Journal articles on the topic 'Lao tropical forests'
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Phompila, Chittana, Megan Lewis, Kenneth Clarke, and Bertram Ostendorf. "Monitoring temporal Vegetation changes in Lao tropical forests." IOP Conference Series: Earth and Environmental Science 20 (June 23, 2014): 012054. http://dx.doi.org/10.1088/1755-1315/20/1/012054.
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Phompila, Chittana, Megan Lewis, Kenneth Clarke, and Bertram Ostendorf. "Applying the Global Disturbance Index for Detecting Vegetation Changes in Lao Tropical Forests." Advances in Remote Sensing 04, no. 01 (2015): 73–82. http://dx.doi.org/10.4236/ars.2015.41007.
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Parache, Helen Blue, Timothy Mayer, Kelsey E. Herndon, Africa Ixmucane Flores-Anderson, Yang Lei, Quyen Nguyen, Thannarot Kunlamai, and Robert Griffin. "Estimating Forest Stand Height in Savannakhet, Lao PDR Using InSAR and Backscatter Methods with L-Band SAR Data." Remote Sensing 13, no. 22 (November 10, 2021): 4516. http://dx.doi.org/10.3390/rs13224516.
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Forest stand height (FSH), or average canopy height, serves as an important indicator for forest monitoring. The information provided about above-ground biomass for greenhouse gas emissions reporting and estimating carbon storage is relevant for reporting for Reducing Emissions from Deforestation and Forest Degradation (REDD+). A novel forest height estimation method utilizing a fusion of backscatter and Interferometric Synthetic Aperture Radar (InSAR) data from JAXA’s Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) is applied to a use case in Savannakhet, Lao. Compared with LiDAR, the estimated height from the fusion method had an RMSE of 4.90 m and an R2 of 0.26. These results are comparable to previous studies using SAR estimation techniques. Despite limitations of data quality and quantity, the Savannakhet, Lao use case demonstrates the applicability of these techniques utilizing L-band SAR data for estimating FSH in tropical forests and can be used as a springboard for use of L-band data from the future NASA-ISRO SAR (NISAR) mission.
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Phompila, Chittana, Megan Lewis, Bertram Ostendorf, and Kenneth Clarke. "Forest Cover Changes in Lao Tropical Forests: Physical and Socio-Economic Factors are the Most Important Drivers." Land 6, no. 2 (March 28, 2017): 23. http://dx.doi.org/10.3390/land6020023.
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Ahumada, Jorge A., Carlos E. F. Silva, Krisna Gajapersad, Chris Hallam, Johanna Hurtado, Emanuel Martin, Alex McWilliam, et al. "Community structure and diversity of tropical forest mammals: data from a global camera trap network." Philosophical Transactions of the Royal Society B: Biological Sciences 366, no. 1578 (September 27, 2011): 2703–11. http://dx.doi.org/10.1098/rstb.2011.0115.
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Terrestrial mammals are a key component of tropical forest communities as indicators of ecosystem health and providers of important ecosystem services. However, there is little quantitative information about how they change with local, regional and global threats. In this paper, the first standardized pantropical forest terrestrial mammal community study, we examine several aspects of terrestrial mammal species and community diversity (species richness, species diversity, evenness, dominance, functional diversity and community structure) at seven sites around the globe using a single standardized camera trapping methodology approach. The sites—located in Uganda, Tanzania, Indonesia, Lao PDR, Suriname, Brazil and Costa Rica—are surrounded by different landscape configurations, from continuous forests to highly fragmented forests. We obtained more than 51 000 images and detected 105 species of mammals with a total sampling effort of 12 687 camera trap days. We find that mammal communities from highly fragmented sites have lower species richness, species diversity, functional diversity and higher dominance when compared with sites in partially fragmented and continuous forest. We emphasize the importance of standardized camera trapping approaches for obtaining baselines for monitoring forest mammal communities so as to adequately understand the effect of global, regional and local threats and appropriately inform conservation actions.
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Hiltner, Ulrike, Andreas Huth, and Rico Fischer. "Importance of the forest state in estimating biomass losses from tropical forests: combining dynamic forest models and remote sensing." Biogeosciences 19, no. 7 (April 5, 2022): 1891–911. http://dx.doi.org/10.5194/bg-19-1891-2022.
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Abstract. Disturbances, such as extreme weather events, fires, floods, and biotic agents, can have strong impacts on the dynamics and structures of tropical forests. In the future, the intensity of disturbances will likely further increase, which may have more serious consequences for tropical forests than those we have already observed. Thus, quantifying aboveground biomass loss of forest stands due to stem mortality (hereafter biomass loss rate) is important for the estimation of the role of tropical forests in the global carbon cycle. So far, the long-term impacts of altered stem mortality on rates of biomass loss have not been adequately described. This study aims to analyse the consequences of long-term elevated stem mortality rates on forest dynamics and biomass loss rate. We applied an individual-based forest model and investigated the impacts of permanently increased stem mortality rates on the growth dynamics of humid, terra firme forests in French Guiana. Here, we focused on biomass, leaf area index (LAI), forest height, productivity, forest age, quadratic mean stem diameter, and biomass loss rate. Based on the simulation data, we developed a multiple linear regression model to estimate biomass loss rates of forests in different successional states from the various forest attributes. The findings of our simulation study indicated that increased stem mortality altered the succession patterns of forests in favour of fast-growing species, which increased the old-growth forests' gross primary production, though net primary production remained stable. The stem mortality rate had a strong influence on the functional species composition and tree size distribution, which led to lower values in LAI, biomass, and forest height at the ecosystem level. We observed a strong influence of a change in stem mortality on biomass loss rate. Assuming a doubling of stem mortality rate, the biomass loss rate increased from 3.2 % yr−1 to 4.5 % yr−1 at equilibrium. We also obtained a multidimensional relationship that allowed for the estimation of biomass loss rates from forest height and LAI. Via an example, we applied this relationship to remote sensing data on LAI and forest height to map biomass loss rates for French Guiana. We estimated a countrywide mean biomass loss rate of 3.0 % yr−1. The approach described here provides a novel methodology for quantifying biomass loss rates, taking the successional state of tropical forests into account. Quantifying biomass loss rates may help to reduce uncertainties in the analysis of the global carbon cycle.
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Calvo-Rodriguez, S., and G. A. Sanchez-Azofeifa. "LIGHT DIFFUSION IN THE TROPICAL DRY FOREST OF COSTA RICA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 579–83. http://dx.doi.org/10.5194/isprs-archives-xli-b8-579-2016.
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Leaf Area Index (LAI) has been defined as the total leaf area (one-sided) in relation to the ground. LAI has an impact on tree growth and recruitment through the interception of light, which in turn affects primary productivity. Even though many instruments exist for estimating LAI from ground, they are often laborious and costly to run continuously. Measurements of LAI from the field using traditional sensors (e.g., LAI-2000) require multiple visits to the field under very specific sky conditions, making them unsuitable to operate in inaccessible areas and forests with dense vegetation, as well as areas where persistent sunny conditions are the norm like tropical dry forests. With this context, we proposed a methodology to characterize light diffusion based on NDVI and LAI measurements taken from the field in two successional stages in the tropical dry forest of Santa Rosa National Park in Costa Rica. We estimate a "K" coefficient to characterize light diffusion by the canopy, based on field NDVI measurements derived from optical phenology instruments and MODIS NDVI. From the coefficients determined, we estimated LAI values and compared them with ground measurements of LAI. In both successional stages ground measurements of LAI had no significant difference to the tower-derived LAI and the estimated LAI from MODIS NDVI.
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Calvo-Rodriguez, S., and G. A. Sanchez-Azofeifa. "LIGHT DIFFUSION IN THE TROPICAL DRY FOREST OF COSTA RICA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 579–83. http://dx.doi.org/10.5194/isprsarchives-xli-b8-579-2016.
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Leaf Area Index (LAI) has been defined as the total leaf area (one-sided) in relation to the ground. LAI has an impact on tree growth and recruitment through the interception of light, which in turn affects primary productivity. Even though many instruments exist for estimating LAI from ground, they are often laborious and costly to run continuously. Measurements of LAI from the field using traditional sensors (e.g., LAI-2000) require multiple visits to the field under very specific sky conditions, making them unsuitable to operate in inaccessible areas and forests with dense vegetation, as well as areas where persistent sunny conditions are the norm like tropical dry forests. With this context, we proposed a methodology to characterize light diffusion based on NDVI and LAI measurements taken from the field in two successional stages in the tropical dry forest of Santa Rosa National Park in Costa Rica. We estimate a "K" coefficient to characterize light diffusion by the canopy, based on field NDVI measurements derived from optical phenology instruments and MODIS NDVI. From the coefficients determined, we estimated LAI values and compared them with ground measurements of LAI. In both successional stages ground measurements of LAI had no significant difference to the tower-derived LAI and the estimated LAI from MODIS NDVI.
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Kuusipalo, Jussi, Jyrki Kangas, and Lauri Vesa. "Sustainable Forest Management in Tropical Rain Forests." Journal of Sustainable Forestry 5, no. 3-4 (April 10, 1997): 93–118. http://dx.doi.org/10.1300/j091v05n03_06.
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PRASAD, AYESHA E. "Tree community change in a tropical dry forest: the role of roads and exotic plant invasion." Environmental Conservation 36, no. 3 (September 2009): 201–7. http://dx.doi.org/10.1017/s0376892909990257.
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SUMMARYAmong the most endangered tropical ecosystems, tropical dry forests are threatened by degradation that includes edge effects arising from perturbations such as the creation and maintenance of roads and other clearings. While much is known about these adverse effects on tree communities in tropical moist forests, similar effects in tropical dry forests are little understood. This paper examines the relationship between roads, road-related exotic plant invasion and tree community change in a tropical dry forest in southern India. Forty pairs of roadside and interior plots across four factorial combinations of road width (wide and narrow) and understorey type (native and exotic) were sampled. Tree death and extant tree community composition were compared using generalized linear models and similarity analyses. Tree death near roads was more than double that away from them, suggesting that roads may increase tree death in these forests. The interactive effect of understorey type (exotic or native) and road width on tree death was significant, with highest tree death near wide roads bordered by exotic understorey. Conversely, tree community composition was influenced by road width and understorey type, but not by proximity to roads. Creation and maintenance of roads for forest management may have serious implications for tree communities in tropical dry forests and should thus be minimized. Exotic plants may also be important contributors to increasing tree death, and further research on their impacts, particularly into underlying mechanisms, is critical to the long-term conservation of tropical dry forest communities.
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Liang, Boyi, Hongyan Liu, Xiaoqiu Chen, Xinrong Zhu, Elizabeth L. Cressey, and Timothy A. Quine. "Periodic Relations between Terrestrial Vegetation and Climate Factors across the Globe." Remote Sensing 12, no. 11 (June 3, 2020): 1805. http://dx.doi.org/10.3390/rs12111805.
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In this paper, cross-spectrum analysis was used to verify the agreement of periodicity between the global LAI (leaf area index) and climate factors. The results demonstrated that the LAI of deciduous forests and permanent wetlands have high agreement with temperature, rainfall and radiation over annual cycles. A low agreement between the LAI and seasonal climate variables was observed for some of the temperate and tropical vegetation types including shrublands and evergreen broadleaf forests, possibly due to the diversity of vegetation and human activities. Across all vegetation types, the LAI demonstrated a large time lag following variation in radiation (>1 month), whereas relatively short lag periods were observed between the LAI and annual temperature (around 2 weeks)/rainfall patterns (less than 10 days), suggesting that the impact of radiation on global vegetation growth is relatively slow, which is in accord with the results of previous studies. This work can provide a benchmark of the phenological drivers in global vegetation, from the perspective of periodicity, as well as helping to parameterize and refine the DGVMs (Dynamic Global Vegetation Models) for different vegetation types.
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Li, Chenyun, Yanfeng Zheng, Xinjie Zhang, Fayun Wu, Linyuan Li, and Jingyi Jiang. "Comparison of Canopy Cover and Leaf Area Index Estimation from Airborne LiDAR and Digital Aerial Photogrammetry in Tropical Forests." Applied Sciences 12, no. 19 (September 30, 2022): 9882. http://dx.doi.org/10.3390/app12199882.
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Digital aerial photogrammetry (DAP) has emerged as an alternative to airborne laser scanning (ALS) for forest inventory applications, as it offers a low-cost and flexible three-dimensional (3D) point cloud. Unlike the forest inventory attributes (e.g., tree height and diameter at breast height), the relative ability of DAP and ALS in predicting canopy structural variables (i.e., canopy cover and leaf area index (LAI)) has not been sufficiently investigated by previous studies. In this study, we comprehensively compared the canopy cover and LAI estimates using DAP- and ALS-based methods over 166 selected tropical forest sample plots with seven different tree species and forest types. We also explored the relationship between field-measured aboveground biomass (AGB) and the LAI estimates. The airborne LAI estimates were subsequently compared with the Sentinel-2-based LAI values that were retrieved using a one-dimensional radiative transfer model. The results demonstrated that the DAP-based method generally overestimated the two canopy variables compared to ALS-based methods but with relatively high correlations regardless of forest type and species (R2 of 0.80 for canopy cover and R2 of 0.76 for LAI). Under different forest types and species, the R2 of canopy cover and LAI range from 0.64 to 0.89 and from 0.54 to 0.87, respectively. Apparently, different correlations between AGB and LAI were found for different forest types and species where the mixed coniferous and broad-leaved forest shows the best correlation with R2 larger than 0.70 for both methods. The comparison with satellite retrievals verified that the ALS-based estimates are more consistent with Sentinel-2-based estimates than DAP-based estimates. We concluded that DAP data failed to provide analogous results to ALS data for canopy variable estimation in tropical forests.
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Wagner, F., V. Rossi, C. Stahl, D. Bonal, and B. Hérault. "Asynchronism in leaf and wood production in tropical forests: a study combining satellite and ground-based measurements." Biogeosciences 10, no. 11 (November 14, 2013): 7307–21. http://dx.doi.org/10.5194/bg-10-7307-2013.
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Abstract. The fixation of carbon in tropical forests mainly occurs through the production of wood and leaves, both being the principal components of net primary production. Currently field and satellite observations are independently used to describe the forest carbon cycle, but the link between satellite-derived forest phenology and field-derived forest productivity remains opaque. We used a unique combination of a MODIS enhanced vegetation index (EVI) dataset, a wood production model based on climate data and direct litterfall observations at an intra-annual timescale in order to question the synchronism of leaf and wood production in tropical forests. Even though leaf and wood biomass fluxes had the same range (respectively 2.4 ± 1.4 and 2.2 ± 0.4 Mg C ha−1 yr−1), they occurred separately in time. EVI increased with leaf renewal at the beginning of the dry season, when solar irradiance was at its maximum. At this time, wood production stopped. At the onset of the rainy season, when new leaves were fully mature and water available again, wood production quickly increased to reach its maximum in less than a month, reflecting a change in carbon allocation from short-lived pools (leaves) to long-lived pools (wood). The time lag between peaks of EVI and wood production (109 days) revealed a substantial decoupling between the leaf renewal assumed to be driven by irradiance and the water-driven wood production. Our work is a first attempt to link EVI data, wood production and leaf phenology at a seasonal timescale in a tropical evergreen rainforest and pave the way to develop more sophisticated global carbon cycle models in tropical forests.
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Wagner, F., V. Rossi, C. Stahl, D. Bonal, and B. Hérault. "Asynchronism in leaf and wood production in tropical forests: a study combining satellite and ground-based measurements." Biogeosciences Discussions 10, no. 5 (May 16, 2013): 8247–81. http://dx.doi.org/10.5194/bgd-10-8247-2013.
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Abstract. The fixation of carbon in tropical forests mainly occurs through the production of wood and leaves, both being the principal components of net primary production. Currently field and satellite observations are independently used to describe the forest carbon cycle, but the link between satellite-derived forest phenology and field-derived forest productivity remains opaque. We used a unique combination of a MODIS EVI dataset, a climate-explicit wood production model and direct litterfall observations at an intra-annual time scale in order to question the synchronism of leaf and wood production in tropical forests. Even though leaf and wood biomass fluxes had the same range (respectively 2.4 ± 1.4 Mg C ha−1yr−1 and 2.2 ± 0.4 Mg C ha−1yr−1), they occured separately in time. EVI increased with the magnitude of leaf renewal at the beginning of the dry season when solar irradiance was at its maximum. At this time, wood production stopped. At the onset of the rainy season when new leaves were fully mature and water available again, wood production quickly increased to reach its maximum in less than a month, reflecting a change in carbon allocation from short lived pools (leaves) to long lived pools (wood). The time lag between peaks of EVI and wood production (109 days) revealed a substantial decoupling between the irradiance-driven leaf renewal and the water-driven wood production. Our work is a first attempt to link EVI data, wood production and leaf phenology at a seasonal time scale in a tropical evergreen rainforest and pave the way to develop more sophisticated global carbon cycle models in tropical forests.
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Truong, Nguyen Cung Que, Dao Nguyen Khoi, Hong Quan Nguyen, and Akihiko Kondoh. "Impact of Forest Conversion to Agriculture on Hydrologic Regime in the Large Basin in Vietnam." Water 14, no. 6 (March 9, 2022): 854. http://dx.doi.org/10.3390/w14060854.
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Deforestation due to agricultural land expansion occurred greatly during 1994 to 2005 with a high proportion of forests being converted into agriculture in the upstream Dong Nai river basin in Vietnam. Most of these conversions included expansions of coffee plantations in Dak Lak and Lam Dong provinces, which are in the world’s Robusta coffee production area. The aim of this study is to quantify the impact on the water cycle due to the conversion of forest to coffee plantations in a tropical humid climate region by the application of a hydrological model: soil and water assessment tool (SWAT). The model was calibrated with climate data from 1980–1994, validated with climate data from 1995–2010, and verified with statistical indicators such as Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), and ratio of the root mean square error (RSR). The simulations indicated that forest conversions into agriculture (expansion of coffee plantations) had significantly increased surface runoff (SUR) while actual evapotranspiration (ET), soil water content (SW), and groundwater discharge (GW) decreased. These changes are mainly related to the decrease in infiltration and leaf area index (LAI) post land cover changes. However, the soil was not thoroughly destroyed after deforestation due to the replacement of the lost forest with crops and vegetation. Therefore, changes in infiltration were marginal and not sufficient to bring large changes in the annual flow. Higher reductions in ET and SW were proposed, resulting in reduced streamflow in the dry season at the basin where the proportion of agricultural land was higher than the forest cover. Besides the plantation expansion, which resulted in streamflow reductions in the dry season, an existing problem was over-irrigation of coffee plantations that could likely deplete groundwater resources. Hence, balancing economic benefits by coffee production and mitigating groundwater depletion issues should be prioritized for land use management in the study area.
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Clark, David B., Steven F. Oberbauer, Deborah A. Clark, Michael G. Ryan, and Ralph O. Dubayah. "Physical structure and biological composition of canopies in tropical secondary and old-growth forests." PLOS ONE 16, no. 8 (August 20, 2021): e0256571. http://dx.doi.org/10.1371/journal.pone.0256571.
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The area of tropical secondary forests is increasing rapidly, but data on the physical and biological structure of the canopies of these forests are limited. To obtain such data and to measure the ontogeny of canopy structure during tropical rainforest succession, we studied patch-scale (5 m2) canopy structure in three areas of 18–36 year-old secondary forest in Costa Rica, and compared the results to data from old-growth forest at the same site. All stands were sampled with a stratified random design with complete harvest from ground level to the top of the canopy from a modular portable tower. All canopies were organized into distinct high- and low-leaf-density layers (strata), and multiple strata developed quickly with increasing patch height. The relation of total Leaf Area Index (LAI, leaf area per area of ground) to patch canopy height, the existence of distinct high and low leaf- density layers (strata and free air spaces), the depth and LAI of the canopy strata and free air spaces, and the relation of the number of strata to patch canopy height were remarkably constant across the entire successional gradient. Trees were the most important contributor to LAI at all stages, while contribution of palm LAI increased through succession. We hypothesize that canopy physical structure at the patch scale is driven by light competition and discuss how this hypothesis could be tested. That canopy physical structure was relatively independent of the identity of the species present suggests that canopy physical structure may be conserved even as canopy floristics shift due to changing climate.
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Thakur, T. K. "Analysis of carbon and nutrient storage of dry tropical forest of chhattisgarh using satellite data." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (November 28, 2014): 659–65. http://dx.doi.org/10.5194/isprsarchives-xl-8-659-2014.
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The purpose of this study was to characterize the carbon, nitrogen, phosphorus and potassium in the Barnowpara Sanctuary, Raipur district, Chhattisgarh, India through the use of satellite remote sensing and GIS The total storage of nutrients in vegetation (OS + US + GS) varied from 105.1 to 560.69 kg ha<sup>−1</sup> in N, 4.09 kg ha<sup>−1</sup> to 49.59 kg ha<sup>−1</sup> in P, 24.59 kg ha<sup>−1</sup> to 255.58 kg ha<sup>−1</sup> for K and 7310 to 4836 kg ha<sup>−1</sup> for C in different forest types. They were highest in Dense mixed forest and lowest in Degraded mixed forest. The study also showed that NDVI and carbon storage was strongly correlated to Shannon Index and species richness thus it indicates that the diversity of forest type play a vital role in carbon accumulation. The study also developed reliable regression model for the estimation of LAI, biomass, NPP, C & N storage in dry tropical forests by using NDVI and different vegetation indices, which can be derived from fine resolution satellite data. The study shows that dry tropical forests of Central India are quite immature and not in standing state and have strong potential for carbon sequestration. Both quantitative and qualitative information derived in the study helped in evolving key strategies for maintaining existing C pools and also improving the C sequestration in different forest types. The study explores the scope and potential of dry tropical forests for improving C sequestration and mitigating the global warming and climatic change.
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Almeida, Danilo Roberti Alves de, Scott C. Stark, Gang Shao, Juliana Schietti, Bruce Walker Nelson, Carlos Alberto Silva, Eric Bastos Gorgens, Ruben Valbuena, Daniel de Almeida Papa, and Pedro Henrique Santin Brancalion. "Optimizing the Remote Detection of Tropical Rainforest Structure with Airborne Lidar: Leaf Area Profile Sensitivity to Pulse Density and Spatial Sampling." Remote Sensing 11, no. 1 (January 7, 2019): 92. http://dx.doi.org/10.3390/rs11010092.
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Airborne Laser Scanning (ALS) has been considered as a primary source to model the structure and function of a forest canopy through the indicators leaf area index (LAI) and vertical canopy profiles of leaf area density (LAD). However, little is known about the effects of the laser pulse density and the grain size (horizontal binning resolution) of the laser point cloud on the estimation of LAD profiles and their associated LAIs. Our objective was to determine the optimal values for reliable and stable estimates of LAD profiles from ALS data obtained over a dense tropical forest. Profiles were compared using three methods: Destructive field sampling, Portable Canopy profiling Lidar (PCL) and ALS. Stable LAD profiles from ALS, concordant with the other two analytical methods, were obtained when the grain size was less than 10 m and pulse density was high (>15 pulses m−2). Lower pulse densities also provided stable and reliable LAD profiles when using an appropriate adjustment (coefficient K). We also discuss how LAD profiles might be corrected throughout the landscape when using ALS surveys of lower density, by calibrating with LAI measurements in the field or from PCL. Appropriate choices of grain size, pulse density and K provide reliable estimates of LAD and associated tree plot demography and biomass in dense forest ecosystems.
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Fownes, James H., Robin A. Harrington, and Darrell A. Herbert. "673 Resistance and Resilience of Native Forests to Disturbance by Hurricane Iniki." HortScience 34, no. 3 (June 1999): 564C—564. http://dx.doi.org/10.21273/hortsci.34.3.564c.
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Two studies were established in upland native forest of northwestern Kauai before Hurricane Iniki (Sept. 1992). One study was a gradient study in Acacia koa forest in the leeward rain shadow and the second study was a replicated fertilization experiment in mesic Metrosideros polymorpha forest. Both studies escaped devastation by high-intensity microbursts. Removal of LAI (from 3% to 80%) was proportional to pre-hurricane LAI, suggesting that resistance to damage was higher in low LAI, low-productivity sites. LAI recovered to prehurricane levels within 2 years, except in plots with major limb and stem loss. In the Acacia forest, damage to overstory trees was less than to understory trees, whereas in Metrosideros forest, larger trees were more damaged than smaller trees. During 2 years of recovery, both forests lost LAI in winter storms nearly equivalent to the hurricane damage. Disturbance is more frequent than previously known, which suggests that chronic disturbance needs to be better understood as a force regulating ecosystem structure and function. In both studies, the relative rate of recovery was faster in the more productive but more disturbed plots, suggesting that ecosystem resistance and resilience were traded off. These results have application to land use planning, agroforestry systems management, and other perennial crop management decisions following damage by a tropical cyclone.
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Zhu, Qi, Huadong Guo, Lu Zhang, Dong Liang, Xvting Liu, Xiangxing Wan, and Jinlong Liu. "Tropical Forests Classification Based on Weighted Separation Index from Multi-Temporal Sentinel-2 Images in Hainan Island." Sustainability 13, no. 23 (December 2, 2021): 13348. http://dx.doi.org/10.3390/su132313348.
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Tropical forests play a vital role in biodiversity conservation and the maintenance of sustainability. Although different time-series spatial resolution satellite images have provided opportunities for tropical forests classification, the complexity and diversity of vegetation types still pose challenges, especially for distinguishing different vegetation types. In this paper, we proposed a Spectro-Temporal Feature Selection (STFS) method based on the Weighted Separation Index (WSI) using multi-temporal Sentinel-2 data for mapping tropical forests in Jianfengling area, Hainan Province. The results showed that the tropical forests were classified with an overall accuracy of 93% and an F1 measure of 0.92 with multi-temporal Sentinel-2 data. As our results also revealed, the WSI based STFS method could be efficient in tropical forests classification by using a fewer feature subset compared with Variable Selection Using Random Forest (14 features and all 40 features, respectively) to achieve the same accuracy. The analysis also showed it was not advisable to only pursue a higher WSI value while ignoring the heterogeneity and diversity of features. This study demonstrated that the WSI can provide a new feature selection method for multi-temporal remote sensing image classification.
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Kelley, G., A. P. O'Grady, L. B. Hutley, and D. Eamus. "A comparison of tree water use in two contiguous vegetation communities of the seasonally dry tropics of northern Australia: the importance of site water budget to tree hydraulics." Australian Journal of Botany 55, no. 7 (2007): 700. http://dx.doi.org/10.1071/bt07021.
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Tree water use in two contiguous communities (eucalypt open-forest and Melaleuca paperbark forest) was measured in tropical Australia, over a 2-year period. The aims of the study were to (1) quantify daily and seasonal patterns of water use in each community, (2) compare patterns of water use among the communities and (3) compare relationships among tree size, sapwood area and water use within the two contrasting vegetation communities. Access to deep soil water stores and the effect of run-on from the eucalypt forest resulted in a relatively high pre-dawn water potential throughout the year, particularly for Melaleuca forest. There were no differences in daily rates of water use, expressed on a sapwood area (Q s) basis, between the two eucalypt species examined (Eucalyptus miniata Cunn. Ex Schauer and E. tetrodonta F.Muell) at any time in the eucalypt forest. For both the eucalypt and Melaleuca forests, there was less seasonal variation in water use expressed on a leaf area (Q l) basis than on a Q s basis, and neither year nor season were significant factors in Q l. In the mono-specific Melaleuca forest, Q s was not significantly different between years or seasons. Water use on a Q l basis was similarly not significantly different between years or seasons in the Melaleuca forest. Leaf area index (LAI) of the eucalypt forest was about half of that of the Melaleuca forest throughout the year but sapwood area per hectare was 33% larger in the eucalypt than the Melaleuca forest, despite the basal area of the Melaeuca forest being almost double that of the eucalypt forest. There was no significant difference in stand water use (mm day–1) between eucalypt and Melaleuca forests during 1998; however, in 1999 Melaleuca stand water use was larger than that of the eucalypt forest. Because of the enhanced dry-season availability of water in the Melaleuca forest and its larger LAI, average annual water use of the Melaleuca forest was almost 60% larger than that of the eucalypt forest. Despite differences in Q l, Q s and annual water use between forests, the ratio of LAI to stand water use was similar for all seasons in both forests. The applicability of ‘universal rules’ linking tree water use and tree hydraulics and the importance of ecosystem location on site water budgets and plant adaptations are discussed.
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Downton, Mary W. "Measuring Tropical Deforestation: Development of the Methods." Environmental Conservation 22, no. 3 (1995): 229–40. http://dx.doi.org/10.1017/s0376892900010638.
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Estimates of the rate and extent of tropical deforestation differ widely. The accuracy of the estimates for many countries has improved greatly during the last decade, especially with increased use of satellite data and advancements in analysis techniques. A good basis for ongoing global monitoring of tropical forests has been established by the FAO in its Forest Resources Assessment for 1990 (though data for some countries are still inadequate). The FAO assessment estimates that over one million km2 of the Earth's tropical rain-forest and moist deciduous forest was destroyed during 1981–90, representing an annual deforestation rate of 0.75% of such forests throughout the decade.This paper traces the controversy over measurements of deforestation in Brazil's Legal Amazon and the resulting confusion and exaggeration of research findings (in both directions). Some widely-cited estimates are highly inaccurate, indicating a need for critical evaluation of any estimates that are used. A substantial narrowing of the range of estimates is found in recent studies. Landsat data indicate that the deforestation rate in the Legal Amazon declined considerably from 1988 to 1991.
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Duan, Menglei, Connor Bax, Kati Laakso, Nooshin Mashhadi, Nelson Mattie, and Arturo Sanchez-Azofeifa. "Characterizing Transitions between Successional Stages in a Tropical Dry Forest Using LiDAR Techniques." Remote Sensing 15, no. 2 (January 13, 2023): 479. http://dx.doi.org/10.3390/rs15020479.
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Secondary succession is defined as natural regeneration following complete forest clearance from anthropogenic or natural disturbances. Traditional strategies aimed to map and characterize secondary succession using remote sensing are usually based on deterministic approaches, where transitions between successional stages are not considered. These transitions represent rich environments between successional stages and play a key role in ecosystem regeneration. Here, we evaluate the use of the Full-waveform Airborne LiDAR to characterize changes in forest structure between the transition of early-to-intermediate and intermediate-to-late forest succession at the Santa Rosa National Park Environmental Monitoring Super Site (SRNP-EMSS), Guanacaste, Costa Rica. The vertical forest structure was analyzed on twenty cross-sections selected between forest transitions previously mapped using machine learning; leaf area density (LAD) and waveform metrics were studied based on the waveform profile derived from twenty-seven plots distributed in different successional forest patches. Results suggest that LiDAR techniques can identify forest structure differences between successional stages and their transitions. The significance proves that transitions exist, highlights the unique transitional characteristics between intermediate and late successional stages and contributes to understanding the significance of inter-successional stages (transitions) in secondary dry forests.
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Wang, Xiaofang, Jialing Li, Guitong Xing, Siwei Mai, Wenjie Liu, Yamin Jiang, Wenxian Xu, et al. "Soil Organic Carbon Distribution, Enzyme Activities, and the Temperature Sensitivity of a Tropical Rainforest in Wuzhishan, Hainan Island." Forests 13, no. 11 (November 17, 2022): 1943. http://dx.doi.org/10.3390/f13111943.
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Soil carbon (C) distribution, which is deeply correlated with soil extracellular enzyme activity and its temperature sensitivity (Q10), are important for predicting the soil organic carbon (SOC) pools under climate warming. However, the high spatial heterogeneity in tropical forest soils makes the predicted results vary significantly. Thus, a total of 87 soil samples of three forest types, eight slope orientations, and four vegetation types were selected from Wuzhishan in Hainan Island, China. SOC distribution, the activities of six soil enzymes, and Q10 at 10, 20, 30, and 40 °C were investigated to supplement the tropical data. The results showed that: (1) SOC ranged from 24.82 to 87.72 g/kg. SOC in the primary forest was significantly higher than that of the secondary forest, and SOC of the cloud forests and hilltop scrub at higher elevations was significantly higher than that of the lowland rainforests and montane rainforests at lower elevations. However, the amount of recalcitrant carbon in the primary forest was the lowest. (2) Under lab temperature conditions, the acid phosphatase and β-1,4-glucosidase in the plantation forest were significantly higher than that of the secondary forest, and the polyphenol oxidase and catalase in the plantation forest were significantly higher than that of the primary forest. Enzyme stoichiometry analysis indicated that microbials were limited by nitrogen in the study area. The six soil enzyme activities were strongly correlated with SOC and total nitrogen. (3) The Q10 of soil enzymes ranged from 0.61 to 1.92 under three temperature gradients. Most hydrolases enzymes (Q10 > 1) showed a positive response with temperatures from 10 to 30 °C, and showed a negative response (Q10 < 1) with temperatures from 30 to 40 °C. We concluded that the negative response of enzyme Q10 with global warming would slow down the SOC decomposition. Primary tropical forests could still sequester SOC; however, their ability to do so may be vulnerable to climate change, as the amount of soil C quality index was low.
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Johnson, C. N., and A. P. McIlwee. "Ecology of the Northern Bettong, Bettongia tropica, a Tropical Mycophagist." Wildlife Research 24, no. 5 (1997): 549. http://dx.doi.org/10.1071/wr96034.
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The diet and seasonal ecology of the northern bettong, Bettongia tropica, was studied at three sites along a moisture gradient from closed Allocasuarina-Eucalyptus forest to dry open woodland in north-eastern Queensland. At each site, fungi (sporocarps of hypogeous ectomycorrhizal species) were the major food, and most of the remainder of the diet consisted of grass leaf and stem, roots and tubers, and lilies. Forbs and invertebrates were also eaten, but in small quantities. Fungus consumption was greatest at the wettest forest type and least at the driest site. Seasonal variation was insignificant except at the driest site, where fungus consumption peaked in the late wet season and dropped during the dry season; this seasonal fall in fungus consumption was associated with an increase in consumption of grass and roots and tubers. There was little seasonal variation in body condition, except at the driest site, where the dry-season decline in the proportional representation of fungus in the diet was associated with a decline in body condition. Breeding was continuous and aseasonal. B. tropica is found only in a narrow zone of sclerophyll forest along the western edge of wet tropical rainforest in north-eastern Queensland. We suggest that this species (like bettongs and potoroos in southern Australia) depends on hypogeous fungi, and that expansion of its geographical range into drier forest types is prevented by shortages of fungus during the dry season.
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Köhler, P., and A. Huth. "Towards ground-truthing of spaceborne estimates of above-ground biomass and leaf area index in tropical rain forests." Biogeosciences Discussions 7, no. 3 (May 5, 2010): 3227–55. http://dx.doi.org/10.5194/bgd-7-3227-2010.
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Abstract. The canopy height of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or lidar. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI). The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. It is found that for undisturbed forest and a variety of disturbed forests situations AGB can be expressed as a power-law function of canopy height h (AGB=a·hb) with an r2~60% for a spatial resolution of 20 m×20 m (0.04 ha, also called plot size). The regression is becoming significant better for the hectare wide analysis of the disturbed forest sites (r2=91%). There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2~60%) between AGB and the area fraction in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot data from the same region and with the large-scale forest inventory in Lambir. We conclude that the spaceborne remote sensing techniques have the potential to quantify the carbon contained in the vegetation, although this calculation contains due to the heterogeneity of the forest landscape structural uncertainties which restrict future applications to spatial averages of about one hectare in size. The uncertainties in AGB for a given canopy height are here 20–40% (95% confidence level) corresponding to a standard deviation of less than ±10%. This uncertainty on the 1 ha-scale is much smaller than in the analysis of 0.04 ha-scale data. At this small scale (0.04 ha) AGB can only be calculated out of canopy height with an uncertainty which is at least of the magnitude of the signal itself due to the natural spatial heterogeneity of these forests.
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Heinrich, Rudolf. "Research on Environmentally Sound Forest Practices to Sustain Tropical Forests." Environmental Conservation 23, no. 2 (June 1996): 169–70. http://dx.doi.org/10.1017/s0376892900038558.
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Nascimento, André Rosalvo Terra, Jeanine Maria Felfili Fagg, and Christopher William Fagg. "Canopy openness and lai estimates in two seasonally deciduous forests on limestone outcrops in central Brazil using hemispherical photographs." Revista Árvore 31, no. 1 (February 2007): 167–76. http://dx.doi.org/10.1590/s0100-67622007000100019.
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Patches of seasonally dry tropical forests occur on limestone outcrops in Central Brazil surrounded by the dominant savanna vegetation. They contain valuable timber species but are threatened by farming and mining activities. The objective of this study was to describe canopy opening and light relations in two seasonally deciduous dry forests on slopes and limestone outcrops, in the Paranã valley at the northeastern region of the Goiás state, Brazil. The studied forests were in the Fazenda Sabonete in Iaciara-Go and Fazenda Forquilha in Guarani-GO. Woody plants were sampled in 25 (20 x 20 m) plots in each forest. In the Sabonete forest 40 species, 705 ind./ha-1 with a basal area of 15.78 m²/ha-1 were found, while in Forquilha there were 55 species, 956 ind./ha-1 with a basal area of 24.76 m²/ha-1. Using hemispherical photographic techniques, 25 black and white photographs were taken at each site, during the dry season, totaling 50 photographs. These were taken at the beginning of each vegetation-sampling plot. The photographs were scanned in grey tones and saved as 'Bitmap'. The canopy opening and leaf area index (LAI) were calculated using the software Winphot. The mean canopy opening was 54.0% (±9.36) for Fazenda Sabonete and 64.6% (±11.8) in Fazenda Forquilha, with both sites presenting significant differences in the opening estimates (P < 0.05). Their floristic richness and structure also differed with the more open canopy forest, Forquilha, being richer and denser, suggesting the need for further studies on species-environment relationships in these forests.
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Köhler, P., and A. Huth. "Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests." Biogeosciences 7, no. 8 (August 25, 2010): 2531–43. http://dx.doi.org/10.5194/bg-7-2531-2010.
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Abstract. The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground life biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI) and identify how correlation and uncertainty vary for two different spatial scales. The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. In both undisturbed and disturbed forests AGB can be expressed as a power-law function of canopy height h (AGB = a · hb) with an r2 ~ 60% if data are analysed in a spatial resolution of 20 m × 20 m (0.04 ha, also called plot size). The correlation coefficient of the regression is becoming significant better in the disturbed forest sites (r2 = 91%) if data are analysed hectare wide. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2 ~ 60%) between AGB and the area fraction of gaps in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot (PSP) data from the same region and with the large-scale forest inventory in Lambir. We conclude that the spaceborne remote sensing techniques such as LIDAR and radar interferometry have the potential to quantify the carbon contained in the vegetation, although this calculation contains due to the heterogeneity of the forest landscape structural uncertainties which restrict future applications to spatial averages of about one hectare in size. The uncertainties in AGB for a given canopy height are here 20–40% (95% confidence level) corresponding to a standard deviation of less than ± 10%. This uncertainty on the 1 ha-scale is much smaller than in the analysis of 0.04 ha-scale data. At this small scale (0.04 ha) AGB can only be calculated out of canopy height with an uncertainty which is at least of the magnitude of the signal itself due to the natural spatial heterogeneity of these forests.
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Bazzaz, Fakhri A., and Manuel T. Lerdau. "Response of Seedlings of Tropical Trees to Cool Temperatures Predicted by ‘Nuclear Winter’ Scenarios." Environmental Conservation 17, no. 4 (1990): 337–40. http://dx.doi.org/10.1017/s0376892900032781.
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Mathematical models predict that a nuclear war could cause widespread reductions in light intensity and temperature. To assess the possible impact of these reductions on lowland tropical rain-forests, we exposed seedlings of three species of the family Moraceae to various combinations of day and night conditions under reduced light. The species represent three stages in tropical rain-forest succession: Cecropia obtusifolia is an early-successional pioneer, Trichospermum mexicanum is a mid-successional tree, and Brosimum alicastrum is a late-successional tree of mature-phase forests.
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Huang, Wending, Veli Pohjonen, Stig Johansson, Michael Nashanda, M. I. L. Katigula, and Olavi Luukkanen. "Species diversity, forest structure and species composition in Tanzanian tropical forests." Forest Ecology and Management 173, no. 1-3 (February 2003): 11–24. http://dx.doi.org/10.1016/s0378-1127(01)00820-9.
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Paulson, Deborah D. "Understanding Tropical Deforestation: the Case of Western Samoa." Environmental Conservation 21, no. 4 (1994): 326–32. http://dx.doi.org/10.1017/s0376892900033634.
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The case of Western Samoa is used to challenge the tendency in the recent literature to polarize the issue of tropical deforestation as caused by either political economic forces or increasing human demands. While it is recognized that political economic forces must be changed in many cases to make just and sustainable use of the forest possible, the case of Western Samoa is used to highlight the difficult challenge of conserving tropical forests and their biodiversity even under customary land-tenure and local control of forest resources.
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Phi, Dinh Cao, and Nguyen Hai Hoa. "USING ATMOSPHERICALLY RESISTANT VEGETATION INDEX TO DETECT FOREST COVER CHANGE IN LAC DUONG DISTRICT, LAM DONG PROVINCE." Journal of Forestry Science and Technology, no. 14 (2022): 129–40. http://dx.doi.org/10.55250/jo.vnuf.2022.14.129-140.
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This study tested the potential of using Sentinel-2-derived ARVI for land covers mapping compared to NDVI in Lac Duong district, Lam Dong province. Overall accuracy assessments of ARVI-based land covers mapping are calculated from 88.9% (in 2016) to 92.0% (in 2022) with Kappa coefficients of 0.79 and 0.86, respectively. The comparison between Sentinel-2-derived NDVI and ARVI for land covers mapping indicated that ARVI has performed well in land covers mapping in Lac Duong district. The Sentinel-2 time series were therefore used to generate spectral-temporal changes in land covers based on ARVI thresholds. Our estimation of land covers and forest cover change shows that the forest cover in Lac Duong increased by 1718.4 ha from 2016 to 2022, while non-forest covers reduced by 1662.1 ha at the same period. Conversely, during the segmented period of 2018-2020, the extent of forest cover reduced by 1156.1 ha, whereas non-forest covers increased by 1032.8 ha. The study also identified the main drivers of LULC change, including forest cover change, these changes are due to the expansion of coffee production, effectiveness of PES policy implementation, and a lack of agricultural production and sustained likelihoods. Our study suggests that ARVI can be used to monitor and detect changes in land covers, especially in deforestation and forest degradation detection in the tropical and mountainous regions of Vietnam. More focus of comprehensive understanding of LULC change and its management should be expanded beyond the poverty-environmental relationships in Lac Duong district.
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Jang, Christine J., Yasuko Nishigami, and Yukio Yanagisawa. "Assessment of global forest change between 1986 and 1993 using satellite-derived terrestrial net primary productivity." Environmental Conservation 23, no. 4 (December 1996): 315–21. http://dx.doi.org/10.1017/s0376892900039175.
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SummaryAlthough forest removal has been well documented at a global level, knowledge of how major forest processes such as photosynthesis have been affected remains poor. Global forest change between 1986 and 1993 was assessed using the NOAA/AVHRR satellite data converted to terrestrial net primary productivity (NPP). Forest loss was a dominant feature in tropical regions, with the most severe destruction in Latin America followed by southeast Asia and Africa. Loss of high-productivity forests over wide areas was observed for countries such as Brazil and Bolivia. Further analysis showed that approximately 12% (9100999 km2) and 19% (2 600000 km2) of the low-NPP regions (<500 g m−2yr−1, e.g., deserts, tundra) and the high-NPP regions (> 2000 g m−2yr−1, e.g., tropical rain forests), respectively, were transformed to intermediate-NPP regions (500–1500 g m−2yr−1, e.g., savanna, grassland, or cultivated land), between 1986 and 1993. The extent of global forest degradation or fragmentation may be more severe than the deforestation itself. Low-latitude ecosystems were more prone to decline in NPP than mid- and high-latitude ecosystems. The NPP method offers insight into global forest change in a timely, practical and consistent manner.
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Dwomoh, Francis K., Michael C. Wimberly, Mark A. Cochrane, and Izaya Numata. "Forest degradation promotes fire during drought in moist tropical forests of Ghana." Forest Ecology and Management 440 (May 2019): 158–68. http://dx.doi.org/10.1016/j.foreco.2019.03.014.
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Brunnée, Jutta, and André Nollkaemper. "Between the forests and the trees – an emerging international forest law." Environmental Conservation 23, no. 4 (December 1996): 307–14. http://dx.doi.org/10.1017/s0376892900039163.
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SummaryInternational forest law remains an undeveloped area of law. It consists of a multitude of treaties and non-treaty instruments dealing in a rather unprincipled and uncoordinated manner with such issues as biodiversity in forests; protection of forests as sinks of carbon dioxide; protection of endangered tree species; and trade in timber. However, in the face of mounting pressure on the world's tropical and other forests, in recent years there have been attempts to clarify and articulate the values and objectives underlying international forest policy that may induce a further development of the law.A tension exists between the firmly-rooted claims of sovereignty over forests and the emerging, increasingly-accepted legal principles which could guide international forest law: the principles of common concern, inter-generational equity and precaution. This shift has begun to influence the development of international forest law in critical international initiatives, including the Biodiversity Convention, the Climate Change Convention and, particularly, through the Intergovernmental Panel on Forests. The various layers of dialogue which have emerged to address different aspects of the forest issue (including legal, trade, and ecological issues) promote a gradual convergence of expectations and interests and thus ultimately may further normative development. Despite the diversity of forests and forest concerns between regions and continents, there is an important role for a set of general legal principles, objectives and procedures defining the parameters and establishing the ground rules of global forest law.
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LELE, SHARACHCHANDRA, and AMIT KURIEN. "Interdisciplinary analysis of the environment: insights from tropical forest research." Environmental Conservation 38, no. 2 (April 26, 2011): 211–33. http://dx.doi.org/10.1017/s037689291100018x.
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SUMMARYTropical forest management is a quintessential interdisciplinary (ID) problem straddling the social-natural divide, and has attracted scholars from many disciplines. This paper is a review of the ID research on tropical forests with a view to understanding the challenges involved in doing ID environmental research in general and the manner in which they might be addressed. Research on two core interdisciplinary questions in tropical forest research, namely causes of tropical forest loss and degradation and its impacts on society, is analysed to illuminate issues facing ID researchers. The challenges stem from differences in implicit values, theories and epistemologies across disciplines, as well as the relationship between individual disciplines, the ID space and the wider applied research audience. Understanding the value-laden nature of terms such as forest loss and degradation leads to a multidimensional and multidisciplinary characterization of the impact of forest change on human well-being. The analysis of causes of change has been enriched by ID research in which forest outcomes are characterized explicitly in terms of their values, measured in terms relevant to these values and linked to chains of socioeconomic variables at the appropriate scale. Explanations from different disciplines may be reconciled to some extent by seeing each as partial and perhaps having context-specific validity, although some core tensions, especially between economists and anthropologists, remain. Insights from ID research have been unevenly internalized in the literature, pointing to the absence of a broadly shared ID space as a consequence of individual social science disciplines appropriating environment as a subject of study. Shifting from theory-driven to problem-driven research and re-engaging self-consciously in this applied ID space will be required to generate more rigorous and relevant ID research on forests.
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Lima, Rayssa Yuki Murakami, and Claudia Azevedo-Ramos. "Compliance of Brazilian forest concession system with international guidelines for tropical forests." Forest Policy and Economics 119 (October 2020): 102285. http://dx.doi.org/10.1016/j.forpol.2020.102285.
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Montagnini, Florencia. "Tropical forests and climate." Forest Ecology and Management 65, no. 2-3 (June 1994): 294–95. http://dx.doi.org/10.1016/0378-1127(94)90178-3.
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HOLDER, CURTIS D. "Changes in structure and cover of a common property pine forest in Guatemala, 1954–1996." Environmental Conservation 31, no. 1 (March 2004): 22–29. http://dx.doi.org/10.1017/s0376892904001171.
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Concern about increasing rates of deforestation of tropical forests has resulted in investigations into the viability of local land-use practices and communal forms of governance. The majority of people in Guatemala live in regions where primary forests are absent. Several secondary forests in the highly populated highlands of Guatemala are communally managed forests, and people depend on forest products from these secondary forests for their livelihood. This study examines changes in forest structure and coverage of a native Pinus oocarpa Schiede communally managed forest in San Jose La Arada, Chiquimula in eastern Guatemala from 1954–1996. The pine forest is a municipal-communal property. The municipality has title to the land, however the forests are communal property. Neither forest committees in the villages nor municipal government regulations establish communal management of the pine forest; instead there are customary rules in the villages that guide forest extraction. People from the surrounding villages extract fuelwood, ocote (resin-rich wood harvested from the tree trunk and used for kindling) and timber from the pine forest. The P. oocarpa forest is situated in a seasonally dry region with nutrient-poor and highly eroded soils. Aerial photographs from 1954 and 1987 were compared to estimated changes in forest cover. Changes in forest structure are based on data collected from stand inventories conducted in 1987 and 1996. The pine forest was reduced in area by 14.4%, from 12.39 km2 in 1954 to 10.61 km2 in 1987. Additionally, stand density and basal area were reduced by 12% and 41%, respectively, from 1987–1996. Fuelwood and timber for domestic use were not extracted at a sustainable rate between 1954 and 1996 from the communally managed pine forest in this study. A sustainable-use management plan, in which all villages surrounding the forest participate, is recommended to provide future forest products for the villages.
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Woinarski, J. C. Z., B. Rankmore, B. Hill, A. D. Griffiths, A. Stewart, and B. Grace. "Fauna assemblages in regrowth vegetation in tropical open forests of the Northern Territory, Australia." Wildlife Research 36, no. 8 (2009): 675. http://dx.doi.org/10.1071/wr08128.
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Context. World-wide, primary forest is in decline. This places increasing importance on understanding the use by biodiversity of regrowth (secondary) forest, and on the management of such regrowth. Aims. This study aimed to compare the terrestrial vertebrate assemblages in tropical eucalypt forests, regrowth in these forests (following clearing for pastoral intensification) and cleared land without regrowth, to provide evidence for developing management guidelines for regrowth vegetation in a region (the Daly catchment of the Northern Territory) subject to increasing demands for land-use intensification. Methods. The terrestrial vertebrate fauna was surveyed consistently at 43 quadrats sampling forest, 38 sampling regrowth and 19 sampling cleared land (formerly forest), and the faunal composition was compared with ordination and analysis of variance. Further analysis used generalised linear modelling to include consideration of the relative importance of disturbance (condition) of quadrats. Key results. Faunal assemblages in regrowth vegetation were found to be intermediate between cleared land and intact forest, and converged towards the faunal assemblage typical of intact forest with increase in the canopy height of the regrowth. However, even the tallest regrowth quadrats that were sampled supported relatively few hollow-associated species. The management of fire, weeds and grazing pressure substantially affected the faunal assemblages of the set of regrowth and intact forest quadrats, in many cases being a more important determinant of faunal attributes than was whether or not the quadrat had been cleared. Conclusions. In this region, regrowth vegetation has value as habitat for fauna, with this value increasing as the regrowth structure increases. The convergence of the faunal composition of regrowth vegetation to that of intact forest may be substantially affected by post-clearing management factors (including fire regime and level of grazing pressure and weed infestation). Implications. Regrowth vegetation should be afforded appropriate regulatory protection, with the level of protection increasing as the regrowth increases in stature.
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Slot, Martijn, Milton N. Garcia, and Klaus Winter. "Temperature response of CO2 exchange in three tropical tree species." Functional Plant Biology 43, no. 5 (2016): 468. http://dx.doi.org/10.1071/fp15320.
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Tropical forests play a critical role in the global carbon cycle, but our limited understanding of the physiological sensitivity of tropical forest trees to environmental factors complicates predictions of tropical carbon fluxes in a changing climate. We determined the short-term temperature response of leaf photosynthesis and respiration of seedlings of three tropical tree species from Panama. For one of the species net CO2 exchange was also measured in situ. Dark respiration of all species increased linearly – not exponentially – over a ~30°C temperature range. The early-successional species Ficus insipida Willd. and Ochroma pyramidale (Cav. ex Lam.) Urb. had higher temperature optima for photosynthesis (Topt) and higher photosynthesis rates at Topt than the late-successional species Calophyllum longifolium Willd. The decrease in photosynthesis above Topt could be assigned, in part, to observed temperature-stimulated photorespiration and decreasing stomatal conductance (gS), with unmeasured processes such as respiration in the light, Rubisco deactivation, and changing membrane properties probably playing important additional roles, particularly at very high temperatures. As temperature increased above Topt, gS of laboratory-measured leaves first decreased, followed by an increase at temperatures >40−45°C. In contrast, gS of canopy leaves of F. insipida in the field continued to decrease with increasing temperature, causing complete suppression of photosynthesis at ~45°C, whereas photosynthesis in the laboratory did not reach zero until leaf temperature was ~50°C. Models parameterised with laboratory-derived data should be validated against field observations when they are used to predict tropical forest carbon fluxes.
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Kraemer, Moritz, and Jörg Hartmann. "Policy Responses to Tropical Deforestation: Are Debt-for-Nature Swaps Appropriate?" Journal of Environment & Development 2, no. 2 (June 1993): 41–65. http://dx.doi.org/10.1177/107049659300200203.
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This paper examines passible causes for the acceleration of tropical deforestation and the role of a popular instrument to reverse this trend, debt-for-nature swamps (DNS). This instrument builds on the contention that the debt crisis of developing countries has created the need to exploit natural resources, such as tropical forest areas. Thus, DNS could potentially protect forests directly (through conservation projects) and indirectly (by reducing debt-induced pressure on the forests). First, an instrumental critique of DNS is given, followed by an empirical examination of the debt-deforestation link that stands behind the instrument of DNS. Neither this nor other plausible causes of the acceleration of deforestation can be identified as significant in a cross-country study. The paper concludes that appropriate policy instruments must be based on case-specific research.
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Cournac, Laurent, Marc-Antoine Dubois, Jérôme Chave, and Bernard Riéra. "Fast determination of light availability and leaf area index in tropical forests." Journal of Tropical Ecology 18, no. 2 (March 2002): 295–302. http://dx.doi.org/10.1017/s0266467402002201.
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An important property of plant communities is the Leaf Area Index (LAI), which is the vertically integrated surface of leaves per unit of ground area. Leaves are the primary sites of photosynthesis and transpiration, thus the LAI, which conditions the light interception by the canopy, is directly related to carbon and water exchange with the atmosphere at the stand scale (McNaughton & Jarvis 1983). LAI also has an impact on tree growth through the interception of light. Light availability below canopies is the principal limiting factor of tree recruitment and growth in forests (Denslow et al. 1990). Several methodologies have been used for measuring LAI in the field. These can be classiffed in four categories (Marshall & Waring 1986): (1) direct measurements by litterfall collection or destructive sampling, (2) allometric correlations with variables such as tree height or tree diameter, (3) gap-fraction assessment (e.g. with hemispherical photographs), (4) measurement of light transmittance with optical sensors.
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Adinugroho, Wahyu Catur, Lilik Budi Prasetyo, Cecep Kusmana, Haruni Krisnawati, Christopher J. Weston, and Liubov Volkova. "Recovery of Carbon and Vegetation Diversity 23 Years after Fire in a Tropical Dryland Forest of Indonesia." Sustainability 14, no. 12 (June 7, 2022): 6964. http://dx.doi.org/10.3390/su14126964.
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Understanding the recovery rate of forest carbon stocks and biodiversity after disturbance, including fire, is vital for developing effective climate-change-mitigation policies and actions. In this study, live and dead carbon stocks aboveground, belowground, and in the soil to a 30 cm depth, as well as tree and shrub species diversity, were measured in a tropical lowland dry forest, 23 years after a fire in 1998, for comparison with adjacent unburned reference forests. The results showed that 23 years since the fire was insufficient, in this case, to recover live forest carbon and plant species diversity, to the level of the reference forests. The total carbon stock, in the recovering 23-year-old forest, was 199 Mg C ha−1 or about 90% of the unburned forest (220 Mg C ha−1), mainly due to the contribution of coarse woody debris and an increase in the 5–10 cm soil horizon’s organic carbon, in the burned forest. The carbon held in the live biomass of the recovering forest (79 Mg C ha−1) was just over half the 146 Mg C ha−1 of the reference forest. Based on a biomass mean annual increment of 6.24 ± 1.59 Mg ha−1 yr−1, about 46 ± 17 years would be required for the aboveground live biomass to recover to equivalence with the reference forest. In total, 176 plant species were recorded in the 23-year post-fire forest, compared with 216 in the unburned reference forest. The pioneer species Macaranga gigantea dominated in the 23-year post-fire forest, which was yet to regain the similar stand structural and compositional elements as those found in the adjacent unburned reference forest.
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da Costa, Thomaz Correa e. Castro, João Herbert Moreira Viana, and Juliana Leite Ribeiro. "Semideciduous Seasonal Forest Production of Leaves and Deciduousness in Function of the Water Balance, LAI, and NDVI." International Journal of Ecology 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/923027.
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This study investigated the relationship between leaf production, litterfall, water balance, Leaf Area Index (LAI), and Normalized Difference Vegetation Index (NDVI) in semideciduous forests. The goal was to model this phenomenon to obtain the estimates of this component as an additional compartment of the ecosystem carbon sink. The tests were conducted in eight semideciduous forest fragments. Twenty-four permanent plots were monitored monthly and LAI measurements and weighing of litterfall deposited in nets were conducted for a period of thirteen months. In this period, Landsat 5 and IRS satellite images were obtained and processed for generation of NDVI. The water balance was calculated for each day. The relationship among the variables “leaf dry weight,” “LAI,” “NDVI,” and “water balance” was verified and a regression model was built and evaluated. The deciduous phenomenon can be explained by hydric balance, and LAI and NDVI are ancillary variables. The tendency of the variables in the period of 13 months was explained by quadratic functions. The varied behavior among the monitoring sites helped to know differences in the deposition of leaves. This study showed that only the leaf component of the litterfall of a semideciduous forest in tropical climate can capture 4 to 8 Mg·ha−1·yr−1of CO2and this amount can be estimated using climate, biophysics, and vegetation index variables.
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Powers, Jennifer S. "Opportunities for Integrating Social Science into Research on Dry Forest Restoration: A Mini-Review." Sustainability 14, no. 12 (June 16, 2022): 7351. http://dx.doi.org/10.3390/su14127351.
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Seasonally dry tropical forest ecosystems have been greatly reduced in areas through conversions to alternate land uses such as grazing and crop production. The U.N. Decade on Restoration has focused attention on both restoration globally, and also regional attention on tropical dry forests, as they are excellent candidates for regeneration and reforestation. As such, the science of how we restore dry forests is advancing; however, few studies of dry forest restoration include collaborations with social scientists. This is unfortunate, because restoration projects that embrace a people-centered approach have the highest chances of success. Here, I review recent studies that have incorporated aspects of social science and human dimensions into the study and design of dry forest restoration practices. I focus on three key topics that merit a closer integration of restoration research and practice and social science: (1) recognizing that local people are central to project success, (2) cost benefit or effectiveness analyses that evaluate the relative costs of alternative management strategies, and (3) identification of land-use tradeoffs, synergisms and priority mapping. I conclude that closer collaborations among dry forest restoration researchers and a wider group of partners including social scientists, local communities, environmental educators, and geographers will increase the value of restoration research and the likelihood that such projects achieve multiple ecological and societal benefits.
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Keese, James, Thomas Mastin, and David Yun. "Identifying and Assessing Tropical Montane Forests on the Eastern Flank of the Ecuadorian Andes." Journal of Latin American Geography 6, no. 1 (2007): 63–84. http://dx.doi.org/10.1353/lag.2007.0004.
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Myers, Norman. "The world's forests: problems and potentials." Environmental Conservation 23, no. 2 (June 1996): 156–68. http://dx.doi.org/10.1017/s0376892900038546.
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SummaryThe accelerating decline of many of the world's forests represents one of the greatest problems and opportunities facing the global community. However little it may be recognized in its full scope, the forests crisis constitutes a profound and often irreversible degradation of both the biosphere and humanity's prospects. If this crisis is not contained and countered, extensive sectors of the world may well lose much, if not most, of their forest cover within the foreseeable future. I have drawn on my 30 years of field research in all three major forest biomes, together with my work with dozens of governments and agencies (FAO, the World Bank, etc.), backed by an in-depth review of the literature, to appraise the forests situation from both natural-science and social-science standpoints. My main finding is that deforestation is due partly to our scientific ignorance of forests' contributions to our welfare, both actually and potentially; partly to our meagre economic understanding of what is at stake; and partly to our lack of institutional capacity to manage forests for everybody's benefit, now and forever. I argue that forests are vital to the sustainable well-being of local communities, national economies and the biosphere. Yet they attract too little attention by governments dealing with the future of forests, also dealing with the future of a world that may eventually find itself with only a fraction as many forests as today.I urge that we broaden our understanding of what it will take to save remaining forests. Primarily we should recognize that in the main this is no longer a forestry problem alone. While much can still be achieved through traditional forestry practices, also through more protected areas within forests and other ‘defensive’ measures, these activities often do no more than tackle symptoms of deeper problems. In tropical forests, for instance, we must address the source problem of shiftcd-cultivator encroachment. Anything less is akin to building a fence around tropical forests (which would take an awful lot of timber), a fence that would be speedily over-run by multitudes of land-hungry farmers.There is growing recognition that forests make multiple contributions to the welfare of people throughout forest zones, of people throughout nations concerned, and of people throughout the world. Similarly the forests' survival depends on factors arising throughout the forests themselves, throughout nations concerned, and throughout the world. Fortunately this new recognition has been matched by growing awareness of the rapid decline of the Earth's forests.Much of the policy programme proposed will be difficult. But it will not be so difficult as living in a world bereft of its forests.
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Brown, S., and G. Gaston. "Use of forest inventories and geographic information systems to estimate biomass density of tropical forests: Application to tropical Africa." Environmental Monitoring and Assessment 38-38, no. 2-3 (1995): 157–68. http://dx.doi.org/10.1007/bf00546760.
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