STEP-BY-STEP DEFENSIBLE SPACE: PNWCG

DEFENSIBLE SPACE: STEP-BY-STEP

This house was sited on flat ground in an area dominated by lodgepole pine and native grasses. The project profiled on this page was completed during the summer of 2003 by a student crew under the supervision of the Oregon Department of Forestry. The text and photos are by Brian Ballou, ODF, and may be used for nonprofit fire prevention education projects. Clicking any photo will get you a larger version.


Pines of all ages were growing close to the house. Many of the older pines were infested with mistletoe, and some standing snags were present. Earlier thinning had left many tall, decadent stumps. The native grass had grown to a height of approximately one foot, and was cured and dry at the time of this project. The home was bordered on two sides by public roads; overhead powerlines paralleled these roads and skirted two edges of the property. The possibility existed for fires causes by downed powerlines, or by passersby in cars or on foot.

This house had several positive points: a metal roof, a driveway with two entrances/exits, and enough space on the lot to allow for a full 50-foot defensible space thinning without compromising the roadside noise/dust barriers.

Trimming of the tall, dry native grass was done around the house on all sides. A gasoline-powered string trimmer was used for this.

Most of the thinning, limbing and lopping work was done with a chainsaw. Ladder fuels were removed to the sawyer's shoulder height on most of the younger trees, and the lowest branches were removed from the older trees.

Thinning and limbing was also done along the driveway. Felled trees had their stumps cut close to the ground, either during felling or afterward.

Defensible space doesn't require a lot of bare ground in the landscape. While bare ground is certainly effective in reducing the wildfire threat, it isn't necessary. Numerous trees around this home were thinned, but many remain in the landscaping.

Thinning of small pines and the lopping of limbs was also done with a bowsaw, loppers, and a pair of pruning shears. This reduced the risk of damaging the trees with use of a chainsaw.

As debris was created, workers hauled the cut limbs and boles to piles on the edge of the property. A chipper was later brought in to dispose of the piles. Once the work was finished, the results were pleasing -- both functionally and aesthetically. Young lodgepole pines had their ladder fuels removed, and the grass was trimmed beneath the trees.

Remaining to be dealt with by the homeowner was a hedge of arborvitae along the front of the house. Should they ever catch fire, there is a good chance that the windows above the plants would shatter, exposing the interior of the house to flame and embers. Skylights on a roof can also shatter or melt if they're struck by falling limbs or exposed to prolonged heat.

Most defensible space guidelines caution homeowners about having adequate distance between a chimney and tree limbs. In this case, the distance was adequate without having to do additional thinning or lopping. The wooden deck off the side of the house had entryways for ground fire and swirling embers (as well as skunks and raccoons). Fine-mesh metal screening should be nailed or stapled over the openings beneath a deck. Note, too, the decadent stump near the deck -- if this caught fire, it could cast embers across much of the yard, and be a sustained heat source that could ignite the wooden deck. The crew cut some of the decadent stumps in the yard, but not all of them.
	This project was completed during the summer of 2003 by a student crew under the supervision of the Oregon Department of Forestry. Text and photos by Brian Ballou.
Stumps should be cut close to the ground. Another point of concern was the firewood stack. Although it was roofed and partially covered on three sides, it was still available to heat, embers, and direct flame impingement.