Journal of Forest Ecosystems Research

Monitoring and correlations soil parameter dynamics in Boyer-Ahmad forests

Yousef Askari

Extended Abstract

Background and Objectives: Long-term monitoring of forest soil variables is essential for assessing ecosystem dynamics, forest health, and the impacts of environmental and anthropogenic factors on soil. Key soil parameters including microbial respiration, soil moisture, organic carbon stocks, available phosphorus, and nitrogen are of strategic importance in forest ecosystems, particularly under current climate change and global warming conditions. This study pursues to measure the physical and chemical properties of the soil in the studied forest stands (in the selected fixed and permanent sample plots), and also to enable long-term monitoring of the trend of changes in the soil of these forest sites.

Materials and Methods: This study aimed to monitor soil changes and analyze correlations between soil factors in two sample plots (Parikdan= south slope and Sarabtaveh= north slope) in Boyer-Ahmad County, Kohgiluyeh and Boyer-Ahmad Province. Two randomly selected one-hectare plots (100×100 m) were inventoried, with five systematic soil samples collected from 0-30 cm depth in each plot to measure carbon, nitrogen, phosphorus, moisture, microbial respiration, bulk density, and gravel percentage. Soil data collection was repeated annually over the three-years (2018-2020) project period.
Results: The results revealed that in the Sarabtaveh site, soil organic carbon (2.94%), total nitrogen (0.26%), available phosphorus (16.21%), soil moisture (15.25%), and microbial respiration (640.88 mg CO₂/kg soil/day) were recorded, while the Parikdan site showed values of 2.85%, 0.22%, 17.57%, 15.44%, and 707.74 mg CO₂/kg soil/day, respectively. The mean soil carbon stock was estimated at 81.91 ton/ha in Sarabtaveh and 86.37 ton/ha in Parikdan.
Conclusion: Monitoring soil parameter dynamics and their interrelationships in forest ecosystems is critically important, as soil serves as the fundamental substrate that governs nutrient cycling, carbon sequestration, and biodiversity maintenance. Three-year monitoring revealed significant differences in soil carbon stock dynamics (p<0.05). In both sites, soil organic carbon demonstrated the strongest correlation (r>0.85, p<0.01) with total carbon stock, indicating its pivotal role in carbon sequestration potential. The soil moisture content, microbial respiration, and available phosphorus were significantly higher in the Parikadan sample plot compared to the Sarabtaveh plot. This difference can be attributed to the greater species diversity, higher vegetation density, and larger canopy cover in the Parikadon plot. The current study's results revealed a significant positive correlation between soil organic carbon content and total nitrogen. The increase in nitrogen mediated through changes in litter quantity and quality as well as alterations in the microbial decomposer community directly influences soil organic carbon levels.

Assessing phenological plasticity and frost resistance in three Zagros oak species using a common garden approach

Khaled Karimi hajii pamogh

Background and objectives: Cold is one of the severe and limiting environmental stresses in forest ecosystems, particularly in temperate regions. With climate change affecting plant phenology and altering cold resistance in spring and autumn (notably in seedlings), it is crucial to identify species and genotypes that exhibit resilience. Therefore, this study focused on assessing the cold tolerance of seedlings from three species: Quercus brantii, Q. infectoria, and Q. libani, and examining how this tolerance relates to their phenological traits, such as bud burst and leaf senescence.
Materials and methods: Seeds from 54 mother trees were collected from the Baneh forest region (located in the Northern Zagros, characterized by higher altitude, latitude, and colder temperatures) and sown in a communal garden in Yasuj (found in the Southern Zagros, with lower altitude, latitude, and warmer conditions) for two years. Various phenological parameters (including the timing, rate, and speed of leaf bud burst and leaf senescence) as well as survival rates and damage of the terminal bud of the seedlings were recorded and analyzed at different time intervals using statistical methods such as repeated measures analysis of variance, Duncan's test, and Pearson correlation.
Results: The results of this research indicated that seedlings of different oak species exhibit notable differences in leaf bud burst speed, damage to seedlings, and survival rates. Specifically, the Q. brantii opened its buds approximately 3-4 days earlier and more rapidly, while, it showed the least damage to the terminal bud and the highest survival rate. In contrast, the Q. infectoria opened its buds later and more slowly than other species and suffered the most damage to the terminal bud and had the lowest survival rate. Additionally, correlation analysis revealed that seedlings with faster bud opening in the early growing season tend to have more terminal bud damage but also higher survival rates. Furthermore, the results of leaf senescence also showed that there was no significant difference among the three species in two years, although a positive correlation between the speed of bud burst and the leaf senescence.
Conclusion: The findings of this research suggest that the Q. brantii exhibits greater resistance to late spring frosts due to its favorable phenology (earlier and faster bud burst) and reduced bud susceptibility to cold. Consequently, it is less affected by late spring frosts associated with climate change compared to the other two species studied. Therefore, it is recommended to planted the Q. infectoria and Q. libani species more in the higher and cooler regions of the Zagros, and to select seeds from genotypes that have a later bud burst in spring for breeding programs.

Estimation of Carbon Storage of Tree Cover in Urban Forest (Study area: Mazandaran Province, Sari City)

Elham Fazeli

Extended Abstract
Background and Objectives: One of the most important factors of global warming is the phenomenon of illegal emission of greenhouse gases; The most important of which are nitrogen dioxide (NO2), carbon dioxide (CO2), and methane (CH4). However, due to the large amount of carbon dioxide accumulation in the atmosphere, this gas is one of the key gases in the phenomenon of global warming. Therefore, to reduce atmospheric carbon dioxide and balance the content of greenhouse gases, atmospheric carbon must be absorbed and deposited in various forms. Urban forests have a high capacity to absorb atmospheric carbon dioxide and provide many environmental services in urban areas. Therefore, it is necessary to obtain correct and accurate information in this regard to optimally manage these forests in increasing carbon sequestration. This research aimed to estimate the amount of carbon stock of the urban forest in Sari City, the capital of Mazandaran province.
Materials and methods: This research Using selective sampling, 150 samples were taken (50 samples in each region) and an effort was made to distribute these samples in the three regions. First, the information related to the general characteristics of each of the samples, including the height above sea level, the slope, and the direction of measurement, were recorded. In each sample plot, species type, breast diameter, height, and small and large crown diameters of all trees were measured, and the number of each tree and shrub species was counted and harvested. The center of each sample and measured tree was recorded with a GPS device and transferred to the GIS software environment. After calculating the carbon sequestration of trees, the relationship between diameter and carbon sequestration was investigated using linear regression in SPSS software version 21. Then, a carbon sequestration zoning map was prepared in all areas of Sari using the conventional kriging method and in GS+ software.
Results: The highest and lowest amount of carbon sequestration of trees was observed in areas one (60.95 ± 31.10 tons per hectare) and three (13.68 ± 3.84 tons per hectare) of Sari city, respectively. Variance analysis of diameter and carbon deposition relationships showed that linear and power regression models were significant. The evaluation results of the linear regression model (R2=0.74) and power (R2=0.97) showed that both models are highly accurate in estimating carbon deposition on the ground of trees. According to the results, the highest potential of carbon sequestration was observed in the northeastern part and located in an area of Sari.
Conclusion: In this research, a high amount of carbon sequestration was observed in the city of Sari. It can be said that the main reason for the high amount of carbon deposition in Sari city is that, most of the trees in the green space of Sari city are old plane trees The reason for the high level of carbon deposition of the plantain tree is the high density of its wood compared to other trees. In general, young trees have a higher amount and speed of carbon deposition than old trees, but old trees also deposit carbon in a larger amount and for a longer period. Obtaining the results that the trees of Sari city can absorb 200 tons of carbon per hectare is remarkable and promising. Prioritizing the preservation and growth of larger and older trees in urban environments may have significant results for carbon sequestration. At the same time, examining the temporal dynamics of carbon sequestration, combining other environmental variables, or modifying the spatial resolution of the analysis can further increase the accuracy of carbon sequestration estimation. Therefore, obtaining more information in this direction is necessary and necessary.

Effects of the Shelterwood System on Changes in Aboveground Biomass of Beech Forest Trees

Hashem Habashi

Background and objectives: The Hyrcanian forests play a crucial role in carbon storage, soil and water conservation, and climate change mitigation. Previous studies on the silvicultural management of these forests have mainly focused on estimating stand volume and structural characteristics, while the impacts of different management regimes—particularly the shelterwood system—on aboveground biomass, as a key indicator of carbon sequestration, remain unclear. The main objective of this study was to quantify and analyze the effects of shelterwood management treatments on tree quantitative characteristics and aboveground biomass in the beech (Fagus orientalis Lipsky) forests of Kelardasht, northern Iran.
Materials and methods: The research was conducted in Compartment 5 of the Kelardasht forest management plan. Five management treatments were selected: control, shelterwood, partial shelterwood, shelterwood with improvement cutting, and unmanaged (outside the management plan). In each treatment, five 0.5-hectare plots were randomly established. Diameter at breast height (DBH), total height, and stem height were measured, and tree volume was calculated. Aboveground biomass was estimated using tree volume, wood specific gravity, and FAO expansion factors. Data were analyzed using one-way ANOVA and independent t-tests.
Results: Mean DBH and total height were significantly higher in unmanaged treatments (control and outside the management plan) than in managed ones. The control treatment had the highest aboveground biomass (613.58 t ha⁻¹), whereas the complete shelterwood treatment had the lowest (272.56 t ha⁻¹), representing a 56% reduction compared to the control. The partial shelterwood and shelterwood with improvement cutting treatments had mean values of 417.13 and 273.61 t ha⁻¹, respectively. These patterns were consistent with structural indices such as stand volume and total height; even-aged stands resulting from complete shelterwood had lower biomass, while uneven-aged structures in partial shelterwood and control treatments performed better.
Conclusion: The findings suggest that the partial shelterwood method is a suitable option for the mid-elevation forests of Kelardasht, as it combines considerable economic benefits with biomass levels closest to the control treatment, while maintaining the advantages of uneven-aged forest structures. For the first time, this study demonstrates that prolonging the shelterwood regeneration period can lead to the formation of natural, uneven-aged stands that exhibit features of sustainable forests, with important implications for enhancing carbon sequestration in these valuable Hyrcanian ecosystems.