Secondary Forest Research Articles

Assessing the effectiveness of vegetation indices in detecting forest disturbances in the southeast Amazon

Amazon forests are becoming increasingly vulnerable to disturbances such as droughts, fires, windstorms, logging, and forest fragmentation, all of which lead to forest degradation. Nevertheless, quantifying the extent and severity of disturbances and their cumulative impact on forest degradation remains a significant challenge. In this study, we combined multispectral data from Landsat sensors with hyperspectral data from the Earth Observing-One (Hyperion/EO-1) sensor to evaluate the efficacy of multiple vegetation indices in detecting forest responses to disturbances in an experimentally burned forest in southeastern Amazonia. Our experimental area was adjacent to an agricultural field and consisted of three 50-ha treatments – an unburned Control, a plot burned every three years, and a plot burned annually from 2004 to 2010. All plots were monitored to assess vegetation recovery after fire disturbance. These areas were also affected by three drought events (2007, 2010, and 2016) over the study period. We evaluated a total of 18 Vegetation Indices (VI), one unique to Landsat, 12 unique to Hyperion/EO-1, and five commons to both satellites (i.e., 6 total from Landsat and 17 from Hyperion). We used linear models (LM) to evaluate how changes in ground observations of forest structure (biomass, leaf area index [LAI], and litter production) associated with fire were captured by the two VIs most sensitive to forest degradation. Our results indicate that the Plant Senescence Reflectance Index (PSRI) derived from Hyperion/EO-1 was the most sensitive to vegetation changes associated with forest fires, increasing by 94% in burned vs. unburned forests. Of the Landsat-derived VIs, we found that the Green-Red Normalized Difference (GRND) were the most sensitive to forest degradation by fire, showing a marked decline (87%) in the burned plots compared with the unburned Control. However, compared to PSRI, the GRND was a better predictor of changes associated with fire, both in the forest interior or forest edge, for the three ground variables: biomass stocks (r2 = 0.5–0.8), LAI (r2 = 0.8–0.9), and litter production (r2 = 0.4–0.7). This study demonstrate that VIs can detect forest responses to fire and other disturbances over time, highlighting the relative strengths of each VI. In doing so, it shows how the integration of multispectral and hyperspectral data can be useful for monitoring tropical forest degradation and recovery. Moreover, it provides valuable insights into the limitations of existing approaches, which can inform the design of next-generation sensors for global forest monitoring.

AI-based Validation of Deforestation Using High-Resolution Satellite Imagery in the Brazilian Amazon

Abstract. Forests play an important role in the Earth systems for carbon sequestration and climate change mitigation, yet they have been increasingly disturbed by deforestation and forest degradation at an unprecedented pace. The Brazilian Amazon, for instance, experienced a 140% rise in deforestation from 2012 to 2020, with a record loss of 13,200 km2 between August 2020 and July 2021. Alarmingly, 87% of 2019 deforestation alerts occurred on private properties, with 61% in legally restricted areas. Existing deforestation monitoring systems, such as PRODES and the Global Forest Change dataset, use about 30m resolution satellite imagery, which is insufficient for operational validation at fine scales. The Deforestation Alert System by Imazon leverages high-resolution PlanetScope data (3-4m) but faces challenges due to fewer spectral bands and variations in reflectance values across different satellite sensors and dates. As a result, current validation is based mainly on manual inspection which is highly time-consuming. To address the challenges and automate the validation process, this work develops a system based on deep learning – known for its ability to capture complex texture patterns in high-resolution images – to inspect and confirm new deforestation sites. Specifically, the system takes inputs from potential deforestation sites suggested by coarse-resolution products and uses a pair of PlanetScope images before and after the change at each site to determine new deforestation (excluding existing deforestation). Our results demonstrate that the new system achieves robust and high-quality accuracy under various test conditions.

Impacts of Participatory Forest Management on Land Use/Land Cover of Adaba-Dodola Forest in South Eastern Ethiopia and its Implication to REDD+ Implementation.

Despite various interventions to protect forests, many developing countries, including Ethiopia, continue to face substantial forest conservation challenges, particularly where local communities heavily rely on forests for their livelihoods. Recognizing the urgency of this issue, the government of Ethiopia introduced Participatory Forest Management (PFM) and devolved forest management responsibilities to enhance forest conservation. Therefore, this assessment examines the impacts of PFM on forest cover based on an analysis of the Land Use/Land Cover Change (LULCC) over the last 23 years in Adaba-Dodola, and its implications for REDD+ implementation. The study involved determining the LULCC of the Adaba-Dodola forest after the introduction of PFM from 2000 to 2023. Landsat images of 2000, 2012, and 2023 were analyzed to detect LULCC. The study result showed that the Adaba-Dodola forest cover increased by 1.83% since the PFM was introduced. The decreased agricultural land by 0.87% was the main factor attributed to the increase in shrub cover, while shrubland attributed to the rise in forest cover. Net areas of about 148 ha/year of shrublands were converted into forest land owing to significant forest regeneration, while shrublands had a net gain of 110.5 ha/year from agriculture and grasslands between 2000 and 2023. The increase in forest cover is attributed to the effectiveness of PFM in halting deforestation and promoting forest conservation. Thus, the PFM approach is a tool for preserving forest ecosystems and mitigating the adverse effects of deforestation and forest degradation, therefore would be used as an umbrella for implementing REDD+.

A Study on the Growth Model of Natural Forests in Southern China Under Climate Change: Application of Transition Matrix Model

This study establishes a climate-sensitive transition matrix growth model and predicts forest growth under different carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, and RCP8.5) over the next 40 years. Data from the Eighth (2013) and Ninth (2019) National Forest Resource Inventories in Chongqing and climate data from Climate AP are utilized. The model is used to predict forest growth and compare the number of trees, basal area, and stock volume under different climate scenarios. The results show that the climate-sensitive transition matrix growth model has high accuracy. The relationships between the variables and forest growth, mortality, and recruitment correspond to natural succession and growth. Although the number of trees, basal area, and stock volume do not differ significantly for different climate scenarios, the forest has sufficient seedling regeneration and large-diameter trees. The growth process aligns with succession, with pioneer species being replaced by climax species. The proposed climate-sensitive transition matrix growth model fills the gap in growth models for natural secondary forests in Chongqing and is an accurate method for predicting forest growth. The model can be used for long-term prediction of forest stands to understand future forest growth trends and provide reliable references for forest management. Forest growth can be predicted for different harvesting intensities to determine the optimal intensity to guide natural forest management in Chongqing City. The results of this study can help formulate targeted forest management policies to deal more effectively with climate change and promote sustainable forest health.

The Acoustic adaptation hypothesis does not support the occurrence of common songs in a neotropical urban bird species

ABSTRACT The Acoustic Adaptation Hypothesis indicates that vocalisations will have acoustic characteristics that maximise their transmission within the habitat where they are produced. Therefore, vocalisations of the same species are expected to vary between habitats if the habitats vary in structure. We conducted a sound transmission experiment to analyse if the common songs of the White-eared ground sparrow, Melozone leucotis, an urban bird species, differ between populations because they are adapted to the characteristics of each habitat to maximise their transmission. The experiment was conducted in four isolated populations within the urban areas of Costa Rica with different habitats: secondary forests, coffee plantations, gardens and thickets. In each population, we reproduced the three common songs of each population, and we compared four song degradation measures (excess attenuation, blur ratio, signal-to-noise ratio, and tail-to-signal ratio). Contrary to our expectations, our results contradicted the Acoustic Adaptation Hypothesis, since the common songs of each population did not transmit better in their own habitat, but the songs are adapted to transmit better in the original habitat. We suggest that common songs of this bird may be selected and maintained in each population by female selection.

Economic Valuation of Ecosystem Services of Coastal Area of Kinondoni District, Tanzania

This study investigates the often overlooked economic values of ecosystem services in the coastal area of Kinondoni District, Tanzania, in the context of spatial and temporal changes in land use and land cover (LULC). The primary objectives were to assess how ecosystem services and functions have been affected by LULC changes over a 30-year period, from 1993 to 2023. The study employs a benefit transfer method, integrating local and global estimations of ecosystem service value (ESV) with field survey, remote sensing and GIS techniques. The findings reveal that the annual changes in ESV during the study period are estimated at US$ 0.024 million and US$ 0.034 million using local and global coefficients, respectively. Over the three decades, there has been a significant annual loss of US$ 0.72 million locally and US$ 2.11 million globally, primarily due to the degradation of mangrove forests and bushland. The decline in ecosystem functions is largely driven by reductions in regulating services, which account for 54.1% of the total decrease in local valuations and 31.6% in global valuations. Supporting services also experienced substantial declines, with reductions of 39.7% in local valuations and 55.8% in global valuations. The study underscores the urgent need to review and enhance management and conservation strategies to ensure the sustainability of the coastal ecosystems in Kinondoni District, Tanzania.

How ambient temperature rise affects mercury dynamics and its pools in secondary forests

The forest ecosystem is a significant pool for capturing atmospheric mercury (Hg) deposition, with most Hg accumulating in forest soils. As secondary forests now dominate global forest cover, they are particularly sensitive to changes in ambient temperature. However, the impact of these changes on Hg dynamics in secondary forests remains poorly understood. Here, we quantified Hg inputs, outputs, and mass balances in two secondary forests in China, each with different ambient temperatures. We found that elevated ambient temperature (~1.0℃) advanced the germination of leaves by 2-3 days and extended the growing season by approximately one week, resulting in increased litterfall biomass by 1.18 Mg hm-2 yr-1 and a thicker litterfall layer by 0.22cm over 34 years. This temperature rise also facilitated Hg methylation within forest and enhanced methylmercury (MeHg) export, heightening the potential risk of MeHg exposure to surrounding ecosystems. Additionally, higher ambient temperature not only increased soil Hg emissions (2.75µgm-2 yr-1) but also led to significant Hg deposition via litterfall (9.26µgm-2 yr-1), resulting in a net annual Hg deposition of 6.88µgm-2 yr-1. This net Hg deposition accumulated in the topsoil, increasing the Hg pool by 0.51mgm-2 in organic and 0-10cm mineral soil horizons. Our findings suggest that even a ~1.0℃ temperature rise could enhance the role of secondary forests as atmospheric Hg sink by 45.10%. Therefore, the impact of ongoing climate warming on Hg cycling and pools in forests should receive increased attention and warrants further research.

Effectiveness, Efficiency, and Equity in Jurisdictional REDD+ Benefit Distribution Mechanisms: Insights from Jambi province, Indonesia

The jurisdictional REDD+ (JREDD+) mechanism, aimed at reducing emissions from deforestation and forest degradation, has been crucial in global climate change mitigation efforts. However, designing effective, efficient, and equitable benefit-distribution policy at the site level remains a challenge. This research assesses three benefit distribution mechanisms in Indonesia for JREDD+ initiatives, facilitated by the Indonesian Environment Fund (IEF). They include: (1) distribution through the provincial revenue and expenditure budget (APBD), (2) distribution through intermediary institutions (LEMTARA), and (3) direct distribution or transfer to beneficiaries. Each mechanism is evaluated on effectiveness, efficiency, and equity, considering bureaucratic processes and stakeholder capacities. The study utilizes public deliberation by involving relevant stakeholders at the national and Jambi province levels and expert judgment by purposively selecting based on certain criteria to help determine the optimal mechanism as the reference for achieving Indonesia's climate mitigation goals and the administrative intricacies involved. The findings suggest that direct distribution to beneficiaries is the most efficient and equitable, although using LEMTARA is deemed slightly more effective for targeted fund allocation. The study provides recommendations for policy makers on enhancing institutional capacities and integrating flexible inclusive mechanisms to optimize JREDD+ benefit distribution at the sub-national level.

Vegetation community recovery on restored bottomland hardwood forests in northeast Indiana, USA.

Vegetation communities in restored bottomland hardwood forests in northeast Indiana were studied 6-21 years after restoration to assess progress toward restoration objectives. The study focused on four sites that were restored to compensate for resource injuries after contaminant releases. The restored sites were compared with four reference-site conditions, including crops (prerestoration condition), old field communities representing a no-management alternative, locally sampled second-growth mature forests, and forest community types described by the US National Vegetation Classification (USNVC), which represent ideal or defining conditions of recognized vegetation communities. Fixed-area plots provided data on field-sampled environmental variables, vegetation, soil, and hydrological conditions for crops, old fields, restored areas, and mature forests. The USNVC database provided quantitative data for three historically and geographically relevant reference forest community types for comparison with the sampled communities. Results of nonmetric multidimensional scaling based on species cover revealed clear gradients relating to site age and canopy development. Along those gradients, restored areas demonstrated increasing similarity to mature forest reference communities in terms of floristic composition. Specifically, the floristic quality of restored areas was significantly greater than that of crops and old fields. Furthermore, soil health measurements of physical, chemical, and hydrological conditions indicated significant improvements in restored site soils compared with prerestoration conditions represented by cropland soils. Descriptions and data from the USNVC provided ecological context for restoration target conditions and facilitated the assessment of restoration recovery along a trajectory from starting conditions to those target conditions. Descriptions by USNVC also helped identify deviations from the intended restoration objectives (e.g., invasive species recruitment) and potential adaptive management actions to return sites to their intended trajectories. Integr Environ Assess Manag 2024;20:1917-1938. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Analyzing the impact of phosphorous and nitrogen on Castanopsis sclerophylla early growth stages

Plant growth elements, particularly nitrogen (N) and phosphorus (P) are vital for their growth and development, particularly for understory vegetation and their excess limits the net productivity of terrestrial ecosystems. This study focuses on the understory vegetation responds and adaptation to key essential nutrients under changing climate scenarios in subtropical evergreen broad-leaved forests, still needs research attention. this, we set up an experiment taking four treatments in a 50-year-old Castanopsis sclerophylla secondary forest under (a) control (CK), (b) N, (c) P, and (d) combined N and P addition, applied to natural forest regeneration seedlings of C. sclerophylla attained similar growth parameters of diameter of 3 cm and 10 cm height. In addition, carbon, N, P, and non-structural carbohydrates (NSC) were determined through the anthrone colorimetric approach in different parts of seedlings. Results show that the combined N + P application enhanced the N and P by 14.48 %−140.55 % in the seedlings in both dry and wet seasons, respectively. However, during wet season, the content of NSC in the plant leaves significantly exceeded under P addition. Remarkably, CK showed increased P in the growing season but lower during the dry season. Furthermore, the root starch content of seedlings showed a significant increase under the application of N and P compared to combined N + P, ranging between 45.60 % and 58.70 %. Overall, the plant growth is attributed to N and P intake. The nutrient addition and seasonal variations have a coupled effect on seedling growth as proved in the in the natural open forest experiment. The study outcomes emphasize that the alterations in NSC allocation in the roots and leaves of C. sclerophylla seedlings under N + P addition could enhance their adaptation to future global climate changes, drought conditions, and high N concentrations.

Content of Humus Compounds in Soils of Secondary Forests and Sub-Mediterranean Steppes of the Northwestern Caucasus (by the Example of the Gruzinka Ridge)

Content of Humus Compounds in Soils of Secondary Forests and Sub-Mediterranean Steppes of the Northwestern Caucasus (by the Example of the Gruzinka Ridge)

The challenges associated with firewood supply and analysis of fuel quality parameters of the tree species used as firewood in Rwanda

Firewood serves as an essential cooking energy source for households in Rwanda. However, the supply of firewood is hindered by various challenges, such as escalating scarcity, long distances traveled to collect firewood, and reliance on low-quality biomass during shortages. This study aimed to assess the challenges associated with firewood supply and analyze the fuel quality of tree species used as firewood in Rwanda, using systematic sampling with 504 and 368 farmers, respectively, in Bugesera and Musanze Districts. The results indicated that women and children are predominantly involved in firewood collection, with households traveling over 9 kilometers for firewood collection and spending 5 to 8 hours per collection session. Additionally, 42% and 43% of households in Bugesera and Musanze Districts gather firewood twice weekly. The most preferred species for firewood were Eucalypts spp, Senna spectabilis, Grevillea robusta, and Alunus acuminata due to their rapid drying, low smoke production, and efficient fuel qualities. The fuel quality analysis indicated that Eucalyptus spp., Grevillea robusta, Croton megalocarpus, Alnus acuminata, and Senna spectabilis exhibit a substantial promising bioenergy characteristic that points to their potential for sustainable energy production. The study advocates for strategically incorporating high fuel qualities, rapid growth, and regeneration of tree species into trees-based systems in the agricultural landscape to ensure a sustainable firewood supply while mitigating forest degradation.

The Role of Ngos in Localizing UN-REDD+ In Sulawesi Tengah, Indonesia

This study explores the role of national and local non-governmental organizations (NGOs) in localizing the UNREDD+ (Reducing Emissions from Deforestation and Forest Degradation) norm in Sulawesi Tengah, Indonesia. UN-REDD+ aims to mitigate climate change by promoting sustainable forest management in developing countries. Sulawesi Tengah was selected as a pilot province due to its extensive forest cover and relatively undisturbed deforestation activities. However, despite international support, the initiative encountered resistance from local communities, influenced by national and local NGOs. This research examines the complex interactions among international, national, and local NGOs by applying Acharya's norm localization theory. While international NGOs provided technical expertise, local NGOs significantly shaped the community perspective. These local NGOs raised concerns about the potential exploitation of forests and disruption to indigenous cultural values, fuelling opposition to the program. Consequently, the localization failed, and UN-REDD+ was discontinued in Sulawesi Tengah in 2012. The findings highlight the importance of considering local actors and their concerns in global environmental governance. Local NGOs, closely connected to communities, played a decisive role in rejecting the program, underscoring it, and addressing local values and governance issues.

Analysis of Land Use and Occupation in a Neighborhood of the City of Manaus-AM Using Geotechnologies

Objective: The objective of this study is to analyze the land use and occupation that occurred between 1999 and 2021 in the Tarumã neighborhood located in the city of Manaus-AM, with the aim of carrying out, through remote sensing techniques, the investigation of the environmental impacts that occurred, considering the classes of soil, vegetation and hydrography. Theoretical Framework: The accelerated population expansion and the lack of environmental planning contribute to the increasing degradation of natural resources. The disorderly distribution of the territory represents one of the main problems in Manaus. Method: Land use and occupation mapping was obtained from the supervised classification of Landsat 7 and Landsat 8 satellite images, RGB bands, through the United States Geological Survey – USGS (Earth Explore). Data comparisons were made based on the temporal analysis of the images and shapefile. Results and Discussion: The results obtained identified the class transformations that occurred in the last 22 years, which corresponds to 41.71% of primary vegetation, 8.98% of secondary vegetation, 17.70% of exposed soil. In the urban area, there was interference of 30.16%, with a 1.74% decrease in the water class, including the Environmental Preservation Area Research Implications: The practical and theoretical implications of this study favor the understanding, measurement and prediction of environmental impacts caused by the ordered and disordered urban occupation of cities. Originality/Value: This study contributes to the monitoring of occupations in the Tarumâ neighborhood, contributing to decision-making in preservation areas.

Congruent Long-Term Declines in Carbon and Biodiversity Are a Signature of Forest Degradation.

Recent global policy initiatives aimed at reducing forest degradation require practical definitions of degradation that are readily monitored. However, consistent approaches for monitoring forest degradation over the long term and at broad scales are lacking. We quantified the long-term effects of intensive wood harvest on above-ground carbon and biodiversity at fine resolutions (30 m2) and broad scales (New Brunswick, Canada; 72,908 km2). Model predictions for above-ground biomass were highly correlated with independent data (r = 0.77). After accounting for carbon stored in wood products, net CO2 emissions from forests for the region from 1985 to 2020 were 141 CO2e Tg (4.02 TgCO2e year-1; 32% of all reported emissions). We found strong positive correlations between locations with declines in above-ground carbon and habitats for old-forest bird species, which have lost > 20% habitat over 35 years. High congruence between biodiversity and forest carbon offers potential for policy incentives to conserve both objectives simultaneously and slow rates of forest degradation. These methods could be used to track forest degradation for managed forest regions worldwide.

An overview on the production, management and impact of microplastic contamination on marine species and marine environments: A review

The purpose of this paper is to review and evaluate published literature on the production, management and impact of microplastic contamination on marine species and marine environments. A systematic method was utilized to access research works of literature on “production, management and impact of microplastic contamination on marine species and marine environments”. A total of Sixty-two (62) research papers published between the years 1972 to 2022 was accumulated and used for this review. A subjective approach was used to select the topics: production, management and impact of microplastic contamination. In this paper, four (4) effects of microplastics on organisms and the environment was assessed. Additionally, the formation and classification of microplastics were evaluated. Subsequently, the paper delves into the production and the management of global plastic production as well as the sources of contamination. Further, this review assessed the quantity of microplastics in the gastrointestinal tract and edible muscles of various fish species. A mini checklist of sixty-one (61) fish species from thirty (30) families dwelling in nine (9) different marine habitats, all contaminated by microplastics was also presented in this review. Moreover, possible solutions to overcome the impact of microplastics on organisms and aquatic environments were also mentioned in this article. The published works of literature established that the global plastic production is constantly increasing with a growing world population thus leading to mismanagement of plastic resources and introducing them to the environment. Microplastics can cause serious complications in humans, marine organisms such as fishes, crustaceans, marine mammals and sea birds and even contribute to the degradation of mangrove forests and the coastal environment. This review highlights the fact that more extensive studies on the impact of microplastic contamination in organisms and the environment should be done in neotropical countries since there is a dearth and gaps of such information on research and published data in these biodiversity rich regions.

Soil Seed Banks Dynamics and Restoration Potential of Some Selected Forest Reserves in Southwest, Nigeria

This research investigated the regeneration potential of soil seed-bank along three soil depths in three secondary forest communities within Southwest Nigeria, for a better understanding of the potentials of the soil seed banks in facilitating succession towards a more natural forest of native tree species in International Institute of Tropical Agriculture (IITA) Forest Ibadan, Elephant Forest reserve Omo and Emerald Forest in Ikoyi Nigeria. Eight temporary plots of 20m by 40m using systematic line transect were laid in each forest. Soil samples were taken at three depths of 0–5 cm, 5–10 cm and 10–15cm and the seed bank composition was determined under a greenhouse condition. The results show that IITA forest has an abundance of 93 species with the highest in soil depth of 5-10 (35) and least exists at 10-15cm (24). The species evenness ranged from 0.92 to 0.96, with an average value of 0.94. Emerald forest had a total of 74 tree species with 0-5 cm depth having the highest species abundance (34), while depth of 5-10 cm (21) exhibit the least species abundance. At the forest, results of Species diversity indices show that at 0-5 cm depth 2.47 index value was recorded, a value much higher than what was recorded at 5-10 cm (2.40) and 10-15cm (2.36) respectively. The result of Elephant Forest reserve shows that a total of 87 tree species were recorded with 0-5 cm depth having the highest species abundance (40) followed by 5-10 cm (27), 10-15 (26) respectively. The Shannon Wiener index for Elephant Forest shows that 2.28 were recorded at 0-5 cm depth, 1.40 at 5-10 cm depth, and 1.70 at 10-15cm depth respectively. The soil seed bank could help in determining the status of regeneration potential of the three forests investigated. However, high dominance of tree species in the soil seed banks implies that the forest is disturbed and there is likelihood of tree species succeeding and dominating the forest ecosystem.

Fiber morphological characteristics of bamboo Ferrocalamus strictus culms from different geographical distribution regions

The fiber index including fiber length, width, wall thickness and lumen diameter of Ferrocalamus strictus culms (1, 2, and ≥ 3 years) from Jinping, Mojiang and Lvchun counties of Yunnan Province was determined and the elemental content of the soil was also determined to analyze the fiber characteristics. The average relative fiber index measured for F. strictus culms were fiber length (1.30 mm), width (21.57 μm), slenderness ratio (60.79 μm), wall thickness (4.21 μm), lumen diameter (7.22 μm), and runkel ratio (1.22 μm), which belonged to the range of middle and long fibers. The fiber length increased with the culm age. The proportion of long fiber increased while short fibers decreased along with culm maturing. The fiber morphology did not show a specific trend with the culm height. Fiber length reached the maximum in the bottom portions of the culms. There is a correlation between fiber morphology and soil elements, the content of organic matter, total potassium, total sulfur, total aluminum, total zinc, total iron, total boron, alkali-hydrolyzed nitrogen and available silicon in the soil affects fiber morphology. The content of organic matter, total boron and alkali-hydrolyzed nitrogen in the soil from Mojiang County was largest. Comparatively, the culm fiber in Mojiang County had the best fiber index performance for utilization, since the greatest proportion of medium and long fibers and the optimal distribution of fiber length frequency was obtained from the culms in Mojiang County. This study can provide a theoretical basis for large-scale bamboo forest cultivation and the development and utilization of bamboo culm fiber.

Landscape-level analysis of disturbance regimes in Chinnar Wildlife Sanctuary, a protected area of Western Ghats, India

ABSTRACT The degradation, fragmentation, and depletion of forests have occurred all over the world, simultaneously, with the exponential growth of the human population. The present study assesses the forest disturbance regime of Chinnar Wildlife Sanctuary (CWS), an ecologically significant biodiversity hotspot of Western Ghats (WG) through satellite image-based forest and land cover mapping and landscape metric analysis. The on-screen analysis based on field knowledge, facilitated, mapping of seven types of vegetation cover. The majority of forest area was covered by dry deciduous forest (39.2 km2 or 43.15%), whereas the minimum area was covered by disturbed forest (2.05 km2 or 2.26%). The disturbance index (DI) was calculated by linearly combining the land use land cover (LULC), road and settlement closeness, fire risk, porosity, patchiness interspersion, normalized difference vegetation index (NDVI), and fragmentation through a probabilistic weight-based linear additive model. The values of the DI (120–310) reclassified into four classes viz. low, moderate, high, and very high. The results revealed that 74.62 km2 (82.52%) of the forest area has low to moderate disturbance, while the rest of the forest area that is 15.8 km2 (17.48%) has high to very high disturbance. These analyses are based on remote sensing and GIS crucial for forest conservation and management strategies formulation.

Protective role of reactive aluminum phases to stabilize soil organic matter against long-term cultivation in the humid tropics under volcanic influence

ABSTRACT Cultivation can cause rapid depletion of soil organic matter (SOM), particularly in the humid tropics. Understanding the factors controlling SOM storage is a key step toward effective soil management for sustainable crop production. While clay + silt content is known to be an important factor for soil organic carbon (SOC) storage, recent studies have shown greater importance of oxalate-extracted Al (Alo; roughly corresponds to short-range-order aluminosilicate minerals and organo-Al complexes) and Fe (Feo). However, the extent to which these mineralogical factors control the response of SOM pool to land-use changes remains unclear, especially in the tropics. This study aimed to clarify the factors regulating SOM content in croplands compared to secondary forests or home gardens in Negros Occidental, Philippines. Along two line transects having a wide range of Alo contents, soil samples were collected at a depth of 0 − 10 cm from sugarcane sites (n = 33; long-term continuous cultivation of >70 years) that were paired with either secondary forests (n = 10) or home gardens (n = 20). Sugarcane sites had significantly lower SOC and total nitrogen (N) contents than secondary forest and home garden sites, whereas there was no clear difference between the latter two land uses. Both SOC and total N contents showed significant positive correlations with Alo content and, to a much less extent, with Feo content, but not with clay + silt content. The slope of the regression line between SOC and Alo was indifferent between sugarcane and the other two land uses, while the intercept was significantly lower in the sugarcane sites. These results suggest the protective role of Alo phases in both agricultural and forest soils and the presence of unprotected SOM (e.g. plant litter) in the latter sites. Furthermore, δ13C analysis suggested that the proportion of forest (C3 plant) derived carbon remaining in the sugarcane soils ranged between 10% and 50% and increased with Alo content. Together, our study showed indirect evidence of Alo-induced stabilization of SOM against long-term cultivation under the humid tropical environment.