Hydrologic Effects of a Changing Forest Landscape (2008) / Chapter Skim
Currently Skimming:
Summary
Summary
Pages 1-12
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
convene a committee to study and produce a report on the present understanding of forest hydrology, connections between forest management and attendant hydrologic effects, and directions for future research and management needs to sustain water resources from forested landscapes (see Statement of Task, Box S-1)
|
From page 2... ...
STATE OF FOREST HYDROLOGY SCIENCE Forest hydrology is the study of water in forests: its distribution, storage, movement, and quality; hydrologic processes within forested areas; and the delivery of water from forested areas. Forest hydrology research uses field measurements, experiments, and modeling to characterize and predict hydrologic processes and their responses to natural disturbance and management of forests.
|
From page 3... ...
A pressing question for forest hydrologists is whether cutting trees in forested headwaters will augment water yield downstream for agricultural, municipal, or other uses while maintaining desired ecological attributes associated with forested landscapes. Although it is possible to increase water yield by harvesting timber, the increases in water yield from vegetation removal are often small and unsustainable, and timber harvest of areas sufficiently large to augment water yield can reduce water quality.
|
From page 4... ...
Changes in 3. Changes in forest flowpaths in water, soil structure soil and subsoil chemistry Specific hydrologic responses Hydrologic responses within forests: Interception & transpiration Infiltration & overland flow Water flowpaths in soil and subsoil Changes in watershed outputs: Water yield Floods Lowflows Sediment Chemistry Temperature Managing forests for water FIGURE S-1 Forest hydrology examines the flowpaths and storage of water in forests and how forest disturbance and management modify hydrologic responses.
|
From page 5... ...
Predictions are needed to understand the indirect and interacting hydrologic responses to changes in forested landscapes associated with climate change, forest disturbances, forest species composition and structure, and land development and ownership, and how these changes will affect water quantity and quality downstream and over long time scales. A Landscape Approach to Forest Hydrology A landscape perspective on forest hydrology links scientific principles from plot, process, and small watershed scales with indirect and interacting hydro
|
From page 6... ...
These legacies affect hydrologic processes. The research needs for a landscape approach to forest hydrology science involve studies that determine the following: • How general principles developed in small, homogeneous watersheds can be used to improve predictions of hydrologic responses across large, heterogeneous watersheds and landscapes; • How forests and forest management activities affect hydrologic processes, runoff, and water quality as a result of their position within a watershed; • How local effects of roads can be scaled up to quantify the effects of road networks on water quantity and quality in larger watersheds and regions, particularly during large storms; and • How long-term legacies of forest disturbance and forest management practices affect forests, water quantity, and water quality.
|
From page 7... ...
Research needs for understanding hydrologic responses to forest management involve: • Studies that determine how contemporary forest management on public and private lands affects water quantity and quality and • Improved forest hydrology models that reliably simulate the hydrologic and water quality responses of watersheds in varied forest conditions. Cumulative Watershed Effects One of the biggest threats to forests, and the water that derives from them, is the permanent conversion of forested land to residential, industrial, commercial, and infrastructure uses.
|
From page 8... ...
More research is needed to better predict indirect effects of climate change, including evaluations of how changes in forests and forest management influence hydrologic response. The research needs related to the hydrologic effects of climate change include: • Direct effects of climate change on hydrologic processes in forests and on water yield and water quality from forests; • Indirect effects of climate change on forest structure and species composition and the consequences of these changes for water yield and water quality; and • Indirect effects of climate change on forest disturbance, including wildfires, insects and diseases, and the consequences of these changes for water yield and water quality.
|
From page 9... ...
To assist the evolution of BMPs, managers should: • Catalogue individual or agency BMP use, design, and goals at the national level and make this information available to the public; • Monitor BMP activities for effectiveness, and coordinate analyses of monitoring data for use in an adaptive management framework; and • Design adaptive management approaches for forested watersheds that coordinate management, research, monitoring, and modeling efforts. Recommendations for Citizens Cumulative watershed effects, changes in land ownership and management, changing population and development patterns, and water supply concerns have spurred activity to protect watersheds and water quality from the grass-roots, community level.
|
From page 10... ...
10 TABLE S-2 Current Understanding, Research Needs, and Recommendations for Sustaining Water Supplies from Forests Information Gaps and Research Current Understanding Recommended Actions Needs Science The body of forest hydrology science Hydrologic effects of past Enhance, maintain, and reestablish derives from almost 100 years of management, such as fire abandoned small watershed studies at small spatial and time suppression, clear-cutting, roads studies scales Ways to quantify hydrologic Combine existing data from the large Forest hydrology science has responses at larger spatial and body of small watershed studies established general principles that temporal scales and analyze them for large-scale are understood with a high degree Ways to scale up findings from small trends as a meta-experiment of certainty describing direct spatial and short time scales to Use new technologies, including hydrologic effects of forest larger spatial and longer time sensor networks and remote management and disturbance scales sensing, to improve understanding Effects can be understood through Use general principles to predict of forest hydrology in changing changes in indirect hydrologic responses to landscapes • Forest structure changes in forest landscapes and Engage in adaptive management to • Magnitudes, rates, and flowpaths interacting responses to forest help managers and community • Erosion, nutrient cycling, and soil management and disturbance groups design monitoring chemistry strategies, develop and test models, and conduct studies Reduced forest cover results in relevant to management increased water yield that is • Generally short-lived • Greatest during times of water excess rather than water scarcity • Small or undetectable in water scarce areas • May be associated with a decline in water quality Management Forests in the United States are Assessment of BMP effectiveness Advance BMP evolution by managed for a wide range of goals Principles and practices of adaptive rigorously assessing and and objectives: timber harvesting, management developing new BMPs and
|
From page 11... ...
road networks and road measuring their effectiveness construction, high-severity At the federal level, provide wildfires, and exurban sprawl sustained support for adaptive modify forest hydrology management activities, enabling Forest management practices are managers to partner with scientists evolving in response to to design and implement environmental change, social and monitoring, develop and test economic forces, and technological models, and conduct studies developments relevant to management issues BMPs are used to mitigate impacts Increase role of agency technical on water resources from forest expertise in watershed councils management activities Community Integrated watershed management How watershed councils and their Use watershed councils to meet is a viable vehicle for both stakeholders view and utilize forest multiple goals of integrated community groups and state and hydrology science and scientific watershed management at the federal agencies to help manage expertise from federal agencies community level water and forest resources at the How industry-sponsored green Expand the number and influence of community scale certification and federal forest watershed councils. Citizens groups can influence local stewardship contracts affect water Engage in adaptive management and integrated watershed quantity and quality from forests with scientists and managers management Community watershed groups benefit from state and federal agency technical expertise Existing laws can be used to strengthen the standing and influence of watershed councils New laws offer increased opportunities for community involvement 11
|
From page 12... ...
The forest landscape is dynamic: it is continually changing in response to climate, natural disturbance, and forest management, as well as demographics and development patterns. Forest hydrology science and management are adapting as land use and ownership within forested watersheds become more heterogeneous, changes in climate and its effects are becoming more evident, and new technologies provide improved capability to predict and visualize cumulative watershed effects over larger spatial scales and longer periods of time.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.