An official website of the United States government
Nepal’s forest cover nearly doubled over the last three decades. While Community Forest (CF) management and agricultural abandonment are primary drivers of forest cover expansion, the contribution of afforestation on privately managed land is not well documented. We mapped forest cover change from 1988 through 2016 in 40 privately managed sites that transitioned from agriculture to forest and assessed how agricultural abandonment influenced private land management and afforestation. We used a mixed method analysis to integrate our 29- year Landsat satellite image-based record of annual forest cover with interview data on historical land cover and land use dynamics from 65 land managers in Bagmati Province. We find that privately managed land accounted for 37% of local forest cover gain, with mean forest area within private forests growing from 9% to 59%. Land managers identified two factors driving these gains on private land: implementation of CF man- agement in adjacent government forests and out-migration. These previously undocumented linkages between forest cover gain on private land and CF management merits further research in community forests and calls for greater policy and technical support for small-scale timber growers and rural households who rely on private forests for income generation.
more »
« less
Green Vegetation Cover Has Steadily Increased since Establishment of Community Forests in Western Chitwan, Nepal
Community forests have been established worldwide to sustainably manage forest ecosystem services while maintaining the livelihoods of local residents. The Chitwan National Park in Nepal is a world-renowned biodiversity hotspot, where community forests were consolidated in the park’s buffer zone after 1993. These western Chitwan community forests stand as the frontiers of human–environment interactions, nurturing endangered large mammal species while providing significant natural resources for local residents. Nevertheless, no systematic forest cover assessment has been conducted for these forests since their establishment. In this study, we examined the green vegetation dynamics of these community forests for the years 1988–2018 using Landsat surface reflectance products. Combining an automatic water extraction index, spectral mixture analysis and the normalized difference fraction index (NDFI), we developed water masks and quantified the water-adjusted green vegetation fractions and NDFI values in the forests. Results showed that all forests have been continuously greening up since their establishment, and the average green vegetation cover of all forests increased from approximately 30% in 1988 to above 70% in 2018. With possible contributions from the invasion of exotic understory plant species, we credit community forestry programs for some of the green-up signals. Monitoring of forest vegetation dynamics is critical for evaluating the effectiveness of community forestry as well as developing sustainable forest management policies. Our research will provide positive feedbacks to local community forest committees and users.
more »
« less
- Award ID(s):
- 1826839
- PAR ID:
- 10287826
- Date Published:
- Journal Name:
- Remote Sensing
- Volume:
- 12
- Issue:
- 24
- ISSN:
- 2072-4292
- Page Range / eLocation ID:
- 4071
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Introduction Integrated social and ecological processes shape urban plant communities, but the temporal dynamics and potential for change in these managed communities have rarely been explored. In residential yards, which cover about 40% of urban land area, individuals make decisions that control vegetation outcomes. These decisions may lead to relatively static plant composition and structure, as residents seek to expend little effort to maintain stable landscapes. Alternatively, residents may actively modify plant communities to meet their preferences or address perceived problems, or they may passively allow them to change. In this research, we ask, how and to what extent does residential yard vegetation change over time? Methods We conducted co-located ecological surveys of yards (in 2008, 2018, and 2019) and social surveys of residents (in 2018) in four diverse neighborhoods of Phoenix, Arizona. Results 94% of residents had made some changes to their front or back yards since moving in. On average, about 60% of woody vegetation per yard changed between 2008 and 2018, though the number of species present did not differ significantly. In comparison, about 30% of woody vegetation changed in native Sonoran Desert reference areas over 10 years. In yards, about 15% of woody vegetation changed on average in a single year, with up to 90% change in some yards. Greater turnover was observed for homes that were sold, indicating a “pulse” of management. Additionally, we observed greater vegetation turnover in the two older, lawn-dominated neighborhoods surveyed despite differences in neighborhood socioeconomic factors. Discussion These results indicate that residential plant communities are dynamic over time. Neighborhood age and other characteristics may be important drivers of change, while socioeconomic status neither promotes nor inhibits change at the neighborhood scale. Our findings highlight an opportunity for management interventions, wherein residents may be open to making conservation-friendly changes if they are already altering the composition of their yards.more » « less
-
Abstract International environmental initiatives, such as the Bonn Challenge and the UN Decade on Restoration, have prompted countries to put the management and restoration of forest landscapes at the center of their land use and climate policies. To support these goals, many governments are promoting forest landscape restoration and management through financial forestry incentives, a form of payment for ecosystem services. Since 1996, Guatemala has implemented a series of forestry incentives that promote active forest landscape restoration and management on private and communal lands. These programs have been widely hailed as a success with nearly 600 000 ha enrolled since 1998. However, there has been no systematic assessment of the effectiveness of these programs on preserving and restoring Guatemalan forests. This study evaluates the impacts of over 16 000 individual PES projects funded through two incentive programs using a synthetic control counterfactual. Overall, a program for smallholders resulted in lower rates of forest loss, while a program for industrial timber owners led to greater gains in forest cover. Across policies, we found dramatically higher forest cover increases from restoration projects (15% forest cover increase) compared to plantation and agroforestry projects (3%–6% increase in forest cover). Projects that protected natural forest also showed a 6% reduction in forest loss. We found forest cover increases to be under 10% of total enrolled area, although positive local spillovers suggest this is an underestimate. Restoration projects show the most promise at promoting forest landscape restoration, but these benefits need to be weighed against priorities like resilience and rural development, which may be better served by other projects.more » « less
-
Retreat of coastal forests in relation to sea level rise has been widely documented. Recent work indicates that coastal forests on the Delmarva Peninsula, United States, can be differentiated into persistence and regenerative zones as a function of sea-level rise and storm events. In the lower persistence zone trees cannot regenerate because of frequent flooding and high soil salinity. This study aims to verify the existence of these zones using spectral remote sensing data, and determine whether the effect of large storm events that cause damage to these forests can be detected from satellite images. Spectral analysis confirms a significant difference in average Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) values in the proposed persistence and regenerative zones. Both NDVI and NDWI indexes decrease after storms triggering a surge above 1.3 m with respect to the North American Vertical Datum of 1988 (NAVD88). NDWI values decrease more, suggesting that this index is better suited to detect the effect of hurricanes on coastal forests. In the regenerative zone, both NDVI and NDWI values recover three years after a storm, while in the persistence zone the NDVI and NDWI values keep decreasing, possibly due to sea level rise causing vegetation stress. As a result, the forest resilience to storms in the persistence zone is lower than in the regenerative zone. Our findings corroborate the ecological ratchet model of coastal forest disturbance.more » « less
-
Abstract Exotic tree species, though widely used in forestry and restoration projects, pose great threats to local ecosystems. They need to be replaced with native species from natural forests. We hypothesized that natural forests contain large, fast-growing, dominant native tree species that are suitable for specific topographic conditions in forestry. We tested this hypothesis using data from a 50-ha forest dynamics plot in subtropical China. We classified the plot into the ridge, slope, and valley habitats and found that 34/87 species had significant associations with at least one topographic habitat. There were 90 tree species with a maximum diameter ≥ 30 cm, and their abundances varied widely in all habitat types. In all habitat types, for most species, rate of biomass gain due to recruitment was < 1% of its original biomass, and rate of biomass gain due to tree growth was between 1 and 5% of its original biomass. For most species, biomass loss due to tree mortality was not significantly different than biomass gain due to recruitment, but the resulting net biomass increment rates did not significantly differ from zero. The time required to reach a diameter of 30 cm from 1 cm diameter forAltingia chinensisin the slope habitat, forQuercus chungiiandMorella rubrain the ridge habitat and forCastanopsis carlesiiin all habitats could be as short as 30 years in our simulations based on actual distributions of tree growth observed in the forest. Principal component analyses of maximum diameter, abundance and net biomass increment rates suggested several species were worthy of further tests for use in forestry.Our study provides an example for screening native tree species from natural forests for forestry. Because native tree species are better for local ecosystems, our study will also contribute to biodiversity conservation in plantations.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/rs12244071
