فصلنامه تحقیقات جنگل و صنوبر ایران
سال سی‌ام شماره 4 (پیاپی 90، زمستان 1401)

The brown tail moth (Euproctis chrysorrhoea L.) is a significant leaf-eating pest that affects oak trees in the Arasbaran forests of Iran. This study aimed to investigate the biological characteristics, distribution, and demographic changes of this pest. The research was conducted in eight sites located in Ahar and Horand counties, East Azarbaijan province of Iran, during 2020-2021. For the study, 20 oak trees (Quercus petraea (Matt.) Liebl.) were chosen from each site, and 10 wintering nests were collected from each tree and taken to the laboratory for analysis. In the lab, the overwintering larvae were counted and weighed using a digital scale. The researchers also measured the width of the head capsule of the larvae and studied the life cycle of the pest in field conditions. The analysis of variance test was conducted to assess the difference between the eight sites concerning the average number and weight of the larvae in the wintering nests. The comparison of the averages was performed using Duncan's test. The results showed that E. chrysorrhoea has five larval instars, with the majority of the larvae in the wintering nests belonging to the third instar (around 90%). All the sample oak trees from the studied sites were infected with this pest, with several larval nests seen on them. The study found that the average number and weight of larvae inside the nests in the three sites of Horand county were significantly higher than the five sites in Ahar county. The control methods applied in Ahar county, including cutting and collecting larval nests, may have had an impact on reducing the number of brown tail moth larvae compared to Horand county.

There is a growing interest in using mosses as primary and evergreen plants in both natural and man-made landscapes. A strategy for biodiversity conservation and restoration in green spaces is to study the spatial distribution patterns of moss species, their relationship with host trees, and their abundance levels and diversity over time. This study aimed to investigate the establishment of moss species with ornamental value on the trunks of five tree species (Fagus orientalis Lipsky, Carpinus betulus L., Alnus subcordata C.A.Mey., Quercus castaneifolia C.A.Mey., and Acer velutinum Boiss.) by measuring canopy level and alpha and beta diversity indices over four six-month periods. The researchers also used indicator value index (IndVal) to determine indicator moss species. The study identified 28 moss species from 15 genera and 12 families on the host trees. Results showed that moss diversity, abundance, and canopy levels decreased over time. Among the host trees, C. betulus had the highest moss species diversity and abundance, while A. velutinum had the lowest. The interaction of mosses with their host trees revealed that F. orientalis and C. betulus had the highest number of combined indicator species. Moss crown coverage had a different function from moss diversity and abundance. At the end of the study period, the highest percentage of moss crown cover was observed in A. velutinum, which had the lowest diversity and abundance indices. Overall, the study suggests that using a combination of canopy percentage and abundance indices, and considering the relationship between mosses and host trees, can help select the most suitable moss species for use in other ecosystems.

Producing seedlings using the correct methods can aid in their better establishment in their habitats and help restore the fragile mangrove forests of southern Iran. This study aimed to investigate the effect of different methods of pericarp removal, irrigation regimes, and their interaction on germination percentage and some vegetative characteristics of Avicennia marina Forssk. Vierh. in the nursery. To achieve this goal, 30 healthy and mature trees were selected from the Sirik forest in Hormozgan province, Iran, and propagules were collected from them. The researchers used a completely randomized factorial design to study the effects of the treatments. Four pretreatments were tested for pericarp removal: pre-soaking propagules in 100% fresh water, 50% fresh water + 50% seawater, 100% sea water for 48 hours, and manually removing the pericarps. The propagules were then planted in plastic pots and irrigated twice a day, daily, every other day, or every three days. The seed germinations were measured for four weeks, and after two leaves appeared, collar diameter and height were recorded at the beginning and end of the six-month period. The results showed that seed germination and the vegetative characteristics of Avicennia marina Forssk. Vierh. seedlings were higher in the 50% fresh water + 50% seawater pretreatment. Additionally, germination, diameter growth, height growth, root length, and leaf number of the seedlings after six months were significantly higher with twice-a-day and daily irrigation regimes. Overall, the best conditions for producing Avicennia marina Forssk. Vierh. seedlings in the nursery were daily irrigation and pericarp removal using 50% fresh water + 50% seawater treatment.

The unique characteristics of Caucasian oak (CO) stands, located at high altitudes in the Hyrcanian forests, provide valuable insights into the variations of organic carbon (OC) and soil nutrients (NPK), as well as biological and physical changes within these habitats. Understanding these variations is crucial for effective forest management and conservation efforts. To this end, the current study established four 20 x 20 m2 sample plots in each of the CO habitats of Panomehsar in Lavij, Kolanga in Neka, and Tuskestan in Gorgan. Soil samples were collected from two depths (0-15 cm and 15-30 cm) in each plot and analyzed in the laboratory. Biophysical characteristics of trees, such as breast height diameter, total height, average crown diameter, density, and physiographical units, were also recorded.The results showed that OC and nitrogen (N) levels in both soil layers were not significantly different across the study forests (p > 0.05), while available phosphorus (P) and potassium (K) levels varied significantly among them (p < 0.05). There were no significant correlations between OC and N levels in the soil layers, or with the biophysical attributes of the trees based on Pearson tests. The findings indicated that OC and NPK variations were independent of each other, with no significant relationship between them observed in the study sites. Moreover, the nature of OC variations was found to be slow, making it challenging to discern the impact of tree species on these variations within the stands.In conclusion, the study sheds light on the slow nature of OC variations in CO stands and highlights the need for careful consideration of their effects on management and conservation efforts.

The remote sensing field faces a significant challenge in preparing land use maps in regions with similar spectral coverages. This research aimed to enhance crop classification accuracy by prioritizing poplar in Guilan province's Soomesara county. To classify poplar plantations, the researchers used data extracted from satellite imagery and field samples employing a random forest classification method. They utilized Sentinel-2 optical images, Sentinel-1 radar polarization data, and the ALOSpalsar digital elevation model produced in a time series to obtain this information. The team selected optimal images with high separability power for distinguishing poplar farms from other classes after analyzing the time series. Results demonstrated that optical images had better capabilities for land use classification than radar images. Additionally, implementing time series data instead of single images and using indices increased overall classification accuracy up to three percent. In conclusion, the researchers found that the proposed method utilizing Sentinel-1, Sentinel-2, and ALOS optical and radar satellite images has a high potential for poplar mapping in large areas. The estimated area of these regions in Soomesara County was 7,778 hectares.

Climate change significantly affects net primary production (NPP) and evapotranspiration (ET). To estimate NPP and reference ET (ET0), long-term (1986-2017) meteorological data collected by 96 synoptic weather stations located in five of Iran's forest vegetation zones: Hyrcanian, Arasbaran, Zagros, Khalijo-Omanian, and Irano-Turanian were used. The synthetic model and FAO Penman-Monteith combination equation were employed for estimation. Mann-Kendall test detected annual trends of NPP and ET0. The Hyrcanian zone demonstrated the highest amount of NPP at 10.7 t ha-1 y-1, while Khalijo-Omanian displayed the highest annual ET0 at 2099 mm. The NPP of Khalijo-Omanian and Irano-Turanian zones were roughly similar, ranging between 2 and 3 t ha-1 y-1. Out of 96 observed annual trends of NPP and ET0 in diverse vegetation zones, statistically significant trends were found in 22 trends (23 percent) of NPP and 73 trends (76 percent) of ET0. Understanding the impact of climate change on ecosystem function requires trending of NPP and ET.

Wood is a valuable material that is produced and treated in the forest workshop using natural resources. The history of these workshops reveals the significance of wood in human life across many regions of the world. As collecting wooden specimens became increasingly popular over time, museums and herbariums emerged to house valuable plant and animal collections. One unique type of collection is the xylarium, or wooden herbarium, where wood samples are stored. The term "xylothek" was originally used when these collections were made available to the public. Xylaria distinguish between collections created for scientific and educational purposes and informal ones made by craftsmen and artisans. The creation of these collections was primarily intended to facilitate collaboration and exchange among the world's greatest xylaria. They also allow for systematic studies by wood anatomists, researchers, and scientists in other fields. Additionally, they serve exhibition, educational, cultural, historical, and commercial purposes. In recent years, modern technologies such as imaging, image analysis, measurement, and artificial intelligence have made it possible for artisans to identify wood with greater precision. These collections have immense value because they increase awareness of biological reserves and attract the attention of experts who record and collect information about them. Wood blocks may seem silent, but they have tremendous potential to enhance our understanding of the natural world and contribute to its preservation.