Amount Of Aboveground Biomass Research Articles

Transcriptome Analysis Reveals Novel Insights into the Hyperaccumulator Phytolacca acinosa Roxb. Responses to Cadmium Stress.

Cadmium (Cd) is a highly toxic heavy metal that causes serious damage to plant and human health. Phytolacca acinosa Roxb. has a large amount of aboveground biomass and a rapid growth rate, and it has been identified as a novel type of Cd hyperaccumulator that can be harnessed for phytoremediation. However, the molecular mechanisms underlying the response of P. acinosa to Cd2+ stress remain largely unclear. In this study, the phenotype, biochemical, and physiological traits of P. acinosa seeds and seedlings were analyzed under different concentrations of Cd2+ treatments. The results showed higher Cd2+ tolerance of P. acinosa compared to common plants. Meanwhile, the Cd2+ content in shoots reached 449 mg/kg under 10 mg/L Cd2+ treatment, which was obviously higher than the threshold for Cd hyperaccumulators. To investigate the molecular mechanism underlying the adaptability of P. acinosa to Cd stress, RNA-Seq was used to examine transcriptional responses of P. acinosa to Cd stress. Transcriptome analysis found that 61 genes encoding TFs, 48 cell wall-related genes, 35 secondary metabolism-related genes, 133 membrane proteins and ion transporters, and 96 defense system-related genes were differentially expressed under Cd2+ stress, indicating that a series of genes were involved in Cd2+ stress, forming a complex signaling regulatory mechanism. These results provide new scientific evidence for elucidating the regulatory mechanisms of P. acinosa response to Cd2+ stress and new clues for the molecular breeding of heavy metal phytoremediation.

Contrasting leaf-scale photosynthetic low-light response and its temperature dependency are key to differences in crop-scale radiation use efficiency.

Radiation use efficiency (RUE) is a key crop adaptation trait that quantifies the potential amount of aboveground biomass produced by the crop per unit of solar energy intercepted. But it is unclear why elite maize and grain sorghum hybrids differ in their RUE at the crop level. Here, we used a non-traditional top-down approach via canopy photosynthesis modelling to identify leaf-level photosynthetic traits that are key to differences in crop-level RUE. A novel photosynthetic response measurement was developed and coupled with use of a Bayesian model fitting procedure, incorporating a C4 leaf photosynthesis model, to infer cohesive sets of photosynthetic parameters by simultaneously fitting responses to CO2 , light, and temperature. Statistically significant differences between leaf photosynthetic parameters of elite maize and grain sorghum hybrids were found across a range of leaf temperatures, in particular for effects on the quantum yield of photosynthesis, but also for the maximum enzymatic activity of Rubisco and PEPc. Simulation of diurnal canopy photosynthesis predicted that the leaf-level photosynthetic low-light response and its temperature dependency are key drivers of the performance of crop-level RUE, generating testable hypotheses for further physiological analysis and bioengineering applications.

Microbial Diversity, Biomass, and Community Structure Differences among Restored and Natural Saltwater Marshes, Louisiana

Tidally influenced, saltwater marsh construction projects are being completed in Louisiana to combat coastal erosion and land loss, as well as to restore critical fisheries and counteract ecosystem injuries caused by oil spills and other anthropogenic activities. Historically, metrics of success for restored marshes have been based on the amount of aboveground biomass, survival of planted vegetation, and recruitment of local endemic versus invasive species. The microbial communities responsible for cycling nutrients within restored soils are not typically evaluated. Therefore, we investigated microbial community structure, biomass, and diversity in marsh soils that had been created from nearby dredge material over the past 10 years in the Lake Hermitage, West Point a La Hache area, and compared the results to those from natural marsh soils from Bay Batiste, as determined using phospholipid fatty acid (PLFA) and gas chromatography/mass spectrometry (GC/MS) techniques and from 16S rRNA gene profiles. Soils were collected from two depths (0-2 cm and 8-10 cm) from four sampling locations along a 100-m transect that extended inland from the coastline. Soil organic carbon content and soil pH were consistently lower at restored sites compared to natural marshes. Natural marsh soil microbial diversity strongly correlated with the biomass of typical marsh plants (e.g., Spartina alterniflora, Juncus roemerianus), whereas restored soil diversity correlated to higher Paspalum spp. (crowngrass) and Schoenoplectus pungens (common bulrush) biomass. Created soils had higher overall microbial diversity, but natural marsh soils had at least twice as much PLFA biomass than the created marshes at the shallow depth and 10X more biomass at the deeper depth. Biomass estimates ranged from below detectable levels to 6 x104 pmol PLFA gdw−1, with shallower soils from all sites exhibiting higher biomass (average 104 pmol PLFA gdw-1) compared to deeper soils (average 103 pmol PLFA gdw-1). Diverse PLFA profiles were observed. Shallow soils were dominated by terminally-branched and midchain-branched saturates that are indicative of Gram-positive microorganisms and actinomycetes. The shallow soils contained polyunsaturates indicative of phototrophs. Deeper soil profiles were dominated by monounsaturates associated with Gram-negative bacteria and sulfate- and metal-reducing bacteria. These monounsaturates contained on average 7% of the total PLFA profile as cyclopropyl fatty acids, which likely indicated anaerobic processes and the presence of nutritional stress. The shallow natural marsh soils exhibited more mid-branched saturates, branched monounsaturates, and polyunsaturates, whereas the shallow created marsh soils had more terminally-branched saturates. In the deeper soils, the natural marshes exhibited more terminally-branched saturates and monounsaturates, but the created marshes contained more saturates. GC/MS analyses of dimethyl disulfide derivatizations revealed shifts in microorganisms, as indicated by the types and bonding positions of monounsaturates, and the changes in the presence/absence of methanotrophic populations within the soils, which was also reflected in the 16S rRNA gene profiles. From these results, the microbial communities from the created marsh soils were different than the natural soil communities, and may reflect not being the best desired outcome for marsh restoration. With time, the expectation would be that created marsh above and belowground microbial diversity and biomass would begin to mimic natural marshes, but continued monitoring through time will be necessary to understand how these linkages develop and affect basic soil processes, nutrient cycling, and recruitment and sustenance of higher organisms like fish or crustaceans.

Aboveground biomass of forest and oil palm land cover mapping using Sentinel 2A imagery, Asahan-Indonesia

Forests are the largest carbon sink, play an important role in the global carbon cycle, and can store at least ten times more carbon than other vegetation types. The study aims to model the aboveground biomass of forest and palm oil land cover, to map the amount of aboveground biomass in the Asahan district. Tree biomass is measured non-destructive or without cutting a tree sample. The independent variables from the biomass estimation model are the normalized difference vegetation index (NDVI), green normalized difference vegetation index (GNDVI), and transformed vegetation index (TVI) from Sentinel 2A images. The coefficient of determination selects the best model from the equation. The selected estimating model of forest coverage biomass is y = 3830,8ln(x) + 2356,6 with a predicted variable of the NDVI by a coefficient of determination of 79 %; palm oil coverage biomass is y = 0,0018x6,8778 with TVI variable by a coefficient of determination of 21%. The total aboveground biomass for forest coverage is 34,57 tons/ha, and oil palm coverage is 0,07 tons/ha

Prioritizing global tall forests toward the 30 × 30 goals.

The Global Deal for Nature sets an ambitious goal to protect 30% of Earth's land and ocean by 2030. The 30 × 30 initiative is a way to allocate conservation resources and extend protection to conserve vulnerable and underprotected ecosystems while reducing carbon emissions to combat climate change. However, most prioritization methods for identifying high-value conservation areas are based on thematic attributes and do not consider vertical habitat structure. Global tall forests represent a rare vertical habitat structure that harbors high species richness in various taxonomic groups and is associated with large amounts of aboveground biomass. Global tall forests should be prioritized when planning global protected areas toward reaching the 30 × 30 goals. We examined the spatial distribution of global tall forests based on the Global Canopy Height 2020 product. We defined global tall forests as areas with the average canopy height above 3 thresholds (20, 25, and 30m). We quantified the spatial distribution and protection level of global tall forests in high-protection zones, where the 30 × 30 goals are being met or are within reach, and low-protection zones, where there is a low chance of reaching 30 × 30 goals. We quantified the protection level by computing the percentage of global tall forest area protected based on the 2017 World Database on Protected Areas. We also determined the global extent and protection level of undisturbed, mature, tall forests based on the 2020 Global Intact Forest Landscapes mask. In most cases, the percentage of protection decreased as forest height reached the top strata. In the low-protection zones, <30% of forests were protected in almost all tall forest strata. In countries such as Brazil, tall forests had a higher percentage of protection (consistently >30%) compared to forests of lower height, presenting a more effective conservation model than in countries such as the United States, where forest protection was almost uniformly <30% across height strata. Our results show an urgent need to target forest conservation in the greatest height strata, particularly in high-protection areas, where most global tall forests are found. Vegetation vertical structure can inform the decision-making process toward the 30 × 30 goals because it can be used to identify areas of high conservation value for biodiversity protection which also contribute to carbon sequestration.

Structural diversity is a key driver of above-ground biomass in tropical forests

ABSTRACT Background A gamut of abiotic and biotic factors is related to the amount of above-ground biomass (AGB) produced in ecosystems. Some factors have direct and others indirect relationships with AGB. Detailed analyses in tropical forests are few but much needed for better understanding the potential impacts of global change drivers and for mitigating impacts. Aims Here, we examined the relationship between AGB and different predictor variables and quantitatively evaluated their relative importance in lowland to lower montane deciduous and lower montane – montane evergreen forest types. We hypothesised that the relationship between AGB and climate, topography, structural diversity, species diversity (alpha and beta) and phylogenetic diversity would differ between the two forest types. Methods We inventoried trees from 114 plots (each 0.1 ha) and used partial least square structural equation modelling to test the direct and indirect relationship between AGB and the predictor variables. Results We found that structural diversity variables, stem density and tree girth, were significantly and positively related to AGB in both forest types, displaying a stronger relationship in montane evergreen forests (w = 0.65 for density and 0.89 for tree girth). In the deciduous forest, alpha and phylogenetic diversity were also important factors, whereas beta and phylogenetic diversity were important in the evergreen forest. The effects of topography and climate varied between forest types, with elevation and precipitation being related to AGB directly and indirectly through their relationship with structural diversity. Conclusion Our results suggest that structural diversity is a key driver of tropical forest biomass, both directly and indirectly. This fundamental understanding can aid in the predictive efforts of biodiversity conservation and forest management.

On the possibility of determining allometric indicators of trees using satellite remote sensing data

In recent decades, the rapid development of remote sensing technologies has led to the development of various methods for determining the amount of aboveground biomass from satellite images. Regression equations were constructed linking fild estimates of aboveground biomass and vegetation indices obtained by remote sensing methods. Such studies make it possible not only to promptly monitor the state of vast forests, but also to solve the problem of assessing global carbon stocks on the planet. The purpose of the study is to create the foundations for the development of new methods for determining allometric indicators by remote sensing methods. The objectives of the study are to determine using remote sensing technologies (1) the total mass of trees of a forest consisting of n number of plots diffring from each other in the number and type of trees; (2) the total mass of a heterogeneous forest in which there is a certain functional relationship between normalized difference vegetation index (NDVI) and the number of trunks in a certain area; (3) the model relationship between NDVI and such allometric indicators as tree height (H) and crown diameter (CD). Research results: some problems of allometric measurements using remote sensing methods have been solved. A formula has been obtained for calculating the biological mass of trees in the forest using the values of the NDVI in individual forest areas; a similar problem for the case of a functional relationship between NDVI and the number of trunks in individual forest areas; the formula of the model relationship between NDVI and the product of such allometric indicators as tree height and crown diameter is obtained.

Estimation of aboveground carbon stock based on mangrove zones in Ijo River Estuary, Ayah Village, Kebumen, Indonesia

Abstract. Ningtyas SRA, Mu’ali AYF, Putri DNAR, Silaningtyas NW, Tsabita FA, Aprianto MK, Sari SP, Fauziyyah MD, Nugraheni RS, Juniati SD, Isa MN, Nofitasari H, Sutarno, Sugiyarto, Yap CK, Budiharta S, Setyawan AD. 2023. Estimation of aboveground carbon stock based on mangrove zones in Ijo River Estuary, Ayah Village, Kebumen, Indonesia. Indo Pac J Ocean Life 7: 148-155. The increasing concentration of greenhouse gases, including carbon dioxide in the atmosphere is the driver of global warming which triggers climate change. One strategy to mitigate climate change is reducing carbon emissions and increasing the carbon stock. Mangrove forest is recognized as the largest carbon sink on the Earth, therefore, the conservation and restoration of mangrove forest are increasingly promoted as an effective way to tackle climate change. While many studies assess the carbon stock of mangrove forests, a context-specific assessment is needed to enrich the existing studies in this field. This study aimed to investigate the aboveground carbon stored in vegetation occurring in three mangrove zones (i.e., seaward, middle and landward zones) in Ijo River Estuary, Ayah Village, Kebumen, Central Java, Indonesia. Purposive sampling on each mangrove zone was conducted with vegetation data at tree and pole stages collected using nested plot methods. Aboveground biomass was calculated using an allometric equation while carbon stock was estimated using the method of the National Standardization Agency. In total, there were 11 mangrove species in the observation plots, consisting of seven true mangrove species and four mangrove associates. The seaward zone had five species and an amount of aboveground biomass (29324.07 MgB/ha), while the middle zone consisted of five species and had biomass of 52776.62 MgB/ha, and the landward zone was composed of five species and had biomass of 6428.74 MgB/ha. The carbon stock in the seaward, middle and landward zones were 43.06, 197.42 and 186.00 MgC/ha, respectively. In total, the Ayah Mangrove Forest contained aboveground biomass of 88529.43 MgB/ha, equal to 1143.31 MgC/ha carbon stock. The findings of this study reiterate the importance of conserving mangrove forests as an effective way to reduce carbon emissions which are the major cause of global warming.

Исследование общего количества надземной биомассы в лесах в зависимости от взаимосвязи высоты и диаметра ствола деревьев

The purpose of this study is to clarify the conditions for achieving the minimum total amount of aboveground biomass in forests, depending on such indicators as stem diameter and tree height. The aboveground biomass contained in forests makes up the bulk of the total biomass available in the forest ecosystem and makes it possible to determine the rate of change in the state of forests. This indicator also plays an important role in the planning of forestry activities. The amount of biomass in forests is of paramount importance when calculating the loss to the ecosystem that is formed due to degradation and deforestation, which ultimately leads to the generation of an additional amount of CO2, which is the main greenhouse gas. In this study, the dependence of the total amount of biomass in forests on such indicators as tree height and trunk diameter has been studied. A zonal model of forest development is proposed and on this basis a target functional is formed in two variants corresponding to the known expressions of the dependence of the total amount of aboveground forest biomass on the abovementioned tree indicators. Optimization problems are formulated taking into account additional restrictive conditions imposed on the functional dependence of the trunk diameter on the height of the tree. The solution of optimization problems, using the method of unconditional variational optimization, showed that the total amount of biomass in forests reaches a minimum in the presence of an inverse dependence of the trunk diameter on the height of trees. The results of the study allow us to determine a guaranteed minimum of biomass in forests, which in the future would lead to increased forest protection measures, to a more accurate assessment of the potential of forests to accumulate carbon.

Mapping individual tree and plot-level biomass using airborne and mobile lidar in piñon-juniper woodlands

Piñon-juniper (PJ) woodlands are a widespread dryland ecosystem in the US containing an immense but poorly-constrained amount of aboveground biomass (AGB). Found at the dry end of the climatic range within which trees can persist, PJ faces an uncertain future in a changing climate, giving unique importance to mapping its AGB, past, present, and future. Lidar remote sensing offers great potential towards that end with research in a range of tree-dominant ecosystems demonstrating a strong capacity for mapping AGB. However, studies applying lidar to the task of mapping AGB in PJ are few. Given the unique structural characteristics of PJ trees, which tend to be short in stature (<10 m), possess multiple stems often obscured by low crown base heights, and irregularly-shaped canopies, there remains a high degree of uncertainty surrounding tree- and stand-level structural mapping in these woodlands. To resolve our limited understanding of how to best quantify AGB in PJ using lidar, we conducted a field-validated analysis comparing lidar platform (airborne laser scanner, ALS vs. mobile laser scanner, MLS) and analytical framework (area-based modeling vs. individual tree-based modeling). We used a random forest machine learning approach to predicting tree- and stand-level structure with leave-one-out cross-validation to assess model performance. In an area-based context, MLS only marginally outperformed ALS, with both able to explain approximately 80 % of variance in AGB. However, in an individual tree-based context, MLS significantly outperforms ALS at several tasks, including: (1) delineating tree crowns (MLS delineated 100 % of trees; ALS delineated 69 %); (2) directly characterizing tree structural parameters including height (R2ALS = 0.52 vs. R2MLS = 0.74) and crown area (R2ALS = 0.26 vs. R2MLS = 0.68); and (3) modeling AGB (R2ALS = 0.38 vs. R2MLS = 0.62). We attribute this difference in performance to the vastly greater structural detail contained within the MLS point cloud data as compared to ALS, with the former possessing an average of approximately 30,000 pts/m2 and the latter 14 pts/m2. Based on our results, we make the following recommendation: if individual tree structure is needed, MLS is the far superior option; however, given the wider availability, ALS data are a suitable substitute when mapping PJ AGB, particularly under an area-based modeling analytical framework. This study represents the first time MLS data have been applied to tree structure mapping in PJ, and provides strong quantitative evidence towards best structural and AGB mapping practices in this unique, widespread, and important ecosystem. It serves as a solid foundation upon which future studies aiming to map AGB in PJ and other similar dryland woodland ecosystems can be built.

Estimating Ecological Characteristics and Carbon Stock in Uneven-Aged Plantations of &amp;lt;i&amp;gt;Acacia senegal&amp;lt;/i&amp;gt; L. in the Savannah Woodlands of Sudan

The aim of this study was to assess Acacia senegal trees’ characteristics as well as evaluate the carbon stock under a variety of ages in the El Demokeya forest in Sudan, where the Gum Arabic belt is located. 12 sample plots, in 2021 were randomly distributed to represent the entire area of the forest prior to the required measurements. The sample was designed as squire plots with one hectare. In each sample plot, all trees were counted, their height (m), and Diameters Breast Height (DBH in cm), respectively. The results showed the highest number of trees per ha at age 20 years old and the lowest number at age 47 years, while the highest values of DBH and volume were found at age 47 years old. As a result, the maximum and minimum values of the aboveground biomass were found in the age 47 years old and 16 years, accounting for 19.87 tons and 1.9 tons respectively. Thus, the amount of carbon stock was 11.92 tons/ha in the 35-years-old and 1.19 tons/ha in the 21-year stands. Furthermore, the average carbon stock in all plots was estimated as 18.70 tons/ha and hence the total carbon stock in the El Demokeya forest is equal to 620.11 tons. Conclusively, the characteristics of trees, amount of aboveground biomass and carbon stock in the El Demokeya forest varied among the uneven-aged plantation groups. The study recommends and encourages the protection of A. senegal in order to increase the carbon sink as well as protect the environment in the era of climatic changes.

Species Composition, Diversity, and Biomass Estimation in Coastal and Marine Protected Areas of Terengganu, Peninsular Malaysia

We investigated and compared the tree species composition and diversity of different forest types in Setiu Wetlands and on the three major islands of Terengganu. A total of 24 plots of 25 m × 25 m with four plots in each study site were established, viz. Melaleuca swamp forest in Kampung Fikri, freshwater swamp forest in Kampung Gong Batu, mangrove forest in UMT Setiu research station, and the islands, namely Pulau Bidong, Pulau Redang, and Pulau Perhentian. We calculated the basal area, stand density, Importance Value Index, species diversity, and above-ground biomass in the designated study areas. We assessed 139 tree species from 96 genera and 50 families based on a total of 2608 tree samples of 5 cm DBH and above. The freshwater swamp forest harbored the highest number of species with 20 species in Setiu Wetlands, and among the islands, Pulau Redang had the highest with 56 species. Melaleuca cajuputi was the most dominant species in the Melaleuca swamp forest, while Alstonia spatulata and Rhizophora apiculata are expected in the freshwater swamp and mangrove forest, respectively. Pulau Bidong, Pulau Redang, and Pulau Perhentian are mostly represented by Licania splendens, Shorea glauca, and Vatica sp., respectively. All the dominant species but Licania splendens contributed to the highest amount of above-ground biomass. Our current study indicated that different forest types vary in composition and structure, which may contribute to their unique ecological roles within their specific environment.

Carbon Storage Expectations on Swamp Jelutung (Dyera polyphylla Miq. Steenis.) on Peatland for Tackling Climate Change

(1) Background: The destruction of peatlands caused by forest fire can significantly damage the ecosystems, flora, and fauna found in forests. Swamp jelutung (Dyera polyphylla) is a tree species that can be planted on peatland and combined with seasonal plants to provide multiple economic and environmental benefits. The aim of this study is to analyze the biomass and carbon stocks above and belowground in stands of swamp jelutung of an age class of 10, 13, and 17 years. (2) Methods: Observation plots were determined based on the age classes of D. polyphylla plants. The plots were determined using a purposive sampling method with a size of 20 m × 5 m with two sample plots in each class of plant age. The biomass calculation measured the diameters of living trees without causing any damage. The understory biomass was obtained by cutting and then placing in a container before weighing and recording the wet weight. The necromass was determined by measuring the diameter and length of all the wood. (3) Results: The amount of aboveground biomass (trees) was divided into 111.73 ton/ha (17 years), 55.96 ton/ha (13 years), and 50.08 ton/ha (10 years) age classes. The root biomass had the highest values of 18.36 ton/ha (17 years), 9.45 ton/ha (13 years), and 9.07 ton/ha (10 years). Meanwhile, the organic C contents in peat soil under stands of D. polyphylla were 33.45% (13 years), 31.32% (17 years), and 26.14% (10 years). (4) Conclusions: D. polyphylla trees play a role in restoring forest ecosystems on peatlands and absorb more CO2 as the trees age. Therefore, they are useful in dealing with climate change.

Sinergia de datos espectrales Landsat, climáticos y LiDAR para el mapeo de biomasa aérea en selvas medianas de la península de Yucatán, México

Introduction: Tropical forests represent complex and dynamic ecosystems that cover extensive areas, hence the importance of determining biomass content and representing spatial variability. Objective: Estimating and mapping aboveground biomass and its associated uncertainty for medium-stature semi-evergreen (SMSP) and semi-deciduous (SMSC) tropical forests of the Yucatan Peninsula. Materials and methods: Aboveground biomass was estimated as a function of explanatory variables taken from Landsat images and climatic variables, using the random Forest algorithm. Aboveground biomass was mapped from previous biomass estimates for stripes of the territory with the presence of LiDAR (Light Detection And Ranging) and field data. Uncertainty at the pixel level was estimated as the coefficient of variation. Results and discussion: A combination of climatic and spectral variables showed acceptable capacity to estimate biomass in the medium-stature semi-evergreen and semi-deciduous tropical forest with an explained variance of 50 % and RMSE (root mean squared error) of 34.2 Mg·ha -1 and 26.2 Mg·ha -1 , respectively, prevailing climate variables. SMSP biomass ranged from 4.0 to 185.7 Mg·ha -1 and SMSC ranged from 11.7 to 117 Mg·ha -1 . The lowest values of uncertainty were recorded for the medium-stature semi-evergreen tropical forest, being higher in areas with lower amounts of aboveground biomass. Conclusion: Aboveground biomass was estimated and mapped by the combined use of auxiliary variables with an acceptable accuracy, against uncertainty of predictions, which represents an opportunity for future improvement.

The effects of different management interventions on degraded rangelands in Iceland

AbstractLoss of vegetation and soil erosion are symptoms of widespread rangeland degradation across most of the Icelandic highlands. Areas at different stages of degradation coexist as a mosaic that includes both vegetated heathlands, and exposed gravelly deserts. Revegetation efforts have included fertilizer applications and grazing exclusion to increase plant biomass and reduce bare ground, but their effectiveness is predicted to differ depending on the stage of degradation for a certain area. In this study, we used a 4‐year field experiment to test the predictions of a state‐and‐transition model for the Icelandic highlands. We measured the combined effects of grazing exclusion and factorial applications of nitrogen (N), phosphorus (P), and potassium (K) fertilizers, on plant biomass, species richness, amount of exposed bare ground and plant community composition in a dwarf‐shrub heathland and a gravelly desert habitat. After 4 years: (1) grazing exclusion alone had no effect in either habitat; (2) fertilizers increased biomass in both habitats, especially in plots treated with NP or NK; (3) the combination of fertilizers and grazing exclusion produced the greatest amount of aboveground biomass, predominantly of forb and graminoid species. In the dwarf‐shrub heath, the increase in biomass in fertilized and fenced plots also corresponded to a loss in species richness, whereas in the gravelly desert, increased biomass reduced the amount of bare ground without reducing species richness. Our results reinforce the importance in understanding the effects of different management interventions across ecological conditions to determine the most effective revegetation approach.

Evaluation of Unmanned Aerial Vehicles (UAV) as a Tool to Predict Biomass and Carbon of Tectona grandis in Silvopastoral Systems (SPS) in Costa Rica

The main objective of this research was to evaluate the use of unmanned aerial vehicles (UAVs) in estimating the aboveground biomass and carbon, and the dasometric characteristics at three different spacings (2.5 m × 1.0 m, 2.5 m × 2.0 m and 2.5 m × 3.0 m) in a silvopastoral system (SPS) for the biomass production of Tectona grandis. A total of 90 trees were sampled, 63 of which were used to perform a dasometric evaluation (vertical and horizontal) in a spacing test in an SPS, and the rest to evaluate the use of UAVs in estimating the aboveground biomass in the spacing test. The results showed significant differences in average diameter at breast height (dbh) between spacings, and in aboveground biomass per tree. The amount of aboveground biomass and carbon per hectare increases at smaller spacings, but the differences were not statistically significant. A logarithmic model was prepared to estimate the dbh based on the crown diameter from the data collected taken in the field, since estimating this variable by means of UAVs is difficult. Significant differences were found in the aboveground biomass estimated using the field data compared to UAV data. The estimation of the crown diameter of the selected trees, hindered by the canopy closure in the SPS, was not adequate, which could influence the amount of aboveground biomass estimated using UAV data.

Suffrutex grasslands in south-central Angola: belowground biomass, root structure, soil characteristics and vegetation dynamics of the ‘underground forests of Africa’

AbstractDespite its importance for carbon stocks accounting, belowground biomass (BGB) has seldom been measured due to the methodological complexity involved. In this study, we assess woody BGB and related carbon stocks, soil properties and human impact on two common suffrutex grasslands (Brachystegia- and Parinari grasslands) on the Angolan Central Plateau. Data on BGB was measured by direct destructive sampling. Soil samples were analysed for select key parameters. To investigate vegetation dynamics and human impact, we used Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) and fire data retrieved via Google Earth Engine. Mean belowground woody biomass of sandy Parinari grasslands was 17 t/ha and 44 t/ha in ferralitic Brachystegia grasslands of which 50% correspond to carbon stocks. As such, the BGB of Brachystegia grasslands almost equals the amount of aboveground biomass (AGB) of neighbouring miombo woodlands. Almost the entire woody BGB is located in the top 30 cm of the soil. Soils were extremely acid, showing a low nutrient availability. Both grassland types differed strongly in EVI and fire seasonality. The Parinari grasslands burnt almost twice as frequent as Brachystegia grasslands in a 10-year period. Our study emphasizes the high relevance of BGB in suffrutex grasslands for carbon stock accounting.

Carbon Sequestration Potential of Tree Species at Isabela State University Wildlife Sanctuary (ISUWS), Cabagan, Isabela, Philippines

This study is conducted to assess the amount of carbon stored in the above-ground biomass of the tree species at the Isabela State University Wildlife Sanctuary (ISUWS). A total of 34 different tree species were found with 285 individuals were identified with a total of 47.50 t/ha Carbon stock and 164.09 t/ha of accumulated CO2. It was found in the study that Alstonia scholaris contains the largest amount of above-ground biomass (AGB) with a mass of 20.97 t/ha and Carbon stock of 9.44 t/ha followed by Samanea saman with a mass of 13.40 t/ha and Carbon stock of 6.03 t/ha. Based on the result and conclusion of this investigation, the following recommendations were drawn: Conduct a study concerning the carbon emission of the area to determine the relationship with its carbon sequestration potential; and conduct tree planting activity to open areas in the study site to increase its carbon stock potential and fully serve the purpose of the area as a wildlife sanctuary.

Short-term improved fallows of Tephrosia vogelii and Cajanus cajan enhanced maize productivity and soil chemical properties of a degraded fallow land in Southwestern Ethiopia

An improved fallow experiment was established in 2013 to examine the contribution of shrub legume species, Tephrosia vogelii and Cajanus cajan, in improving the productivity of a degraded tropical soil and crop yields compared with traditional fallow. The study was conducted on five farmers’ fields in southwestern Ethiopia laid out in randomized complete block design with farmers as replicates. After 2 years, the amount of aboveground biomass produced was 5–8 t ha−1 for Tephrosia and 3–5 t ha−1 for Cajanus. Maize grain yield was 80% higher for Tephrosia and 41% for Cajanus compared with the traditional fallow. The legume species significantly increased soil pH, organic carbon and total nitrogen levels compared with the natural fallow but there was no significant effect for available phosphorus. The magnitude of fallow benefit from Tephrosia in terms of yield advantage and nitrogen availability could be related to its high biomass production capacity compared to Cajanus. Fallowing with Tephrosia has the potential for improving productivity of degraded tropical soils. Farmers’ responses to the improved fallows were in general positive and their preference was Tephrosia fallow. Farmers can therefore use Tephrosia to enhance soil fertility by increasing N-levels, soil pH and organic matter of the soil. However, phosphate fertilizer is required as basal application to enhance N-fixation by legumes.

Do Coffee Agroforestry Systems Always Improve Soil Carbon Stocks Deeper in the Soil?—A Case Study from Turrialba, Costa Rica

Shaded perennial agroforestry systems (AFS) are regarded as desirable land-use practices that improve soil carbon sequestration. However, most studies assume a positive correlation between above ground and below ground carbon without considering the effect of past and current land management, textural variations (silt and clay percentage), and such other site-specific factors that have a major influence on the extent of soil C sequestration. We assessed SOC stock at various depths (0–10, 10–30, 30–60, and 60–100 cm) in shaded perennial coffee (Coffea arabica L.) AFS in a 17-year-old experimental field at the Centro Agronómico Tropical de Investigación y Enseñanza, (9°53′44′′ N, 83°40′7′′ W; soil type: Ultisols and Inceptisols, Turrialba, Costa Rica. The treatments included coffee (Coffea arabica L.) grown conventionally (with chemical fertilizers) and organically (without chemical fertilizers) under two shade trees, Erythrina poeppigiana (Walp.) O.F. Cook., and Terminalia Amazonia J.F.Gmel., Sun Coffee (Coffea arabica L.) (Sole stand of coffee without shade), and Native Forest. Three replicated composite soil samples were collected from each system for each depth class, and SOC stocks in three soil aggregate fractions (2000–250 µm, 250–53 µm, and &lt;53 µm) and in the whole soil determined. The total SOC stocks were highest under forest (146.6 Mg C ha−1) and lowest under sun coffee (92.5 Mg C ha−1). No significant differences were noted in SOC stock within coffee AFS and sun coffee across fraction sizes and depth classes. Organic management of coffee under heavily pruned E. poeppigiana, with pruned litter returned to soil, increased SOC stocks for 0–10 cm depth soil only. High input of organic materials including pruned litter did not improve SOC stocks in deeper soil, whereas variations in silt and clay percentages had a significant effect on SOC stocks. The study suggests that high amounts of aboveground biomass alone are not a good indicator of increased SOC storage in AFS, particularly for soils of sites with historical characteristics and management similar to this study.