Credit 2.4: Woody Material
This credit applies to the retention of existing or addition of woody material along shores where it naturally occurs.
Woody material (often referred to as woody debris) includes downed trees, stumps, branches, leaves and other tree-sourced materials that wash up onto or fall naturally on a beach or into the water.
In the marine environment, woody material that influences shore processes and shoreline features tends to be large, and is often referred to as “large woody debris” (LWD). On lake shores, woody debris tends to be of smaller dimensions, ranging from twigs to small logs and referred to as “small woody debris” (SWD). LWD typically occurs above the high tide line, whereas due to the absence of tides and strong currents, SWD may be submerged or partially submerged.
Where this credit applies
This credit applies to all types of shores, with particular significance on sediment-based shorelines. Adding woody material to a shoreline should provide or enhance habitat value; installing logs or root wads solely to retain sediment or attenuate waves does not qualify under this credit.
This credit offers up to 3 base points.
|Woody material||Base points|
|Where woody material already occurs along a minimum of 50% of the length of the shoreline, maintain and do not disturb a minimum 80% of that existing woody material;OR||
|Where woody material is diminished from natural conditions based on nearby reference beaches (see “How to proceed”), add woody material in a way that provides habitat value and is consistent with naturally occurring woody material in the area.||
1 point per 10% of length of shoreline occupied by added woody material to a maximum 3 points
How to proceed
To apply for this credit, identify and map the distribution of existing woody material as part of the existing conditions plan in order to integrate it in the site design plan. In marine sites, LWD may be mapped on a per-piece basis. On lakes, it may be more feasible to show the zone or length of shoreline occupied by SWD.
Temporarily moving, saving, and re-installing natural woody material to facilitate a development project is allowed. Check with local authorities if there are any regulatory requirements to do this, particularly when large pieces are involved.
Consult with a qualified professional such as a marine or freshwater biologist before introducing woody material to determine the most effective placement from a habitat perspective and to avoid creating hazards.
On marine sites, base the addition of LWD on nearby reference beaches when it comes to selecting material size, type and location—particularly with respect to elevation on the beach. LWD can be placed on the beach or semi buried, particularly if it is placed as part of a “soft shore” beach nourishment project (see Credit 1.5 “Soft Shore Protection or Enhancement”) or loosely on the upper and back beach areas, in wetlands, and along the shoreline of lakes. Anchor LWD by mechanical means only when recommended by a qualified professional and with approval by local authorities.
The Marine Shoreline Design Guidelines (Johannessen et al., 2014) devotes an entire chapter to the use of LWD in shoreline protection and enhancement. (See “For more information” for where to find this useful reference.)
On lake shores, it is more difficult to try to replicate “natural” conditions due to the density to which SWD often occurs in nature; however, the addition of even a few logs or branches, particularly in conjunction with overhanging vegetation, can add significant habitat for fish and invertebrates. Consider dedicating a section of your shore as juvenile fish rearing habitat by planting emergent vegetation or adding clusters of branches along the high water mark.
Freshwater: Examples of large woody debris placement where woody material was diminished.
Marine: Examples of before and after with addition of anchored logs to aid log recruitment (MSDG LW-1, LW-3).
Marine: Examples of site design plan showing placement of woody material. (MSDG LW-17).
For more information
Johannessen, J., A. MacLennan, A. Blue, J. Waggoner, S. Williams, W. Gerstel, R. Barnard, R. Carman, and H. Shipman, 2014. Marine Shoreline Design Guidelines. Washington Department of Fish and Wildlife, Olympia, Washington. 419 p. http://wdfw.wa.gov/publications/01583/
King County. 2011. Large Woody Debris as an Ecological Function. Go to http://www.kingcounty.gov/environment/waterandland/shorelines.aspx and enter “large woody debris” in the search box.