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R. B. Mapa - One of the best experts on this subject based on the ideXlab platform.
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Effect of reforestation using Tectona grandis on infiltration and soil water retention
Forest Ecology and Management, 1995Co-Authors: R. B. MapaAbstract:Many studies have reported changes in the soil physical properties of tropical soils after Deforestation, whereas studies on reforestation are scarce. This paper reports on the effects of reforestation using Tectona grandis on infiltration and soil water retention of a Rhodudult in Sri Lanka. Adjacent land which has been reforested, cultivated and neglected as grassland for more than 12 years was studied. The results showed that the reforested land has the highest steady infiltration rate. This is due to better soil structure and more macro-pores created by root activity and high organic matter content. The soil water retention at any given suction was highest in the reforested soil at both depths studied. The increase in water retention at low suctions is attributed to soil structure development and that at higher suctions to the hydrophilic nature of organic matter. The cultivated and grassland soils did not show any significant difference in infiltration or soil water retention. The bulk density was lowest in reforested soils, indicating high porosities. This illustrates that reforested areas can accept and store more water than cultivated and grassland areas. Even though the plant available water did not show any significant increase with reforestation, increased infiltration and water retention will decrease surface run off and conserve soil and water, restoring the hydrological balance, a major objective of reforestation in these areas.
Ning Liu - One of the best experts on this subject based on the ideXlab platform.
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Forest-water interactions in the changing environment of south-western Australia
Annals of Forest Science, 2019Co-Authors: Richard Harper, K. R. J. Smettem, J. K. Ruprecht, B. Dell, Ning LiuAbstract:AbstractKey messageIn a major Australian city, water supply has been decoupled from forests as a result of management and climate change. Water yield and quality are closely related to forest cover and have been manipulated through broad-scale intervention. The forests remain important for biodiversity protection and considering water as a forest product will fund interventions that maintain the forest’s environmental values.ContextPerth, an Australian city of 2 million people and a potable water demand of 300 GL/year, occurs in a region that has experienced a decline in rainfall and a major reduction in surface runoff to water supply reservoirs over the last 40 years. This has led to a major impact on water policies, with the collapse of surface water supply from forested watersheds resulting in the almost complete substitution of Perth’s water supply with groundwater and desalinated water. Thus, water supply has been decoupled from forests and forest management processes.AimsIn this paper, we review the interactions between forest cover and water supply in the drying environment of south-western Australia, exploring studies on the hydrological effects of extensive Deforestation for agricultural development, widespread reforestation, forest management, and reduced annual rainfall. We draw conclusions applicable to other regions that are experiencing the combined impacts of climate change and pressures from land-use intensification.ResultsWe find that streamflow and water quality are clearly linked to forest cover and this is affected by both climate and forest management. Streamflow increases with a reduction of forest cover (through Deforestation or thinning) and decreases with reforestation and reduced rainfall. Stream salinity increases with Deforestation and decreases with reforestation. Hydrological responses occur where forest cover treatments have been applied and maintained at watershed-scales. Surprisingly, where water yield or quality has been improved, this has not been rewarded financially and there is a need to develop methods of financing treatments to maintain streamflow.ConclusionWhereas forests were initially maintained for water and timber supply, with biodiversity protection as a co-benefit without a defined value, the decoupling of forests from water supply has substantially reduced the financial resources for any form of direct forest management. As the forests remain important for biodiversity protection, a key recommendation is to consider water as a forest product and thus provide funds for watershed-scale treatments, such as forest thinning, that maintain the forest’s environmental values in a drying climate.
Richard J Horwitz - One of the best experts on this subject based on the ideXlab platform.
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riparian Deforestation stream narrowing and loss of stream ecosystem services
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Bernard W Sweeney, Thomas L. Bott, John K Jackson, Louis A Kaplan, Denis J Newbold, Laurel J Standley, Cully W Hession, Richard J HorwitzAbstract:A study of 16 streams in eastern North America shows that riparian Deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of Deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries.
Thomas Rudel - One of the best experts on this subject based on the ideXlab platform.
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forest transitions trade and the global displacement of land use
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Patrick Meyfroidt, Thomas Rudel, Eric F LambinAbstract:Reducing tropical Deforestation is an international priority, given its impacts on carbon emissions and biodiversity. We examined whether recent forest transitions—a shift from net Deforestation to net reforestation—involved a geographic displacement of forest clearing across countries through trade in agricultural and forest products. In most of the seven developing countries that recently experienced a forest transition, displacement of land use abroad accompanied local reforestation. Additional global land-use change embodied in their net wood trade offset 74% of their total reforested area. Because the reforesting countries continued to export more agricultural goods than they imported, this net displacement offset 22% of their total reforested area when both agriculture and forestry sectors are included. However, this net displacement increased to 52% during the last 5 y. These countries thus have contributed to a net global reforestation and/or decrease in the pressure on forests, but this global environmental benefit has been shrinking during recent years. The net decrease in the pressure on forests does not account for differences in their ecological quality. Assessments of the impacts of international policies aimed at reducing global Deforestation should integrate international trade in agricultural and forest commodities.
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tropical forests regional paths of destruction and regeneration in the late twentieth century
2005Co-Authors: Thomas RudelAbstract:List of FiguresList of TablesPrefaceAcknowledgments1. Introduction2. Theory and Method in Studying Regional Deforestation Processes3. Central America and the Caribbean: Island and Isthmus Deforestation4. The Amazon Basin: The Breakdown of Passive Protection5. West Africa: From Cocoa Groves in Forests to Food Crops in Scrub Growth6. Central Africa: Passive Protections for Rain Forests7. East Africa: Sustainable Spots Surrounded by Degrading Expanses8. South Asia: A Turning Point for Forests?9. Southeast Asia: Deforesting the Lowlands, Afforesting the Highlands10. Through a Regional Lens: Conservation Policies in Large and Small ForestsAppendix: Case Studies and Accompanying QCAs for Each RegionNotesReferencesIndex
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a tropical forest transition agricultural change out migration and secondary forests in the ecuadorian amazon
Annals of The Association of American Geographers, 2002Co-Authors: Thomas Rudel, Diane C Bates, Rafael MachinguiashiAbstract:Could old colonization zones in the urbanizing and industrializing countries of Latin America become sites for a tropical forest transition in which reforestation becomes more prevalent than Deforestation? We try to answer this question through a case study of land-use change and migration since 1985 in a long-settled region of the Ecuadorian Amazon. Data from remote sensing analyses, household surveys, and land-use maps of individual farms reveal two disparate patterns of reforestation in the region, one on peripheral lands far from roads and the other on lands close to roads. The former pattern characterizes most places experiencing a forest transition; the latter pattern does not. Roadside reforestation has occurred in part because Amerindian smallholders have abandoned cattle ranching in order to practice short-cycle shifting cultivation of crops for expanding urban and export markets. This example suggests that tropical forest transitions may differ from earlier temperate forest transitions in that r...
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is there a forest transition Deforestation reforestation and development1
Rural Sociology, 1998Co-Authors: Thomas RudelAbstract:Abstract Environmental social scientists have recently begun to use the term 'forest transition' to describe how forest cover changes as economic development occurs in nations. The hypothesized transition occurs as follows. An initial surge in economic activity in impoverished societies spurs Deforestation, but as economic activity continues to intensify and cities grow larger, a 'turnaround' occurs, and Deforestation gives way to reforestation. This paper uses cross-national data from five successive surveys of world forest resources to assess this empirical claim. A turnaround in forest cover trends does occur in a significant number of nations. The paper also evaluates two explanations for the turnaround, a wood scarcity hypothesis derived from microeconomic theory and an industrialization hypothesis linked to central place theory. It finds period specific support for the industrialization hypothesis. The paper concludes with a brief discussion of the implications of these findings for proposals to alleviate the biodiversity crisis through programs of reforestation.
Mark Wishnie - One of the best experts on this subject based on the ideXlab platform.
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initial performance and reforestation potential of 24 tropical tree species planted across a precipitation gradient in the republic of panama
Forest Ecology and Management, 2007Co-Authors: Mark Wishnie, Daisy H Dent, Emilio Mariscal, Jose Deago, Norma Cedeno, Diogenes Ibarra, Richard Condit, P M S AshtonAbstract:Decades of Deforestation and unsustainable land use have created large expanses of degraded lands across Central America. Reforestation may offer one means of mitigating these processes of degradation while sustaining resident human communities. However, a lack of information regarding tree species performance has been identified as an important limitation on the success and adoption of diversified reforestation strategies. We analyzed the initial growth of 22 native and 2 exotic tree species planted at three sites across a precipitation gradient in the Republic of Panama (1100–2200 mm year � 1 ), and identify promising species for use in forest restoration, timber production and on-farm systems. At all sites, Acacia mangium, Diphysa robinoides, Gliricidia sepium, Guazuma ulmifolia and Ochroma pyramidale rapidly developed large, dense crowns and attained canopy closure after just 2 years. These species might be used in restoration efforts to rapidly stabilize soils and establish crown cover. As nitrogen-fixing legumes, D. robinoides and G. sepium may also have the potential to increase soil fertility. Several species valued for their timber performed well at all sites attaining high wood volume indices, these species included Tectona grandis, Pachira quinata and Tabebuia rosea. Albizia guachapele and Samanea saman were among the best performers at the driest site. The most promising species for use in silvopastoral systems varied among sites;A. guachapele,G. sepium,S.saman andG.ulmifolia performed best at the driest site, whileG.sepium,G. ulmifolia and Spondias mombin were the top performers at the two wetter sites. It is hoped that the results of this trial will improve the success of reforestation efforts by allowing landholders to select species based upon both local site conditions and their specific reforestation objectives. # 2007 Elsevier B.V. All rights reserved.
