Implications For Biomass Research Articles

The implications of biomass and carbon sequestration of exclosure for climate change mitigation in arid areas, Sekota district, northern Ethiopia

Climate dynamics management plays a crucial role in safeguarding the environment from a global to local scale. Land degradation poses a significant threat to the livelihoods of millions of people living in drylands. Arid regions are particularly vulnerable when it comes to finding suitable habitats for ecological processes. Various global initiatives have been developed to restore degraded drylands. In addition, exclosures have important implications in arid areas for regulating environmental services. However, there is a lack of systematic studies on the biomass improvement and climate change mitigation effects of exclosures. A study was carried out in the Sekota district of northern Ethiopia to evaluate the impact of exclosures on biomass production and carbon stock. Three sites—Gateno, Jinqaba, and Mildam—were chosen for the pilot study. Data was collected from 27 quadrats, with different sizes used for sampling saplings, seedlings, litter, and soil. Soil samples were taken at depths of 0–20 cm and 0–40 cm. The data was analyzed using Excel and R Studio, and a linear mixed-effect model was used to determine the differences between land uses. The results indicated significant variations in above-ground biomass carbon, soil organic carbon, and total carbon stock between the two land uses. Furthermore, the observational perspective of exclosures in the Sekota district reveals a sustainable and suitable environment for interested parties. Exclosures prove to be effective in the restoration of degraded lands, as well as in enhancing biomass accumulation and carbon sequestration.

Ecological Dynamics of Water Hyacinth in Coimbatore Lakes: Implications for Biomass, Carbon Stock, and Nutrient Management

In aquatic ecosystems, water hyacinth (Eichhornia crassipes) often proliferates, impacting water quality and ecological balance. This study investigates the density, biomass, carbon stock, and nutrient concentrations of E. crassipes across five significant lakes in Coimbatore: Krishnampathy, Kurichi, Ukkadam, Singanallur, and Sulur. Field surveys, laboratory analyses and statistical methods were adopted in this study. The highest density of E. crassipes was observed in Krishnampathy Lake (59±2.5, no./m2). The biomass values (kg/m2) ranged from 1.00 to 7.33 for leaf, 3.23 to 8.03 for stalk, and from 1.47 to 10.80 for root samples. The carbon stock values (kg/m2) ranged from 0.51 to 3.74 for leaf, 1.49 to 3.73 for stalk, and from 0.68 to 4.19 for root samples, revealing the species potential role in reducing atmospheric carbon in mitigation of climate change. We have studied the macro and micro-nutrient concentrations present in E. crassipes, and also we checked the relationship between chlorophyll content and nutrient concentration with the carbon stock of different plant parts of E. crassipes. This study contributes to a better understanding of the ecological dynamics of water hyacinth in inland water bodies and its potential implications for carbon cycling and nutrient dynamics.

Effects of competition reduction on intra-annual radial growth of European beech (Fagus sylvatica L.) at stem base and crown base

Key messageIn beech stands, thinning affects growth differently along tree stems, with higher and longer duration increment at stem base than at crown base while unmanaged stands depict opposite patterns.Forest management affects individual tree growth dynamics at different levels of the tree bole. Here, we assessed stem-growth patterns as a function of bole height (stem base and crown base) and competition reduction using high-resolution dendrometer records. We measured radial increments throughout the vegetation periods of 2015 and 2016 in two differently managed European beech (Fagus sylvatica L.) stands in central Germany. In one stand, trees had been repeatedly released from competition while the other had remained unmanaged for about 40 years. To assess different temporal phases of diameter increment, we fitted Weibull growth curves to dendrometer data. Stem basal area and crown base area increments of trees in the managed stand were always higher than in the unmanaged stand. In the managed stand, crown base and stem base monthly diameter increments were highly correlated until July when diameter increment at stem base surpassed the diameter increment at crown base. Conversely, in the unmanaged stand, monthly diameter increment at the stem base was often lower than at crown base. In both stands, diameter growth started earlier at crown base than at stem base. However, stem base growth in the managed stand began earlier and lasted longer than in the unmanaged stand. Our results confirm that competition reduction affects diameter increment along the stem differently than in unmanaged stands and increases growth duration. Future research is needed to test whether different growth patterns and tapers of residual trees in managed and unmanaged stands have implications for biomass and carbon storage modeling.

Application of Hydrochar, Digestate, and Synthetic Fertilizer to a Miscanthus x giganteus Crop: Implications for Biomass and Greenhouse Gas Emissions

Miscanthus x giganteus (miscanthus), a perennial biomass crop, allocates more carbon belowground and typically has lower soil greenhouse gas (GHG) emissions than conventional feedstock crops, but best practices for nutrient management that maximize yield while minimizing soil GHG emissions are still debated. This study evaluated the effects of four different fertilization treatments (digestate from a biodigester, synthetic fertilizer (urea), hydrochar from the hydrothermal carbonization of digestate, and a control) on soil GHG emissions and biomass yield of an established miscanthus stand grown on abandoned agricultural land. Soil GHG fluxes (including CH4, CO2, and N2O) were sampled in all treatments using the static chamber methodology. Average biomass yield varied from 20.2 Mg ha−1 to 23.5 Mg ha−1, but there were no significant differences among the four treatments (p > 0.05). The hydrochar treatment reduced mean CO2 emissions by 34% compared to the control treatment, but this difference was only statistically significant in one of the two sites tested. Applying digestate to miscanthus resulted in a CH4 efflux from the soil in one of two sites, while soils treated with urea and hydrochar acted as CH4 sinks in both sites. Overall, fertilization did not significantly improve biomass yield, but hydrochar as a soil amendment has potential for reducing soil GHG fluxes.

Overheads of truck transport in Australia: implications for biomass as feedstock for bio-energy

ABSTRACTTransport of feedstock for transformation to usable fuel, and/or utilized, are overheads in the use of biomass for bio-energy. The inclusive costs for truck transport were evaluated for different truck types. Using small trucks, operational costs (1.1 Aus$/t/km) are an overwhelming liability in terms of the value of carbon and/or energy delivered, unless transport distances are a few kilometres. When larger trucks are used, transport costs (0.15 Aus$/t/km) represent a significant impost on the actual value of the commodity (carbon or energy) and the degree to which it is competitive with other sources of energy (e.g. existing electricity, gas or petroleum) or with the likely values placed on carbon. For example, transport costs are equivalent to the retail value of electricity when a large truck has travelled about 600 km. These results are also relevant to how transportation distances influence the economics of value chains for various commodities.

Kin recognition in plants with distinct lifestyles: implications of biomass and nutrient niches

Kin recognition has been demonstrated by plant biomass allocation and morphology traits as well as by nitrogen (N) uptake, but has not been examined from a nutrient-niche view yet. In this study, four species with distinct lifestyles, including Glycine max (L.) Merr. (herbaceous legume), Belamcanda chinensis (L.) DC. (herbaceous non-legume), Caesalpinia pulcherrima (L.) Sw. (woody legume), and Populus tomentosa (L.) Carr. (woody non-legume) were used to demonstrate kin recognition by estimating their biomass and allocation, as well as nutrient niches based on their uptake efficiency for N, phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), and iron (Fe). For G. max, kin recognition was achieved by increased biomass, and by reduced nutrient-uptake efficiency of N, P, S, K, Ca, Mg, and Fe (decreased nutrient niches) to decrease nutrient competition among kin plants compared to the strangers. Although B. chinensis and C. pulcherrima had no biomass response, kin plants of B. chinensis increased, whereas C. pulcherrima decreased their S-uptake efficiency compare to strangers. Therefore, kin competition occurred in B. chinensis through increased nutrient niche whereas kin recognition occurred in C. pulcherrima through decreased nutrient niche. By comparison, P. tomentosa showed the co-occurrence of kin recognition and competition by increased root allocation and decreased P-uptake efficiency. These findings suggest that the biomass allocation and plant nutrient niches based on their nutrient-uptake efficiency can be used as potential parameters to identify kin recognition.

Comprehensive assessment of sugarcane straw: implications for biomass and bioenergy production

AbstractSugarcane straw, consisting of green tops and dry leaves, can be maintained on fields to improve soil quality, or harvested for bioenergy production. The optimum option between these two uses is still uncertain and requires further study. This study, conducted across three crop cycles, provides an assessment of the moisture, nutrients, ash, extractives, cellulose, hemicelluloses, and lignin contents of four sugarcane varieties across seven regions of south‐central Brazil. Suitability of the straw fractions for nutrient recycling, bioelectricity, and second‐generation ethanol production were also evaluated. Results showed that the sugarcane straw yield (dry mass) was 14.0 Mg ha−1, and the ratio of dry straw/fresh stalk was 12%. The composition of green tops and dry leaves differed consistently across varieties, sites, and crop cycles. Dry leaves represented 60% of the straw, but green tops contained about 70% of the total N, P, and K content. Therefore, green tops recycled up to four times more nutrients than dry leaves. Green tops also had six times higher moisture and greater chlorine content which decreased the mill process efficiency. In turn, dry leaves had higher lignin, cellulose, and hemicelluloses content, greater heating value (higher: 17.3 MJ kg−1; lower: 15.6 MJ kg−1) and tended to be a better second‐generation ethanol production feedstock. Overall, the results show that it is preferable to use dry leaves for bioenergy production while leaving green tops on the field for nutrient recycling. This study pointed out that more efficient methods for separating these fractions in the field need to be developed. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

Response of plankton to nutrients, planktivory and terrestrial organic matter: a model analysis of whole-lake experiments.

Terrestrial organic matter can be assimilated by aquatic consumers but implications for biomass and production are unresolved. An ecosystem model was fit to estimate effects of phosphorus (P) load, planktivory, and supply rate of terrestrial particulate organic carbon (TPOC) on phytoplankton and zooplankton in five whole-lake experiments. Phytoplankton biomass increased with P load and planktivory and decreased with TPOC supply rate. Zooplankton biomass increased with P load and responded weakly to planktivory and TPOC supply rate. Zooplankton allochthony (proportion of carbon from terrestrial sources) decreased with P load and planktivory and increased with TPOC supply rate. Lakes with low allochthony (<0.3) had wide ranges of phytoplankton and zooplankton biomass and production, depending on P load and planktivory. Lakes with high allochthony (>0.3) had low biomass and production of both phytoplankton and zooplankton. In summary, terrestrial OC inhibits primary production and is a relatively low-quality food source for zooplankton.

Dissecting variation in biomass conversion factors across China's forests: implications for biomass and carbon accounting.

Biomass conversion factors (BCFs, defined as the ratios of tree components (i.e. stem, branch, foliage and root), as well as aboveground and whole biomass of trees to growing stock volume, Mg m−3) are considered as important parameters in large-scale forest biomass carbon estimation. To date, knowledge of possible sources of the variation in BCFs is still limited at large scales. Using our compiled forest biomass dataset of China, we presented forest type-specific values of BCFs, and examined the variation in BCFs in relation to forest type, stand development and environmental factors (climate and soil fertility). BCFs exhibited remarkable variation across forest types, and also were significantly related to stand development (especially growing stock volume). BCFs (except Stem BCF) had significant relationships with mean annual temperature (MAT) and mean annual precipitation (MAP) (P<0.001). Climatic data (MAT and MAP) collectively explained 10.0–25.0% of the variation in BCFs (except Stem BCFs). Moreover, stronger climatic effects were found on BCFs for functional components (i.e. branch, foliage and root) than BCFs for combined components (i.e. aboveground section and whole trees). A general trend for BCFs was observed to decrease and then increase from low to high soil fertility. When qualitative soil fertility and climatic data (MAT and MAP) were combined, they explained 14.1–29.7% of the variation in in BCFs (except Stem BCFs), adding only 4.1–4.9% than climatic data used. Therefore, to reduce the uncertainty induced by BCFs in forest carbon estimates, we should apply values of BCFs for a specified forest type, and also consider climatic and edaphic effects, especially climatic effect, in developing predictive models of BCFs (except Stem BCF).

Comparative energetics and kinetics of autotrophic lipid and starch metabolism in chlorophytic microalgae: implications for biomass and biofuel production.

Due to the growing need to provide alternatives to fossil fuels as efficiently, economically, and sustainably as possible there has been growing interest in improved biofuel production systems. Biofuels produced from microalgae are a particularly attractive option since microalgae have production potentials that exceed the best terrestrial crops by 2 to 10-fold. In addition, autotrophically grown microalgae can capture CO2 from point sources reducing direct atmospheric greenhouse gas emissions. The enhanced biomass production potential of algae is attributed in part to the fact that every cell is photosynthetic. Regardless, overall biological energy capture, conversion, and storage in microalgae are inefficient with less than 8% conversion of solar into chemical energy achieved. In this review, we examine the thermodynamic and kinetic constraints associated with the autotrophic conversion of inorganic carbon into storage carbohydrate and oil, the dominant energy storage products in Chlorophytic microalgae. We discuss how thermodynamic restrictions including the loss of fixed carbon during acetyl CoA synthesis reduce the efficiency of carbon accumulation in lipids. In addition, kinetic limitations, such as the coupling of proton to electron transfer during plastoquinone reduction and oxidation and the slow rates of CO2 fixation by Rubisco reduce photosynthetic efficiency. In some cases, these kinetic limitations have been overcome by massive increases in the numbers of effective catalytic sites, e.g. the high Rubisco levels (mM) in chloroplasts. But in other cases, including the slow rate of plastoquinol oxidation, there has been no compensatory increase in the abundance of catalytically limiting protein complexes. Significantly, we show that the energetic requirements for producing oil and starch relative to the recoverable energy stored in these molecules are very similar on a per carbon basis. Presently, the overall rates of starch and lipid synthesis in microalgae are very poorly characterized. Increased understanding of the kinetic constraints of lipid and starch synthesis, accumulation and turnover would facilitate the design of improved biomass production systems.

Woody Debris Volume Depletion Through Decay: Implications for Biomass and Carbon Accounting

Woody debris decay rates have recently received much attention because of the need to quantify temporal changes in forest carbon stocks. Published decay rates, available for many species, are commonly used to characterize deadwood biomass and carbon depletion. However, decay rates are often derived from reductions in wood density through time, which when used to model biomass and carbon depletion are known to underestimate rate loss because they fail to account for volume reduction (changes in log shape) as decay progresses. We present a method for estimating changes in log volume through time and illustrate the method using a chronosequence approach. The method is based on the observation, confirmed herein, that decaying logs have a collapse ratio (cross-sectional height/ width) that can serve as a surrogate for the volume remaining. Combining the resulting volume loss with concurrent changes in wood density from the same logs then allowed us to quantify biomass and carbon depletion for three study species. Results show that volume, density, and biomass follow distinct depletion curves during decomposition. Volume showed an initial lag period (log dimensions remained unchanged), even while wood density was being reduced. However, once volume depletion began, biomass loss (the product of density and volume depletion) occurred much more rapidly than density alone. At the temporal limit of our data, the proportion of the biomass remaining was roughly half that of the density remaining. Accounting for log volume depletion, as demonstrated in this study, provides a comprehensive characterization of deadwood decomposition, thereby improving biomassloss and carbon-accounting models.

Wood density in forests of Brazil's ‘arc of deforestation’: Implications for biomass and flux of carbon from land-use change in Amazonia

Wood density is an important variable in estimates of forest biomass and greenhouse-gas emissions from land-use change. The mean wood density used in estimates of forest biomass in the Brazilian Amazon has heretofore been based on samples from outside the “arc of deforestation”, where most of the carbon flux from land-use change takes place. This paper presents new wood density estimates for the southern and southwest Brazilian Amazon (SSWA) portions of the arc of deforestation, using locally collected species weighted by their volume in large local inventories. Mean wood density was computed for the entire bole, including the bark, and taking into account radial and longitudinal variation. A total of 403 trees were sampled at 6 sites. In the southern Brazilian Amazon (SBA), 225 trees (119 species or morpho-species) were sampled at 4 sites. In eastern Acre state 178 trees (128 species or morpho-species) were sampled at breast height in 2 forest types. Mean basic density in the SBA sites was 0.593 ± 0.113 (mean ± 1 S.D.; n = 225; range 0.265–0.825). For the trees sampled in Acre the mean wood density at breast height was 0.540 ± 0.149 ( n = 87) in open bamboo-dominated forest and 0.619 ± 0.149 ( n = 91) in dense bamboo-free forest. Mean wood density in the SBA sites was significantly higher than in the bamboo dominated forest but not the dense forest at the Acre site. From commercial wood inventories by the RadamBrasil Project in the SSWA portion of the arc of deforestation, the wood volume and wood density of each species or genus were used to estimate average wood density of all wood volume in each vegetation unit. These units were defined by the intersection of mapped forest types and states. The area of each unit was then used to compute a mean wood density of 0.583 g cm −3 for all wood volume in the SSWA. This is 13.6% lower than the value applied to this region in previous estimates of mean wood density. When combined with the new estimates for the SSWA, this gave an average wood density of 0.642 g cm −3 for all the wood volume in the entire Brazilian Amazon, which is 7% less than a prior estimate of 0.69 g cm −3. These results suggest that current estimates of carbon emissions from land-use change in the Brazilian Amazon are too high. The impact on biomass estimates and carbon emissions is substantial because the downward adjustment is greater in forest types undergoing the most deforestation. For 1990, with 13.8 × 10 3 km 2 of deforestation, emissions for the Brazilian Amazon would be reduced by 23.4–24.4 × 10 6 Mg CO 2-equivalent C/year (for high- and low-trace gas scenarios), or 9.4–9.5% of the gross emission and 10.7% of the net committed emission, both excluding soils.

Disturbances and the sustainability of long-term site productivity in lodgepole pine forests in the central interior of British Columbia—an ecosystem modeling approach

The ecosystem-management model FORECAST was used to compare some ecological impacts of natural disturbance (wildfire) and timber harvesting. The scientific objective of the study was to assess whether or not two types of timber harvesting at various rotation lengths would have biogeochemical and biomass implications that are within the natural range of variation caused by wildfire. The practical objective was to identify management strategies that would sustain or improve long-term site productivity in lodgepole pine forests in the central interior of British Columbia. We defined three fire severity categories (low, medium and high), three fire return intervals (40, 80 and 120 years), two utilization levels (including stem-only harvesting [SOH] and whole-tree harvesting [WTH]), and three timber production rotation lengths (40, 80 and 120 years). Differences in simulated productivity, decomposing litter mass, total available soil nitrogen and nitrogen removals were compared for all 15 combinations of the five levels of disturbance at the three frequencies. The simulated nutritional impacts of timber harvesting were within the simulated range of impacts caused by the wildfire defined in this study. They were similar to the simulated long-interval, low-severity wildfire regimes. Simulations suggest that ecological rotation lengths for long-term site productivity for lodgepole pine forests in the study area would be 80–120 years. These rotation lengths are close to the average wildfire return intervals (100–125 years) in the study area, supporting the idea that the present harvesting strategies should sustain tree growth at this frequency of harvest and severity of harvesting impacts. Both WTH and SOH are acceptable harvesting methods for the maintenance of long-term site productivity in these lodgepole pine forests if harvest intervals are 80 years or longer. However, SOH is a more nutrient conservative harvest method, and should be used instead of WTH for rotations less than 80 years. The importance of initial site quality in assessing sustainable long-term site productivity by modeling is demonstrated.