Biodiversity Guidebook Table of Contents]

Designing forest ecosystem networks

This section provides planners with direction in designing landscape units that meet old-growth and connectivity objectives while minimizing negative impacts on timber and range resource values. The recommended long-term landscape management approach is that of creating forest ecosystem networks (FENs) within the landscape units.

A FEN is a contiguous network of representative old-growth and mature forests (some of which provide forest interior habitat conditions) delineated in a managed landscape. Not only does a FEN aim to meet the needs of native species and ecological processes, it also serves to maintain or restore the natural connectivity within a landscape unit.

FENs are composed of a variety of protected areas, as well as classified areas (such as riparian management areas and wildlife habitat areas), any other areas that have been designated as sensitive, high visual quality areas, and areas of unstable terrain or other conditions that make them inoperable.

Most landscapes already contain significant areas within which timber harvesting is constrained. FENs should therefore be designed to take advantage of these areas, using them to form the network “building blocks.” This approach makes efficient use of the land base by allowing existing areas with harvesting constraints to serve the dual purpose of protecting a particular resource value while also contributing to the overall structure and composition of the FEN.

In mountain and valley ecosystems with wet climates, where contiguous old-growth forest was a dominant component of the natural landscapes, the delineation of FENs is especially important. However, FENs may also be used in other ecosystems to link important habitats such as wetlands. At the same time, not all components need to be connected and, overall, the need for connectivity varies among disturbance types.

Forest ecosystem networks provide the following benefits:

Several general considerations in FEN design are: Figures 6 and 7 illustrate how a landscape unit incorporating FENs, might be managed to maintain biodiversity.

Principal steps in designing a FEN

  1. dentify and map representative and rare old-growth stands:

  2. Identify and map the forest areas that will not be harvested. Determine the extent to which they can meet old-growth retention objectives for rare and representative ecosystems.

    A. Existing protected areas
    B. Ecological reserves and wilderness areas
    C. Areas subject to harvesting constraints:

    – riparian management areas
    – lake shore management areas
    – wildlife habitat areas
    – terrain sensitive areas
    – recreation areas
    – visually sensitive areas.
    D. Inoperable areas
    E. Areas that provide habitat for threatened or endangered species (contact the Conservation Data Centre for information)

  3. Assess the complex of areas identified above and list representative and rare ecosystems not protected as potential old-growth management areas.

    Figure 6. A landscape managed to maintain biodiversity.

    Figure 7. A portion of the landscape managed to maintain biodiversity.

  4. Where old-growth retention or representativeness objectives have not been achieved, create old-growth management areas (OGMAs) between the mapped areas.

  5. Assess whether connectivity objectives have been achieved. If connectivity objectives were not achieved through retention or representation, use mature and old-growth forest in OGMAs to link stands.

  6. Review the resultant FEN with respect to the biodiversity objectives for the landscape unit and check that, within the FEN:

Old-growth management areas

Management within FENs


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