Geographic Information Systems
at VDOF

GIS AT THE VIRGINIA DEPARTMENT OF FORESTRY

GIS plays an important role at VDOF as an information repository and as a decision support tool. VDOF also leverages other geographic technologies to complement its GIS. In the field, VDOF personnel use Geographic Positioning System (GPS) units to map, measure and navigate to features. Remote Sensing (RS) uses data such as aerial photography, satellite imagery and LIDAR, and is used to inventory and investigate the forest resources in Virginia. GIS, GPS, and RS are used alone or in combination in various VDOF applications including:

• Wildfire Risk Analysis
• Urban-Wildland Interface analysis
• Forest Resource Assessment
• Forest Land Use Mapping and Forest Inventory and Analysis DATA AVAILABLE - click here
• Mapping of Gypsy Moth Defoliation and Tree Mortality DATA AVAILABLE - click here
• State Forest Property Inventory and Stand Mapping DATA AVAILABLE - click here
• Riparian Buffer Tax Credit Program Management
• Forest Sustainability Project – Louisa County DATA AVAILABLE - click here

Wildfire Risk Analysis

To better serve the citizens of Virginia, VDOF performed a GIS analysis of wildfire risk across the Commonwealth. For each of their jurisdictions, local VDOF foresters mapped and ranked three variables that contribute to the overall wildfire risk. First they mapped and ranked areas for the threat of forest fire ignition. To this they added a ranking of the potential for forest fire spread. Lastly, they evaluated the resource value at risk during a forest fire in these areas. The three layers of rankings (Low, Medium, or High) were then weighted and aggregated to derive an overall score of forest fire risk. The resulting map is used by VDOF for planning, resource allocation, and educational outreach.

Urban-Wildland Interface Analysis

The areas at greatest risk for forest fire are those at the urban-wildland interface, or where people and forests meet. A wildfire mitigation project is currently underway that will update and refine the wildfire risk analysis described above. Another goal of this project is to improve decision-making capabilities for fire suppression and prevention activities by adding to the GIS database. Data are being collected on locations and attributes of wildfire suppression resources, woodland home communities, and historical fire incidents. Understanding the spatial relationship of these and other features will help VDOF concentrate their prevention education, resource allocation, and emergency response efforts where fire poses the greatest risk.

Forest Resource Assessment

There are many factors that influence the quantity, quality and sustainability of the forest resources in Virginia. In 1995 VDOF augmented its 1992 forest inventory with GIS analysis to perform the Forest Resource Assessment. This assessment examined the impact of growing rural and suburban populations on the forest resource as a whole, and more specifically on the forestlands available to support commercial timber production. The assessment showed that forestland is becoming increasingly fragmented by residential and commercial development, and that it is difficult to determine which portion of the timber resource is truly available for production. At the time of the study only 55% of the 15.4 million acres of forestland was considered to available for timber production.

Forest Land Use Mapping and Forest Inventory and Analysis

To act as stewards for the development and sustainability of Virginia’s forest resources, it is critical for DOF to evaluate not just the quantity of forestlands, but also their spatial arrangement. To this end, DOF is using their Forest Inventory and Analysis (FIA) plot data in conjunction with 2000 Landsat TM satellite imagery to classify the landscape into forest, non-forest, and water. The resulting raster layer will be used in numerous GIS analyses, including future forest resource assessments, forest fire risk modeling, water quality management, fragmentation analyses, forest economics, and conservation efforts.

Mapping of Gypsy Moth Defoliation and Tree Mortality

As part of its forest health monitoring efforts, DOF has used GIS to help quantify and track the spatial patterns of forest disturbance from insect infestations and extreme weather events. The primary focus has been on gypsy moth defoliation and tree mortality; however, damage from cicada, leaf-scratch, cankerworm, as well as ice and hail storms have been mapped when appropriate. Impacted forestlands have been mapped since 1984 using aerial surveys of known problem areas.

State Forest Property Inventory and Stand Mapping

DOF owns and manages over 46,000 acres of forestlands on 14 State Forests and manages an additional 10,000 acres of forestland on 2 State Parks across the Commonwealth. All State Forest property boundaries are mapped and using GIS. In addition, timber stands have been mapped for Cumberland, Appomattox-Buckingham and Prince Edward-Gallion State Forests. By using GIS to track stand attributes such as forest type, stand age, and management activities, DOF can more efficiently manage the forests than when these data were kept in a card filing system.

Riparian Buffer Tax Credit Program Management

The 2000 Virginia General Assembly enacted the Riparian Buffer Tax Credit to provide a tax credit to those who, during a harvest, retain forest buffers along waterways. The forested riparian buffer must remain intact for 15 years once established, and DOF has been mandated to perform annual compliance checks of the buffers. To efficiently manage the compliance monitoring, DOF is using GIS and satellite imagery change detection analysis to minimize unnecessary field visits. By using multiple dates of satellite imagery, DOF can evaluate whether there has been disturbance of the buffer area and notify the DOF Forester in that work area to perform a visual field inspection.

Forest Sustainability Project – Louisa County

To sustain the quality and quantity of forests to meet the environmental, economic, and recreational needs of Virginians, DOF must understand and mitigate the threats to the forest resource. Forest sustainability was examined in Louisa County, a jurisdiction greatly influenced by forests and forestry. Louisa County is also influenced by its location between Richmond and Charlottesville and the Interstate 64 corridor running through it. DOF used GIS and 1-m resolution digital aerial photography to map forest areas as a basis for the analysis. An overlay of tax parcel boundaries showing the property ownership divisions in the county demonstrated that although Louisa County may have large contiguous blocks of forested area, these blocks are usually owned my numerous people and that the potential for fragmentation is high.

RELATED GIS DATA LINKS