Standing Stock Research Articles

Relationships between Tree Diameter, Height, and Stocking in Even-Aged Eucalypt Stands in Pointe-Noire (Republic of Congo)

Relationships between Tree Diameter, Height, and Stocking in Even-Aged Eucalypt Stands in Pointe-Noire (Republic of Congo)

Effect of elevation and aspect on carbon stock of bamboo stands (Bambusa nutans subsp. Cupulata) outside the forest area in Eastern Nepal

Bamboo has emerged as a promising option for climate change mitigation due to its rapid growth, versatility, and renewability. However, in Nepal, there exists a substantial knowledge gap on carbon (C) stock and the influence of aspect and elevation on C stock of bamboo species, particularly in areas outside forests where bamboo is dominant. Therefore, this research was conducted to quantify C stock and aspect-elevation influence on the C stock of Bambusa nutans subsp. cupulata outside the forest area. For this study, three elevation zones (0–400 m, 400–800 m, 800–1200 m) and two aspects (East and West) were considered. A total of 30 square plots having a 100 m2 area were established utilizing purposive sampling due to the scattered distribution of bamboo. Non-destructive methods were applied to measure bamboo culm diameters, while composite soil samples were systematically collected from 30 cm depth using soil augers and core samplers. Clump density (400 ha⁻¹), culm density (42,480 ha⁻¹) and culm diameter (6.82 ± 0.41 cm) were highest at middle elevations (p < 0.05), with no significant difference due to aspect (p > 0.05). The total mean C stock potential of B. nutans was 148.73 ± 3.43 Mg ha⁻¹. Our results indicated a significant difference in C stock among elevation zones, with middle elevation zones (161.77 ± 6.74 Mg ha-1) exhibiting notably higher C stock compared to both lower (150.26 ± 2.69 Mg ha-1) and higher (134.17 ± 4.26 Mg ha-1) elevation zones. Furthermore, East aspect was found to have significantly (p < 0.05) higher soil organic C stock (18.52 ± 1.32 Mg ha-1) compared to West aspect (11.4 ± 1.01 Mg ha-1). Further research is needed to explore other complex environmental interactions with C stock potential for better climate change strategies. Incorporating bamboo C into Nepal's REDD+ initiative can be crucial for optimizing opportunities to earn C credits.

Effect of the irregular shelterwood system on soil organic carbon stock and soil quality of Shorea robusta Gaertn. f. forest in Nepal

The effective management of forests relies on the crucial role played bysilvicultural systems. However there exist a significant knowledge gap regarding impact of these systems in Nepalese forests. Therefore, this research was conducted to assess the effects of the forest management activities under irregular shelterwood system on soil organic carbon (SOC) stock and the overall soil quality of Sal (Shorea robusta Gaertn. f.) forests in Terai region of Nepal. Stratified random sampling method with 1.67 % sampling intensity was adopted in this study where management of stands was used as basis of strata. A total of 30 composite soil samples (15 each from managed and unmanaged forest stands) were collected from a depth of 0–30 cm, taken from the four corners and the center of each plot. Soil quality index (SQI) method was used for soil quality assessment using indicators on the basis of prior studies conducted in Nepal. Our study found significant difference in soil parameters except organic carbon, pH, silt, and clay among the managed and unmanaged forest stands (p < 0.05). SOC stock of unmanaged forest stands (48.87 ± 1.34 ton ha−1) was significantly greater than managed forest stands (27.76 ± 1.27 ton ha−1). Similarly, unmanaged forest stands demonstrated better soil quality with higher SQI value (0.66) than managed forest stands (0.50). This negative impact of irregular shelterwood silviculture system highlights the necessity for management interventions to enhance SOC stock and overall soil quality. To establish a robust conclusion, further replication of similar studies at different soil depths and in other management regimes, along with longitudinal studies, is essential.

Contrasted effects of shade tree legumes on soil organic carbon stock and carbon balance in 20-year cacao agroforestry, Ivory Coast

Cacao–based agroforestry systems are promoted as adaptation and mitigation solutions for cacao production and carbon sequestration. Based on a 20-year experiment, we assessed the impact of associated shade tree legume (ATL), Albizia lebbeck and Acacia mangium on the total carbon stock (in soil at 60 cm depth + tree biomass + litter) of cacao stands. This study included cacao systems shaded with either A. lebbeck (Cacao-Alb) or A. mangium (Cacao-Aca) and full-sun cacao stands (Control). Soil organic carbon (SOC) contents (up to 60 cm deep) were estimated by a calibrated near-infrared spectroscopy model. Total tree biomasses were estimated using allometric equations. Leaf litter was sampled from 1-m2 quadrats. Compared to Control, Cacao-Aca had a significant negative impact on the carbon stock in the cacao biomass (−47%) as well and in the soil at depths of 10 cm (−23%), 30 cm (−21%) and 60 cm (−12%). In contrast, Cacao-Alb had a nonsignificant effect on carbon storage in the cacao biomass, whereas it generally had a positive influence on the SOC stock regardless of depth, i.e., +6% at the 0–10 cm depth, +7% at 0–30 cm, +20% at 30–60 cm and + 11% at 0–60 cm. Cacao-Aca had a significant positive impact (+71%) on the total carbon stock per hectare. The increase in Cacao-Alb relative to that in the Control reached +38%, but the difference was not significant. These contrasting results between the two tree legume species could be explained by the high-quality litter, reflected by the lower C/N and C/P ratios produced by A. lebbeck, and the greater negative impact of A. mangium on cacao biomass. The main finding of this study is that the impact of intercropping cacao with shade tree legumes on the stand-level total carbon stock depends on the ATL species.

Standing dead wood stocks in forest stands of Middle Dnieper region (Forest-Steppe of Ukraine)

Standing dead wood is an important component of forest ecosystems of temperate zone. The aim of the article is to study the forestry and ecological features of the distribution of standing dead wood stocks in forest stands of Middle Dnieper region (Forest-steppe of Ukraine). The study was carried out based on State forest inventory data of the part of territory of state forest enterprise with a total area of 24558.6 ha in northern part of Cherkasy region. According to forest inventory data standing dead wood was found on area of 3439.4 ha or 14.0% of the total forest area. The average standing dead wood volume was the highest in forests of nature conservation, scientific, historical and cultural purposes (13.0 m3∙ha–1), somewhat lower — in forests with commercial purpose (11.0 m3∙ha–1), in protective, and recreational and health-improving forests (9.8 m3∙ha–1). Standing dead wood was found in the forest stands of 15 tree species with a total stock of 34660 m3. In those forests the average volume of by tree species ranging from 5.0 m3∙ha–1 up to 20.0 m3∙ha–1, in general for all tree species — 10.1 m3∙ha–1. In the stands of the prevailing tree species — Scots pine (Pinus sylvestris L.), black locust (Robinia pseudoacacia L.) and Common oak (Quercus robur L.) the average volume of standing dead wood was 10.4, 9.0 m3∙ha–1 and 7.5 m3∙ha–1, respectively. In the stands of the first two specified tree species, a tendency to increase the average volume of standing dead wood with an increase in the age of the stand was revealed. Standing dead wood was found in 17 out of 32 forest types that are represented in the forest fund of the studied object, with an average volume of 5.7 m3∙ha–1 (fresh eroded hornbeam dibrova) to 22.4 m3∙ha–1 (damp black alder hrud). In general, standing dead wood stocks are low, which may be caused by forestry activities (cutting). The data we obtained are important for research into the peculiarities of the formation of woody detritus stocks in the forests of Middle Dnieper region of Ukraine and nature protection functions of dead wood.

Оценка секвестрационного потенциала осиново-березовых древостоев островных лесостепей Средней Сибири

The forest-steppes of Central Siberia occupying submontane troughs and intermountain basins separated by taiga vegetation are considered insular. Forest woody vegetation is mainly represented by birch, aspen, larch and pine stands. A decisive role in the ecological sustainability of forest areas is played by larch plantations. This study has aimed to identify the characteristics of the dynamics of individual forest elements in the mixed deciduous stands within the forest area. The tasks have been to identify the characteristics of the forest area, characterize the dynamics of the taxation parameters of major and minor elements of the mixed stands and assess the contribution of the stands to the carbon balance. The work is based on the data of 548 strata. We have established the characteristics of the forest area age structure and how the stands of various completeness and productivity are represented in it. We have also estimated the variability of the average stands taxation parameters in different age periods. The average values obtained have become the basis for mathematical modeling of the table of the dynamics of the taxation parameters of the mixed stands. It turns out that the process to a reasonable degree of adequacy is reflected by the Weibull distribution. The accuracy of the equations has been estimated by the value of the coefficient of determination (R2) and the standard error of the equation (S). On the basis of the obtained mathematical models, we have constructed the table of the dynamics of the average taxation parameters of the stands of the forest elements and of the mixed stand as a whole. The biological system of forest woody vegetation under consideration has a significant carbon sequestration potential. However, there is currently no generally accepted procedure for assessing the effectiveness of this process. Russian and foreign researchers have collected a large amount of data from different regions, but they have been using different methods. To estimate carbon stocks in the stands that are the object of the study, we have used the conversion-volume method for estimating carbon stocks in forest plantations. The result is the obtained data illustrating the dynamics of carbon stocks in the aspen-birch stands in the insular forest-steppes of Central Siberia.

Thinning increases forest ecosystem carbon stocks

Thinning, a major measure of forest management, is known to alter carbon sequestration by affecting the forest microclimate and soil environmental conditions. However, how thinning effect on forest ecosystem carbon stocks have presented inconsistent results. Therefore, we conducted 1776 pairs of thinning experiment observations worldwide to explore how thinning affects forest vegetation and soil carbon stocks. The results showed that overall thinning significantly increased total tree aboveground biomass carbon stocks (AGCtotal, +23.9%, +1.3 Mg ha-1 yr-1), understory vegetation carbon stocks (UVC, +68.3%, 0.12 Mg ha-1 yr-1), and soil organic carbon stocks (SOCstocks, +4.8%, 1.0 Mg ha-1 yr-1) at the global, but exhibited significantly decreased carbon stocks of litterfall (LBC, –9.6%, –0.03 Mg ha-1 yr-1). Belowground biomass carbon stocks remained unchanged under thinning. The sensitivity of carbon sequestration to thinning gradually disappeared after 6 years, except for AGCtotal, as they were jointly subject to stand density and thinning intensity and not just recovery ages. The response to UVC was more positive in medium-density (1500 – 3000 trees ha-1) and moderately thinned (30 – 50%) stands, and the thinning effects on UVC and SOCstocks were more noticeable in the subtropical and temperate zones. In summary, thinning enhanced forest ecosystem carbon sinks (+2.4 Mg ha-1 yr-1) but reduced carbon stocks in low-density stands (≤ 1500 trees ha-1). Soil moisture content (SMC, +6.6%) and bulk density (BD, –1.5%) dynamics after thinning were important factors regulating vegetation growth and soil carbon cycling processes.

The Effects of Stand Development Stages on Soil Carbon and Nitrogen Stocks in Black Pine, Scots Pine and Fir Stands in Türkiye

The influence of stand development stages on soil organic carbon (SOC) and total nitrogen (TN) stocks was examined in black pine (Pinus nigra Arnold.), Scots pine (Pinus sylvestris L.), and Kazdağı fir (Abies nordmanniana subsp. equi-trojanı (Aschers. &amp;amp; Sint. ex Boiss) Coode et Cullen), differing in the mean tree diameters in which reproduction stages (RS)=&amp;lt;8 cm, sapling or pole stages (SPS)= 8-19.9 cm, large pole stages (LPS)= 20-35.9 cm, and medium wood stages (MWS)=36-51.9 cm in three tree species located in northwestern Turkey. A total of 216 soil samples were collected and analyzed for pH, organic matter, bulk density, maximum water holding capacity, carbon, and nitrogen concentrations, and the SOC and TN stocks were calculated. SOC and TN stocks varied significantly among the four stand development stage classes. The SOC stock at 0-30 cm increased significantly due to an increase in the diameter of black stands (BPLPS and BPMWS). SOC stocks in all stand development stages peaked in the large pole (44.94 Mg/ha) and declined as the sapling or pole (37.71 Mg/ha) was replaced by medium wood stands (30.17 Mg/ha), and a low point (27.94 Mg/ha) was found in the reproduction stages of stand development for Scots pine. The TN stock at a soil depth of 0-30 cm ranged from 1.66 to 6.46 Mg/ha. The highest TN stock was observed in the SPSPS (6.46 Mg/ha) and FirRS (5.48 Mg/ha), and the lowest was observed in the BPLPS (1.66 Mg/ha) stands. The results illustrate that soil was the main storage of C and N in all different stand development stages of tree species.

Development of a footprint description tool utilizing SMEAR Estonia eddy-covariance data and footprint modelling in combination with remote sensed forest species and land cover data

Abstract Understanding how forest ecosystems respond to environmental factors, particularly in the context of global climate change, is essential for devising effective mitigation strategies. This study focuses on quantifying the interaction between forest ecosystems and atmospheric gases. To achieve our objectives, we are using the eddy covariance (EC) flux method to measure air turbulence and gas concentrations above the forest canopy at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) in southern Estonia. We apply a flux footprint (FFP) model to describe the spatial extent and position of the surface area contributing to the turbulent flux measurements. The FFP analysis provides valuable insights into the long-term changes in SMEAR Estonia, the FFP and its relationship with forest management and land use changes. Our findings reveal that the FFP area varies from year to year due to changes in wind speed and direction, affecting the contribution of different land cover elements to the overall FFP. The average changes in the FFP area at a height of 30 meters were approximately 4.9%, while those at a height of 70 meters were only 1.6%. Moreover, human activities, such as thinning and clear-cutting, influence the growing stock and increment of forest stands.

Forestry and ecological features of fallen dead wood stocks distribution in forest ecosystems of Kaniv Dnieper region

Dead wood is an important component of forest ecosystems that performs a number of ecological functions. The purpose of the article is to study the forestry and ecological features of the distribution of fallen dead wood (lying woody debris) stocks in forest stands of the Kaniv Dnieper region (Middle Right Bank Dnieper, Forest-steppe of Ukraine). The study was carried out based on State forest inventory data of the forest fund of the former State Enterprise «Kanivsky Forestry» with a total area of 24,558.6 ha. The area of forest stands in which fallen dead wood was found during forest inventory was 2,550.3 ha or 10.4% of the total forest area. In general, fallen dead wood was found in the forest stands of 18 tree species with a total stock of 21,255 m3. In forest stands where fallen dead wood was found the average volume of by tree species ranging from 5.0 m3∙ha–1 (elm (Ulmus minor Mill.), small-leaved linden (Tilia cordata Mill.), black poplar (Populus nigra L.), common ash (Fraxinus excelsior L.), green ash (Fraxinus lanceolata Borkh.) up to 17.8 m3∙ha–1 (white willow (Salix alba L.), in general for all tree species — 8.5 m3∙ha–1. In the stands of the prevailing tree species — Scots pine (Pinus sylvestris L.) and black locust (Robinia pseudoacacia L.), the average volume of fallen dead wood was 9.1 m3∙ha–1 and 8.5 m3∙ha–1, respectively. The average volume among trophotopes was the largest in hrud (dibrova) — 8.7 m3∙ha–1, and the smallest — in bir, 5.2 m3∙ha–1. Among hygrotopes, the average volume was from 5.3 m3∙ha–1 (damp conditions) to 11.0 m3∙ha–1 (wet conditions). Fallen dead wood was found in 16 out of 32 forest types that are represented in the forest fund of the studied object, with an average volume of 5.0 m3∙ha–1 (wet oak-pine subir, damp black alder suhrud) to 18.4 m3∙ha–1 (wet floodplain willowpoplar suhrud). In general, the average volumes of fallen dead wood in forest stands are low, which may be related to forestry activities (cutting). The data we obtained are important for research into the peculiarities of the formation of woody detritus stocks in the forest types of the Middle Right Bank Dnieper of Ukraine and protective functions of dead wood.

Long-term dynamics of aboveground carbon stocks in managed loblolly pine plantations in the southeast United States

Intensively managed pine plantations in the southeastern US could not only meet the increasing demand for traditional wood products and biomass for energy, but also play a critical role in meeting US greenhouse gas emission reduction goals through additional carbon (C) sequestration. Adapting forest management to help mitigate climate change requires better understanding of long-term effects of silvicultural treatments on forest production and C sequestration. With two long-term culture-by-density research experiments for loblolly pine plantations across the southern US, we assessed the impacts of site quality, cultural intensity (operational and intensive), and planting density (741, 1483, 2224, 2965, 3706 and 4448 trees ha−1) on dynamics of aboveground net primary production in C (ANPPC), aboveground live tree C stocks (AGC), and cumulative C lost to tree mortality and other litter production (CLC), and total gross C capture (TGC). Cultural intensity significantly affected ANPPC and AGC before age 15 years, and CLC and TGC during the whole study period; while planting density significantly affected ANPPC before age 15 years, CLC after age 6 years, and AGC and TGC over time. Site quality significantly affected AGC at early and late ages, CLC at mid-rotation, and TGC at early ages. After age 20 years, higher quality sites still resulted in higher AGC than lower quality sites, while higher-planting densities might no longer promote aboveground live tree C stock. Intensive management practices that promote growth along with C accumulation in young stands do not necessarily result in higher C stocks in older stands. There exist a maximum C sequestration rate and a maximum C storage in loblolly pine plantations. Continuing carbon capture in the extended rotation or deferred harvest forests is in no way guaranteed to continuously increase carbon stocks. To develop effective climate-smart forest management recommendations, long-term dynamics of carbon capture, release, and storage, especially in managed forest plantations, need more research.

Формирование рубками ухода биологически устойчивых сосняков защитного назначения в Северном Казахстане

The article deals with the effect of thinning in a permanent trial plot (PTP). The objects of care were natural clean even-aged pine forests growing in arid conditions of the Kazakh Uplands (case study of the Burabay National Park). The first thinning led by A.A. Weisman was carried out in 1994 in 25–30-year-old stands with the care intensity from 12.5 to 49.7 %. Besides the operating sections, the trial plot laid out during the research had control sections, where thinning was not carried out. The inventory indicators of the stands were determined, and the effects of thinning were analyzed in all the control and operating sections 70 years after the experiment began. The experiment proves that in dry pine forests of Northern Kazakhstan, the stock of stands in the operating sections, even 70 years after the care does not reach the volume of stock in the control sections. This also applies to the sections covered by low-intensity thinning. At the same time, thinning reduces the stock of ground flammable materials and deadwood. It increases the average diameter of trees relative to the care intensity. This enhances the fire resistance and recreational attractiveness of the plantations. An expanded distribution series of trees by natural diameter classes is observed in all sections: the number of natural diameter classes is 1.8 times greater than the normative distribution, which is one of the proofs of the specificity of the structure of the studied pine forests. The use of thinning with high intensity by the stock is the most promising. Dead standing, diseased and stunted trees are removed from the stand in the course of thinning. Thinning is recommended for 20–25 and 40–50 years old trees.

Current state and productivity of Scots pine modal stands of the Forest Steppe of Ukraine

The development of regulatory and reference support for the inventory assessment of the state of modal stands is an urgent issue, since it allows obtaining reliable and up-to-date information on the current state of existing forests. The purpose of the study was a statistical substantiation of the division of pine stands into groups by region of growth and stand composition, and their detailed inventory characteristics with an analysis of the distribution in the Forest-Steppe and their productivity. To conduct the study, a stand-wise database of the Production Association “Ukrderzhlisproekt” for Forest-Steppe zone of Ukraine was used. Using a number of non-parametric criteria for evaluating samples (Kruskal-Wallis one-way analysis of variance, the median criterion, Jonckheere-Terpstra test), the study established a difference in the stands parameters of the samples under study and divided the stands of the Forest-Steppe zone into four groups. The main task was to describe the current state of modal pine stands of the Forest-Steppe zone of Ukraine for selected groups, with a detailed distribution of areas and stocks according to the main stand parameters According to the results of the database analysis, it was found that about 92% of the total area of pine stands of the Forest-Steppe zone are artificial forests. Depending on the region of growth, the stands were divided into the left- and right-bank parts of the Forest-Steppe, in composition – into pure and mixed stands. Within the groups under study, the distribution of areas and stocks of pine stands was analysed according to site index classes, types of forest-growing conditions, forest types, relative stand density, and age groups. Site index classes in all groups are dominated by high site index stands of I and Ia site index classes. The proportion of high-grade mixed stands is greater compared to pure stands. In terms of the forest-growing conditions, stands in condition B2 dominate in all groups under study. From the left bank to the right bank, there is an increase in soil fertility from condition B to condition C, and this dependence is also observed from pure to mixed stands. Productivity in terms of the average growing stock of mixed stands of the rightbank and left-bank parts of the Forest-Steppe is very close and considerably less than the stocks of pure stands. The presented research results can be used by scientists as a description of the modal inventory characteristics of the Forest-Steppe region and for the grouping of experimental data when compiling forestry and forest inventory standards

Производительность и возобновление насаждений притундрового леса в Республике Коми

The paper highlights the evaluation results of the productivity and regeneration of stands in the Pechora forestry of the Komi Republic. At the research sites, the stands are mixed by composition and simple to complex by shape (with one or two stories). They are dominated by sphagnum spruce stands of Va - Vb quality classes. The total standing volume of stands varies from 44 to 161 m3/ha whereas the average volume increment varies from 0.49 to 1.46 m3/ha per year. The dependence of standing volume on the absolute and relative forest density is a closely correlated value being reliable at a high level of significance. Young spruce trees grow at 87 % and young birch trees - at 73 % of sample plots. 1/3 of the sample plots is characterized by the density of large spruce new growth exceeding 1.2 thousand units/ha. In this case, we can recommend natural reforestation by young growth conservation and care for it. At the other areas, the forest density varies from 0.25 to 0.8 thousand units/ha. Here, we also think that natural reforestation is an appropriate forest regeneration method but on condition of soil mineralization and with leaving seed trees. The relationship between the density of spruce or birch regrowth and the total stand stock can be expressed by the parabola equations. The maximum density of large spruce regrowth (1.75 thousand units/ha), calculated by these equations, corresponds to the stand stock of 84 m3/ha and relative stand density of 0.93. The maximum density of large birch regrowth (0.95 thousand units/ha) corresponds to the stand stock of 88 m3/ha and relative stand density of 0.98. Along with decreasing or increasing the stand stock value providing for the maximum regrowth density, the regrowth density values decrease. We explain the identified dependency as follows. In the given conditions, the maximum density of large regrowth that can further become a stand, can be achieved on condition of the optimal density and stock of stands that provide favorable conditions for regeneration and growth of young trees. Any decrease or increase in the density and stock of stands from the values being optimal for regeneration and growth of young trees weakens the protective role of maternal stand or, vice versa, increases its negative impact on the younger generation and, as a result, decreases the regrowth density under the canopy. The above mechanisms should be taken into account when conducting selective cuttings and cleaning cuttings under these conditions.

State of the raw wood growing stocks and prediction of further development of cutting in the context of coniferous stands calamity in the Czech Republic

The extremely dynamic development of calamities caused by the effects of global climate change followed by the spread of under-bark insect pests mainly in coniferous stands and the ongoing incidental felling have raised concerns in the woodworking industry about the developments in the source material with respect to ensuring production in a short-term view. Since the overall standing stock in spruce stands of all age classes in the Czech Republic amounts to 399.6 million m&lt;sup&gt;3&lt;/sup&gt; (2017–2026) and the theoretical outlook of the logging potential based on the percentage of logging accounts for 112.62 million m&lt;sup&gt;3&lt;/sup&gt; (2017–2026), the concerns might be deemed justified. The article presents an updated view of the current situation based on official statistics and offers an analytic prediction of the possible development, considering the possible consequences, even in the production of the forestry sector. The statistical data on the current situation have been compiled for the last two decades of development. The results show that with a continued high rate of bark beetle calamities, assuming a total annual cutting with a permanent limitation on the planned harvests of more than 30 million m&lt;sup&gt;3&lt;/sup&gt;, the complete stands of spruce from age class 5 onwards could be harvested in approximately 14–16 years.

Mapping of mangrove forest and carbon stock estimation of east coast Surabaya, Indonesia

Abstract. Hidayah Z, Rachman HA, As-Syakur AR. 2022. Mapping of mangrove forest and carbon stock estimation of east coast Surabaya, Indonesia. Biodiversitas 23: 4826-4837. The mangrove forests on Surabaya's east coast are an important protected area, providing habitat for a variety of marine organisms and water birds. This area is also vital for carbon storage and sequestration. The purpose of this research is to determine the changes in mangrove areas over the last 20 years and to calculate the amount of carbon stored in these mangrove forests. Changes in the area of mangrove forests and Normalized Difference Vegetation Indices (NDVI) were determined using Landsat-7 in 2000 and Landsat-8 in 2020. The vegetative carbon stock of mangrove stands was calculated using allometric measurements. The study results reveal that the mangrove forest area has increased significantly from 257.13 ha in 2000 to 753.48 ha in 2020. The results of regression models also show that NDVI has a significant influence on aboveground biomass (AGB), as indicated by the coefficient of determination (R2) = 0.7 (F test, df = 28, p-value &lt; 0.05). The estimated aboveground and belowground carbon stock is 46.35 ± 13.65 ton C ha-1 and 13.65 ± 6.74 ton C ha-1 respectively. Accordingly, it is observed that the mangrove forest of East Coast Surabaya can sequester at least a total of 192.72 tons CO2 ha-1 in above and belowground biomass.

Carbon stocks across different environments, disturbance regimes, and stand age in Fitzroya cupressoides forests, the longest-lived species of the southern hemisphere

Forest disturbances influence Fitzroya cupressoides forest structure and carbon stocks at multiple spatial and temporal scales. Natural disturbances such as landslides and volcanism affect and give rise to the mostly pristine Fitzroya stands present in the Andean cordillera. On the other hand, mostly human-caused fires and logging have been the main processes shaping the structure of Fitzroya stands in the Coastal range and of Fitzroya small remnants in the Central depression. The main goal of this study was to assess the carbon stocks and accumulation rates of Fitzroya forest stands according to their development stage under different disturbance regimes and environmental conditions given by the three physiographic units where the species grows (Coastal range, Central depression, and Andean range). The site selection included an age sequence of stands, known as a chronosequence approach. We identified Fitzroya post-disturbance stands in three different stages of development: young forest stage (mean stand age of the main cohort ≤ 200 years old), mature forest stage (200–800 years old), and old growth forest stage (800–1,500 years old). The following biomass components were considered: living standing trees, dead standing trees (snags), and logs from dead trees laying on the ground (coarse woody debris). Old-growth Fitzroya forests reached a mean total carbon stock (standing live trees, snags, and coarse woody debris) of 507, 279, and 331 Mg C ha−1 in the Andean and Coastal ranges, and Central depression, respectively. Fitzroya cupressoides contributes, in average, more than 80% to the total carbon stock in the Andean and Coastal ranges, and 63% in the Central depression. The remainder corresponds mainly to Nothofagus spp. The high carbon stocks in old-growth stands in the Andean range are explained by Fitzroya longevity, larger size, wood decay resistance, and the low recurrence of volcanic events. Carbon accumulation rates differ between the forests in the three physiographic units (Central depression&amp;gt;Andean range&amp;gt;Coastal range), mainly due to the different growth rates and environmental conditions present in each unit. In the context of climate change, conserving old-growth stands with large biomass and carbon stocks and restoring Fitzroya forests should be recognized as a key contribution toward national and global goals to mitigate global warming.

Biomass allocation and carbon stock in Douglas fir and Norway spruce at the tree and stand level

Abstract The effect of changing tree species composition in favor of a greater representation of Douglas fir at the expense of Norway spruce on the carbon pool of Central European forests has not yet been investigated. Here, we compare the allocation of aboveground biomass and carbon stock in Douglas fir and spruce at the tree and stand level. At the tree level, Douglas fir accumulated, on average, 16.9% more aboveground biomass than Norway spruce. A greater amount of biomass was allocated mainly in the wood and bark of Douglas fir stem. For these biomass compartments, the difference between Douglas fir and Norway spruce was 21.1% and 60.3%, respectively. Spruce allocated more biomass in the crown, where the difference was 25.6% compared to Douglas fir. In needle biomass, Norway spruce exceeded Douglas fir by 84%. At the stand level, the analysis of model stands revealed that pure Norway spruce stands accumulated more carbon in the high and medium quality sites. As the site quality decreased, so did the differences in the amount of stored carbon. The higher carbon sink in Norway spruce stands was also confirmed in the analysis of real Norway spruce and Douglas fir stands. The difference in the carbon stock of young, medium-aged, and mature stands was 11.5%, 14.8%, and 1%, respectively. The positive balance in favor of spruce is mainly due to significantly higher numbers of trees per ha in Norway spruce stands. A positive effect of a greater representation of Douglas fir on the carbon budget of forest stands was not confirmed.

How hydrogen sulfide deposition from oil exploitation may affect bacterial communities and the health of forest soils in Congolese coastal plains?

The hydrogen sulfide (H2S) deposition from oil exploitation occurring since 1969 may potentially affect bacterial communities in acacia and eucalyptus plantations of the Congolese coastal plains. These plantations have been implemented on previous native savannas to use the unsuitable soils for agriculture, provide pulp wood and fuel wood energy, and preserve the natural forests. Increased carbon (C) and nitrogen (N) stocks in stands containing acacia relative to baseline (eucalyptus) stocks have been reported. Phosphorus availability also improved in coarse particulate organic matter (4,000–250 µm) in afforested stands as compared to natural savannas. Investigation of the abundance of bacterial phyla by metabarcoding of the 16S rRNA bacterial gene in different stands of monocultures and mixed-species stands reveals the prevalence of Actinobacteria in all stands. This phylum is generally associated with the presence of sulfur in industrial areas and has a crucial role in organic matter decomposition. This may be linked to improved soil attributes (C, N, and P) and related to oil exploitation in addition to natural processes. This review shows, therefore, how potentially human activities may impact bacterial community composition, which may further change other soil attributes. It also acknowledges that the sustainability of forest plantations on inherently nutrient-poor soils strongly relies on interactions between soil functions, the environment, and human activities driven by soil organisms.

ТАКСАЦИОННЫЕ ПОКАЗАТЕЛИ И ТОВАРНАЯ СТРУКТУРА СПЕЛЫХ СМЕШАННЫХ ДРЕВОСТОЕВ СОСНЫ И ЕЛИ В ЗЕЛЕНОМОШНЫХ ТИПАХ ЛЕСА

The influence of the stand composition on taxation indicators and the stock of mature pine and spruce stands have been considered. The objects of study are forest stands with different proportions of pine and spruce in the most represented green moss forests of the landscape of the Tikhvin Ridge (Boksitogorsky forestry) of the Leningrad region. Stock assessment and determination of taxation indicators were carried out on trial plots laid out according to standard forestry methods. Commodity structure of the stand and different yield of assortments by size categories depend on the share of participation of one or another species in the composition of the plantation by the age of clear-cutting in the taiga zone in different types of forests. The purpose of the study was to determine optimal plantation composition in terms of stock and large-scale marketability by the age of maturity of the stand. The most productive in terms of stock and output of large-scale coniferous wood under the studied growing conditions are pine forests with a stand composition of 8C2E, 7C1E2B, 5C4E1B and spruce forests with a composition of 7E1C2B, 4E2C4Os+B. The obtained results of the study show that with an increase in the share of pine in the plantations of the green moss group of forest types, the yield of large-sized coniferous wood assortments increases by the age of a ripe forest stand