Dynamics Of Forest Cover Change Research Articles

Quantifying Forest Cover Loss as a Response to Drought and Dieback of Norway Spruce and Evaluating Sensitivity of Various Vegetation Indices Using Remote Sensing

The Norway spruce is one of the most important tree species in Europe. This tree species has been put under considerable pressure due to the ongoing impacts of climate change. Meanwhile, frequent droughts and pest outbreaks are reported as the main reason for its dieback, resulting in severe forest cover loss. Such was the case with Norway spruce forests within the Kopaonik National Park (NP) in Serbia. This study aims to quantify, spatially and temporally, forest cover loss and to evaluate the sensitivity of various vegetation indices (VIs) in detecting drought-induced response and predicting the dieback of Norway spruce due to long-lasting drought effects in the Kopaonik NP. For this purpose, we downloaded and processed a large number of Landsat 7 (ETM+), Landsat 8 (OLI), and Sentinel 2 (MSI) satellite imagery acquired from 2009 to 2022. Our results revealed that forest cover loss was mainly driven by severe drought in 2011 and 2012, which was later significantly influenced by bark beetle outbreaks. Furthermore, various VIs proved to be very useful in monitoring and predicting forest health status. In summary, the drought-induced response detected using various VIs provides valuable insights into the dynamics of forest cover change, with implications for monitoring and conservation efforts of Norway spruce forests in the Kopaonik NP.

Reconstruction of Agriculture-Driven Deforestation in Western Hunan Province of China during the 18th Century

Reconstruction of historical deforestation helps to understand the dynamics of forest cover change and provides a basis for the further study of human-nature interactions over the long term. Significant agriculture-driven deforestation occurred in the 18th century in China due to its socio-cultural transformation. To understand this deforestation during the 18th century, we took typical counties in western Hunan as a case study area and reconstructed the settlements’ expansion and densification as indicators of socio-cultural factors. We then reconstructed the agricultural land expansion and agriculture-driven deforestation based on these settlements. The results showed that the agricultural land area increased by 40.4% from the early to the late 18th century, while the proportion of forest area covering the region decreased from 78.0% to 69.1%. Meanwhile, agriculture-driven deforestation mainly unfolded in the eastern and western parts of the region at relatively low elevation in the early 18th century, and this mainly happened in the middle of the region lying at relatively high elevation in the late 18th century. This study’s results provide an improved spatial resolution for the reconstruction of historical land use/cover change, thus enabling insights to be gained from a more detailed spatiotemporal pattern of historical deforestation trends. This study helps to understand the anthropogenic land cover change on a larger spatiotemporal scale through a regional case study.

Study of Forest Cover Change Dynamics between 2000 and 2015 in the Ikongo District of Madagascar Using Multi-Temporal Landsat Satellite Images

Satellite images are considered reliable data that preserve land cover information. In the field of remote sensing, these images allow relevant analyses of changes in space over time through the use of computer tools. In this study, we have applied the “discriminant” change detection algorithm. In this, we have verified its effectiveness in multi-temporal studies. Also, we have determined the change in forest dynamics in the Ikongo district of Madagascar between 2000 and 2015. During the treatments, we have used the Landsat TM satellite images for the years 2000, 2005 and 2010 as well as ETM+ for 2015. Thus, analyses carried out have allowed us to note that between 2000-2005, 1.4% of natural forest disappeared. And, between 2005-2010, forests degradation was 1.8%. Also, between 2010-2015, about 0.5% of the natural forest conserved in 2010 disappeared. Furthermore, we have found that the discriminant algorithm is considerably efficient in terms of monitoring the dynamics of forest cover change.

Ecosystem Service Values Changes in Response to Land-Use/Land-Cover Dynamics in Dry Afromontane Forest in Northern Ethiopia.

Despite their importance as sources of ecosystem services supporting the livelihoods of millions of people, forest ecosystems have been changing into other land use systems over the past decades across the world. While forest cover change dynamics have been widely documented in various ecological systems, how these changes affect ecosystem service values has received limited attention. In this study we assessed the impact of land-use/land-cover dynamics on ecosystem service values in dry Afromontane forest in Northern Ethiopia. We estimated ecosystem service values and their changes based on the benefit transfer method using land cover data of the years 1985, 2000, and 2016 with their corresponding locally valid value coefficients and from the Ecosystem service valuation database. The total ecosystem service values of the whole study area were about USD 16.6, 19.0, and 18.1 million in 1985, 2000, and 2016, respectively. The analyses indicated an increase in ecosystem service values from 1985 to 2000 and a decrease in ecosystem service values from 2000 to 2016. Similarly, the contribution of specific ecosystem services increased in the first study period and decreased in the second study period. The findings highlight how forest cover dynamics can be translated into changes in ecosystem service values in dry Afromontane forest ecosystems in Northern Ethiopia and showed how specific ecosystem services contributed to the observed trends. The findings also illustrated the temporal heterogeneity in the impacts of land-use/land-cover dynamics on values of ecosystem services. The findings can serve as crucial inputs for policy and strategy formulations for the sustainable use and management of forest resources and can also guide the allocation of limited resources among competing demands to safeguard the ecosystems that offer the best-valued services.

Detecting and Attributing Drivers of Forest Disturbance in the Colombian Andes Using Landsat Time-Series

The Colombian Andes foothills have seen an expansion of forest disturbance since the 1950s. While understanding the drivers of disturbance is important for quantifying the implications of land use change on regional biodiversity, methods for attributing disturbance to specific drivers of change at a high temporal and spatial resolution are still lacking in the Andes region, in part due to persistent cloud cover. Using 20 years of Landsat images (1996–2015) covering Picachos National Park in the Colombian Andes, we detected sub-annual forest cover disturbances using the Breaks For Additive Season and Trend (BFAST) Monitor algorithm; characterized different types of disturbance using spectral, spatial, and topographic indicators; and attributed causes of forest disturbance such as conversion to pasture, conversion to agriculture, and non-stand replacing disturbance (i.e., thinning) using a Random Forest (RF) classifier. Conversion to pasture has been the main driver of forest disturbance in Picachos, responsible for 11,395 ± 72 ha (17%) of forest cover loss, followed by non-stand replacing disturbance and conversion to agriculture. Disturbance detection had 96% overall agreement with validation data, although we had a high omission error of 21% primarily associated with forest to agriculture conversion. Other change drivers had a much more reliable attribution with forest to pasture conversion or non-stand-replacing disturbance, showing only 1–5% commission and 2–14% omission errors. Our results provide spatially-explicit information on sub-annual disturbances and associated drivers of change that are necessary for evaluating and improving domestic conservation efforts and establishing systematic ecological observations, which is currently absent from Colombia. While effective at revealing forest change dynamics in a geographically remote and socio-politically complex region like Picachos, our approach is highly automated and it can be easily extended to the rest of Andes-Amazon transition belt where low availability of remote sensing data and high cloud cover impede efforts at consistent monitoring of forest cover change dynamics and drivers.

Multi-temporal trajectories of landscape change explain forest biodiversity in urbanizing ecosystems

Forest loss and fragmentation negatively affect biodiversity. However, disturbances in forest canopy resulting from repeated deforestation and reforestation are also likely important drivers of biodiversity, but are overlooked when forest cover change is assessed using a single time interval. We investigated two questions at the nexus of plant diversity and forest cover change dynamics: (1) Do multitemporal forest cover change trajectories explain patterns of plant diversity better than a simple measure of overall forest change? (2) Are specific types of forest cover change trajectories associated with significantly higher or lower levels of diversity? We sampled plant biodiversity in forests spanning the Charlotte, NC, region. We derived forest cover change trajectories occurring within nested spatial extents per sample site using a time series of aerial photos from 1938 to 2009, then classified trajectories by spatio-temporal patterns of change. While accounting for landscape and environmental covariates, we assessed the effects of the trajectory classes as compared to net forest cover change on native plant diversity. Our results indicated that forest stand diversity is best explained by forest change trajectories, while the herb layer is better explained by net forest cover change. Three distinct forest change trajectory classes were found to influence the forest stand and herb layer. The influence of forest dynamics on biodiversity can be overlooked in analyses that use only net forest cover change. Our results illustrate the utility of assessing how specific trajectories of past land cover change influence biodiversity patterns in the present.

FOREST COVER ANALYSIS THROUGH THE WEIGHTS OF EVIDENCE METHOD IN THE CAMPANHA OCIDENTAL REGION - RS (BRAZIL)

ABSTRACT The uncontrolled expansion of human activities may lead to a reduction in vegetation cover, an increase in erosion processes and soil sealing. The aim of this study is to examine forest cover using the Weights of evidence method based on land use maps between the years of 1996 and 2011 in the micro-region of the Campanha Ocidental located in the state of Rio Grande do Sul (Brazil). The spatial database was constructed in SPRING software (version 5.2.1) based on LANDSAT 5 images, which were georeferenced and classified. Geophysical and socioeconomic variables were included in the database for further analysis in Dinamica EGO software (version 2.2.8). In order to parameterize the probabilistic model for the analysis of the dynamics of forest cover change, we calculated the percentage of class change through transition matrices; calculated the intervals for discretization of continuous variables; calculated the weights of evidence (W+); analyzed the correlation between the weights of the input variables for all transitions; simulated future scenarios and; validated the simulated final map based on the historical map. This model was adequate for understanding the variables that most contribute to forest cover change in the region. The results showed that the emergence of new forest areas was influenced by hypsometry, distance to sandy lands and per capita income, while deforestation by rural population and distance to the sandy lands.

Cambios en la cobertura arbolada de comunidades indígenas con y sin iniciativas de conservación, en Oaxaca, México

We analyzed the dynamics of forest cover change between 1990-2010 in eleven Chinantec indigenous communities in the Sierra Norte of the state of Oaxaca, Mexico. Five communities exhibited collective action for forest conservation (with-cac) and the remaining six did not (without-cac). Using supervised classification of Landsat satellite images from three dates (1990, 2000 and 2010) we obtained maps of forested/non-forested conditions. We then crossed maps for 1990-2000 and 2000-2010 to generate maps of change processes (deforestation and re-vegetation) and annual rates of change. In general, forest cover was relatively stable (~90%), but there were significant differences between the forest cover in communities with-cac and without-cac. In the first, there was greater forest cover, less permanence of the non-forested condition, and lower rates of change. In the communities without-cac there was greater re-vegetation between 2000-2010, but forest recovery does not appear to have been intentional, since the communities had no initiatives for taking care of their forests. In the communities with-cac there has been influence of advisors, academics, and programs with governmental and non-governmental entities, and these have had little presence in the without-cac communities. Improved understanding of the dynamics of high ecological value forests in common property, such as those in the northern part of Oaxaca State, is fundamental for better orientation of public policy focused at local forest in Mexico.

Assessing impact of forest cover change dynamics on high nature value farmland in Mediterranean mountain landscape

A general trend of scrub encroachment and natural forest expansion (old-field succession) has been occurring in the past fifty years in Mediterranean mountain areas. While this phenomenon enhances a series of ecological processes and environmental services, it may represent a threat for biodiversity conservation when occurring on high nature value (HNV) extensive farmland. These open areas, created by traditional farming systems, have been recognized as a critically important European biodiversity resource. Understanding the drivers of Land Use and Land Cover Change (LUCC) and their implications on the dynamics of forest and HNV farmland habitats plays a crucial role in biodiversity conservation in protected areas. In this perspective, the case study here presented aims to model recent (1989-2008) LUCC in a National Park of the Central Apennines (Italy) and to produce a mid-term forecast (2008-2020). In the past twenty years, 57% of the land uptake by shrubland and 46% by forest has been occurring on former HNV farmland. Mid-term projections (2008-2020) confirm further HNV farmland decline. Localization of HNV farmland habitats vulnerable to change is a valuable decision-making tool to tradeoff in protected areas the conservation of traditional landscapes with the increase of forest and shrubland areas. In this perspective, concrete socio-economical and silvicultural measures are outlined to preserve these socially and economically-fragile open habitats.

The effects of land use change on carbon content in the aerial biomass of an Abies religiosa (Kunth Schltdl. et Cham.) forest in central Veracruz, Mexico

Aim of study.) Were analyzed patterns and dynamics of forest cover change and land use for the period 1995-2005, and estimated carbon content in biomass in a forest of fir (Abies religiosa).Area of study. Ejido El Conejo in the Cofre de Perote National Park, Veracruz, Mexico.Material and Methods. Spatial data (maps, orthophotographs) were used: (UTM); GRS 80 spheroid; zone 14, datum ITRF92; units: metres. Maps for 1995 and 2005 were constructed and compared. Carbon content in the aboveground biomass of fir (Abies religiosa) was estimated using an equation specific to species.Main results. After one decade, the forested area had increased slightly (0.25%). The main type of land cover change was from shrubland to forest (probability of change 0.41); the change from forestland to shrubland with trees was 0.05%, and from forest to agriculture was 0.02%. Data from 2008 confirmed that the A. religiosa forest located in the ejido is distributed in largely unconnected fragments, of which some have a high density of young trees. Estimated carbon content in the aboveground biomass (163.51 Mg ha-1) was higher than that estimated for other forests of the same species in Mexico.Research highlights. It is recommended that ecological corridors be established throughout the reforested area, in order to connect these fragments (and increase carbon sequestration) and favour faunal and floral conservation. Finally, recognition should be given to the high vulnerability of A. religiosa forests to climate change, given their high degree of fragmentation and critical altitudinal limit.Key words: Aboveground biomass; carbon storage; ecological corridors; fir forest.

Long-term changes in forest cover 1780–2007 in central Bohemia, Czech Republic

Many studies have recently been devoted to the study of landscape change, and some have even focused on an analysis of the dynamics of forest cover change. However, few of the studies have worked on a methodology for making a detailed investigation of long-term forest change dynamics based on historic cartographic sources. The goal of this study is to further develop a method for analyzing long-term changes in forest cover on the basis of old maps and orthophoto maps in the GIS environment. The study area is located in Central Bohemia, to the east of Kutna Hora, a UNESCO World Heritage Site. The area consists of 21 cadastral units with a total area of 113 km2. The maps of the First (1780), Second (1851) and Third Military Surveys (1877) and the present-day orthophotomap (2007) of the Czech Republic were used as data resources. Source data have been processed in GIS. Forest cover is the subject of our study. However, the term is perceived from a broader perspective. What we call forest cover in our study refers to forest wood elements and other wood species in the landscape. In this study, forest cover has been structurally considered as a whole, without dividing it into the two categories mentioned. We counted the extent of the forest cover in each particular time horizon in hectares and as a percentage of the area under study, also the absolute changes in forest cover between the individual time horizons in hectares as well as the intensity of the changes in forest cover in hectares per year. The spatial changes in forest cover were evaluated in a GIS environment using specialized features to analyze spatial variation. The forest cover occupied 16.60% (1,880 ha) of the total area in the First Military Survey (1780). In 2007, the proportion was slightly higher at 16.64% (1,884 ha). More than half of all forest land (53%) from the time of the Second Military Survey (1851) survived until 2007. Not only the information on absolute changes but also the information on the rate of change is of great importance. The old Military Survey maps and the orthophotomap enable us to carry out studies of long-term changes in forest cover. However, the geodetic inaccuracy of the First Military Survey maps precludes reliable and exact quantification of the landscape changes between the First Military Survey and the Second Military Survey, and also between the First Military Survey and present-day (orthophoto map). These maps cannot be used for evaluating forest cover changes on the level of individual plots. The method presented in our paper may contribute to a better understanding of the long-term dynamics of forest land, covering a period of more than 250 years. This knowledge can be applied in forest management planning procedures. Apart from their application in forestry, the methods presented in this study may be of interest for historians and biologists.

Dynamics of forest cover conversion in and around Bwindi impenetrable forest, Southwestern Uganda

Forest cover has been converted to agricultural land use in and around the protected areas of Uganda. The objectives of this study were; to examine the dynamics of forest cover change in and around Bwindi impenetrable forest between 1973 and 2010 and to identify the drivers of forest cover change. The trend in forest cover change was assessed by analyzing a series of orthorectified landsat imageries of 1973, 1987 and 2001 using unsupervised and supervised classification. Land use/cover map for 2010 was reconstructed by analyzing 2001 image, validated and/or reconstructed by ground truthing, use of secondary data and key informant interviews. A series of focused group discussions and key informant interviews were also used to identify drivers of land use/cover change. Policies and institutional arrangements that could have affected forest cover change for the studied time period were also identified. Results showed that protected forest and woodlot in unprotected area had declined by 7.8% and 70.7% respectively as small scale farming and tea plantations had increased by 13.9% and 78.3% respectively between 1973 and 2010. The conversions were attributed to land use pressure due to population growth, change in socio-economic conditions and institutional arrangements. The severe loss of woodlot outside the protected area not only poses a potential threat to the protected forest but also calls for intervention measures if efforts to mitigate climate change impacts are to be realized.

Gross forest cover loss in temperate forests: biome-wide monitoring results using MODIS and Landsat data

The temperate forest is a complex biome due to the diversity of forest types, forest cover change dynamics and forest use management practices. While temperate forests play an important role in the global carbon cycle, their net carbon exchange is uncertain. Quantifying forest cover change is an important step in documenting disturbance regimes and carbon exchange estimates. Biome-wide gross forest cover loss was estimated using a probability-based sampling approach that integrated moderate and high spatial resolution satellite data sets. Area of gross forest cover loss from 2000 to 2005 within the temperate forest biome is estimated to be 1.03% of the total biome area, or 18.41 Mha. Estimated forest cover loss represented a 3.5% reduction in year 2000 forest area. About 68% of the total forest cover loss occurred in Eastern North America and in Europe. The mid-latitude forests of the United States exhibited the highest forest cover loss rates within the biome. Biome-wide rate of gross forest cover loss gradually increased from 2001 to 2005. The lowest change was detected in 2004, followed by the year of the highest change over the 5-year period. The regional forest cover change dynamics were confirmed by official forest fire and timber production statistics. The validation of the MODIS-based product demonstrated its efficiency in forest cover mapping and monitoring. Forest cover change monitoring using the approach presented should bring greater understanding on forest cover dynamics in temperate forests and enable improved carbon accounting.

Change vector analysis to categorise land cover change processes using the tasselled cap as biophysical indicator

The continuous extraction of wood and the conversion of forest to small- and large-scale agricultural parcels is rapidly changing the land cover of the mount Cameroon region. The changes occur at varying spatial scales most often not more than 2ha for the small-scale subsistence farms and above 10ha for the extensive agricultural plantations of cocoa and palm. Given the importance of land use and land cover data in conservation planning, accurate and efficient techniques to provide up-to-date change information are required. A number of techniques for realising the detection of land cover dynamics using remotely sensed imagery have been formulated, tested and assessed with the results varying with respect to the change scenario under investigation, the information required and the imagery applied. In this study the Change Vector Analysis (CVA) technique was implemented on multitemporal multispectral Landsat data from the Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) sensors to monitor the dynamics of forest change in the mount Cameroon region. CVA was applied to multi-temporal data to compare the differences in the time-trajectory of the tasseled cap greenness and brightness for two successive time periods - 1987 and 2002. The tasseled cap was selected as biophysical indicator because it optimises the data viewing capabilities of vegetation, representing the basic types of land cover - vegetation, soil and water. Classes were created arbitrarily to predict the technique's potential in monitoring forest cover changes in the mount Cameroon region. The efficiency of the technique could not be fully assessed due to the inavailability of sufficient ground truth data. Assessment was based on the establishment of an error matrix of change versus no-change. The overall accuracy was 70%. The technique nevertheless demonstrated immense potentials in monitoring forest cover change dynamics especially when complemented with field studies.