scholarly journals Smallholder agriculture results in stable forest cover in riverine Amazonia

2021 ◽  
Author(s):  
Oliver T. Coomes ◽  
Margaret Kalacska ◽  
Yoshito Takasaki ◽  
Christian Abizaid ◽  
Tristan Grupp
Keyword(s):  
Satellite Imagery ◽  
Shifting Cultivation ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Disturbance ◽  
Secondary Forests ◽  
Smallholder Agriculture ◽  
Peruvian Amazon ◽  
Terra Firme ◽  
Old Growth

Abstract Recent studies point to a rapid increase in small-scale deforestation in Amazonia. Where people live along the rivers of the basin, customary shifting cultivation creates a zone of secondary forest, orchards and crop fields around communities in what was once was old-growth terra firme forest. Visible from satellite imagery as a narrow but extensive band of forest disturbance along rivers, this zone is often considered as having been deforested. In this paper we assess forest disturbance and the dynamics of secondary forests around 275 communities along a 725 km transect on the Napo and Amazon rivers in the Peruvian Amazon. We used high-resolution satellite imagery to define the ‘working area’ around each community, based on the spatial distribution of forest/field patches and the visible boundary between old-growth and secondary forests. Land cover change was assessed between ca. 1989 and 2015 using CLASliteTM image classification. Statistical analyses using community and household-level data from the Peruvian Amazon Rural Livelihoods and Poverty (PARLAP) Project identified the predictors of the extent of forest disturbance and the dynamics of secondary forests around communities. Although shifting cultivation is the primary driver of old-growth forest loss, we find that secondary forest cover which replaces old-growth forests is stable through time, and that both the area and rate of expansion into old-growth forests are modest when compared to forest conversion in Peru for colonization and plantation development. Our findings challenge the notion that smallholder agriculture along rivers is an important threat to terra firme forests in Amazonia and point to the importance of protecting forests on community lands from loggers, colonists and other outsiders.

scholarly journals The Role of Recent (1985–2014) Patterns of Land Abandonment and Environmental Factors in the Establishment and Growth of Secondary Forests in the Iberian Peninsula

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 817
Author(s):  
Marina Palmero-Iniesta ◽  
Josep Maria Espelta ◽  
Mario Padial-Iglesias ◽  
Òscar Gonzàlez-Guerrero ◽  
Lluís Pesquer ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Iberian Peninsula ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Growth ◽  
Deciduous Forests ◽  
Secondary Forests ◽  
Study Region ◽  
Leaf Habit ◽  
Forest Establishment

Farmland abandonment has been a widespread land-use change in the Iberian Peninsula since the second half of the 20th century, leading to the establishment of secondary forests across the region. In this study, we aimed to address changes in the recent (1985–2014) emergence patterns of these forests and examine how environmental factors affected their growth by considering differences in leaf-habit types. We used a combination of Landsat-derived land-cover maps and aboveground biomass (AGB) maps from the European Space Agency to assess the secondary forest establishment and growth, respectively, in the study region. We also obtained a set of topographic, climatic and landscape variables from diverse GIS layers and used them for determining changes over time in the environmental drivers of forest establishment and AGB using general linear models. The results highlight that secondary forest cover was still increasing in the Iberian Peninsula at a rate above the European average. Yet, they also indicate a directional change in the emergence of secondary forests towards lower and less steep regions with higher water availability (mean rainfall and SPEI) and less forest cover but are subjected to greater drought events. In addition, these environmental factors differentially affect the growth of forests with different leaf-habit types: i.e., needleleaf secondary forests being less favoured by high temperature and precipitation, and broadleaf deciduous forests being most negatively affected by drought. Finally, these spatial patterns of forest emergence and the contrasting responses of forest leaf-habits to environmental factors explained the major development of broadleaf evergreen compared to broadleaf deciduous forests and, especially, needleleaf secondary forests. These results will improve the knowledge of forest dynamics that have occurred in the Iberian Peninsula in recent decades and provide an essential tool for understanding the potential effects of climate warming on secondary forest growth.

Bewirtschaftung von tropischen Sekundärwäldern

2002 ◽  
Vol 46 (1) ◽  
Author(s):  
Dietrich Schmidt-Vogt
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Stand Structure ◽  
Secondary Forest ◽  
Secondary Forests ◽  
Tropical Asia ◽  
Land Use Systems ◽  
The Future ◽  
The Tropics ◽  
Primary Forests

AbstractManagement of secondary tropical forests: a new perspective for sustainable use of forests in Asia. The decline of primary forests in the tropics is leading to a reassessment of the role secondary forests might play within the context of tropical forest management. Recent research has shown that secondary forests in the tropics can be both rich in species and complex in terms of stand structure. There is, moreover, a growing recognition of the importance of secondary forests for traditional subsistence economies in the tropics and of their economic potential for land use systems in the future. Management of secondary forests in Asia as an alternative to the extraction of timber from primary forests but also as one among other options to intensify traditional land use systems has a potential for the future especially because of the existence of vast tracts of valuable secondary forest cover, and because of the store of traditional knowledge that can still be found in tropical Asia.

scholarly journals Mexican agricultural frontier communities differ in forest dynamics with consequences for conservation and restoration

2021 ◽  
Author(s):  
Madelon Lohbeck ◽  
Ben DeVries ◽  
Frans Bongers ◽  
Miguel Martinez-Ramos ◽  
Armando Navarrete-Segueda ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Forest Conservation ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Loss ◽  
Secondary Forests ◽  
High Quality ◽  
Agricultural Frontier ◽  
Forest Regrowth ◽  
Land Availability

Forest regrowth is key to achieve restoration commitments, but we need to better understand under what circumstances it takes place and how long secondary forests persist. We studied a recently colonized agricultural frontier in southern Mexico. We quantified the spatiotemporal dynamics of forest loss and regrowth and tested how temporal variation in climate, and spatial variation in land availability, land quality and accessibility affect forest disturbance, regrowth and secondary forest persistence. Marqués de Comillas consistently exhibits more forest loss than regrowth, resulting in a net decrease of 30% forest cover (1991-2016). Secondary forest cover remained relatively constant while secondary forest persistence increased, suggesting that farmers are moving away from shifting cultivation. Temporal variation in disturbance and regrowth were explained by the annual variation in the Oceanic El Niño index combined with dry season rainfall and key policy and market interventions.Across communities the availability of high-quality soil overrules the effects of land availability and accessibility, but that at the pixel-level all three factors contributed to explaining forest conservation and restoration. Communities with more high-quality soils were able to spare land for forest conservation, and had less secondary forest that persisted for longer. Old forest and secondary forests were better represented on low-quality lands and on communal land. Both old and secondary forest were less common close to the main road, where secondary forests were also less persistent. Forest conservation and restoration can be explained by a complex interplay of biophysical and social drivers across time, space and scale. We warrant that stimulating private land ownership may cause remaining forest patches to be lost and that conservation initiatives should benefit the whole community. Forest regrowth and secondary forest persistence competes with agricultural production and ensuring farmers can access restoration benefits is key to success.

Long-term performance and herbivory of tree seedlings planted into primary and secondary forests of Central Amazonia

2013 ◽  
Vol 29 (4) ◽  
pp. 301-311 ◽  
Author(s):  
Julieta Benítez-Malvido ◽  
Miguel Martínez-Ramos
Keyword(s):  
Secondary Forest ◽  
Tree Seedlings ◽  
Secondary Forests ◽  
Old Growth ◽  
Old Growth Forest ◽  
Central Amazonia ◽  
One Year ◽  
Term Performance ◽  
Over Time

Abstract:Plant survival and growth in tropical rain forest are affected by different biotic and abiotic forces. As time elapses and plants grow the relative importance of such forces as regeneration inhibitors and/or facilitators may change according to habitat and species. To detect within- and among-species divergences in performance over time in different habitats we followed, for nearly a decade, the survival, growth and herbivory of seedlings of the native tree species: Chrysophyllum pomiferum, Micropholis venulosa and Pouteria caimito. In Central Amazonia, young seedlings were planted into old-growth and secondary forests dominated by Vismia spp. One year after planting, C. pomiferum ranked first (i.e. fast growth, fewer dead and less herbivory) for both habitats, followed by M. venulosa and P. caimito. Initial trends changed over time. In the long term, M. venulosa ranked first for both habitats, followed by C. pomiferum and P. caimito ranked consistently lowest. Within-species divergences in growth and herbivory were greater in secondary forest. Initial seedling responses cannot always be used to predict species persistence in the long term. Contrary to previous estimations, old-growth-forest species can persist under Vismia spp. stands, at least when planted.

scholarly journals Constraints or Cooperation? Determinants of Secondary Forest Cover Under Shifting Cultivation

2011 ◽  
Vol 40 (3) ◽  
pp. 471-487 ◽  
Author(s):  
Heather Klemick
Keyword(s):  
Shifting Cultivation ◽  
Crop Production ◽  
Forest Cover ◽  
Econometric Model ◽  
Market Access ◽  
Secondary Forest ◽  
Market Failures ◽  
Cultivation System ◽  
Using Data ◽  
On Farm

This study examines the drivers of land use in a shifting cultivation system with forest fallow. Forest fallow provides on-farm soil quality benefits, local hydrological regulation, and global public goods. An optimal control model demonstrates that farmers have an incentive to fallow less than is socially optimal, though market failures limiting crop production can have a countervailing effect by encouraging fallow. An econometric model estimated using data from the Brazilian Amazon suggests that fallowing does not result from internalization of local fallow services but instead is associated with poor market access and labor and liquidity constraints.

scholarly journals Recovery of Functional Diversity Following Shifting Cultivation in Tropical Monsoon Forests

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 506 ◽  
Author(s):  
Fuying Deng ◽  
Yunling He ◽  
Runguo Zang
Keyword(s):  
Functional Diversity ◽  
Functional Traits ◽  
Shifting Cultivation ◽  
Forest Ecosystems ◽  
Recovery Process ◽  
Secondary Forests ◽  
Old Growth ◽  
Old Growth Forests ◽  
Tropical Monsoon ◽  
Monsoon Forests

The relationship between biodiversity and ecosystem functioning is an important issue in ecology. Plant functional traits and their diversity are key determinants of ecosystem function in changing environments. Understanding the successional dynamics of functional features in forest ecosystems is a first step to their sustainable management. In this study, we tested the changes in functional community composition with succession in tropical monsoon forests in Xishuangbanna, China. We sampled 33 plots at three successional stages—~40-year-old secondary forests, ~60-year-old secondary forests, and old growth forests—following the abandonment of the shifting cultivation land. Community-level functional traits were calculated based on measurements of nine functional traits for 135 woody plant species. The results show that the community structures and species composition of the old-growth forests were significantly different to those of the secondary stands. The species diversity, including species richness (S), the Shannon–Weaver index (H), and Pielou’s evenness (J), significantly increased during the recovery process after shifting cultivation. The seven studied leaf functional traits (deciduousness, specific leaf area, leaf dry matter content, leaf nitrogen content, leaf phosphorus content, leaf potassium content and leaf carbon content) changed from conservative to acquisitive syndromes during the recovery process, whereas wood density showed the opposite pattern, and seed mass showed no significant change, suggesting that leaf traits are more sensitive to environmental changes than wood or seed traits. The functional richness increased during the recovery process, whereas the functional evenness and divergence had the highest values in the 60-year-old secondary communities. Soil nutrients significantly influenced functional traits, but their effects on functional diversity were less obvious during the secondary succession after shifting cultivation. Our study indicates that the recovery of tropical monsoon forests is rather slow; secondary stands recover far less than the old growth stands in terms of community structure and species and functional diversity, even after about half a century of recovery, highlighting the importance of the conservation of old growth tropical monsoon forest ecosystems.

scholarly journals On the Management of Large-Diameter Trees in China’s Forests

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 111 ◽  
Author(s):  
Chuping Wu ◽  
Bo Jiang ◽  
Weigao Yuan ◽  
Aihua Shen ◽  
Shuzhen Yang ◽  
...  
Keyword(s):  
Biodiversity Conservation ◽  
Forest Cover ◽  
Large Diameter ◽  
Management Strategies ◽  
Ecosystem Functions ◽  
Secondary Forests ◽  
Critical Question ◽  
Old Growth ◽  
Plantation Forests ◽  
Old Growth Forests

Large-diameter trees have mainly been used for timber production in forestry practices. Recently, their critical roles played in biodiversity conservation and maintenance of ecosystem functions have been recognized. However, current forestry policy on the management of large-diameter trees is weak. As China is the biggest consumer of large-diameter timbers, how to maintain sustainable large-diameter timber resources as well as maximize ecological functions of the forests is a critical question to address. Here we summarize historical uses, distribution patterns, and management strategies of large-diameter trees in China. We found that large-diameter trees are mainly distributed in old-growth forests. Although China’s forest cover has increased rapidly in the past decades, large-diameter trees are rarely found in plantation forests and secondary forests. We suggest that knowledge of large-diameter trees should be widely disseminated in local forestry departments, especially their irreplaceable value in terms of biodiversity conservation and ecosystem functions. Protection of large-diameter trees, especially those in old-growth forests, is critical for sustainable forestry. To meet the increasing demand of large-diameter timbers, plantation forests and secondary forests should apply forest density management with thinning to cultivate more large-diameter trees.

Nonfrontier Deforestation in the Eastern Amazon

2010 ◽  
Vol 14 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Arlete Silva de Almeida ◽  
Thomas A. Stone ◽  
Ima Célia G. Vieira ◽  
Eric A. Davidson
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Secondary Forest ◽  
Average Rate ◽  
Landsat Imagery ◽  
Steady Increase ◽  
Initial Increase ◽  
Secondary Forests ◽  
Human Occupation

Abstract While interest in Amazonian deforestation mostly focuses on frontier areas, the amount of forest cover in areas already dominated by human settlement is also changing. Secondary forests play an increasingly important role for maintaining genetic diversity, hydrological functioning, and greenhouse gas emissions of altered landscapes, but secondary forests are also being converted to more intensive agricultural uses. Five dates of Landsat imagery from 1984 to 2002 were analyzed, covering 8000 km2 of the Zona Bragantina of the eastern part of the Brazilian state of Pará, which underwent its most intensive wave of deforestation several decades ago. However, even in this area of relatively long-term human occupation, ongoing decreases of forest cover were found, both in the small remaining areas of mature forest and in the more widespread areas of secondary forests, as human population increased and land use intensified. Although there was an initial increase in the area of secondary forest from 1984 to 1994, there has been a steady decline since then, from 75% secondary forest cover in 1994 to 54% in 2002. The amount of pasture was relatively stable from 1984 to 1994 but more recently has shown a steady increase, reaching 37% cover in 2002. The average rate of carbon loss over the 18-yr study period was 0.9 Mg C ha−1 yr−1 for the 8000 km2 study area. Forests in this long-settled region of eastern Amazonia continue to be degraded, resulting in the loss of ecosystem services and carbon stocks due to continued land-use change.

scholarly journals Understanding Land Cover Change in a Fragmented Forest Landscape in a Biodiversity Hotspot of Coastal Ecuador

2018 ◽  
Vol 10 (12) ◽  
pp. 1980 ◽  
Author(s):  
Xavier Haro-Carrión ◽  
Jane Southworth
Keyword(s):  
Land Cover ◽  
Forest Cover ◽  
Secondary Forest ◽  
Dry Forest ◽  
Training Data ◽  
Forest Types ◽  
Landsat Images ◽  
Old Growth ◽  
Plantation Forests ◽  
Forest Regrowth

Understanding forest cover changes is especially important in highly threatened and understudied tropical dry forest landscapes. This research uses Landsat images and a Random Forest classifier (RF) to map old-growth, secondary, and plantation forests and to evaluate changes in their coverage in Ecuador. We used 46 Landsat-derived predictors from the dry and wet seasons to map these forest types and to evaluate the importance of having seasonal variables in classifications. Initial RF models grouped old-growth and secondary forest as a single class because of a lack of secondary forest training data. The model accuracy was improved slightly from 92.8% for the wet season and 94.6% for the dry season to 95% overall by including variables from both seasons. Derived land cover maps indicate that the remaining forest in the landscape occurs mostly along the coastline in a matrix of pastureland, with less than 10% of the landscape covered by plantation forests. To obtain secondary forest training data and evaluate changes in forest cover, we conducted a change analysis between the 1990 and 2015 images. The results indicated that half of the forests present in 1990 were cleared during the 25-year study period and highlighted areas of forest regrowth. We used these areas to extract secondary forest training data and then re-classified the landscape with secondary forest as a class. Classification accuracies decreased with more forest classes, but having data from both seasons resulted in higher accuracy (87.9%) compared to having data from only the wet (85.8%) or dry (82.9%) seasons. The produced cover maps classified the majority of previously identified forest areas as secondary, but these areas likely correspond to forest regrowth and to degraded forests that structurally resemble secondary forests. Among the few areas classified as old-growth forests are known reserves. This research provides evidence of the importance of using bi-seasonal Landsat data to classify forest types and contributes to understanding changes in forest cover of tropical dry forests.

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