Principle - Ecological

Criterion- Landscape patterns support native populations

Indicator –– GFE 15. Road densities should be minimized.

CIFOR 3.3.2 Infrastructure is laid out prior to harvesting in accordance with

prescriptions.

Revised indicator – Road network density, type, use and location.

Box B: Definition:

This indicator is defined as the length or roads found in a given area of land, expressed as Km/km² or miles per square mile. In addition to road density, the definition includes road use and location.

Box D: Applicability to Different Landowners. Explain any differences:

From a timber perspective, roads are required for forest harvesting and silvicultural activities such as thinning and planting. Road networks are also valuable for accessing and controlling forest fires. However from an ecological perspective, roads at high densities may have a wide range of impacts. Because roads are key parts of most forest management, road management issues are applicable to all landowners.

Box E: Overlap:

CCFM 1.1.4 – Levels of fragmentation and connectedness in ecosystem components. Road density is an explicit measure of fragmentation in this indicator and there is no mention of the other impacts of roads.

Box F: Geo-Political Scale:

Notes: Road densities are applicable primarily at the home range of the organism, which is generally covered by the study area.

Notes: The relationship between road density and population variables has been demonstrated for many species. However, such relationships are highly specific to both species and area. There is not a generalized model that is applicable across a range of species. Where data exists, it can be useful as both a predictive and diagnostic indicator.

Notes: Form an ecological perspective, roads are considered a perturbation on the system.

Box I: Underlying Concepts:

Roads have been shown to affect biodiversity in many ways. They cause direct mortality to wildlife through collisions and modify rates of harvest by changing access for people. Roads also remove habitat, change habitat, fragment contiguous ecosystems, alter species movements and act as corridors for the introduction of exotic species. Physically roads change water flows, the movement of fire, and change local wind and temperature patterns. (see McGurk and Fong, 1995, Forman, 1995, Evink et al., 1996). The impact of roads appears to be a function of their density, level of use and location on the landscape. It appears possible to mitigate many of the impacts of roads by good planning which avoids steep or unstable slopes, etc. In addition it is possible to mitigate some impacts by road closures and post-harvest road reclamation. Suitable construction methods can also avoid many impacts by paying attention to stream crossings, surfacing materials, etc.

In many ecosystems it is critical to look at road density by position on the landscape. For example, In Banff National Park, Canada the overall road density is very low. However the park is very mountainous and the roads tend to be located in the montane valley lands. Road density in just the montane lands is very high. Because the montane lands are the key productive community type in the park, the overall impact of roads in the park is very high.

Box J: Relevance to Sustainable/Unsustainable Management:

Roads are a major land use in North America. In the United States alone there are some six million kilometers of public roads covering about 1% of the land area of the contiguous US. Some 200 million vehicles use these roads. Roads have a wide range of ecological impacts. They are also a key part of societies infrastructure for the movement of people and goods. This discussion is about roads in the forested hinterland, on lands that aim to manage for ecological sustainability.

Box K: Measurement Methods:

Calculations of road densities simply require the length of road in a given unit area. This can be done manually from topographic maps or by using spatially-referenced vector data in Geographic information systems. A more complex road density analysis requires road type, traffic volumes, use relative to ecosystem components (i.e. hunting, fishing) and position on the landscape. However these later types of use data many not be available. Simple road densities are easily calculated. However, taken by itself, simple road density can be misleading. Densities are best interpreted with road use and location on the landscape information.

Infrastructure assessment must take into account road engineering, which involves the specification of design standards and the actual design, field layout, construction and maintenance of forest roads and subsidiary structures such as bridges and culverts. For the Boise test, we looked at the Forest Practices Act inspection reports, and compared the numbers of inspections with the numbers where management activities had to be stopped in order to assure compliance with the provision of the Act.

Box L: Data Required:

See Measurement methods.

Box M: Data Used for the North American Test:

The GIS lab at Boise State University has compiled a detailed spatial data from the Boise National Forest as well as limited coverages from the State of Idaho and Boise Cascade. Road data was taken from 1:24000 scale map sheets and is undoubtedly incomplete. Other road density data relevant to North America was taken from the literature. Thus, data presented is for illustrative purposes only.

Box N: Example Results:

Road density is currently used by a range of land management agencies or has been suggested as a useful indicator by several ecosystem management studies (i.e. Interior Columbia Basin Ecosystem Management Plan). The Canadian Council of Forest Ministers Technical Report (1977) recorded measure road density levels for a variety of areas in Canada. While the Atlantic Maritime ecozone has a moderate road density throughout (>0.25 km/km2), while in the Taiga Plains and Boreal Cordillera ecozones of British Columbia, there are vast stretches with sparse road densities (<0.25 km/km 2 ). Comparative figures are available for Alaska (0.08 km/km 2), Maine (0.53 km/km2), the United Kingdom (2.29 km/km2), and Connecticut (8.76 km/km2).

Another way to look at road density is to look at the area of influence of a road, as most human influences occur close to roads and decline rapidly with distance. Assuming 1 km to be the critical distance, British Columbia has roughly 22% of the landscape within this distance; the remaining 78% has less human disturbance (Canadian Council of Forest Ministers Technical Report, 1977). Such calculations are routine with a geographic information system.

In the Boise study area there was a full range of relevant spatial information to conduct an analysis of road density. We measured road density as miles of road per square mile of area and then assessed the value by different tenure type. The density of roads in each of the land tenures are given below and on the next page as a table and a map:

It should be noted that these are average values for the entire tenure. Individual management areas in the Boise National Forest, for example, can go as high is 14 mi./sq. mi.(Lynette Morelan, pers. Comm).

For the Boise test, all aspects of road and skid trail construction, including location with reference to streams and slopes, installation of bridges and culverts, cross ditching, rolling dips, etc., must be done in accordance with the Idaho Forest Practices Act, Title 38, Chapter 13, Idaho Code, with the associated rules and Best Management Practices. This Act is administered by various state agencies and applies to all forested lands, and all ownerships, including Federal Lands, in the State. Similar laws have been passed in the states of Nevada, Washington, Oregon and California.

The following charts illustrate monitoring on compliance with road standards (and other regulations) by the Idaho Department of Lands to verify compliance with the state Forest Practices Act. These charts show the total number of forest practices conducted in the respective administrative areas compared to the number that were judged to be in violation of the rules, and issued a notice of violation. We could determine if the violations involved any aspect of road or skid trail construction and maintenance by going to the state records and sorting through the reports to determine the actual cause of the violation report.

There are some norms and standards available in North America for road densities, based on the survival of individual species in areas of different densities. For example, Mech et al. (1988) described the primary wolf range in Minnesota as having a mean road density of 0.36 km/km2, and the peripheral and disjunct parts of the range having a road density of 0.54 km/km2. Other studies indicate road densities of greater than 1 mile/mile2 have been shown to reduce habitat security and increase mortality for a range of mammals, including elk, bears, wolverines, and lynx. The Interior Columbia Basin Ecosystem Management Study classed road densities at extremely high (4.7+ mi./sq.mi.), high (1.7-4.7 mi./sq.mi.), moderate (.7-1.7 mi./sq.mi.), low (.1-.7 mi./sq.mi.), and very low (.02-.1 mi./sq.mi.). In the Boise National Forest, there are road density standards for each forest management area, based on a habitat effectiveness model for elk. Typical values are 3.0 mi./sq.mi. Forman et al. (1997) suggested a road density of 0.6 km/km2 was a threshold value of the loss of many large mammals. In general, standards for assessing road density are not well developed. They can vary by road use type and species. However, road density is an easily obtained value with an increasing body of biological impacts information.

There are many good sets of practices for forest road planning and construction, such as those located in the British Columbia Forest Practices Code. (http://www.for.gov.bc.ca/ tasb/ legsregs/ fpc/fpcguide/road/fre-toc.htm)

Box O: Assessing the Practicality:

It is feasible to conduct an analysis of road density in any management area that has spatially referenced data. The density of the roads and the position on the landscape, relative to such features as watercourses or vegetation types, can be examined. If there is data on road use, the analysis can be stratified by location and use type or intensity.

Box P: Assessing the Information Value:

Roads certainly can impact ecosystems dramatically and their effects can be very widespread. However it is difficult to generalize their impacts between areas. Impacts depend on road type, traffic loads, traffic patterns, seasonality, who uses the roads and by sensitivity of particular species. Thus the information value of road densities must be interpreted by place.

Box Q: Overall assessment

Accepted but needs further development

The use of road densities is somewhat controversial. Certainly the impacts of roads are variable. However there is an increasing body of information on the wide range of ecological impacts caused by roads. Because of the overwhelming presence of roads associated with forestry and the relative ease of collection, it is difficult to ignore road density as an indicator.

The key impacts from roads are direct and indirect impacts in population. There may also be a major impact on water quality and in some cases air quality.

Used by itself, road density has weaknesses. It may be strengthened by adding information of type of use, road location and road effect zone. The difficulty is that this data is often not available and the correlations with ecological impacts are not well established. At present, road density is a useful indicator of stress on the ecosystem. With increasing research, more elements can be added to this indicator. It appears to be a useful "work in progress".

There are excellent guidelines that have been developed in North America for forestry road planning and construction standards. The use of such standards will go a long way in mitigating the impacts of roads.

Box R: Did you rewrite or revise to a new indicator. If so what?

Road network density, type, use and location.

Box S: References:

• Evink, G.L., P. Garnett, D. Zeigler and J. (Barry eds.). 1996. Trends in addressing transportation related wildlife mortality. Florida Dept. Of Transportation Report Fl-ER-58-96. Tallahassee, Florida.
• Forman, R.T.T. 1995. Land Mosaics: The ecology of landscapes and regions. Cambridge University Press, Cambridge.
• Forman, Richard T., Debra S. Friedman, David Fitzhenery, Jay D. Marten, Allen S. Chen and Lauren E. Alexander. 1997. Ecological effects of roads: Toward three summary indices and an overview for North America. Habitat fragmentation and infrastructure – proceedings.
• McGurk, B. J. and D. Fong. 1995. Equivalent roaded area as a measure of cumulative effect of logging. Environmental Management 19:609-621.