riparian forest buffer
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Riparian Forest BufferAn agroforestry practice
This presentation was developed by the USDA National Agroforestry Center
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Define riparian forest buffer Describe the benefits and uses Recognize basic design considerations Identify potential riparian buffer crops
Presentation Objectives
Riparian forest buffer
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What is Agroforestry?
…the intentional combining of agriculture and working trees to
create sustainable farming systems.
Silvopasture
Alley cropping
Windbreaks
Forest farming
Riparian buffer
Riparian forest buffer
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What: An area of predominantly trees and/or shrubs located adjacent to and up-gradient from watercourses or water bodies
Where: On areas adjacent to permanent or intermittent streams, lakes, ponds, wetlands and areas with ground water recharge that are capable of supporting woody vegetation.
Riparian Forest Buffer
Riparian forest buffer
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Why use Riparian Forest Buffers?
Riparian forest buffer
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Create shade to lower water temperatures to improve habitat for cold water aquatic organisms
Provide a source of detritus and large woody debris for aquatic and terrestrial organisms
Create wildlife habitat and establish wildlife corridors Restore natural riparian plant communities Reduce excess amounts of sediment, organic material, nutrients
and pesticides in surface runoff and reduce excess nutrients and other chemicals in shallow ground water flow
Provide a harvestable crop of timber, fiber, forage, fruit, or other crops consistent with other intended purposes.
Provide floodplain protection Increase carbon storage
Use Riparian Forest Buffers to:
*Source: NRCS National Standard 391
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Riparian Forest Buffer
Canopy cover and vertical vegetative
structure from established plants
Canopy cover and vertical vegetative
structure from established plants
Wood fiber in established
plants
Wood fiber in established
plants
Woody plant root systems
of established
plants
Woody plant root systems
of established
plants
(+) Trapping of sediment
and sediment-attached pollutants
(+) Trapping of sediment
and sediment-attached pollutants
(+) Uptake of soil nutrients
during growing season
(+) Uptake of soil nutrients
during growing season
(+) Infiltration of precipitation
and soil storage
(+) Infiltration of precipitation
and soil storage
(-) Streambank erosion and
sedimentation
(-) Streambank erosion and
sedimentation
(+) Denitrificatio
n of soil nitrates
(+) Denitrificatio
n of soil nitrates
(+) Carbon storage
(+) Carbon storage
(-) Crop production
(non-woody)
(-) Crop production
(non-woody)
(-) Crop business and
support infrastructure
(-) Crop business and
support infrastructure
(+) Quality of receiving waters (+) Quality of
receiving waters
(+) Income and income
stability (individuals
and community)
(+) Income and income
stability (individuals
and community)
(-) Atmospheric
CO2 and greenhouse
effect
(-) Atmospheric
CO2 and greenhouse
effect
(+) Wood-forest
business and support
infrastructure
(+) Wood-forest
business and support
infrastructure
(+) Shade (+) Shade (+) Arboreal
and understory habitat
(+) Arboreal and understory
habitat
(+) Aesthetics (+) Aesthetics
(-) Stream water temperature
(-) Stream water temperature
I (+) Forest and forest
edge wildlife
I (+) Forest and forest
edge wildlife
(+) Recreation opportunities
(+) Recreation opportunities
(+) Stream fauna, e.g., fish,
invertebrates
(+) Stream fauna, e.g., fish,
invertebrates (+) Recreation
business and support
infrastructure
(+) Recreation
business and support
infrastructure
(-) Income and income stability (individuals and
community)
(-) Income and income stability (individuals and
community)
(-) Non-woody agricultural land(-) Non-woody
agricultural land
StartStartInitial Setting: Former riparian forests and habitat used for forage, cropland, speculation property, or other non-forest use. Includes cutover riparian zones within forested areas.
(+) Aquatic health for humans, domestic and wild animals; reduced
costs
(+) Aquatic health for humans, domestic and wild animals; reduced
costs
(+) Wood fiber growth rate
(+) Wood fiber growth rate
(-) Later wood fiber growth
rate
(-) Later wood fiber growth
rate
Periodic tree removal
Harvested wood fiber (manufactured wood products) and
other tree/understory-related products
Harvested wood fiber (manufactured wood products) and
other tree/understory-related products
(+) Landowner
income; contractor
income
(+) Landowner
income; contractor
income
LEGEND
Created by practice
Direct effect Direct effect
Indirect effect Indirect effect
Cumulative effect Cumulative effect
pathway(+) increase; (-) decrease
Associated treatment
(+) Detritus and large woody
debris in streams
(+) Detritus and large woody
debris in streams
(+) Leaf/debris
fall and woody plant
mortality
(+) Leaf/debris
fall and woody plant
mortality
What are the Effects of Riparian Forest Buffers?
Riparian forest buffer
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Design Considerations
Three-zone buffer system Buffer widths and zones
influence use and functionality
Minimum zone widths will vary by region
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Location Species Height Density Length Management and use Operation and maintenance
Other Design Considerations
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Table. Proportion of National Stream and River Mileage in Headwater Streams (Leopold, Wolman, Miller, 1964)
Stream Order* Number of Streams
Total Length of Streams (miles)
Mean Drainage Area (square
miles)**
1 1,570,000 1,570,000 1.0
2 350,000 810,000 4.7
3 80,000 420,000 23
4 18,000 220,000 109
5 4,200 116,000 518
6 950 61,000 2,460
7 200 30,000 11,700
8 41 14,000 55,600
9 8 6,200 264,000
10 1 1,800 1,250,000
Total 2,023,400 3,250,000 N/A
*stream order based on Strahler (1957) method, analyzing maps at a scale of 1:24,000
**cumulative drainage area, including tributaries
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Sun angle will vary by season, latitude and, of course, by time of day.
Understand what is happening at the site and plan accordingly.
In mountainous terrain, elevation and topographic shading can influence layout.
Create Shade
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Detritus and large debris are particularly important for lower order stream/riparian food chains and downstream effects on higher order streams.
Placement in close proximity to the stream or water body insures that some leaf drop, twigs, and other detritus (and eventually large woody debris) enters the aquatic system.
Provide detritus and woody debris
Riparian forest buffer
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Create wildlife habitat
Riparian forest buffer
Use widths to match desired conditions
The value of riparian habitat is greatly increased if adjacent upland habitat is created and complementary
Natural mortality can increase habitat diversity and mimic natural development
Full site functionality takes time
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Wildlife usually benefit most from a mosaic of natural plant communities
Connect fragmented riparian forests.
Isolated patches or short strips may be poorly utilized or act as a magnet for predators
Use native species where ever possible
Restore natural plant communities
Riparian forest buffer
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Understand the origin and boundaries of the source contaminants and locate the buffer down-gradient from them.
Contaminants (sediment, chemicals, etc.) may be transported by surface sheet or concentrated flows or by subsurface flows.
Subsurface flows in many settings bypass riparian buffer root systems
Reduce excess contaminants
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Provide harvestable crops Marketable products depend on current and future demand.
Potential products:›wood (sawlogs, post, poles, veneer)
›fiber (pulp, firewood, energy biomass)
›forage (livestock)›fruit (nuts, berries)›other crops (ginseng, mushrooms, herbs and floral greenery, etc.)
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Riparian buffers reduce floodwater velocity and erosive power
Stream debris is blocked from entering cropland, grassland, and urban lands
Roots hold stream banks and keep the soil in place
Peak storm flows may be reduced, lowering flooding levels
Provide floodplain protection
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Riparian buffers are effective at storing carbon
Trees grow rapidly in riparian zones due to favorable moisture and nutrient conditions
Net carbon benefits are realized if the wood fiber is used for solid wood products or fuel
Increase carbon storage
Riparian forest buffer
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Riparian forest buffers provide many benefits and their effects are far reaching
Determine the desired purposes and design to optimize those purposes
Many purposes are partly achieved just by virtue of installing the buffer (carbon storage, contaminant reduction, wildlife habitat, detritus)
Use native species where ever possible unless product-required species are needed to achieve a specific purpose…or if adequate native stock is not available
Summary
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For Additional Information
A number of web sites are available to provide more detailed information on riparian forest buffers. Here are a few:
USDA National Agroforestry Center http://www.unl.edu/nac/riparianforestbuffers.htm
The Center for Agroforestry http://www.centerforagroforestry.org/practices/rb.php
Association for Temperate Agroforestry http://www.aftaweb.org/riparian_buffers.php
USDA Natural Resources Conservation Servicehttp://www.nrcs.usda.gov/wps/portal/nrcs/home
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Acknowledgements
This presentation was developed by the USDA National Agroforestry Center (NAC), Lincoln NE.
NAC is a USDA partnership between the U.S. Forest Service and the Natural Resources Conservation Service.
"The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).
To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer."
"The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).
To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer."
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