Global analysis of mountain forest distribution and change during 2000 to 2018

2020 ◽  
Author(s):  
Xinyue He ◽  
Dominick Spracklen ◽  
Joseph Holden ◽  
Zhenzhong Zeng
Keyword(s):  
Forest Cover ◽  
River Flow ◽  
Global Analysis ◽  
Tree Cover ◽  
Mountain Forest ◽  
Mountain Forests ◽  
Forest Change ◽  
Elevation Data ◽  
Forest Distribution ◽  
Hydrological Cycles

<p>Mountain forests cover a small fraction of the Earth’s surface, but may exert important influence on the hydrological cycles of river basins (e.g., evapotranspiration, river flow). Many montane ecosystems are currently experiencing forest loss or gain, due to direct land-use change and due to changes in climate. Previous studies revealed most deforestation and afforestation occur in the lowlands, while how forest cover changes at different altitudes in the mountains has not been fully understood. Here we present a study that aims to better understand the distribution of mountain forest change. We use a high-resolution global map of forest change during 2000-2018 combined with elevation data to complete a global analysis of the relationship of elevation with tree cover and tree cover loss and gain. We also assess which climate variables (temperature, rainfall, wind speed) might explain observed variations in tree cover. Our analysis provides new information on how and why mountain forests are changing.</p>

scholarly journals Evaluating Forest Cover and Fragmentation in Costa Rica with a Corrected Global Tree Cover Map

2020 ◽  
Vol 12 (19) ◽  
pp. 3226
Author(s):  
Daniel Cunningham ◽  
Paul Cunningham ◽  
Matthew E. Fagan
Keyword(s):  
Costa Rica ◽  
Forest Cover ◽  
Agricultural Land ◽  
Forest Area ◽  
Tree Cover ◽  
Agricultural Crop ◽  
Forest Change ◽  
Alos Palsar ◽  
Tropical Regions ◽  
The Impact

Global tree cover products face challenges in accurately predicting tree cover across biophysical gradients, such as precipitation or agricultural cover. To generate a natural forest cover map for Costa Rica, biases in tree cover estimation in the most widely used tree cover product (the Global Forest Change product (GFC) were quantified and corrected, and the impact of map biases on estimates of forest cover and fragmentation was examined. First, a forest reference dataset was developed to examine how the difference between reference and GFC-predicted tree cover estimates varied along gradients of precipitation and elevation, and nonlinear statistical models were fit to predict the bias. Next, an agricultural land cover map was generated by classifying Landsat and ALOS PalSAR imagery (overall accuracy of 97%) to allow removing six common agricultural crops from estimates of tree cover. Finally, the GFC product was corrected through an integrated process using the nonlinear predictions of precipitation and elevation biases and the agricultural crop map as inputs. The accuracy of tree cover prediction increased by ≈29% over the original global forest change product (the R2 rose from 0.416 to 0.538). Using an optimized 89% tree cover threshold to create a forest/nonforest map, we found that fragmentation declined and core forest area and connectivity increased in the corrected forest cover map, especially in dry tropical forests, protected areas, and designated habitat corridors. By contrast, the core forest area decreased locally where agricultural fields were removed from estimates of natural tree cover. This research demonstrates a simple, transferable methodology to correct for observed biases in the Global Forest Change product. The use of uncorrected tree cover products may markedly over- or underestimate forest cover and fragmentation, especially in tropical regions with low precipitation, significant topography, and/or perennial agricultural production.

scholarly journals Assessing the Importance of Tree Cover Threshold for Forest Cover Mapping Derived from Global Forest Cover in Myanmar

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1062 ◽  
Author(s):  
Kay Khaing Lwin ◽  
Tetsuji Ota ◽  
Katsuto Shimizu ◽  
Nobuya Mizoue
Keyword(s):  
Large Scale ◽  
Forest Cover ◽  
Remote Sensing Data ◽  
Tree Cover ◽  
Tropical Rainforests ◽  
Forest Change ◽  
Tropical Regions ◽  
Ecological Zones ◽  
Optimal Tree ◽  
Forest Cover Mapping

Comprehensive forest cover mapping is essential for making policy and management decisions. However, creating a forest cover map from raw remote sensing data is a barrier for many users. Here, we investigated the effects of different tree cover thresholds on the accuracy of forest cover maps derived from the Global Forest Change Dataset (GFCD) across different ecological zones in a country-scale evaluation of Myanmar. To understand the effect of different thresholds on map accuracy, nine forest cover maps having thresholds ranging from 10% to 90% were created from the GFCD. The accuracy of the forest cover maps within each ecological zone and at the national scale was assessed. The overall accuracies of ecological zones other than tropical rainforest were highest when the threshold for tree cover was less than 50%. The appropriate threshold for tropical rainforests was 80%. Therefore, different optimal tree cover thresholds were required to achieve the highest overall accuracy depending on ecological zones. However, in the unique case of Myanmar, we were able to determine the threshold across the whole country. We concluded that the threshold for tree cover for creating a forest cover map should be determined according to the areal ratio of ecological zones determined from large-scale monitoring. Our results are applicable to tropical regions having similar ecological zones.

scholarly journals EVALUATION OF ANNUAL MODIS PTC DATA FOR DEFORESTATION AND FOREST DEGRADATION ANALYSIS

2016 ◽  
Vol XLI-B2 ◽  
pp. 9-13
Author(s):  
Y. Gao ◽  
A. Ghilardi ◽  
J. F. Mas ◽  
J. Paneque-Galvez ◽  
M. Skutsch
Keyword(s):  
Case Studies ◽  
Forest Cover ◽  
Forest Degradation ◽  
Tree Cover ◽  
Visual Interpretation ◽  
Forest Change ◽  
Validation Data ◽  
Degradation Analysis ◽  
Spot 5 ◽  
Quality Layer

Anthropogenic land-cover change, e.g. deforestation and forest degradation cause carbon emissions. To estimate deforestation and forest degradation, it is important to have reliable data on forest cover. In this analysis, we evaluated annual MODIS Percent Tree Cover (PTC) data for the detection of forest change including deforestation, forest degradation, reforestation and revegetation. The annual MODIS PTC data (2000 – 2010) were pre-processed by applying quality layer. Based on the PTC values of the annual MODIS data, forest change maps were produced and assessed by comparing with the data from visual interpretation of SPOT-5 images. The assessment was applied to two case-studies: Ayuquila Basin and Monarch Reserve. Results show that the detected deforestation patches by visual interpretation are roughly 4 times in quantity more than those by MODIS PTC data, which can be partially due to the much higher spatial resolution of SPOT-5, being able to pick up small deforestation patches. This analysis found poor spatial overlapping for both case-studies. Possible reasons for the discrepancy in quantity and spatial coincidence were provided. It is necessary to refine the methodology for forest change detection by PTC images; also to refine the validation data in terms of data periods and forest change categories to ensure a better assessment.

scholarly journals Forest transitions: a new conceptual scheme

2017 ◽  
Vol 72 (4) ◽  
pp. 465-474 ◽  
Author(s):  
Christian A. Kull
Keyword(s):  
Forest Cover ◽  
Forest Recovery ◽  
Tree Cover ◽  
Native Forest ◽  
Heuristic Model ◽  
Forest Change ◽  
Ecological Processes ◽  
Political Processes ◽  
Political Effect ◽  
Forest Transitions

Abstract. Forest transitions have recently received much attention, particularly in the hope that the historical transitions from net deforestation to forest recovery documented in several temperate countries might be reproduced in tropical countries. The analysis of forest transitions, however, has struggled with questions of forest definition and has at times focussed purely on tree cover, irrespective of tree types (e.g. native forest or exotic plantations). Furthermore, it has paid little attention to how categories and definitions of forest are used to political effect or shape how forest change is viewed. In this paper, I propose a new heuristic model to address these lacunae, building on a conception of forests as distinct socio-ecological relationships between people, trees, and other actors that maintain and threaten the forest. The model draws on selected work in the forest transition, land change science, and critical social science literatures. It explicitly forces analysts to see forests as much more than a land cover statistic, particularly as it internalizes consideration of forest characteristics and the differential ways in which forests are produced and thought about. The new heuristic model distinguishes between four component forest transitions: transitions in quantitative forest cover (FT1); in characteristics like species composition or density (FT2); in the ecological, socio-economic, and political processes and relationships that constitute particular forests (FT3); and in forest ideologies, discourses, and stories (FT4). The four are interlinked; the third category emerges as the linchpin. An analysis of forest transformations requires attention to diverse social and ecological processes, to power-laden official categories and classifications, and to the discourses and tropes by which people interpret these changes. Diverse examples are used to illustrate the model components and highlight the utility of considering the four categories of forest transitions.

scholarly journals Autochthone Gebirgswälder in der Schweiz anhand von baumbewohnenden Flechten erkennen

2019 ◽  
Vol 170 (5) ◽  
pp. 258-265
Author(s):  
Lyudmyla Dymytrova ◽  
Urs-Beat Brändli ◽  
Silvia Stofer ◽  
Christoph Scheidegger
Keyword(s):  
Indicator Species ◽  
Forest Cover ◽  
Species Conservation ◽  
National Forest Inventory ◽  
Forest History ◽  
Mountain Forest ◽  
Epiphytic Lichens ◽  
Mountain Forests ◽  
Forest Stands ◽  
Clear Cutting

Recognizing autochthonous mountain forests in Switzerland by means of epiphytic lichens Old undisturbed forest stands with a long forest history are of particular interest for nature and species conservation. Epiphytic lichens are often used as indicators for such autochthonous stands. In this study, we tested to what extent 14 taxa of epiphytic lichens, which are easy to identify by forest practitioners and have a low dispersal potential, have specific requirements for micro habitats and are often dependent on old trees, would be suitable indicator species for autochthonous forest stands in the Swiss mountain forests. As autochthonous, we considered forest stands with a near-natural conifer composition, a minimum age of 90 years, a continuous forest cover over 120 years and no evidence of historical intervention such as clear cutting or afforestation. For the study, the regular field teams of the Swiss National Forest Inventory (NFI) included the potential indicator species in the third survey (2004–2006) on all plots in the 1.4 km network on about three trees each. The data for the 3510 plots in the mountain forest were then evaluated using the NFI data on forest structure, forest history and forest management. Overall, the number of indicator species was significantly higher in autochthonous forest stands than in non-autochthonous ones, although it varied considerably with altitude and biogeographical region. Our investigations showed that fruticose lichens of the genera Bryoria and Usnea, Evernia divaricata and Letharia vulpina, foliose lichens such as Cetrelia olivetorum and Lobaria pulmonaria, and crustose lichens such as Lecanactis abietina and Microcalicium disseminatum, Calicium sp. div. and Chaenotheca sp. div. as well as Chrysothrix candelaris are reliable indicators for autochthonous stands in Swiss mountain forests, especially if several indicator species occur together. The lichens tested are therefore suitable in practice for a simple identification of autochthonous forest stands, e.g. for delimiting forest reserves or old forest patches. These stands are of high importance for the promotion of biodiversity in a forest landscape that has been managed for centuries.

scholarly journals EVALUATION OF ANNUAL MODIS PTC DATA FOR DEFORESTATION AND FOREST DEGRADATION ANALYSIS

2016 ◽  
Vol XLI-B2 ◽  
pp. 9-13
Author(s):  
Y. Gao ◽  
A. Ghilardi ◽  
J. F. Mas ◽  
J. Paneque-Galvez ◽  
M. Skutsch
Keyword(s):  
Case Studies ◽  
Forest Cover ◽  
Forest Degradation ◽  
Tree Cover ◽  
Visual Interpretation ◽  
Forest Change ◽  
Validation Data ◽  
Degradation Analysis ◽  
Spot 5 ◽  
Quality Layer

Anthropogenic land-cover change, e.g. deforestation and forest degradation cause carbon emissions. To estimate deforestation and forest degradation, it is important to have reliable data on forest cover. In this analysis, we evaluated annual MODIS Percent Tree Cover (PTC) data for the detection of forest change including deforestation, forest degradation, reforestation and revegetation. The annual MODIS PTC data (2000 – 2010) were pre-processed by applying quality layer. Based on the PTC values of the annual MODIS data, forest change maps were produced and assessed by comparing with the data from visual interpretation of SPOT-5 images. The assessment was applied to two case-studies: Ayuquila Basin and Monarch Reserve. Results show that the detected deforestation patches by visual interpretation are roughly 4 times in quantity more than those by MODIS PTC data, which can be partially due to the much higher spatial resolution of SPOT-5, being able to pick up small deforestation patches. This analysis found poor spatial overlapping for both case-studies. Possible reasons for the discrepancy in quantity and spatial coincidence were provided. It is necessary to refine the methodology for forest change detection by PTC images; also to refine the validation data in terms of data periods and forest change categories to ensure a better assessment.

scholarly journals India’s Commitments to Increase Tree and Forest Cover: Consequences for Water Supply and Agriculture Production within the Central Indian Highlands

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 959
Author(s):  
Benjamin Clark ◽  
Ruth DeFries ◽  
Jagdish Krishnaswamy
Keyword(s):  
Groundwater Recharge ◽  
Forest Cover ◽  
Hydrological Modeling ◽  
Monsoon Season ◽  
Forest Policy ◽  
Central India ◽  
Field Measurements ◽  
Tree Cover ◽  
Policy Goals ◽  
The Impact

As part of its nationally determined contributions as well as national forest policy goals, India plans to boost tree cover to 33% of its land area. Land currently under other uses will require tree-plantations or reforestation to achieve this goal. This paper examines the effects of converting cropland to tree or forest cover in the Central India Highlands (CIH). The paper examines the impact of increased forest cover on groundwater infiltration and recharge, which are essential for sustainable Rabi (winter, non-monsoon) season irrigation and agricultural production. Field measurements of saturated hydraulic conductivity (Kfs) linked to hydrological modeling estimate increased forest cover impact on the CIH hydrology. Kfs tests in 118 sites demonstrate a significant land cover effect, with forest cover having a higher Kfs of 20.2 mm hr−1 than croplands (6.7mm hr−1). The spatial processes in hydrology (SPHY) model simulated forest cover from 2% to 75% and showed that each basin reacts differently, depending on the amount of agriculture under paddy. Paddy agriculture can compensate for low infiltration through increased depression storage, allowing for continuous infiltration and groundwater recharge. Expanding forest cover to 33% in the CIH would reduce groundwater recharge by 7.94 mm (−1%) when converting the average cropland and increase it by 15.38 mm (3%) if reforestation is conducted on non-paddy agriculture. Intermediate forest cover shows however shows potential for increase in net benefits.

scholarly journals Effects of Windthrows on Forest Cover, Tree Growth and Soil Characteristics in Drought-Prone Pine Plantations

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 817
Author(s):  
Jesús Julio Camarero ◽  
Michele Colangelo ◽  
Antonio Gazol ◽  
Manuel Pizarro ◽  
Cristina Valeriano ◽  
...  
Keyword(s):  
Vegetation Index ◽  
Forest Cover ◽  
Normalized Difference Vegetation Index ◽  
Pinus Halepensis ◽  
Soil Characteristics ◽  
Tree Cover ◽  
Mediterranean Forests ◽  
Soil Microbial Community Structure ◽  
Soil Features ◽  
Disturbance Intensity

Windstorms are forest disturbances which generate canopy gaps. However, their effects on Mediterranean forests are understudied. To fill that research gap, changes in tree, cover, growth and soil features in Pinus halepensis and Pinus sylvestris plantations affected by windthrows were quantified. In each plantation, trees and soils in closed-canopy stands and gaps created by the windthrow were sampled. Changes in tree cover and radial growth were assessed by using the Normalized Difference Vegetation Index (NDVI) and dendrochronology, respectively. Soil features including texture, nutrients concentration and soil microbial community structure were also analyzed. Windthrows reduced tree cover and enhanced growth, particularly in the P. halepensis site, which was probably more severely impacted. Soil characteristics were also more altered by the windthrow in this site: the clay percentage increased in gaps, whereas K and Mg concentrations decreased. The biomass of Gram positive bacteria and actinomycetes increased in gaps, but the biomass of Gram negative bacteria and fungi decreased. Soil gaps became less fertile and dominated by bacteria after the windthrow in the P. halepensis site. We emphasize the relevance of considering post-disturbance time recovery and disturbance intensity to assess forest resilience within a multi-scale approach.

Suitability of Global Forest Change data to report forest cover estimates at national level in Gabon

2016 ◽  
Vol 173 ◽  
pp. 326-338 ◽  
Author(s):  
Christophe Sannier ◽  
Ronald E. McRoberts ◽  
Louis-Vincent Fichet
Keyword(s):  
Forest Cover ◽  
National Level ◽  
Forest Change

scholarly journals The importance of glacier and forest change in hydrological climate-impact studies

2013 ◽  
Vol 17 (2) ◽  
pp. 619-635 ◽  
Author(s):  
N. Köplin ◽  
B. Schädler ◽  
D. Viviroli ◽  
R. Weingartner
Keyword(s):  
Land Cover ◽  
Water Balance ◽  
Catchment Area ◽  
Forest Cover ◽  
Control Period ◽  
Climate Impact ◽  
Glacier Retreat ◽  
Climate Scenarios ◽  
Forest Change ◽  
Impact Studies

Abstract. Changes in land cover alter the water balance components of a catchment, due to strong interactions between soils, vegetation and the atmosphere. Therefore, hydrological climate impact studies should also integrate scenarios of associated land cover change. To reflect two severe climate-induced changes in land cover, we applied scenarios of glacier retreat and forest cover increase that were derived from the temperature signals of the climate scenarios used in this study. The climate scenarios were derived from ten regional climate models from the ENSEMBLES project. Their respective temperature and precipitation changes between the scenario period (2074–2095) and the control period (1984–2005) were used to run a hydrological model. The relative importance of each of the three types of scenarios (climate, glacier, forest) was assessed through an analysis of variance (ANOVA). Altogether, 15 mountainous catchments in Switzerland were analysed, exhibiting different degrees of glaciation during the control period (0–51%) and different degrees of forest cover increase under scenarios of change (12–55% of the catchment area). The results show that even an extreme change in forest cover is negligible with respect to changes in runoff, but it is crucial as soon as changes in evaporation or soil moisture are concerned. For the latter two variables, the relative impact of forest change is proportional to the magnitude of its change. For changes that concern 35% of the catchment area or more, the effect of forest change on summer evapotranspiration is equally or even more important than the climate signal. For catchments with a glaciation of 10% or more in the control period, the glacier retreat significantly determines summer and annual runoff. The most important source of uncertainty in this study, though, is the climate scenario and it is highly recommended to apply an ensemble of climate scenarios in the impact studies. The results presented here are valid for the climatic region they were tested for, i.e., a humid, mid-latitude mountainous environment. They might be different for regions where the evaporation is a major component of the water balance, for example. Nevertheless, a hydrological climate-impact study that assesses the additional impacts of forest and glacier change is new so far and provides insight into the question whether or not it is necessary to account for land cover changes as part of climate change impacts on hydrological systems.

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