How to estimate future forest cover in a watershed

0 %
100 %
Information about How to estimate future forest cover in a watershed

Published on September 30, 2008

Author: watershedprotection

Source: slideshare.net

How to estimate future forest cover in a watershed

future land cover projections GIS-based method to estimate future land cover in a watershed “ Leafout analysis” focuses on forest cover Local governments and watershed groups can use method to: evaluate the effect of different watershed protection scenarios on future land cover predict future stream health set numeric land cover goals develop watershed protection recommendations

GIS-based method to estimate future land cover in a watershed

“ Leafout analysis” focuses on forest cover

Local governments and watershed groups can use method to:

evaluate the effect of different watershed protection scenarios on future land cover

predict future stream health

set numeric land cover goals

develop watershed protection recommendations

why land cover is important to watersheds Impervious cover – excellent indicator of stream health More than 200 studies on relationship between IC and various measures of stream quality Forest and wetlands are a beneficial cover type from hydrologic, water quality, and habitat standpoint Other pervious areas – majority is often maintained as turf, may include cropland, pasture or grasslands

Impervious cover – excellent indicator of stream health

More than 200 studies on relationship between IC and various measures of stream quality

Forest and wetlands are a beneficial cover type from hydrologic, water quality, and habitat standpoint

Other pervious areas – majority is often maintained as turf, may include cropland, pasture or grasslands

link between forest cover and stream health Stream health rating of Excellent requires no more than 6% IC and at least 65% riparian forest cover (Goetz et al, 2003) Stream health rating of Good requires no more than 10% IC and at least 60% riparian forest cover (Goetz et al, 2003) Watersheds with at least 65% forest cover usually had a healthy aquatic insect community (Booth, 2000)

Stream health rating of Excellent requires no more than 6% IC and at least 65% riparian forest cover (Goetz et al, 2003)

Stream health rating of Good requires no more than 10% IC and at least 60% riparian forest cover (Goetz et al, 2003)

Watersheds with at least 65% forest cover usually had a healthy aquatic insect community (Booth, 2000)

steps for estimating future land cover Identify developed and undeveloped parcels Calculate the area of each zoning category for undeveloped land Identify and subtract protected land from undeveloped land for each zoning category Multiply the remaining buildable land in each zoning category by the corresponding land cover coefficients Calculate the area of each land cover type for developed land and protected land Sum future land cover on buildable, developed and protected land

Identify developed and undeveloped parcels

Calculate the area of each zoning category for undeveloped land

Identify and subtract protected land from undeveloped land for each zoning category

Multiply the remaining buildable land in each zoning category by the corresponding land cover coefficients

Calculate the area of each land cover type for developed land and protected land

Sum future land cover on buildable, developed and protected land

GIS data needs for future land cover analysis Property boundaries and parcel data Current land cover – impervious, forest, turf, etc Zoning Protected land – conservation easements, conservation zones, parkland, stream buffers, steep slopes, wetlands, erodible soils, floodplains (will vary with local regs) Land cover coefficients (more on this later…) Recent aerial photos may also be helpful

Property boundaries and parcel data

Current land cover – impervious, forest, turf, etc

Zoning

Protected land – conservation easements, conservation zones, parkland, stream buffers, steep slopes, wetlands, erodible soils, floodplains (will vary with local regs)

Land cover coefficients (more on this later…)

Recent aerial photos may also be helpful

assumptions Full buildout of the watershed will occur based on allowable zoning (e.g., no rezoning) Current land cover on developed land will remain the same with the future buildout Protected land will remain the same in future buildout scenario Buildable land will be converted to impervious cover, forest, or other pervious cover, as dictated by land cover coefficients

Full buildout of the watershed will occur based on allowable zoning (e.g., no rezoning)

Current land cover on developed land will remain the same with the future buildout

Protected land will remain the same in future buildout scenario

Buildable land will be converted to impervious cover, forest, or other pervious cover, as dictated by land cover coefficients

No buildings. Parcels not selected Parcels intersect with buildings so they are selected as “developed” parcels Step 1: identify developed and undeveloped parcels

Step 1: results

Step 2: calculate the area of each zoning category for undeveloped land

Step 3: identify and subtract protected land from undeveloped land for each zoning category Protected land includes specific parcels that are under permanent conservation (e.g., easements, conservation zones, parkland) Also includes types of land that must be preserved during development according to local regulations: stream buffers, wetlands, steep slopes, erodible soils, floodplains… This will vary locally and requires a little research or local knowledge

Protected land includes specific parcels that are under permanent conservation (e.g., easements, conservation zones, parkland)

Also includes types of land that must be preserved during development according to local regulations: stream buffers, wetlands, steep slopes, erodible soils, floodplains…

This will vary locally and requires a little research or local knowledge

protected lands

undeveloped land…

… minus protected land…

… equals buildable land

Step 3: results buildable land by zoning category

Step 4: multiply the remaining buildable land in each zoning category by the corresponding land cover coefficients Land cover coefficients represent the fraction of a particular land use that is a certain land cover type Land cover coefficients vary by land use type and intensity Impervious cover coefficients are available from Cappiella and Brown (2001) Forest cover coefficients are an important data gap

Land cover coefficients represent the fraction of a particular land use that is a certain land cover type

Land cover coefficients vary by land use type and intensity

Impervious cover coefficients are available from Cappiella and Brown (2001)

Forest cover coefficients are an important data gap

impervious cover coefficients vary by land use Source: Cappiella and Brown (2001) Land use ICC Agriculture .019 Open urban land .086 2 acre lot residential .106 1 acre lot residential .143 ½ acre lot residential .212 ¼ acre lot residential .278 1/8 acre lot residential .326 Townhomes .409 Multifamily residential .444 Institutional .344 Light industrial .534 Commercial .722

 

 

factors affecting forest cover coefficients Land use type and intensity Age of development Local forest conservation regulations Pre-development land cover (agriculture versus forest) Local clearing and grading practices Reforestation and landscaping requirements

Land use type and intensity

Age of development

Local forest conservation regulations

Pre-development land cover (agriculture versus forest)

Local clearing and grading practices

Reforestation and landscaping requirements

forest conservation regulations influence forest cover coefficients Photo courtesy of Harford County DPW Photo courtesy of Randall Arendt Forest cover coefficient = .057 Forest cover coefficient = .40

options for deriving forest cover coefficients Assume the worst: 95% of the site (except for protected lands) will be cleared If local forest conservation regulations exist, use the required conservation thresholds Use data from Urban Ecosystems Analyses www.americanforests.org or Urban Forests Effects Model www.ufore.org for your area Do your own detailed calculation using methods described in Cappiella and Brown (2001)

Assume the worst: 95% of the site (except for protected lands) will be cleared

If local forest conservation regulations exist, use the required conservation thresholds

Use data from Urban Ecosystems Analyses www.americanforests.org or Urban Forests Effects Model www.ufore.org for your area

Do your own detailed calculation using methods described in Cappiella and Brown (2001)

Zoning Category Buildable Area (acres) Forest Cover Coefficient Future Forest Cover on Buildable land (acres) Agriculture 765 .168 128.5 Open Urban Land 50 .268 13.4 LDR 732 .321 235.0 MDR 645 .248 160.0 HDR 220 .203 44.7 Institutional 88 .134 11.8 Commercial 130 .067 8.7 Total 2,630 602.1

Step 5: calculate the area of each land cover type for developed land and protected land Impervious cover – good indicator of stream health Forest cover – most beneficial type of cover from hydrologic, water quality, and habitat standpoint Other pervious areas – majority is often maintained as turf, may include cropland, pasture or grasslands

Impervious cover – good indicator of stream health

Forest cover – most beneficial type of cover from hydrologic, water quality, and habitat standpoint

Other pervious areas – majority is often maintained as turf, may include cropland, pasture or grasslands

sources of land cover data Maryland DNR Urban Tree Canopy assessment (includes impervious surfaces from IKONOS data) Chesapeake Bay Program land cover data (includes 2000 impervious surface data and RESAC land cover data http://www.chesapeakebay.net/data/index.htm Local government impervious surfaces (roads, parking lots, etc) and forest cover data

Maryland DNR Urban Tree Canopy assessment (includes impervious surfaces from IKONOS data)

Chesapeake Bay Program land cover data (includes 2000 impervious surface data and RESAC land cover data http://www.chesapeakebay.net/data/index.htm

Local government impervious surfaces (roads, parking lots, etc) and forest cover data

common scale issue: Map B contains alot more detail on forest cover while Map A is fairly generalized B A

Impervious cover layers

Step 5: results

Step 6: sum future land cover on buildable, developed and protected land Current land cover on developed and protected land: Impervious: 1,917 acres Forest: 639 acres Turf: 1,278 acres Future land cover on buildable land (estimated using land cover coefficients): Impervious: 680 acres Forest: 600 acres Turf: 1,350 acres +

Current land cover on developed and protected land:

Impervious: 1,917 acres

Forest: 639 acres

Turf: 1,278 acres

Future land cover on buildable land (estimated using land cover coefficients):

Impervious: 680 acres

Forest: 600 acres

Turf: 1,350 acres

Step 6: results Future land cover in the watershed =

future land cover spreadsheet

you’ve got results: now what? Identify ways to increase future forest cover Repeat Steps 1-6, making adjustments for these measures May need to run several scenarios to find acceptable and realistic future forest cover Set/adopt forest cover goal Implement techniques to maintain or increase forest cover

Identify ways to increase future forest cover

Repeat Steps 1-6, making adjustments for these measures

May need to run several scenarios to find acceptable and realistic future forest cover

Set/adopt forest cover goal

Implement techniques to maintain or increase forest cover

techniques to maintain or increase forest cover Protect priority forests Prevent forest loss during development and redevelopment Maintain existing forest canopy Plant trees during development and redevelopment Reforest public land Reforest private land

Protect priority forests

Prevent forest loss during development and redevelopment

Maintain existing forest canopy

Plant trees during development and redevelopment

Reforest public land

Reforest private land

additional resources Urban Watershed Forestry Manual Part 1: Methods for Increasing Forest Cover in a Watershed. Available for free download from www.cwp.org Impervious Cover and Land Use in the Chesapeake Bay. Available for free download from www.cwp.org USDA Forest Service’s Urban Forests Effects Model (UFORE) www.ufore.org American Forests’ Urban Ecosystem Analysis www.americanforests.org

Urban Watershed Forestry Manual Part 1: Methods for Increasing Forest Cover in a Watershed. Available for free download from www.cwp.org

Impervious Cover and Land Use in the Chesapeake Bay. Available for free download from www.cwp.org

USDA Forest Service’s Urban Forests Effects Model (UFORE) www.ufore.org

American Forests’ Urban Ecosystem Analysis www.americanforests.org

group exercise: estimating future forest cover in the Green River Watershed Identify group reporter Read the Green River Watershed scenario Select a combination of Urban Watershed Forestry techniques to implement in the Green River Watershed Report your results to the entire group Be ready to report out in 30 minutes!

Identify group reporter

Read the Green River Watershed scenario

Select a combination of Urban Watershed Forestry techniques to implement in the Green River Watershed

Report your results to the entire group

Be ready to report out in 30 minutes!

Add a comment

Related pages

How to Estimate Future Land Cover in a Watershed

How to Estimate Future Land Cover in a Watershed ... future forest cover in the watershed increases from 20% to 24% with implementation of the ...
Read more

Estimating Future Forest Cover in a Watershed

Estimating Future Forest Cover in a Watershed Karen Cappiella Center for Watershed Protection A Watershed Approach to Community Greening November 8, 2006
Read more

Estimating Future Forest Cover in the Green River ...

Estimating Future Forest Cover in the Green ... Out Analysis to estimate future forest cover ... forest cover in the watershed is 1,963 acres ...
Read more

Increasing Forest Cover in Maryland’s Developing Watersheds

estimate future forest cover. ... a GIS analysis that estimates future forest cover in a watershed, ... Increasing Forest Cover in Maryland’s Developing ...
Read more

Helpful Hints for Instructors of “Estimating Future ...

Helpful Hints for Instructors of “Estimating Future Forest Cover in the Green ... Total watershed area ... Add total acres reforested to future forest ...
Read more

Estimates of Current and Future Impervious Area and Forest ...

Forest Lands Vulnerable to Urban Conversion . ... Cover photos: Clockwise from ... Estimates of Current and Future Impervious Area and Vulnerable Forest ...
Read more

Introduction Watershed Management - International Society ...

Introduction Watershed Management ... 9Dense Coniferous Forests and Multi-Storied Canopies of ... USLE Estimates Sheet and Rill Erosion from uplands.
Read more

Estimates of Current and Future Impervious Area and Forest ...

A. Historic Estimates of Forest Canopy Cover ... Watershed Health Estimates of future impervious area and forest cover loss can be used by a community to
Read more