Belowground Tree Biomass Research Articles

Carbon stock of shatto forest along altitudinal gradients in masha district, southwest ethiopia: a contribution to climate change mitigation

Forests play a significant role in climate change mitigation through carbon sequestration from the atmosphere and retaining carbon in above and belowground biomass of trees, litter biomass and soil. However, there is little empirical data on the potential carbon stock of Ethiopia’s various forests. Therefore, this study was carried out to estimate the carbon stock potential of Shatto Forest along altitudinal gradients and its contribution to climate change mitigation in Masha district, southwest Ethiopia. Using a systematic sampling design, a total of 30 plots measuring 20 x 20 m were established at 200 m intervals along seven transect lines in order to inventory the woody species. Within the main plot, a 1 m x 1 m sub-plot was used to collect soil samples and litter biomass. The biomass carbon stock was estimated using allometric equations. Results revealed that the mean total carbon stock of the study forest was 714.4 ton/ha, of which 337.38ton/ha, 67.48 ton/ha, 0.79 ton/ha and 308.75 ton/ha were stored in the aboveground carbon, belowground carbon, leaf litter carbon and soil organic carbon, respectively. The mean total CO2 equivalent of the study forest was also 2621.85 ton/ha. Along the altitudinal gradients of the study forest, the total carbon stocks contributed by the forest varied significantly at (p < 0.05), with the largest stock found at lower elevation and the lowest stock found at higher elevation. Based on the study findings, it is concluded that the forest under investigation possessed a substantial carbon stock capacity, allowing it to sequester a significant amount of CO2 and mitigate climate change while offering other ecosystem services. Thus, in order to optimize the forest’s capacity to store carbon and obtain the financial benefits of CO2 mitigation, reduced emission from deforestation and degradation (REDD+) program in the area should be integrated with carbon sequestration.

Tree belowground biomass in Congo Basin forests: allometric equations and scaling with aboveground biomass

Abstract Many allometric models to predict tree aboveground biomass have been developed in tropical moist forests, but few models are available for tree belowground biomass. Theory predicts that belowground biomass scales in an isometric way with aboveground biomass. Estimates of belowground biomass could then be derived from aboveground biomass using the root:shoot ratio. Using a dataset of 118 tropical trees for which both aboveground and belowground biomass and other tree and species characteristics were measured in Gabon and Cameroon, we found a near isometric, yet significantly allometric, relationship between belowground biomass (B, in kilograms) and aboveground biomass (A, in kilograms): B = 0.324 A0.939. The root:shoot ratio was 0.20–0.22, regardless of tree size. An efficient model to predict belowground biomass from tree diameter (D, in centimeters), height (H, in meters) and wood density (ρ, in grams per cubic centimeter) was B = 0.0188 (ρD2H)0.977. A significant residual effect of species and leaf habit was found in this model, indicating that further tree and species characteristics are likely to explain additional variation in belowground biomass. Yet, the future development of belowground allometric models can benefit from the many models already developed for aboveground biomass. On the basis of this unprecedented sampling effort on tree belowground biomass in the dense tropical forests of the Congo Basin, we conclude that the scaling of belowground biomass with aboveground biomass should be the relationship to focus on.

Forest carbon stock variation with altitude in bolale natural forest, Western Ethiopia

This study was initiated to assess forest carbon stock variation with altitude. A systematic sampling technique was used to select sample plots. A total of 36 (12 plots from each altitude class) square plots with size of 20 m × 20 m were obtained. Diameter at breast height (DBH) and height of individual trees of DBH > 5 cm were measured from all the selected sample plots. A total of 216 soil samples, 108 for analysis of soil organic carbon (SOC) fraction (% C), and 108 for bulk density determination (BD), were collected. Altitude had a significant effect on above and belowground tree biomass, and litter carbon stock, but not on deadwood, and soil organic carbon stock. The aboveground and belowground biomass and litter carbon were higher at lower altitudes, which were attributed to higher biomass production due to higher photosynthesis and higher net primary production. Soil organic carbon varied significantly with depth. A higher soil organic carbon stock was observed at the upper soil depth (0–10 cm). At lower soil depths, carbon stocks were smaller due to less plant residue and less biological activity in the deeper soil. In general, the study found that carbon density is high at lower altitudes and lower at higher altitudes. Therefore, altitude should be given due consideration for forest development and management for climate change mitigation. The result suggests that different governmental and nongovernmental organizations have to give due attention for forest conservation to reduce the CO2 emmission.

Vegetation diversity, structure, composition and carbon stock of community managed forests of Mid-hills, Nepal

Abstract. Joshi P, Joshi R, Sapkota RP, Panta M, Chand P. 2023. Vegetation diversity, structure, composition and carbon stock of community managed forests of Mid-hills Nepal. Asian J For 7: 29-36. Depending on management practices, forests can serve as both carbon sinks and sources. The goal of reducing carbon emissions and increasing the carbon sink is thought to be feasible if carbon reservoirs in current forests are protected and conserved. This study was objectively conducted to assess the vegetation diversity, structure, and carbon stock of the Mid-hills of Nepal. The study was undertaken in the Lanta Community Forest, Jajarkot District, Nepal, which has an extent of 38.65 hectares. Data for vegetation analysis and carbon stock assessment were collected using systematic random sampling using quadrats of 10×10 m with a total number of 35 quadrats. Within each quadrat, individual trees and bamboo were identified in the sites, and their height (m) and DBH (cm) were measured. Density, frequency, basal area, and Important Value Index (IVI) were calculated as structural parameters of vegetation. The Above-Ground Tree Biomass (AGTB) and Below-Ground Tree Biomass (BGTB) were calculated using an allometric equation based on tree diameter, height, and wood-specific gravity. The species diversity, species richness, and evenness were found to be 2.2, 2.35, and 0.83, respectively. A total of 14 tree species, with 723 individuals and one bamboo species were recorded. Rhododendron arboreum Sm. had the highest tree density with 211 trees/ha, while Tsuga dumosa (D.Don) Eichler had the highest IVI. Total wood volume, biomass, and total carbon stock were estimated at 15.37 m3 ha-1, 31.99 t ha-1, and 15.03 t ha-1, respectively. There was a strong negative correlation (r = -0.59) between R. arboreum and R. campanulatum D. Don and a strong positive correlation (r = +0.65) between Malus sikkimensis and Machilus species. For the preservation and sustainable management of community forests, information regarding the structure, composition, and dominance of tree species is provided by the study. The establishment of community forests is thus demonstrated in this article as a means of promoting the protection and preservation of regional biodiversity.

Tree-size heterogeneity modulates the forest age-dependent carbon density in biomass and top soil stocks on Mediterranean woodlands

AimsCarbon accumulation in terrestrial ecosystems is inherent to the vegetation development and ageing process. Primary productivity synthetize biomass which is constantly incorporated to soil. Vegetation community composition, and other ecological drivers, are known to mediate biomass production. However, links between forest developmental stage and ecological drivers of carbon stocks are unexplored. We address this topic under the prediction that species-rich and uneven-sized forests can improve carbon storage potential in biomass and topsoil fraction across its development.MethodsThe study was carried in forest stands growing under Mediterranean conditions in Central Spain. Carbon content in both above- and below-ground tree biomass and in topsoil organic matter (0–40 cm) was measured in 30 sampling plots of variable size (900–3000 m2). We also assessed Shannon species diversity index, Gini tree-size inequality index and forest developmental stage using dendrochronological procedures to derive the mean age of the oldest trees. First-order interaction terms between diversity factors and forest age were regressed against carbon density in compartment-independent regressions.ResultsForest-age and tree-size heterogeneity coupling was the main factor driving carbon density of both compartments. The interaction showed that woodlands maximize density in aged forests composed by uneven-sized trees. Models gave not support to consider species diversity as a mediator of carbon stocks.ConclusionOur results shed light on how tree-size heterogeneity can regulate the temporal dimension of forest ageing to rise the carbon storage potential. Mature forests in semi-arid environments cannot store carbon due to their intrinsic ontogeny, they need to grow structurally diverse.

Vegetation Assemblage and Carbon Stock in the Sacred Groves of Kathmandu Valley, Nepal

Sacred groves (SG) play crucial roles in maintaining vegetation diversity and storing carbon. In Nepal, there is relatively little information about the carbon sequestration potential of SGs compared to other forest types. To address this research gap, this study analyzed the vegetation assemblage and carbon stock in three SGs, namely Bajrabarahi, Mhepi, and Swayambhu forests, located in the Kathmandu Valley. Systematically distributed square plots (15 m × 15 m) were used as sampling units. Above-ground tree biomass and below-ground tree biomass were estimated by using the allometric equation of trees, considering the diameter, height, and specific gravity of wood. A total of 479 individuals of woody species belonging to 37 species were recorded from the three SGs. Species diversity and species richness were relatively higher in Swayambhu SG. Based on the importance value index, Celtis australis, Schimawallichii, and Neolitseacuipala were dominant in Mhepi, Swayambhu, and Bajrabarahi SGs, respectively. Total biomass and carbon stock were highest in the Bajrabarahi Forest and lowest in the Swayambhu Forest. The average biomass and carbon stock in the three urban SGs were approximately 405 ton/ha and 191 ton/ha, respectively. The findings of the present study suggested that maintaining vegetation assemblage, biomass, and carbon stock in SGs might have important contributions to sequestering carbon, conserving biodiversity, and enhancing the aesthetic values of the religious areas.

Contribution of species and functional richness to carbon storage in eucalypt woodland restoration

Biologically diverse forest and woodland restoration can mitigate climate change and biodiversity loss. Understanding the trade-off between carbon storage and biodiversity is important to maximise the value of restoration opportunities. Ecological theory suggests biological diversity contributes positively to carbon storage until the relationship plateaus (i.e., species are added with no effect on carbon storage), and yet in practice, tree monocultures are perceived to sequester more carbon than diverse plantings. Here, we measured the contribution of plant diversity to carbon storage in trees and shrubs ten years after planting for yate (Eucalyptus occidentalis) woodland restoration. We found no evidence for a trade-off between carbon storage and plant diversity. We planted yate with mixes of yate woodland species including native grasses, shrubs, and trees. Ten years after planting, grass establishment was poor, and density of trees and shrubs was patchy. There was some unassisted recruitment of woody species. Diversity was measured as observed species richness and observed functional richness, which incorporated taxonomic diversity, structural diversity, and presence/absence of nitrogen-fixing legumes. Carbon stocks measured were above and belowground tree and shrub biomass, leaf and twig litter biomass, and organic carbon (%) in the topsoil. Across all three carbon stocks diverse yate plantings sequestered as much carbon as yate monocultures. Observed species richness had a weak negative effect on tree and shrub biomass in the best linear mixed model but this effect diminished with the removal of an outlier. Tree density had a positive effect on tree and shrub biomass in models with and without the outlier. There was no effect of diversity on litter biomass and soil organic carbon. Instead, linear mixed models of these stocks showed the influence of soil properties. Litter biomass increased with soil potassium and decreased with soil pH. Soil organic carbon increased with initial soil organic carbon and soil nitrogen. There are potential additional biodiversity benefits of diverse plantings that we did not measure (e.g., soil erosion control, wildlife habitat). We call for more field experiments to explore these potential benefits and to generate the ecological knowledge needed to improve the quality of global forest and woodland restoration efforts.

Mangrove species diversity and carbon stock in silvofishery ponds in Deli Serdang District, North Sumatra, Indonesia

Abstract. Harefa MS, Nasution Z, Mulya MB, Maksum A. 2021. Mangrove species diversity and carbon stock in silvofishery ponds in Deli Serdang District, North Sumatra, Indonesia. Biodiversitas 23: 655-662. Mangrove-based silvofishery ponds are promoted as a win-win solution for biodiversity conservation, climate change mitigation as well as income generation for coastal communities. This study aimed to analyze the species diversity and carbon stock of mangrove vegetation in silvofishery ponds in Tanjung Rejo Village, Percut Seituan Sub-district, Deli Serdang District, North Sumatra, Indonesia. Data of the mangrove species were obtained using vegetation analysis, and the potential carbon stock was estimated based on allometric equations of both above- and below-ground tree biomass. For this purpose, plot samples from 22 silvofishery ponds were taken by establishing 5 aligned circular plots, each with a radius of 5.64 m, perpendicular to the coastline and with a distance of 15 meters between their perimeters. The results show that the mangrove species with the highest Importance Value Index (IVI) was Rhizophora apiculata (122.05%), followed by Excoecaria agallocha (42.29%) and Avicennia marina (36.84%), and the lowest IVI was Sonneratia caseolaris (1.48%). Higher IVI values indicate a larger carbon deposit from mangrove vegetation in silvofishery ponds. Our results indicate that mangrove area coverage of 44-80% per hectare in silvofishery ponds can deposit 40-50 tonnes of carbon per hectare and have greater potential carbon stock compared to coverage below 40%. The mangrove management activities with the sylvofishery scheme have a good impact on the community's economy and also maintain the existence of mangroves as carbon storage.

Carbon stocks of above- and belowground tree biomass in Kibate Forest around Wonchi Crater Lake, Central Highland of Ethiopia.

Forests play an important role in the global carbon (C) balance, but their biomass has decreased globally mainly because of deforestation and a reduction in forest cover. However, little is known about the C stock of tree biomass related to environmental factors in the remnant forest patches. Thus, the present study aimed at assessing the status of C stocks of tree biomass using an allometric equation in Kibate Forest (Ethiopia). Sixty–six plots (30×30 m) were laid out at 100 m interval distance along the altitudinal gradients in five transects. The results revealed that the highest C stocks (67.4%) per species were contributed by Juniperus procera, Ilex mitis var. mitis, Nuxia congesta, and Olea europaea subsp. cuspidata. The mean total tree biomass was 91.9 ± 10.01 Mg ha−1. The mean total C stock was 45.9 ± 5.17 Mg ha−1, out of which 38.3 ± 4.31 and 7.7 ± 0.91 Mg ha−1 were stored in above- and belowground C pools, respectively. Anthropogenic factors were negatively associated with the C-stock distribution in the study area. Thus, the status of the C stock of tree biomass related to anthropogenic factors indicates that sustainable forest management practice is needed in the study area to conserve biodiversity and mitigate climate change.

Aboveground and belowground tree biomass and carbon stocks in the miombo woodlands of the Copperbelt in Zambia

Globally, belowground biomass (BGB) accounts for 20–26% of total biomass, and as such it is an important carbon (C) pool for many vegetation types. However, large uncertainty exists for belowground biomass C compared to aboveground stocks. Using data from 108 destructively harvested trees belonging to 36 miombo species, we estimated root to shoot ratios, and developed models for estimation of aboveground biomass (AGB), BGB and total biomass C stocks in the Copperbelt province of Zambia. We also validated our models using independent datasets from elsewhere in Zambia and Malawi. The C fractions in wood ranged between 51.9 and 58.9%, which was higher than the IPCC default value. The root to shoot ratio was found to be 0.303. The analysis also demonstrated isometric scaling of BGB with AGB. According to cross-validation results, the model that incorporated wood density (ρ), diameter at breast height (D) and total stem height (H) formulated as AGB =0.093(ρD2H)0.97 *1.08 outperformed existing models developed for the miombo woodlands in Zambia. The best model for BGB was BGB = 0.476(AGB)0.88*1.126. Using the top-ranked models, the stand-level AGB stocks were estimated at 222.2 Mg ha−1, while BGB stocks were estimated at 52.4 Mg ha−1. Aboveground and belowground C stocks were 125.3 Mg ha−1 and 29.5 Mg ha−1, respectively. Total biomass C stocks were estimated at 152.1 Mg ha−1 or 558.3 Mg ha−1 CO2 equivalent sequestered in tree biomass. These estimates may be used as baseline data for future carbon management and for emerging payment for ecosystem services projects in miombo woodlands.

Effects of tree species diversity and stand structure on carbon stocks of homestead forests in Maheshkhali Island, Southern Bangladesh

BackgroundThe homestead forests of Bangladesh occupy 0.27 million hectares (10% of the total forested area) and have potential to store carbon (C) and conserve biodiversity. Small scale forestry practices, however, are lacking reliable estimation of C stocks and tree species diversity. This may hinder successful implementation of REDD + and similar mechanisms as they concentrate on large-scale forests. This study aimed to estimate the above- and below-ground carbon stocks in homestead forests of Maheshkhali Island in Bangladesh and how tree species diversity and stand structural variation affect these C stocks. We randomly surveyed a total of 239 homestead forests in the hillside, beachside, and inland in 2019.ResultsTree biomass C stocks were 48–67% greater in the inland and hillside forests than in the beachside due to significantly greater stand density, basal area, tree diameter. In total we found 52 tree species, but most abundant species in the inland and hillside forests, Mangifera indica, Samanea saman, and Artocarpus heterophyllus stored the most C in tree biomass. Greater tree species richness and diversity index in the inland and hillside forests indicated greater above- and below-ground tree biomass C stocks. An increase in tree species richness and diversity index by one unit was found to increase the tree biomass C stock by 22 and 30 Mg C ha−1, respectively. The total soil C stock was also affected by tree species diversity, stand density, and their interaction with soil properties. Total soil C stocks were greatest (51 Mg ha−1) in the inland forests, having also the greatest stand density and tree species richness. C stock in soil surface was greatest in the hillside forests due to the greatest litterfall, but the average share of litterfall from the total biomass C was only 0.1%.ConclusionsHomestead forest ecosystems could store 96 Mg C ha−1 in total, which can contribute to climate change mitigation by generating C credits for small-scale homestead forests owners. Above- and below-ground tree biomass C stocks were found to correlate with tree species diversity, which may also contribute to biodiversity conservation in the REDD + in Bangladesh and countries alike.

Carbon stock potential of Sekele Mariam forest in North Western Ethiopia: an implication for climate change mitigation

Forest plays a crucial role in climate change mitigation by sequestering and retaining carbon in above and below-ground biomass of trees, dead tree and deadwood biomass, litter biomass, and soil. Thus the study was conducted to estimate the carbon stock potential of the Sekele Mariam forest, North Western Ethiopia. The field data were collected through systematic random sampling techniques from the 20 m × 20 m area of 48 sample plots. The above-ground biomass, below-ground biomass, dead tree, and deadwood biomass of the study area were collected from 20 m × 20 m area of the main plot, while the soil sample and litter biomass was collected from 1 m × 1 m area of subplots, which located at the four corners and one at the center of the main plot. The carbon stock of different carbon pools was estimated using different selective allometric and mathematical models and analyzed by statistical package for social science (SPSS) software version 21. The result showed that the mean carbon stock of each carbon pool such as above-ground carbon, below-ground carbon, dead tree, and deadwood carbon, litter carbon, and soil organic carbon accounted for about 362.72, 72.55, 3.43, 2.01, and 179.68 t/ha, respectively. The carbon stock variation along altitudinal gradients indicated altitude had no statistically significant effect on any of the carbon pools of the study area at α (0.05). The ultimate result showed that the study area stored and sequestered 620.39 t carbon per ha and 2776.83 t CO2 equivalents per ha, respectively.

Biomass and carbon storage in an age-sequence of Acacia mangium plantation forests in Southeastern region, Vietnam

Aim of the study: The major objective of this study was to estimate the biomass increment and carbon (C) storage of the main ecosystem components in an age-sequence of three Acacia mangium plantation stands.Area of study: Chang Riec Historical - Cultural Forest, Southeastern region, Vietnam.Material and methods: In order to assess the biomass of different tree components, 36 trees with diameter at breast height ranging from 13.38 to 22.87 cm were harvested from the different aged stands. Biomasses of understory (shrubs and herbs), and litter were also determined. Carbon storage in the trees and understory biomass, litter, and mineral soil (0-50 cm) were determined by analyzing the C content of each compartment.Main results: The biomass in trees, understory vegetation, litter, and ecosystem increased with stand age. Soil C represented 61.99% of the total, aboveground tree biomass C made up 26.73%, belowground tree biomass C accounted for 7.01%, and litter comprised 2.96%, whereas only a small amount (1.30%) was associated with understory vegetation. The average C content of total tree (47.97%) was higher than those of understory and litter. Soil organic C stock in the top 50 cm depth in 4-, 7- and 11-year-old stands of A. mangium were 86.86, 126.88 and 140.94 Mg. C ha-1 respectively. Soil C concentration decreased continually with increasing soil depth. Total C storage of three planted forests ranged from 131.36 to 255.86 Mg. C ha-1, of which 56.09 - 67.61% of C storage was in the soil and 26.88 - 40.40% in the trees.Research highlights: These results suggest that A. mangium is a promising afforestation tree species with fast growing, high biomass accumulation and high C sequestration potential.Keywords: Acacia mangium plantations; Biomass; Ecosystem carbon storage; Age-sequence; Vietnam.

Carbon sequestration in the bio-edaphic ecosystem of National Highway-27 in Guwahati, Assam, India

Vehicular pollution in cities is engendering the need to enhance the sequestration of CO2 through bio-edaphic factors, such as trees and soil. Hence, this pioneering study aimed to analyze the interdependencies of the bio-edaphic ecosystem during carbon sequestration on a national highway in Guwahati, Assam, India. To quantify the tree carbon stock, soil physicochemical properties, soil nutrients, bulk density, organic carbon, and soil carbon stock, trees with diameters at breast height (dbh) ≥ 2 cm and soil samples from different depths (0–15 cm, 15–30 cm, and 30–45 cm) were taken from six areas spread over 36 plots of equal size (2 × 10 m) arranged in a zig-zag manner. The studied parameters were compared among the different areas. It was found that the tree and soil carbon stock, along with soil nutrients, were greater in the Garchuk-Lokhra area (sample area-4). A significantly strong correlation was observed between the soil carbon stock and the above and below-ground biomass of trees (AGB, r = 0.865; BGB, r = 0.847), which indicated the co-dependencies of the bio-edaphic ecosystem in accumulating carbon. Peltophorum ferrugineum (Decne.) Benth is recommended for planting because it has emerged as a tolerant species and has the greatest carbon storage potential. The bio-edaphic ecosystem of the national highway is now on a carbon-friendly trajectory that follows the UNFCCC guidelines and the REDD+ (reducing emissions from deforestation and forest degradation) strategy. However further research on carbon budgeting is required.

Tree diversity and carbon stock in a subtropical broadleaved forest are greater than a subtropical pine forest occurring in similar elevation of Meghalaya, north-eastern India

Studies on relationship between tree diversity and carbon stock has not been consistent. The present study was undertaken to quantify and compare the plant diversity and carbon stock in a subtropical broadleaved and a subtropical pine forest of Meghalaya, northeast India. Biomass-based carbon estimation was undertaken in two subtropical broadleaved forest stands viz., Mawnai (MBF) and Nongkrem (NBF) and adjacent Pinus kesiya dominated forest stands (MPF and NPF), occurring in similar topography, climatic conditions and soil type. The aboveground and belowground tree biomass was estimated using existing allometric models. Carbon was estimated as 47.4% of the total biomass. Tree species richness was greater in the subtropical broadleaved forest stands at MBF and NBF (117 and 21 species) than in the adjacent pine forests, MPF and NPF (15 and 16 species). The density values were 1294 and 1127 individuals ha−1 in the broadleaved forest stands, and 894 and 1032 individuals ha−1 in the adjacent pine forest stands, respectively. The broadleaved forest stands, MBF and NBF had tree biomass carbon stock of 140.4 Mg C ha−1 and 133.6 Mg C ha−1, respectively, which were significantly greater (F = 26.6; P 66 cm) to the total biomass carbon was greatest in MBF, while the lower diameter trees belonging to 5–15 cm and 16–25 cm were the major contributors to the total biomass carbon in the pine dominated stands.

Are vegetation–soil systems drivers of ecosystem carbon contents along an elevational gradient in a highland temperate forest?

Vegetation–soil systems differentially influence the ecosystem processes related to the carbon cycle, particularly when one tree species is dominant over wide geographic regions that are undergoing climate change. The objective of this study was to quantify the stocks of ecosystem carbon in three vegetation–soil systems along a highland elevational gradient in central Mexico. The vegetation–soil systems, from lower to higher elevation, were dominated by Alnus jorullensis Kunth, Abies religiosa (Kunth) Schltdl. &amp; Cham., and Pinus hartwegii Lindl., respectively. Above- and below-ground tree biomass was determined in each system, along with the litter, coarse woody material, roots, and litterfall. The A. religiosa system had the greatest stock of aboveground biomass carbon (216 ± 31 Mg C·ha−1). The A. jorullensis system had the greatest production of litterfall (3.1 ± 0.08 Mg·ha−1·year−1); however, the carbon content of this litter layer (1.2 ± 0.32 Mg C·ha−1) was lower than that of P. hartwegii (10.1 ± 0.28 Mg C·ha−1). Thus, the litter layer in the A. jorullensis system had markedly the shortest residence time (8 years), suggesting high rates of litter decomposition. The soil carbon stock (at soil depth of 1 m) was greater in A. jorullensis (189 Mg C·ha−1) and P. hartwegii (137 Mg C·ha−1) than in A. religiosa (68 Mg C·ha−1). The A. religiosa and A. jorullensis systems had the highest and lowest total ecosystem C content (301 and 228 Mg C·ha−1, respectively). Upward migration of the A. religiosa system in response to global climate change, however, could cause losses by 2030 of 187 Mg C·ha−1 associated with aboveground biomass.

Carbon stocks in biomass and soils of woody species fodder banks in the dry tropics of Mexico

AbstractUnderstanding carbon (C) dynamics of the silvopastoral systems can help mitigate greenhouse gas emissions. The aim of this study was to evaluate the C concentration and storage in above‐ and belowground tree biomass as well as in the soils of fodder banks of Leucaena leucocephala (Lam.) de Wit, Guazuma ulmifolia (Lam.) or a combination of the both species. The above‐ and belowground biomass was quantified by the destructive sampling. We also obtained samples from soil pits, 20‐cm deep, and determined bulk density and organic carbon concentration. The mixed species banks produced more foliage dry matter (DM) (6.3 t DM/ha) than the pure fodder banks. The total living biomass stocks ranged from 31.5 to 33.5 t DM/ha and did not differ between fodder bank types. The tissue C concentration was greater in stems (45.1%) and roots (44.9%) compared to the foliage component (43.4%). Total soil carbon (TSC) in the 5–10 cm layer was greater in the fodder banks with legumes alone than in mixed species banks (35.7 vs. 30.8 t C/ha). TSC storage in the 15–20 cm layer was greater in the nonlegume fodder bank than in the legume fodder bank (39.8 vs. 34.5 t C/ha). However, to the 0–20 cm layer, TSC was similar for all fodder banks. Thus, the three types of fodder banks had similar total C storage in plant biomass and soil, but the production of foliage biomass was higher in the mixed species banks.

The effect of heterogeneous soil bulk density on root growth of field-grown mangrove species

Mangroves harbour large organic carbon (C) reservoirs in their soils that are important in the global C cycle. The below-ground biomass of mangrove trees is a major contributor to these organic C stocks. Root system development tends to be highly plastic in response to environmental conditions such as soil bulk density (BD). Hence, this study aimed to assess the role of soil BD on mangrove root growth. Root in-growth bags filled with root-free soil ranging in BD from 0.2 to 1.2 g cm−3 were buried in the soil of three mangrove species. Root image analysis indicated that BD had a significant positive effect on root length and root biomass suggesting trees increase biomass allocation to roots and enhance root elongation, possibly to increase the acquisition of water and nutrients in dense soils. However, the responses to variation in BD were species-specific which was attributed to differences in species growth rates and the background soil conditions. Soil BD affects mangrove root growth with dense patches likely to have increased root growth and organic C sequestration potential compared to less dense soil patches.

The imprint of logging on tropical forest carbon stocks: A Bornean case-study

In tropical forests, selective logging generates a significant reduction of above-ground carbon stocks, due to direct removal of a few large merchantable individuals, and the death of smaller injured or smashed trees following harvesting. Several studies have shown a strong correlation between logging intensity and a reduction of biodiversity, wood production, and biomass stocks. However, little is known about the long-term effects of logging on the main forest carbon (C) stocks in above and below-ground tree biomass, deadwood, litter, and soil. In this study we quantified C stocks in 28 0.25-ha plots located in a mixed Dipterocarp forest, Borneo, Indonesia, logged 16 years ago at different intensities ranging from 0 to 57% of initial biomass removed. We investigated the effect of logging intensity, topography, and soil variables on each C stock using linear mixed models. Sixteen years after logging, total C stocks ranged from 218 to 554 Mg C ha−1 with an average of 314 ± 21 Mg C ha−1, of which more than 75% were found in live trees. Logging intensity was found to be the main factor explaining the variability in carbon stored in above- and below- ground biomass of tree DBH >20 cm and deadwood. Simultaneously, the proportion of deadwood increased with logging intensity reaching 13.5% of total C stocks in intensively logged plots (>20% removal of initial biomass). This study confirmed, therefore, the need to limit logging intensity to a threshold of 20% of initial biomass removal in order to limit the long-term accumulation of deadwood after logging, probably due to high post-logging mortality. With more than half of all Bornean forests already logged, accounting for total C post-logging is key to better assess the long-term carbon footprint of commercial logging in the region, and is a necessary step towards the development of C-oriented forest management in the tropics.

Tree Biomass Estimation in Central African Forests Using Allometric Models

Quantifying the tropical forests’ carbon stocks is presently an important component in the implementation of the emerging carbon credit market mechanisms. This calls for appropriate allometric equations predicting biomass which currently are scarce. In this study, we aimed to estimate above- and below-ground biomass and carbon stocks of trees, and to identify the variation in diameter-height allometry of Ipendja mixed terra firme lowland tropical forest’s trees. The study area is located at Ipendja forest management unit (UFA), close to Dongou district (Likouala Department), in Northern Republic of Congo. This study combined forest inventory data of 1340 trees recorded from eight studied plots distributed in two sites, respectively Mokelimwaekili (i.e., Old-growth forest) and Sombo (i.e., Selective logging forest). Trees measurements were done with rectangular plots, each 25 × 200 m (i.e., 0.5 ha, 5000 m2). In eight studied plots (4 plots per site), only trees with DBH ≥ 10 cm were measured and identified. 1340 trees founded were belonged 145 species and 36 botanical families (n = 733 and n = 607, for Sombo and Mokelimwaekili respectively). The analyses were conducted using allometric method for aboveground biomass (AGB) and belowground biomass (BGB) estimations. The results showed that in Ipendja forest ecosystem the mean biomass is built up for AGB (346 Mg·ha-1) as well as for BGB (81.3 Mg·ha-1), with a significant difference between forest types (F = 23.46, df = 7.771, P = 0.001). It was obvious that biomasses in Mokelimwaekili (AGB: 559.7 Mg·ha-1, BGB: 131 Mg·ha-1) were higher than those of Sombo (AGB: 291.8 Mg·ha-1, BGB: 68.5 Mg·ha-1). By this study, Ipendja forest ecosystem has clearly variations on the diameter-height relationship and biomass across the plots and the sites.