فصلنامه جنگل و فرآورده های چوب
سال هفتاد و یکم شماره 1 (بهار 1397)

Germination of hazelnut seed faces with problems due to hard pericarp and dormancy period. The present study aimed to overcome these problems and improve the germination traits. For this purpose, hazelnut riped seeds were collected from three areas in Makesh in Aqh-Evlar, Fandoglou, and Makidi in Arasbaran, northwestern Iran. The seeds with pericarp and without pericarp were cold stratified in moist sand and kept in the refrigerator (5 ±1 °C) for 3 and 4 months and then grown in room conditions (20-22 °C) in order to record the seed germination daily. The experiment was done based on factorial in a completely randomized design with three replicates of 20 seeds. The highest germination (51.66 %), germination speed (2.86 per day), germination evenness (4.28 per day), germination energy (45.33%), root length (11.55 cm), shoot length (10.35 cm) and seed vigor index (112.84) belonged to without pericarp seeds of Makesh exposed to four months cold stratification. The seeds with pericarp of the three ecotypes, stratified particularly at four months, indicated the satisfactory germination percentage (≈ 40%) and seed vigor index (≈ 70). Although, germination of seeds without pericarp had better ability, however, in case of using the seeds with pericarp for the propagation of hazelnut in the nursery or for seed direct sowing in the deforested areas, the seeds of cold stratified (if possible four months) are recommended.

The aim of this study was to determine the humus quality using Rogister method along an elevation gradient in beech forests. For this purpose, first, along a transect (north-south) in the forests ofdistricts one and five of Kelardasht forest, 30 releves in tree and shrub layers and 30 releves in herb layer were sampled with dimensions of 20m × 20m and 10m × 10m, respectively. Then, the amount of vegetation was estimated using modified Braun-Blanquet scores. The A-horizon was sampled up to a maximum of 10 cm and its available moisture, pH and nitrogen was measured. After extracting ecological indicators’ values from three different sources and calibration values with measured data, classification of vegetation was performed using TWINSPAN and finally, the humus quality for ecological groups was determined using suggested ecogram by Rogister. The results showed that humus type at low, middle and high elevations is active mull, typical mull and acid mull, respectively. In other words, the humus quality decreases with increasing elevation. In addition, it was found that humus type for beech is acid mull. It is concluded that plant species (herb layer) can be a useful indicator for determining the humus quality of a forest ecosystem. In other words, after calibration of the main ecological indicators’ values, Rogister method can be used for sites classification in beech forests of Iran.

Spatial disturbance occurs in the forest through the creation of gaps. Updated information in the field of disturbance is essential for the management and protection of the forests. This research was carried out with the aim of providing the status of spatial disturbance of Sarvelat protected area in northern Iran using remote sensing and landscape metrics. The accurate map of the forest/non-forest was prepared by onscreen digitizing method using Landsat 8 data. Based on the metrics graph analysis for ten random points in the zones with different area, the optimal area for gridding was determined. Moreover, the studied area was divided into 252 hexagonal zones with the area of 100 hectares each one. Spatial distribution, connectivity and composition of non-forest patches in each zone were measured using eight spatial metrics (MESH, NP, PD, ENN-MN, AREA-MN, DIVISION, PLAND and SHAPE-MN) in Fragstats software and the map of any metric was prepared. After standardization of metrics values, Principal Component Analysis was done to determine the weight of metrics in the spatial disturbance model. Afterwards, based on the weighted metrics, the map of disturbance index was prepared and classified in four classes of disturbance including very low, low, medium, and high. According to the results, the mentioned classes cover 51, 25, 14 and 10 percentage of the studied area, respectively. It should be mentioned that the high level of disturbance is related to the mountainous areas and rangelands. If these sections are removed from the prepared map, the forest protected area has a relatively good situation. However, due to the beautiful nature and tourism attractions, the area is highly exposed to conversion to road and villa constructions and therefore increasing disturbance.

This study was conducted to recognize diversity of arbuscular mycorrhizal fungi )AMF) with some tree and shrub species of sites in Ilam province. For this purpose, four soil and root samples were colected from the depth of 0-30 cm in the rhizosphere of Cercis griffithii, Cerasus microcarpa, Amygdalus alaeagnifolia, Daphne mucronata, Lonicera nummularifolia, Crataegus pontica, Acer monspessulanum and Amygdalus arabica for soil analysis and AMF spore extraction. In total, 42 species of mycorrhizal fungi belonged to 13 genera were identified. The root colonization percentage varied from 34.97% in A. alaeagnifolia, to 99.90% in A. arabica. Also,spore density ranged soil from eight in A. arabica to 33 g -1 in C. pontica. Mycorrhizal fungi biodiversity indices showed no significant difference for richness in studied plant species. While Shannon-Weiner index of diversity (Hʹ), Simpson index of diversity and evenness were significantly different among studied tree species. The highest Shannon-Weiner index of diversity (Hʹ) values belonged to the L. nummularifolia and A. arabica respectively. Furetheremore, the highest Pailo evenness index value belonged to the A. monspessulanum and L. nummularifolia. AMF Simpson index of diversity for L. nummularifolia, A. monspessulanum, C. microcarpa, C. griffithii, A. alaeagnifolia and A. arabica were classified in one group. The high valued of AMF diversity could reperesnt a high level of soil diversity in the current studied sites. The higher level of AMF diversity in L. nummularifolia, A. monspessulanum and A. arabica rizhosphere can be explaned by the more soil nutrient element and productivity of mentioned species.

The natural durability of a wood in laboratory is usually determined by measuring the resistance of its heartwood against a specific rotting-fungi species. The most common way for the measuring of the natural durability is the standard guidelines given in EN 113. Although the heartwood of yew trees is experimentally known as a very durable wood, but so far no data is recorded about its resistance against fungal decay. In this study, the natural durability of yew wood was measured against different types of rotting fungi, and then the impact of extractive materials was discussed on that. The density (660.89 kg m-3) and the extractives content (10.75 %) of yew’s heartwood was similar to other softwood species. The result of fungal test showed that the heartwood of yew tree is very durable against rotting fungi. The samples showed below 1% weight loss after 16 weeks incubation with fungi including Trametes versicolor (as white rot), Coniphora puteana and Antrodia vallanti (as brown rot), while at the same time the controls from beech and sapwood of pine lost approximately 45 and 60 % of their initial weight against C. puteana. The extraction with hot water and or ethanol/aceton markedly decreased resistance of samples against rotting fungi. This proves that the extractive content of heartwood in yew tree is the main factor could affect its natural durability. No clear difference was observed between different ways of extraction on the durability of yew’s wood.

The aim of this study was to manufacture of green particleboard with natural adhesive from corn / soybean meal flour. The physical and mechanical properties of obtained particleboard were characterized under different conditions of press at dry environment. Variable agents of adhesive were two levels of press pressure; 15 and 17.5 kg/cm2 and three levels of press time; 600, 660 and 720 seconds. The corn / soybean meal flour with a ratio of equal, mixed with water to produce the adhesive. Sulfuric acid and sodium hydroxide were added to the adhesive mixture to decrease viscosity and increase adhesion, respectively. Then the particles blended with adhesive 15 wt%, and pressed at 190°C. In addition, the samples were prepared for physical and mechanical tests according to the European standards. The results showed that the bending properties and internal bonding increased with increasing press time to 660 seconds. while, the highest internal bonding was obtained at 0.5 MPa under 17.5 kg/cm2 pressures and time of 660 seconds. Also, water absorption and thickness swelling of the specimens after 2 and 24 h immersion decreased with increasing in press time to 660 seconds. Therefore, this adhesive can be used as a suitable alternative for the urea formaldehyde glue that has a risk of formaldehyde emission in interior locations.

Oak decline is a complex phenomenon affecting vast areas of Zagros forests. Dust is the most important factors in the decline of Zagros forest. In order to assess the impacts of dust on oak decline, six dust traps were installed in Helen protected area at the beginning of spring 2016. Dust samples were collected using the traps surface in autumn. The weight of dust samples and the amount of heavy metals were measured in the laboratory. Three transects (replicates) with fixed distances were designed in each of northern and southern directions. In each transect, three circular plots (with an area of 1000 m2) were laid out in three altitudinal ranges (1500-1800, 1800-2000, and more than 2000 meter a.s.l.). In each plot, leaf samples of five trees were collected from healthy and unhealthy trees, and the amounts of heavy elements including lead, cadmium, nickel, arsenic and mercury were measured. The results showed that cadmium and lead in leaves of healthy and unhealthy trees had a significant difference and the amount of these elements in the leaves of healthy tree was more than unhealthy trees. Higher amounts of heavy metals were absorbed by oak trees located in the southern aspect compared with those in the northern one. Moreover, the amounts of intercepted cadmium and lead had significant differences. It seems that the stress caused by the absorption of these heavy elements in the leaves of trees is one of the most important factors for oak trees decline.

Stand density management diagram is one of the effective methods for designing, displaying and evaluating various density regime management options in the even-aged stand. The aim of this study was to determine the tools for density management in Quercus brantii even-aged stands. This diagram can be used to manage stand density and estimate the stand volume quickly. For the development of this diagram, four variables were used including dominant heights, number of tree per hectare, quadratic mean diameter and volume per hectare. Data were collected from 15 even-aged stands in 71 plots in the central Zagros located in Charmahal Va Bakhtiari province, Iran. The construction of this diagram was carried out with two equations of the volume and quadratic mean diameter with the dependent variables of the number of tree per hectares and the dominant height. Because of the error in the estimation of left and right sides of the diagram, simultaneous fitting was used. Among different indices of density, relative density index due to its independence on site quality and age of the stand as well as dominant heights as a criterion for determining the interval thinning were used for determining the growth status in this diagram. Finally, in order to clarify the application of this diagram, a practical example of the thinning schedule with a dominant height of 8 m and two thinning intervals was proposed for a stand with medium stocking volume. This diagram can be used for rapid estimation of the volume and to suggest thinning schedules in coppice management planning of Quercus brantii stands.