hemlock forest change in great smoky mountains national park

Forest Loss by Community Type in Great Smoky Mountains National Park

Tanner JesselSchool of Information Sciences

Ephraim LoveDepartment of Geology

The University of Tennessee

Hemlock Forest Change in GSMNP

Source: Global Biodiversity Information Facility

Where is Forest Decline Occurring?

LANDSAT data characterizing forest change

Where is Hemlock Decline Occurring?

Hemlock Wooly Adelgid

Adelgid Impact to Landscape

Source: LANDSAT program

Where Does Hemlock Occur?

Satellite image of Great Smoky Mountains

Source: GRSM Overstory Vegetation Map

Remote Sensing

Polygons depicting Hemlock Distribution

Source: ATBI Database

Physical Inventory

Visualization of 1,017 Hemlock occurrences

Source: Maxent output

Predictive Modeling

Predictive model of Hemlock

Source: Maxent output

Predictive Modeling

Predictive model of Hemlock

Environmental Variables• Continuous– Digital Elevation

Model– Solar radiation– Topographic

convergence index

• Categorical– Bedrock geology– Soil organic type– Slope in degrees– Terrain shape index– Leaf on canopy cover– Understory density– Vegetation classes

Source: Alltaxa Web Interface

Environmental Variables

Digital Elevation Model

Source: Alltaxa Web Interface

Environmental Variables

Solar input

Source: Alltaxa Web Interface

Environmental Variables

Slope in degrees

Source: Alltaxa Web Interface

Environmental Variables

Bedrock Geology

Source: Alltaxa Web Interface

Environmental Variables

Soil organic type

Source: Alltaxa Web Interface

Environmental Variables

Topographic convergence index

Source: Alltaxa Web Interface

Environmental Variables

Terrain shape index

Source: Alltaxa Web Interface

Environmental Variables

Vegetation class

Source: Alltaxa Web Interface

Environmental Variables

Understory density

Source: Alltaxa Web Interface

Environmental Variables

Leaf-on canopy cover

Source: Alltaxa Web Interface

Contribution

Contributions of environmental layers to model

Source: ATBI database

Occurrence Records

Point Data

Source: ATBI Database, GRSM Hemlock Forest Polygon

Accuracy?

Physical inventory vs. remote-sensing

Source: Maxent output, ATBI occurrence records, GRSM polygons

Accuracy?

Prediction model versus remote sensing

Research Question

Can forest loss be quantified in context of community structure?• Mesic (Cove Hardwood)• Xeric (Pine)

Forest Communities• Cove Hardwood

– Sugar maple– Yellow buckeye– American beech– Fraser magnolia– Silverbell– American basswood– Tulip tree– Birch– Ash

• Pine– Shortleaf pine– Table Mountain

pine– Pitch pine– Eastern white pine– Virginia Pine

Source: ATBI database, maxent output

Sugar Maple

Acer saccharum records

Source: ATBI database, maxent output

Yellow Buckeye

Aesculus flava specimens

Source: ATBI database, maxent output

American Beech

Fagus grandiflora, specimens

Source: ATBI database, maxent output

Fraser Magnolia

Magnolia tripetala records

Source: ATBI database, maxent output

Silverbell

Halesia carolina records

Source: ATBI database, maxent output

American Basswood

Tilia americana records

Source: ATBI database, maxent output

Tulip Tree

Liriodendron chinense records

Source: ATBI database, maxent output

Ash

Fraxinus americana spp.

Source: ATBI database, maxent output

All Birch Species

Betula spp. records

Source: ATBI database, maxent output

All Pine Species

Pinus spp. records

Source: Maxent output processed in Modelbuilder

Threshold

Boundary of likely present / likely absent

Source: All birch trees SDM from maxent, processed by modelbuilder

All Birch Map

All birch trees

Source: Model Builder Output

Combined Birch-Hemlock Map

Birch and Hemlock Together

Source: Raw data, unpublished model output

Pine-Hemlock v. Birch-Hemlock

All pine with hemlock, all birch with hemlock

Source: Maxent output, processed by modelbuilder

Forest Loss by Community

Forest loss in Mesic vs. Xeric

Source: Modelbuilder

Modelbuilder

Model overview

Source: Modelbuilder

Modelbuilder

Model overview

Source: Modelbuilder

Modelbuilder

Model overview

Questions?• Slides Available

Online