Hydrologic Effects of a Changing Forest Landscape (2008) / Chapter Skim
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4 From Principles to Prediction: Research Needs for Forest Hydrology and Management
4 From Principles to Prediction: Research Needs for Forest Hydrology and Management
Pages 75-94
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From page 75... ...
Forest hydrologists have long recognized the need to understand indirect and interacting effects of forest management at much larger spatial scales and longer temporal scales than is possible in plot studies, process studies, and watershed experiments. Indirect effects are responses to forest management that are displaced in time or space, such as fire suppression leading to insect outbreaks that affect forest hydrology.
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From page 76... ...
This problem of prediction in ungauged basins has preoccupied hydrology researchers for several decades, and is compounded by a lack of information about how direct hydrologic effects interact under the multiple sets of specific conditions that occur in changing forest landscapes. By examining forest hydrologic processes under a wide range of conditions, landscape-scale studies could provide data and understanding to help extend basic forest hydrology principles to make predictions needed by water managers.
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From page 77... ...
de veloped in small, homogeneous watersheds Road networks are a pervasive feature of forest landscapes (Figure 4-2)
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From page 78... ...
Research Need: Landscape-scale studies of the effects of road networks and road decommissioning on water quantity and quality in larger watersheds and landscapes, particularly during extreme storm events TEMPORAL RESEARCH NEEDS Water management systems have been designed and operated under the assumption that hydrologic variables such as annual water yield, while varying over time, can be predicted reliably based on instrument records. However, increased understanding of long-term variability and trends in climate has undermined this assumption (Milly et al., 2008; Barnett et al., 2008)
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From page 79... ...
Regional Forest Histories in the United States Each region of the United States has a different history of forest conversion and management by humans that has yielded forests of different types with different capacities to produce clean, abundant water. Hydrologic effects of regional forest histories in most areas were not documented and may be difficult, but not impossible, to reconstruct.
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From page 80... ...
. Research Need: Studies of the direct effects of exotic tree species introduction or removal and indirect effects of introduced insects and diseases, on water quantity and quality from forests.
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From page 81... ...
. The longer-term, indirect and interacting effects of fire suppression on forest ecology, water yield, and water quality over large watersheds are difficult to estimate because the changes in forest density and composition are largely undocumented.
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From page 82... ...
Research Need: Studies of the indirect and interacting effects on water yield and quality of reduced grazing by domestic cattle and sheep and of predator removal and reintroduction on ungulate browsing in riparian forests. Future Climate Change Effects on Forests Climate changes over the past half-century are likely to have major effects on water quantity and timing from forests; some of these effects are already apparent.
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From page 83... ...
Current issues involving forests and water encompass practices that extend beyond the traditional scope of timber production and now include multiple public and private groups, past and future land use trends, and non-market resource valuation and trading schemes. Changing forest landscapes also include rapid changes in the public policy setting.
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From page 84... ...
. Much is known about the localized and larger-scale effects of urbanization on hydrology, but it is not clear whether the hydrologic effects of exurban sprawl can be predicted by these past studies because of differences between sprawl and urbanization.
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From page 85... ...
Research Need: Studies of effects on water quantity and quality of contemporary forest management on public lands, including thinning for fuel reduction or forest restoration, salvage logging, road decommissioning, and redesigned riparian buffers. CUMULATIVE WATERSHED EFFECTS Cumulative watershed effects (CWEs)
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From page 86... ...
However, all three of these studies represent the spatial patterns of forests in large watersheds, implicitly draw on principles of forest hydrology, and aggregate scientific principles relevant to policy making at the large-watershed scale. These studies illustrate the potential for forest hydrologists to use geospatial and geostatistical tools to analyze and display hydrologic processes in large, hetero geneous watersheds, and they are excellent examples of how forest hydrology
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From page 87... ...
Today, forest and water managers need predictions of direct, indirect, and interacting hydrologic responses to changing forest landscapes and guidance in applying these predictions at the scales of large watersheds, landscapes, and regions, over multiple decades. Spatial, temporal, and socioeconomic factors and climate are important sources of change in forested landscapes, and each of these has research needs and challenges associated with improving forest hydrology applications to manage forests for forest and water resources.
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From page 88... ...
. It combines technological capacities for reconstructing past landscapes and modeling future landscapes with public consultation to provide a long-term, large-area perspective on the combined effects of multiple policies and regulations affecting the quality of the environment and natural resources within a geographic area.
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From page 89... ...
FROM PRINCIPLES TO PREDICTION 89 FIGURE 4-4 Trajectories of landscape change in the Willamette River Basin, from preEuroAmerican settlement, to ca. 1990, to three alternative futures for 2050.
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From page 90... ...
Forests are seen by some to be the vacant part of the landscape, waiting for a higher and better use. However, forests are essential to maintaining basic environmental functions, and explicit methods to maintain forest on the landscape will be needed to meet basic water quality goals.
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From page 91... ...
FROM PRINCIPLES TO PREDICTION 91 FIGURE 4-5 Classification of land cover west of the Chesapeake Bay. White and red areas are urban and impervious zones, yellow is agriculture, and green is forest.
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From page 92... ...
Forests in the watershed are managed for timber production and other uses, but these uses have the potential to adversely affect water quality and quantity in the reservoir. To protect the municipal water resources, a decision support system (the Watershed Forest Management Information System)
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From page 93... ...
Watershed Forest Management Information System (WFMIS) User's Guide Version 1.0.
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From page 94... ...
Barten. Watershed Forest Management Information System (WFMIS)
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