alkali charges, 0.2% AQ, three cooking time (60, 90, and 120 min.), three cooking temperature (155, 165, and 175 °C) and 7:1 liquor to core ratio. Pulp freeness was increased to 33 °SR by PFI mill beater and 127 g/m2 handsheets were made from the selected pulps including three harvest ages, two alkali charges (14% and 16%), cooking time of 120 min. and cooking temperature of 165 °C. The results showed that the green and dry biomass of kenaf was 32 and 7.7 ton/ ha, respectively. Screen yield, kappa number, and reject contents of optimal cooking combinations were measured in range of 53.71% to 48.76%, 78.73 to 118.27, and 1.58% to 4.41%, respectively. These results indicated that kenaf harvest age of 5 months that cooked by 16% alkali (F4 treatment) is the optimal treatment. It was found a direct relationship between harvest age with increasing of kappa number and screen yield of pulp. The results of physical properties of hand sheet showed that there are significant differences among the means of all these properties. Handsheet properties made from the optimal treatment, including tensile index of 85.7 Nm/g, burst index of 3.8 kPam2/g, tear index of 4.7 mNm2/g, RCT index of 16.8 Nm/g and CMT index of 1.9 Nm2/g are superior compare to the national standard specification of floating paper.

Development and application of natural and renewable resources in the manufacture of wood composites is one of the important issues that are always considered by various researchers and are looking for solutions to reduce the share of harmful and hazardous chemical compounds. Therefore the aim of this study was to investigate the use of black liquor powder obtained from alkali sulfite anthraquinone pulping process in the production of wood plastic composite with wheat straw residue and polypropylene polymer and using MAPP coupling agent. In order to make  the wood plastic composites, wheat straw flour enhancer in three levels of 30, 40 and 50% and black liquor powder obtained from alkaline sulfite anthraquinone (AS-AQ) pulping process in four levels of zero, 5, 10 and 15%  relative to dry weight of wheat flour was used. Then the flexural strength and modulus, tensile strength and modulus, impact resistance and thickness swelling within 2 and 24 hours immersion in water of the test specimens prepared from the wood plastic composites were measured and statistically analyzed. The results showed that by using liqueur powder obtained from alkali sulfate-anthraquinone process with wheat straw flour, the flexural strength increased about 50% compared to pure propylene. The flexural and tensile modulus and impact resistance of the composites approximately 100% compared to pure polymer. The thickness swelling of the composites also increased with increasing the amount of black liquor powder and wheat straw. In general, the results showed that replacing the black liquor powder with a part of wheat straw flour not only did not lead to significant negative changes in the properties of wood plastic composites but also improved some mechanical properties.