Restoration of Degraded Natural Limestone Forests in Cat Ba Biosphere Reserves, Vietnam

2021 ◽  
pp. 14-26
Author(s):  
Tran Hai Long ◽  
Trieu Thai Hung ◽  
Sangjun Im ◽  
Dang Thi Hai Ha ◽  
Ninh Viet Khuong ◽  
...  
Keyword(s):  
Natural Regeneration ◽  
Forest Restoration ◽  
Forest Cover ◽  
Biosphere Reserve ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Overstory Trees ◽  
Artificial Restoration

Vietnam experienced significant forest cover change during the last half of the twentieth century, and restoration of natural forests have increased since the 1990s. This study developed comparisons of human-intervened and naturally restored forests in Cat Ba Biosphere Reserve, Vietnam in order to gain a better understanding of restoration options for the dual objectives of biodiversity conservation and forest cover. The overstory trees (species composition, growth, and diameter distribution) and natural regeneration (species richness, density, and height distribution) were measured and compared in twelve plots established in natural (NPS) and artificial restoration (RPS) models for post-selective-logged forest, and natural (NPC) and artificial restoration (RPC) models for post-clear-cut forest. Results indicated that the overstory trees and natural regeneration of RPS and RPC was higher than that of NPS and NPC. We concluded that the forest restoration models had shown successes, although extensive silvicultural techniques should be applied for a more stabilized development, especially in the RPC.

scholarly journals Structural Characteristics of Natural Limestone Forests in Cat Ba Biosphere Reserves, Vietnam

2020 ◽  
pp. 161-172
Author(s):  
Tran Hai Long ◽  
I. M. Sangjun ◽  
Trieu Thai Hung ◽  
Qiwen Li ◽  
Ninh Viet Khuong ◽  
...  
Keyword(s):  
Species Richness ◽  
Sustainable Forest Management ◽  
Structural Characteristics ◽  
Biosphere Reserve ◽  
Basal Area ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Natural Forests ◽  
Clear Cut ◽  
Anthropogenic Intervention

An ecological understanding of natural forests after anthropogenic intervention is important for sustainable forest management. This study analyzed the overstory characteristics (species composition, growth, and diameter distribution) and regeneration (species richness, density, and height distribution) in natural limestone forests in Cat Ba Biosphere Reserve, Vietnam. Data were collected in nine study plots established in selective-logged (SLF), clear-cut (CCF), and unlogged (UF) forests. Results indicated that the overstory characteristics of SLF and CCF were lower than that of UF (species richness was 33 in UF, 20 in SLF, and 16 in CCF; DBH was 20.6 ±13.7 cm in UF, 16.9 ±9.7 cm in SLF, and 10.5 ±3.8 cm in CCF; Basal area was 38.2 m2 ha-1 in UF, 24.0 m2 ha-1 in SLF, and 11.4 m2 ha-1 in CCF). For regeneration, species richness also varied from UF (25) to SLF (13) and CCF (5), while seedling density reversely increased. We concluded that a 20-year restoration was insufficient for artificially disturbed forests to recover their ecological functions, regardless of logging intensities and techniques applied.

scholarly journals Value Chain of Charcoal Production and Implications for Forest Degradation: Case Study of Bié Province, Angola

Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 113 ◽  
Author(s):  
Vasco Chiteculo ◽  
Bohdan Lojka ◽  
Peter Surový ◽  
Vladimir Verner ◽  
Dimitrios Panagiotidis ◽  
...  
Keyword(s):  
Value Chain ◽  
Forest Cover ◽  
Forest Degradation ◽  
Primary Data ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Charcoal Production ◽  
Order Of Magnitude ◽  
Alternative Sources ◽  
Urban Consumption

Forest degradation and forest loss threaten the survival of many species and reduce the ability of forests to provide vital services. Clearing for agriculture in Angola is an important driver of forest degradation and deforestation. Charcoal production for urban consumption as a driver of forest degradation has had alarming impacts on natural forests, as well as on the social and economic livelihood of the rural population. The charcoal impact on forest cover change is in the same order of magnitude as deforestation caused by agricultural expansion. However, there is a need to monitor the linkage between charcoal production and forest degradation. The aim of this paper is to investigate the sequence of the charcoal value chain as a systematic key to identify policies to reduce forest degradation in the province of Bié. It is a detailed study of the charcoal value chain that does not stop on the production and the consumption side. The primary data of this study came from 330 respondents obtained through different methods (semi-structured questionnaire survey and market observation conducted in June to September 2013–2014). A logistic regression (logit) model in IBM SPSS Statistics 24 (IBM Corp, Armonk, NY, USA) was used to analyze the factors influencing the decision of the households to use charcoal for domestic purposes. The finding indicates that 21 to 27 thousand hectares were degraded due to charcoal production. By describing the chain of charcoal, it was possible to access the driving factors for charcoal production and to obtain the first-time overview flow of charcoal from producers to consumers in Bié province. The demand for charcoal in this province is more likely to remain strong if government policies do not aim to employ alternative sources of domestic energy.

scholarly journals Combining global tree cover loss data with historical national forest-cover maps to look at six decades of deforestation and forest fragmentation in Madagascar

2017 ◽  
Author(s):  
Ghislain Vieilledent ◽  
Clovis Grinand ◽  
Fety A. Rakotomalala ◽  
Rija Ranaivosoa ◽  
Jean-Roger Rakotoarijaona ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Forest Cover ◽  
National Level ◽  
Tree Cover ◽  
National Forest ◽  
Area Network ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Current Conservation ◽  
Forest Maps

AbstractThe island of Madagascar has a unique biodiversity, mainly located in the tropical forests of the island. This biodiversity is highly threatened by anthropogenic deforestation. Existing historical forest maps at national level are scattered and have substantial gaps which prevent an exhaustive assessment of long-term deforestation trends in Madagascar. In this study, we combined historical national forest cover maps (covering the period 1953-2000) with a recent global annual tree cover loss dataset (2001-2014) to look at six decades of deforestation and forest fragmentation in Madagascar (from 1953 to 2014). We produced new forest cover maps at 30 m resolution for the year 1990 and annually from 2000 to 2014 over the full territory of Madagascar. We estimated that Madagascar has lost 44% of its natural forest cover over the period 1953-2014 (including 37% over the period 1973-2014). Natural forests cover 8.9 Mha in 2014 (15% of the national territory) and include 4.4 Mha (50%) of moist forests, 2.6 Mha (29%) of dry forests, 1.7 Mha of spiny forests (19%) and 177,000 ha (2%) of mangroves. Since 2005, the annual deforestation rate has progressively increased in Madagascar to reach 99,000 ha/yr during 2010-2014 (corresponding to a rate of 1.1%/yr). Around half of the forest (46%) is now located at less than 100 m from the forest edge. Our approach could be replicated to other developing countries with tropical forest. Accurate forest cover change maps can be used to assess the effectiveness of past and current conservation programs and implement new strategies for the future. In particular, forest maps and estimates can be used in the REDD+ framework which aims at “Reducing Emissions from Deforestation and forest Degradation” and for optimizing the current protected area network.

scholarly journals Change in tropical forest cover of Southeast Asia from 1990 to 2010

2014 ◽  
Vol 11 (2) ◽  
pp. 247-258 ◽  
Author(s):  
H.-J. Stibig ◽  
F. Achard ◽  
S. Carboni ◽  
R. Raši ◽  
J. Miettinen
Keyword(s):  
Southeast Asia ◽  
Satellite Imagery ◽  
Forest Cover ◽  
Satellite Image ◽  
Image Interpretation ◽  
Important Change ◽  
Automated Classification ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Forest Change

Abstract. The study assesses the extent and trends of forest cover in Southeast Asia for the periods 1990–2000 and 2000–2010 and provides an overview on the main causes of forest cover change. A systematic sample of 418 sites (10 km × 10 km size) located at the one-degree geographical confluence points and covered with satellite imagery of 30 m resolution is used for the assessment. Techniques of image segmentation and automated classification are combined with visual satellite image interpretation and quality control, involving forestry experts from Southeast Asian countries. The accuracy of our results is assessed through an independent consistency assessment, performed from a subsample of 1572 mapping units and resulting in an overall agreement of >85% for the general differentiation of forest cover versus non-forest cover. The total forest cover of Southeast Asia is estimated at 268 Mha in 1990, dropping to 236 Mha in 2010, with annual change rates of 1.75 Mha (∼0.67%) and 1.45 Mha (∼0.59%) for the periods 1990–2000 and 2000–2010, respectively. The vast majority of forest cover loss (∼2 / 3 for 2000–2010) occurred in insular Southeast Asia. Complementing our quantitative results by indicative information on patterns and on processes of forest change, obtained from the screening of satellite imagery and through expert consultation, respectively, confirms the conversion of forest to cash crops plantations (including oil palm) as the main cause of forest loss in Southeast Asia. Logging and the replacement of natural forests by forest plantations are two further important change processes in the region.

scholarly journals 30-year changes of natural forests under human activities in the Indochina peninsula - case studies in Cambodia, Laos and Vietnam

2021 ◽  
Vol 43 (3) ◽  
Author(s):  
Duong Nguyen Dinh ◽  
Cam Lai Vinh
Keyword(s):  
Forest Cover ◽  
Hydrological Cycle ◽  
Regional Scale ◽  
Google Earth ◽  
Natural Forest ◽  
Infrastructure Development ◽  
Natural Forests ◽  
Forest Cover Change ◽  
Remotely Sensed Data ◽  
Automated Method

Natural forests are a basic component of the earth's ecology. It is essential for biodiversity, hydrological cycle regulation, and environmental protection. Natural forests are gradually degraded and reduced due to timber logging, conversion to cropland, production forests, commodity trees, and infrastructure development. Decreasing natural forests results in loss of valuable habitats, land degradation, soil erosion, and imbalance of water cycle on the regional scale. Thus, operational monitoring of natural forest cover change has been in the interest of scientists for a long time. Current forest mapping methods using remotely sensed data provide limited capability to separate natural forests and planted forests. Natural forest statistics are often generated using official forestry national reports that have different bias levels due to different methodologies applied in different countries in forest inventory. Over the last couple of decades, natural forests have been over-exploited for various reasons. This led to forest cover degradation and water regulation capability, which results in extreme floods and drought of a watershed in general. This situation demands an urgent need to develop a fast, reliable, and automated method for mapping natural forests. In this study, by applying a new method for mapping natural forests by Landsat time series, the authors succeeded in mapping changes of natural forests of Cambodia, Laos, and Vietnam from 1989 to 2018. As a focused study area, three provinces: Ratanakiri of Cambodia, Attapeu of Laos, and Kon Tum of Vietnam were selected. The study reveals that after 30 years, 51.3% of natural forests in Ratanakiri, 27.8% of natural forests in Attapeu, and 50% of natural forests in Kon Tum were lost. Classification results were validated using high spatial resolution imagery of Google Earth. The overall accuracy of 99.3% for the year 2018 was achieved.

Forest cover change in the Los Tuxtlas Biosphere Reserve and its future: The contribution of the 1998 protected natural area decree

2018 ◽  
Vol 72 ◽  
pp. 443-450 ◽  
Author(s):  
Juan José Von Thaden ◽  
Javier Laborde ◽  
Sergio Guevara ◽  
Crystian S. Venegas-Barrera
Keyword(s):  
Forest Cover ◽  
Biosphere Reserve ◽  
Los Tuxtlas ◽  
Forest Cover Change ◽  
Natural Area ◽  
Protected Natural Area

Climate resilience through natural regeneration in degraded natural forests of south-eastern hilly region of Bangladesh

2019 ◽  
Vol 48 (3) ◽  
pp. 417-425
Author(s):  
Md Khayrul Alam Bhuiyan ◽  
Md Akhter Hossain ◽  
Abdul Kadir Ibne Kamal ◽  
Mohammed Kamal Hossain ◽  
Mohammed Jashimuddin ◽  
...  
Keyword(s):  
Tree Species ◽  
Natural Regeneration ◽  
Diversity Indices ◽  
Acacia Auriculiformis ◽  
Quantitative Structure ◽  
Natural Forests ◽  
Climate Resilience ◽  
Hilly Region ◽  
Major Cluster ◽  
Ecological Dominance

A study was conducted by using 5m × 5m sized 179 quadrates following multistage random sampling method for comparative regenerating tree species, quantitative structure, diversity, similarity and climate resilience in the degraded natural forests and plantations of Cox's Bazar North and South Forest Divisions. A total of 70 regenerating tree species were recorded representing maximum (47 species) from degraded natural forests followed by 43 species from 0.5 year 39 species from 1.5 year and 29 species from 2.5 year old plantations. Quantitative structure relating to ecological dominance indicated dominance of Acacia auriculiformis, Grewia nervosa and Lithocarpus elegans seedlings in the plantations whereas seedlings of Aporosa wallichii, Suregada multiflora and Grewia nervosa in degraded natural forests. The degraded natural forests possess higher natural regeneration potential as showed by different diversity indices. The dominance-based cluster analysis showed 2 major cluster of species under one of which multiple sub-clusters of species exists. Poor plant diversity and presence of regenerating exotic species in the plantations indicated poor climate resilience of forest ecosystem in terms of natural regeneration.

scholarly journals Shedding New Light on Mountainous Forest Growth: A Cross-Scale Evaluation of the Effects of Topographic Illumination Correction on 25 Years of Forest Cover Change across Nepal

2021 ◽  
Vol 13 (11) ◽  
pp. 2131
Author(s):  
Jamon Van Den Hoek ◽  
Alexander C. Smith ◽  
Kaspar Hurni ◽  
Sumeet Saksena ◽  
Jefferson Fox
Keyword(s):  
Remote Sensing ◽  
Geographic Distribution ◽  
Classification Accuracy ◽  
Forest Cover ◽  
Forest Growth ◽  
Forest Cover Change ◽  
Scale Evaluation ◽  
Beneficial Effects ◽  
Affect Detection

Accurate remote sensing of mountainous forest cover change is important for myriad social and ecological reasons, but is challenged by topographic and illumination conditions that can affect detection of forests. Several topographic illumination correction (TIC) approaches have been developed to mitigate these effects, but existing research has focused mostly on whether TIC improves forest cover classification accuracy and has usually found only marginal gains. However, the beneficial effects of TIC may go well beyond accuracy since TIC promises to improve detection of low illuminated forest cover and thereby normalize measurements of the amount, geographic distribution, and rate of forest cover change regardless of illumination. To assess the effects of TIC on the extent and geographic distribution of forest cover change, in addition to classification accuracy, we mapped forest cover across mountainous Nepal using a 25-year (1992–2016) gap-filled Landsat time series in two ways—with and without TIC (i.e., nonTIC)—and classified annual forest cover using a Random Forest classifier. We found that TIC modestly increased classifier accuracy and produced more conservative estimates of net forest cover change across Nepal (−5.2% from 1992–2016) TIC. TIC also resulted in a more even distribution of forest cover gain across Nepal with 3–5% more net gain and 4–6% more regenerated forest in the least illuminated regions. These results show that TIC helped to normalize forest cover change across varying illumination conditions with particular benefits for detecting mountainous forest cover gain. We encourage the use of TIC for satellite remote sensing detection of long-term mountainous forest cover change.

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