Organic Carbon Storage in Evergreen Oak Forest Ecosystems of the Middle and High Moroccan Atlas Areas

Improving the accuracy of estimating greenhouse gas absorption remains an urgent problem. Identification of the ratio of carbon stocks in soils and stand biomass of young and mid-aged forests will allow clarifying the direction of carbon fluxes in forest ecosystems during the development period most productive for atmospheric decarbonization. Increasing the accuracy of carbon stocks in components of forest ecosystems is necessary to recognize the real absorption capacity of Russian forests at the international level. The purpose of this study was to determine the carbon stocks in stand biomass and soils of young and mid-aged forests in the Republic of Tatarstan, as well as their ratio for forests of different species composition and origin. The studies were conducted on 6 sample plots in the most common forest stands aged 10 to 40 years. Organic carbon stocks in soils, stand biomass and other components of forest ecosystems located on sod-podzolic soils were determined. Total carbon stocks, the share of individual components and the ratio of stocks in stand biomass and soils were calculated. It was found that carbon stocks in the biomass of young stands of natural origin ranged from 8.5 to 50.8 t/ha, while in artificial stands they were 123.0 t/ha, and in mid-aged forests – 102.6–173.4 t/ha. Maximum carbon stocks were found in the biomass of stands of mid-aged birch forest, minimum — in young birch forest. Total organic carbon stocks in the studied ecosystems can vary by up to five times and range from 41.4 t/ha to 208.4 t/ha. The share of stand biomass in the structure of total ecosystem stocks ranged from 20.4 % to 91.4 %. Carbon stocks in sod-podzolic soils of the sample sites varied from 5.5 t/ha to 38.9 t/ha. This was lower than the reference values, but even in this case, soil carbon stocks account for 4.1 % to 73.7 % of the total ecosystem carbon stocks. Clarification of carbon stocks in soils of forested areas should be continued. Perhaps, regional databases on soil carbon stocks should be created, taking into account not only the species and age composition of the forest, but also the taxonomic affiliation of soils. In a 10-year-old birch forest the ratio of carbon stocks in the stand and soil was 3:10, in a 25-year-old birch forest it changed to 11:2, in a young pine forest of natural origin it was about 2:1, in artificial pine plantations of the same age it was 22:1. In natural birch forests, during the transition from young forests of age class I to mid-aged forests, carbon stocks in stand biomass increased by 20.5 times. The results obtained demonstrate the active participation of young and mid-aged natural forests in atmospheric decarbonization, with the main carbon sink at this stage of forest ecosystem development occurring in phytomass. Carbon stocks in soil are more conservative. The ratio of carbon stocks in stand biomass and soils of young aspen and middle-aged oak forests was close to the values for natural forests of other species of the same age. Carbon stocks in stand biomass of artificial pine planting was 2.5 times higher than in natural pine forest of the same age (25 years). Further research is required to draw scientifically grounded conclusions on the contribution of natural and planted forests to carbon sequestration.

BackgroundThe spruce forests are dominant communities in northwest China, and play a key role in national carbon budgets. However, the patterns of carbon stock distribution and accumulation potential across stand ages are poorly documented.MethodsWe investigated the carbon stocks in biomass and soil in the natural spruce forests in the region by surveys on 39 plots. Biomass of tree components were estimated using allometric equations previously established based on tree height and diameter at breast height, while biomass in understory (shrub and herb) and forest floor were determined by total harvesting method. Fine root biomass was estimated by soil coring technique. Carbon stocks in various biomass components and soil (0–100 cm) were estimated by analyzing the carbon content of each component.ResultsThe results showed that carbon stock in these forest ecosystems can be as high as 510.1 t ha−1, with an average of 449.4 t ha−1. Carbon stock ranged from 28.1 to 93.9 t ha−1 and from 0.6 to 8.7 t ha−1 with stand ages in trees and deadwoods, respectively. The proportion of shrubs, herbs, fine roots, litter and deadwoods ranged from 0.1% to 1% of the total ecosystem carbon, and was age-independent. Fine roots and deadwood which contribute to about 2% of the biomass carbon should be attached considerable weight in the investigation of natural forests. Soil carbon stock did not show a changing trend with stand age, ranging from 254.2 to 420.0 t ha−1 with an average of 358.7 t ha−1. The average value of carbon sequestration potential for these forests was estimated as 29.4 t ha−1, with the lower aged ones being the dominant contributor. The maximum carbon sequestration rate was 2.47 t ha−1 year−1 appearing in the growth stage of 37–56 years.ConclusionThe carbon stock in biomass was the major contributor to the increment of carbon stock in ecosystems. Stand age is not a good predictor of soil carbon stocks and accurate evaluation of the soil carbon dynamics thus requires long-term monitoring in situ. The results not only revealed carbon stock status and dynamics in these natural forests but were helpful to understand the role of Natural Forest Protection project in forest carbon sequestration as well.

The study was conducted in the forest concession area of PT. Diamond Raya Timber, Riau Province, Indonesia. Measurement and calculation carbon stocks in soil and vegetation of tropical peat forest should be done accurately to anticipate carbon trading. The objective of the study is to estimate carbon stocks in soil and vegetation in 4 forest conditions. The study found that biomass and carbon stocks in the soil was 8 times higher than in the vegetation in primary forest condition, and 10 times in logged over forest and secondary forest condition. Carbon stocks in vegetation and soil were 189.45 ton C ha -1 and 1537.37 ton C ha -1 in primary forest, 161.76 ton C ha -1 , and 1713.77 ton C ha -1 in logged over area, 139.05 ton C ha -1 and 1486.39 ton C ha -1 in secondary forest, and 43.09 ton C ha -1 and 1205.59 ton C ha -1 in degraded forest. Allocation of carbon stocks in the standing trees in primary forest, logged over area, secondary forest, and degraded forest were 70, 60, 62, and 7% respectively.

Above- and belowground carbon stocks are decoupled in secondary tropical forests and are positively related to forest age and soil nutrients respectively

The date palm (Phoenix dactylifera) is a fruit tree that grows from 392 to 1500 m above sea level. In addition to their socioeconomic, traditional, and religious value, it is a tree that tolerates high temperatures, drought, and salinity better than many other fruit crop plant species and plays an important role in the balancing and sequestration of atmospheric carbon. Date palm has been cultivated by agro pastoralists in Northeastern Ethiopia since ancient times, but no research has been done on the carbon stock of date palm farms (DPF) in the region. Therefore, the focus of the current study was to examine the carbon storage capacity in the biomass and soil of a DPF in the Aysaita and Afambo Districts of Northeastern Ethiopia. The ages of recorded date palm on the plot were classified into three age classes using information collected from the farm owners: 1st age class (for plantations less than 10 years), 2nd age class (for plantations between 10 and 20 years), and 3rd age class (for plantations older than 20 years). In the DPF, 45 main plots (20 m × 20 m) were established for tree species inventory. In the main plots, three 1 m × 1 m subplots were set up to collect soil samples. A total of 360 soil samples were collected; 180 for soil organic carbon fraction analysis and 180 for bulk density determination. The total carbon stock was calculated by adding the carbon stocks in biomass and soil (0–60 cm depth). Date palm trees accounted for 98.79% of total biomass carbon stocks in the date palm farm. The average aboveground biomass carbon stock of date palm trees older than 20 years was 1.55 and 1.36 times higher than the first and second age classes, respectively. Date palm trees between the ages of 5 and 20 years contributed 69.45% of total biomass carbon stocks (Mg C ha−1). Soil organic carbon made for 32.9% of total carbon stocks. Our research found that the date palm farm of this study would contribute to emission reduction and carbon sink enhancement, as well as improving local livelihoods in the study area.

Forests play a crucial role in climate change mitigation by acting as a carbon sink. Understanding the influence of soil properties on carbon stocks in forests is essential for developing effective forest management strategies. The aim of the study was to assess the impact of soil texture on carbon stocks in the biomass of deciduous and coniferous tree stands of a forest-steppe ecotone. Soil samples were collected from 55 soil pits, and forest inventory data were obtained from eight permanent sample plots. The results showed that the distribution of mechanical particles in soils, particularly the stocks of silt and clay, significantly influenced the accumulation of carbon in tree stands. The stock of silt and clay was shown to increase with an increase in the diversity of tree species in forests and carbon stocks in forest stands. While soil organic carbon stocks did not exhibit a clear relationship with tree stand carbon stocks, a strong positive correlation (r = 0.802, p < 0.05) was found between the stocks of fine particles in the 2 m root-inhabited soil layer and the carbon stocks in tree biomass. The study provides a classification of forest types based on soil texture, which can facilitate differentiated forest management strategies for enhancing the carbon sequestration potential of forest ecosystems in the forest-steppe zone.

Patterns and driving factors of biomass carbon and soil organic carbon stock in the Indian Himalayan region

Organic carbon stock in forest soils in Japan

IntroductionTrees on agricultural landscape play a vital role in ecosystem services including food security that supports human livelihood. They can further offer synergy between adaptation and mitigation in addressing climate change impact. Understanding aboveground tree biomass and soil organic carbon stocks along the altitudinal gradient provide opportunities for better management of the carbon pools. However, little is known on how altitudinal gradient influences on carbon stock of woody biomass and soil of scattered trees on farmland, particularly in a dry area.MethodsThe study area were stratified in to five class (500–1000, 1000–1500, 1500–2000, 2000–2500, and 2500–3000 m a.s.l). Quadrats (100 m × 50 m) were randomly selected from each of stratified altitudinal gradients. At every sampling point, one composite soil sample was taken at 60 cm soil depth for soil organic carbon analysis. For the purpose of woody biomass estimation, allometric equations developed for a similar area were used. Finally, aboveground biomass carbon (AGC), belowground biomass carbon (BGC), soil organic carbon (SOC), and total carbon stock (TC) status were estimated and variables were compared using one-way analysis of variance (ANOVA).ResultsThe result indicated that AGC, BGC, SOC, and TC varied significantly (p < 0.05) along with an altitudinal gradient. The upper altitude (2500–3000 m a.s.l) AGC, BGC, SOC, and TC stock was estimated as 17.97 Mg C ha−1, 6.53 Mg C ha−1, 23.09 Mg C ha−1, 47.59 Mg C ha−1 respectively, and significantly higher than the other altitudinal gradient.ConclusionsWe conclude that scattered trees on farmland hold a high potential of carbon storage which may greatly contribute to the climate resilience green economy strategy and their conservation should be promoted.

Agroforestry systems (AFSs) that have rubber tree as the main tree component are important productive systems in the Brazilian Amazon. This work aimed to evaluate carbon stock (CS) of tree biomass, litter and soil in rubber based AFSs in South-Western Amazon. The analytical observational study was carried out in Rolim de Moura (RO) from June 2018 to March 2019 and it consisted of five areas: three AFSs, a forest fragment (FL), and a pasture (PA). CS of tree biomass was determined using allometric equations, while litter and soil carbon stocks were performed through material collection and chemical analysis. Total carbon stock of AFS 1, AFS 2, and AFS 3 was 181.36, 165.77, and 99.08 Mg ha-1, and soil was the compartment that most contributed to the EC of these systems, with stocks of 108.06, 88.71, and 72.68 Mg ha-1, respectively. Total stock of FL was 188.02 Mg ha-1 and PA was 88.19 Mg ha-1. The older AFSs, with greater floristic richness, greater basal area and with the presence of cupuassu tree as a secondary crop had total carbon stock similar to the forest area, evidencing the potential of these systems to sequester atmospheric CO2.

Variations and drivers of biomass and soil carbon stocks in planted forests across India

Residues from forest harvesting operations may be utilized as a renewable energy source. However, the sustainability of this practice has been questioned due to the losses of nutrients and exchangeable base cations, which may impair the forest's carbon sequestration capacity and lead to soil acidification. We report the 18 year response of biomass growth, soil carbon stock and soil chemistry to whole‐tree harvest at thinning and associated compensatory measures in a Pinus sylvestris forest in northern Sweden. The whole‐tree harvest at thinning was combined with nutrient additions to compensate for the nutrient loss caused by extracting the residues. Four main treatments, stem‐only thinning, whole‐tree thinning, whole‐tree thinning with one‐time nitrogen fertilization and whole‐tree thinning with repeated nitrogen fertilization every third year were applied, with plots split for wood‐ash treatment. Eighteen years after the treatments, whole‐tree thinning that had removed 3.0 ± 0.2 Mg C/ha in residues had no effect on forest growth, soil carbon and nitrogen stocks or soil chemistry. Both nitrogen fertilization regimes increased biomass growth, but neither one resulted in a significant increase in soil carbon stock. Wood‐ash addition increased soil pH and exchangeable base cations, but did not affect carbon stock in biomass or soil. Our long‐term data suggest that utilizing harvesting residues for biofuel feedstocks is appropriate in this type of forest. Hence, any nitrogen and wood‐ash additions appear unnecessary as compensatory measures for the removal of harvesting residues, but nitrogen can be applied to increase forest growth following thinning.

The Kyoto-protocol permits the accounting of changes in forest carbon stocks due to forestry. Therefore, forest owners are interested in a reproducible quantification of carbon stocks at the level of forest management units and the impact of management to these stocks or their changes. We calculated the carbon stocks in tree biomass and the organic layer including their uncertainties for several forest management units (Tharandt forest, Eastern Germany, 5,500 ha) spatially explicit at the scale of individual stands by using standard forest data sources. Additionally, soil carbon stocks along a catena were quantified. Finally, carbon stocks of spruce and beech dominated stands were compared and effects of thinning intensity and site conditions were assessed. We combined forest inventory and data of site conditions by using the spatial unions of the shapes (i.e., polygons) in the stand map and the site map. Area weighted means of carbon (C) stocks reached 10.0 kg/m² in tree biomass, 3.0 kg/m² in the organic layer and 7.3 kg/m² in mineral soil. Spatially explicit error propagation yielded a precision of the relative error of carbon stocks at the total studied area of 1% for tree biomass, 45% for the organic layer, and 20% for mineral soil. Mature beech dominated stands at the Tharandt forest had higher tree biomass carbon stocks (13.4 kg/m²) and lower organic layer carbon stocks (1.8 kg/m²) compared to stands dominated by spruce (11.6, 3.0 kg/m²). The difference of tree biomass stocks was mainly due to differences in thinning intensity. The additional effect of site conditions on tree carbon stocks was very small. We conclude that the spatially explicit combination of stand scale inventory data with data on site conditions is suited to quantify carbon stocks in tree biomass and organic layer at operational scale.

Estimation of carbon sequestration in the forest sector should take into consideration changes in carbon stock in all carbon pools, including above-ground and below-ground biomass, litter, deadwood and soil. In this review, we discuss current knowledge of carbon stocks in litter, deadwood and soil in Japan’s forest sector. According to data from published reports and nationwide surveys, the carbon stock in forest litter is less than that indicated in the Intergovernmental Panel on Climate Change (IPCC) guidelines for temperate and cool temperate forests; for example, coniferous species showed 4.4 Mg C ha−1 for Cryptomeria japonica and 3.1 Mg C ha−1 for Chamaecyparis obtusa, and broad-leaved species ranged from 3.5 Mg C ha−1 for Castanopsis spp. to 7.3 Mg C ha−1 for Fagus spp. For deadwood carbon stock, coniferous plantations with a record of non-commercial thinning showed 17.1 Mg C ha−1 and semi-natural broad-leaved forests showed 5.3 Mg C ha−1 on average, although only limited data were available. The black soil group (comparable to Andosols and Andisols) showed large carbon stocks in soil layers 0–30 cm deep (130 Mg C ha−1). The brown forest soil group (Cambisols and Inceptisols), occupying the most dominant area, showed a carbon stock of 87.0 Mg C ha−1 on average, which was similar to the data shown in the IPCC guidelines. In a comparison of land use between the forest sector and the agricultural sector for the same soil group, the carbon stock in the agricultural soil was 21% lower and in the grassland soil it was 18% higher than the stock in the forest soil. In this review, we also discuss issues for improving the estimation method and inventory of carbon stock in litter, deadwood and soil in Japan.

Carbon stocks in four forest stands in Sweden 25 years after harvesting of slash and stumps