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Forestry: Before the Fire

Before the Fire Header

Preparing Your Forestland for the upcoming Wildfire Season

These treatments are designed to improve your forest’s resistance to and resiliency in the aftermath of wildfires. 

Thin, prune and cleaning up the slash is the general starting place for improving your wood’s resistance to wildfire impacts.  Installing Fuel breaks or Firebreaks in strategic locations is often a prudent next step. 

Step 1: Thinning your woods

When you thin your trees, you are selecting the healthiest, tallest, largest diameter, fullest crown, least damaged trees to remain and cutting down all the rest based on an average spacing guideline. Forestry Technical Note 10 provides you that average spacing. There can be variability in spacing between individual trees so you can pick the best one to leave but for your woods overall you should try to come close to the targeted average spacing and associated stocking levels (trees per acre). When you are thinning to reduce the risk of wildfire impacts then the goal is to leave space between the green crowns of the trees that are left standing (leave trees). By thinning you are breaking the continuity of the crown fuels.  While you are thinning, cutting the taller shrubs will also be helpful by removing what are considered ladder fuels. By cutting down the brush you are breaking the continuity of the ladder fuels that take the fire from the ground to the crowns.  Remember to leave a few snags per acre for wildlife, if available.  

Pruning Trees

Step 2: Pruning leave trees

By pruning you are breaking the continuity of the ladder fuels that take the fire from the ground to the crowns. If forest understory shrubs are cut down so woody material and plants are less than 2’ off the ground, then a pruning height (from ground to bottom of the crown) from 8-12’ is usually adequate. Pruning heights up to 18’ are common, especially around structures.  Remember to remove both dead and live branches up to the target pruning height.  

Slash-PilePile

Lop and ScatterLop and Scatter

Step 3: Treating slash created from thinning and pruning

Forest slash is basically woody debris, usually on the ground but could be leaning against live trees and shrubs. There are several methods to treat slash: Lop and scatter, crush, pile, chip, and remove.  Lop and Scatter is used only when the slash currently on the ground and the slash you create from thinning and pruning is limited and non-continuous.  You can easily cut it up so that all the woody material is within 2’ of the ground and there is space between groups of slash.  If the slash is continuous and/or too deep to get all the material within 2’ of the ground, then piling, crushing, chipping or removal are more appropriate treatment methods. When piling your slash, keep the piles small - no larger than 10' long x 10' wide x 6' high. When crushing slash, keep it low to the ground and less than 2' above the ground. When chipping, spread the chips out instead of piling them. Treating the slash will break up the continuity of the ground fuels.  Burning slash piles is a common way to remove slash. 

Contact your local Washington Department of Natural Resources Forest Stewardship Forester for information on Forest Practice Rules and Regulations covering burning, burn plans and burn permits. Remember to leave 3-5 large down logs (12" diameter and 20' long and longer) per acre for wildlife if you have them. Slash piles can also be left for wildlife. 

If you would like to create a slash pile specifically for wildlife habitat see NRCS Fish and Wildlife Habitat Management Leaflet No. 18 to learn the best way to construct a slash pile for improved wildlife habitat.  

Forest Road

 

 

 

 

Forest roads can be used as fire breaks in combination with fuel breaks on both sides.

Step 4: Fuel breaks

Fuel breaks are specific strips of land with designated length and width, where most of the woody fuels are removed. There can still be trees standing but there must be at least 10’ between their crowns or even wider when on a slope of greater than 20%. All of the woody shrubs have been cut down, all of the remaining standing trees have been pruned to a height of 8-18’, and all of the woody slash has been removed or chipped.  Fuel breaks are usually placed along roads with multiple users (100’ wide on each side of the road); and along boundaries with neighbors (100’ wide), neighbors structures (Minimum 200’ wide), public access areas (minimum 200’ wide); and adjacent to or up-slope of rail road tracks (minimum of 100’ but greater on slopes). In addition, Fuel breaks are often established along ridge tops.  

Fire breaks are also specific strips of land with designated length and width but are less common because they generally remove all vegetation, vegetation debris and duff down to mineral soil. Fire breaks will often use roads and trails as their center and expand its size and ditches. On the other hand, a fire break could also include strips of land that has low vegetation that remains green and moist year round or irrigated strips of land.  Remember to implement erosion control measures if using a fire break that removes all vegetation, vegetation debris and duff down to mineral soil.  

If a home or other buildings are found on the forest land see Washington Department of Natural Resources Small Forest Landowner’s office website or contact your local Conservation District office for a Firewise assessment.

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