An Improved Method for An Improved Method for Classifying Forest Classifying Forest

FragmentationFragmentation

Jason Parent and James HurdJason Parent and James Hurd

jason.parent@uconn.edujason.parent@uconn.edu

Center for Land use Education and Research

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““Forest fragmentation is the Forest fragmentation is the process of dividing large tracts process of dividing large tracts of forest into smaller isolated of forest into smaller isolated tracts surrounded by human-tracts surrounded by human-modified environments.”modified environments.”

Society of American Foresters (1998)

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“ …continued declines and fragmentation of the forestland base may lead to the impairment of our forest ecosystems’ ability to protect water flow and quality, to provide healthy and diverse forest habitat, and to remain a viable economic resource that provides recreation, timber, and other forest products.”

Society of American Foresters (1998)

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Why map forest Why map forest fragmentation?fragmentation?

► Identify areas in which to focus Identify areas in which to focus management efforts aimed at management efforts aimed at minimizing forest fragmentation.minimizing forest fragmentation.

►Allow better land use planning to Allow better land use planning to minimize forest fragmentation in the minimize forest fragmentation in the futurefuture

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An improved method to map An improved method to map forest fragmentationforest fragmentation

►Vogt Vogt et al.et al. (2007) propose a method (2007) propose a method that classifies forest based on pixel-that classifies forest based on pixel-level patterns.level patterns. The authors found this method to yield The authors found this method to yield

more accurate results than the method more accurate results than the method proposed by Riitters proposed by Riitters et al.et al. (2002). (2002).

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Forest classesForest classes

►Four classes of forest are identified – in Four classes of forest are identified – in terms of the type of fragmentation terms of the type of fragmentation present:present: CoreCore – interior forest pixels that are not – interior forest pixels that are not

degraded from “edge effects”.degraded from “edge effects”. PerforatedPerforated – forest along the inside edge of – forest along the inside edge of

an small forest perforation.an small forest perforation. EdgeEdge – forest along the outside edge of a – forest along the outside edge of a

forest patch.forest patch. PatchPatch – small fragments of forest that are – small fragments of forest that are

entirely degraded by “edge effects”.entirely degraded by “edge effects”.

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Forest classesForest classes

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A tool for mapping fragmentation A tool for mapping fragmentation in the landscapein the landscape

► We present the We present the Landscape Fragmentation AnalysisLandscape Fragmentation Analysis tool (LFA) for mapping fragmentation in the tool (LFA) for mapping fragmentation in the landscape.landscape.

► Based on the method developed by Vogt Based on the method developed by Vogt et al.et al. (2007).(2007). LFA procedures are functionally equivalent and yield identical LFA procedures are functionally equivalent and yield identical

results but are more efficient.results but are more efficient. LFA procedures are more intuitive.LFA procedures are more intuitive.

► Can analyze fragmentation for any land cover type:Can analyze fragmentation for any land cover type: Forest land, shrub land, urban land, etc.Forest land, shrub land, urban land, etc.

► The LFA tool is a python script that runs in The LFA tool is a python script that runs in ArcToolbox.ArcToolbox.

► Requires ArcView 9.2 with Spatial AnalystRequires ArcView 9.2 with Spatial Analyst

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Input land cover mapInput land cover map

► The LFA tool requires a 3 class land cover The LFA tool requires a 3 class land cover map as input:map as input:……assuming forest is the land cover type of interest…assuming forest is the land cover type of interest… 1 = non-forest1 = non-forest 2 = water2 = water 3 = forest3 = forest

►Water is not considered to be a fragmenting Water is not considered to be a fragmenting feature and does not affect the analysis.feature and does not affect the analysis.

► To include water as a fragmenting feature, To include water as a fragmenting feature, include water in the non-forest class (value include water in the non-forest class (value = 1).= 1).

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Extracting land covers of Extracting land covers of interestinterest

Forest

Non-forest

Water

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Edge widthEdge width

► Edge-widthEdge-width is the distance over which non- is the distance over which non-forest land covers can degrade forest land forest land covers can degrade forest land covers.covers.

► Core, perforated, edge, and patch forest are Core, perforated, edge, and patch forest are defined in terms of the “edge width”.defined in terms of the “edge width”.

►Numerous studies have documented “edge Numerous studies have documented “edge effects” on wildlife habitat:effects” on wildlife habitat: Edge-width varies by species and can range from Edge-width varies by species and can range from

50 meters to several hundred meters.50 meters to several hundred meters. 100 meters is often used as a general edge-width.100 meters is often used as a general edge-width.

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Defining core, peripheral, Defining core, peripheral, and patch forestand patch forest

Assuming an edge-width of 100 meters…Assuming an edge-width of 100 meters…► CoreCore forests consist of any forest pixels that forests consist of any forest pixels that

are more than 100 meters from non-forest.are more than 100 meters from non-forest.► PeripheralPeripheral forest consists of forest pixels forest consists of forest pixels

that are within 100 meters of non-forest and that are within 100 meters of non-forest and the tract contains core forest.the tract contains core forest. Further classified into Further classified into edgeedge and and perforatedperforated forest forest

► PatchPatch forests do not contain any forest forests do not contain any forest pixels that are more than 100 meters from pixels that are more than 100 meters from non-forest – they are entirely encompassed non-forest – they are entirely encompassed by the edge-effect.by the edge-effect.

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core forest

<= 100 m fromnon-forest

> 100 m from non-forest

core pixels in tract

peripheral forestNote: assuming Note: assuming

edge-width is 100 edge-width is 100 metersmeters

no core pixels in tract

patchforest

Classifying core, peripheral, and patch forestClassifying core, peripheral, and patch forest

Forest

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Core, patch, and Core, patch, and peripheral forestperipheral forest

100100 200200 30030000 mm

core

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<= 100 m fromforest

all pixels less than100 m of forest

non-forestpatch

Classifying non-forest patchesClassifying non-forest patches

Note: assuming Note: assuming edge-width is 100 edge-width is 100

metersmeters

Non-forest

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Non-forest Non-forest patches patches

100100 200200 30030000 mm

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peripheral forest

not adjacent to non-forest patch

adjacent to non-forest patch

perforated forest edge forest

Classifying perforated and edge forestClassifying perforated and edge forest

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core

100100 200200 30030000 mm

Core, patch, edgeCore, patch, edgeand perforated forestand perforated forest

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Specifying parameters for Specifying parameters for LFALFA

Output map

Input edge width

Input land cover

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Downloading the LFA toolDownloading the LFA tool

► The Landscape Fragmentation Analysis tool The Landscape Fragmentation Analysis tool is available through the Center for Land use is available through the Center for Land use Education and Research (CLEAR) at:Education and Research (CLEAR) at: http://www.clear.uconn.edu/tools/geospatial/Landhttp://www.clear.uconn.edu/tools/geospatial/Land

scape_Fragmentation.zipscape_Fragmentation.zip

► Forest fragmentation analysis results for Forest fragmentation analysis results for Connecticut Changing Landscape land cover Connecticut Changing Landscape land cover data will also be available through CLEAR’s data will also be available through CLEAR’s website:website: www.clear.uconn.eduwww.clear.uconn.edu

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ReferencesReferences

► Vogt, P., K. Riitters, C. Estreguil, J. Kozak, T. Wade, Vogt, P., K. Riitters, C. Estreguil, J. Kozak, T. Wade, J. Wickham. 2007. Mapping spatial patterns with J. Wickham. 2007. Mapping spatial patterns with morphological image processing. Landscape morphological image processing. Landscape Ecology 22: 171-177.Ecology 22: 171-177.

► Riitters, K., J. Wickham, R. O’Neill, K. Jones, E. Riitters, K., J. Wickham, R. O’Neill, K. Jones, E. Smith, J. Coulston, T. Wade, J. Smith. 2002. Smith, J. Coulston, T. Wade, J. Smith. 2002. Fragmentation of continental United States forests. Fragmentation of continental United States forests. Ecosystems 5 : 815-822.Ecosystems 5 : 815-822.

An Improved Method for An Improved Method for Classifying Forest Classifying Forest

FragmentationFragmentation

Jason Parent and James HurdJason Parent and James Hurd

jason.parent@uconn.edujason.parent@uconn.edu

Center for Land use Education and Research

Questions?