SAFR Issue: Potential Forest / Canopy Loss to Development and Recreation Pressure

Issue: Potential Forest / Canopy Loss to Development and Recreation Pressure

- [Map PDF] Potential Canopy Loss from Development, Urbanization and Recreation (DRAFT)

The intent of this issue is to:

1. Identify the areas at greatest risk of conversion from forestland to other uses - specifically development. Often forested areas are highly desirable for home sites or new subdivisions. With this conversion comes a loss of productive forests, increased wildfire risk to property as more homes are "in the woods," and pressure to reduce or eliminate management on adjacent lands. Also important are those areas that may be converted from one housing density to a significantly higher density within developed areas as this may also lead to loss of canopy and the benefits it provides.
   
   
2. Identify those areas where pressure from off road vehicle (ORV) use in undesignated areas can lead to degradation of forested areas. Such use has increased erosion, user conflicts, spread of invasive species, damage to cultural sites, disturbance to wildlife, destruction of wildlife habitat and risks to public safety. Along with fire and fuels, invasive species and loss of open space, this issue is one of the US Forest Service's "four threats." managing the areas where impact or potential impact is greatest, in addition to educational efforts will help alleviate these impacts.

Originally Canopy Loss due to Urbanization and Development and Recreation Pressure were separate issues. IDL staff made the decision to combine them as they are both impacted by population density and because we were only measuring ORV pressure within the Recreation dataset. It was felt that to separate them would be placing too great an emphasis on population density by counting it twice.

Data Used

Development Potential

- [Map PDF] Development Risk Based on Estimated Changes in Housing Density within idaho (DRAFT)

The National Guidance suggested using the "Forests on the Edge" data developed by Dr. David Theobold, Colorado State University. These data use the SERGoM v3 model, described in the rearch paper Watersheds at Risk to Increased Impervious Surface Cover in the Conterminous United States to predict housing density in ten-year increments from 2000 to 2030. By subtracting 2000 housing densities from 2030 predicted housing densities, we can express the potential areas of new development.

The Theobold data broke out housing density into ten classess. We modified these to eight classes as follows:

1. No Development or >80 acres per unit (rural)
2. 40-80 acres per unit (rural 1)
3. 20-40 acres per unit (rural 1)
4. 10-20 acres per unit (rural 2)
5. 1.7-10 acres per unit (rural 2)
6. 6. 0.6-1.7 acres per unit (exurban/urban)
7. <0.6 acres per unit (exurban/urban)
8. Urban/built up (commercial, industrial, transportation)

When considering the movement from one density class to another, we wanted to make some judgment about the relative impact of that change. IDL Staff developed the following matrix showing values from 0 (no change) and 1 (low impact change) to 5 (highest impact change) and classified the data accordingly. The numbers in the colored boxes represent the housing density classes shown above. So, movement from density class 2 (one unit per 40-80 acres) in 2000 to density class 5 (1.7-10 units per acre) by 2030 is considered a very high impact (value of five), A movement from density class 2 (one unit per 40-80 acres) in 2000 to density class 4 (one unit per 10-20) acres in 2030, on the other hand, is considered low-moderate change.

0 or -- = no or negative change
1 = low impact change
2 = low-moderate impact change
3 = moderate impact change
4 = high-moderate impact change
5 = high impact change

Recreation Pressure from ORVs

— [Map PDF] Off Highway Recreation Pressure in Idaho (DRAFT)

We used a model developed by the Idaho Department of Lands that incorporated US Census data for population density, the number of ORV registrations by county, TIGER 2000-based streets dataset and travel distance preferences from 2002 Recreation Demand Assessment by the Idaho Department of Parks and Recreation.

We used the following assumptions in developing the model:

• Census population can be used as a surrogate for overall recreation pressure;
• OHV registration totals by county can be used to estimate motorized recreation
  pressure;
• The public road network is how recreation pressure is transmitted and dispersed to forested lands;
• Recreation pressure comes primarily from urban population centers within and outside the state:
  1. Boise/Nampa/Caldwell
  2. Twin Falls
  3. Pocatello
  4. Ogden/Layton, UT
  5. Logan, UT
  6. Idaho Falls
  7. Moscow, ID/Pullman, WA
  8. Clarkston, WA/Lewiston, ID
  9. Spokane, WA/Coeur d’Alene, ID
• Recreation pressure on a forestland can come from multiple population centers and is additive;
• Recreation pressure decreases as travel time to a recreation destination increases (actually, not an assumption but confirmed by IDPR recreation demand surveys);
• All parts of the state are equally desirable recreation destinations and certain destinations (such as resort areas, parks, etc.) do not attract more recreation pressure than others;
• Recreation activity is defined as that which lasts a day or less; multi-day recreation activities are not considered.

The result is a map that shows ORV pressure based on a 1 to 3 hour travel time. Those areas closest to urban areas (requiring less time to get to) were scored highest. Data was divided into three classes, scored 1 through 3. More information on this model can be found by reading the Modeling Recreation Pressure on Idaho Forest Lands.

Data considered, but not used:

Development Potential

The Core Development Team also suggested using the industrial forestlands owned by Real Estate Investment Trusts (REITs) and Timber Investment Management Organization (TIMOs), since the potential divestiture of these lands for development is increasing. Upon further
investigation, IDL GIS staff determined these datasets were unavailable and were therefore not used.

Recreation Pressure

One of the datasets considered early on was the High-Use Dispersed Recreation Areas from the Interior Columbia Basin Ecosystem Management Project, a model that incorporated several other datasets. This was ultimately not used due to currency of data and the feeling that the model we had available to us was better.

We also wanted to incorporate data from Idaho Parks and Recreation, and this is part of the model we are using. Additionally, we contacted the Idaho Conservation League and the Wilderness Society, but they did not have the type of geospatial data we needed.

 

Related Links

— Issue: Threats to Forest Health

— Issue: Wildfire Impacts

— Issue: Water Quality and Quantity

— Issue: Air Quality

— Issue: Sustainable Forest-Based Markets

— Issue: Relative Potential Benefit to Wildlife and Biodiversity

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For more information please contact the project leaders:

• Dave Stephenson  dstephenson@idl.idaho.gov    208-666-8621
• Steve Kimballskimball@idl.idaho.gov    208-666-8646