riparian forest buffer

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


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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


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Why use Riparian Forest Buffers?


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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


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


infrastructure

(+) Recreation


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?


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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


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Create wildlife habitat


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


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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


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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


http://www.unl.edu/nac/riparianforestbuffers.htm

http://www.centerforagroforestry.org/practices/rb.php

http://www.aftaweb.org/riparian_buffers.php

http://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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