State-mandated tree clearings will not improve wildfire resiliency - Salish Current

One hundred feet of tree removal would be required around new or expanded homes in all red and yellow areas of this Department of Natural Resources map, which would impact most areas of all coastal communities. (Washington DNR)


The essays, analyses and opinions presented as Community Voices express the perspectives of their authors on topics of interest and importance to the community, and are not intended to reflect perspectives on behalf of the Salish Current.

Signed into law in 2018, Washington State’s SB 6109 asked the State Building Code Council (SBCC) to add “ignition-resistant construction” requirements to the International Building Code used in building projects within our state.

This request is a good idea — for homes truly at wildfire risk. Due to climate change, our state is becoming increasingly hot and dry. As a result, there’s a growing threat of wildfire even in historically moist coastal Washington communities.

For at-risk homes, building hardening is a proven way to increase wildfire survivability. That doesn’t mean living and working in concrete bunkers. Simple steps are very effective, such as using noncombustible roofing (asphaltic shingles or metal), covered gutters so debris cannot accumulate and fine mesh attic vents. All are relatively low in cost. Also very important is to keep plants, fences and other combustible elements (bark, etc.) five feet away from structures.

The problem is that the SBCC unfortunately has approved much wider landscape “defensible space” requirements, which are flawed and not supported by wildfire science.

The new defensible space rules require removing virtually all trees within 30 feet of any structure. In many cases, thinning and pruning trees from 30 feet to 100 feet away also will be required so each remaining tree’s canopy is 10 feet from any adjacent canopy.

Worse, this extensive tree removal would be mandated for virtually all new or expanded building projects (not existing homes) occurring in red or yellow areas of DNR’s Wildland Urban Interface Map. This map is low in resolution, creating confusion as to where it applies. It also does not map fuel-load — the most accurate way to determine wildfire potential — as other states such as California do.

An illustration of defensible space around a dwelling indicates clearings of 10, 30 and 100 feet. Required tree clearing of 30 to 100 feet around structures for greater wildfire resilience is not supported by the latest wildfire science. (Colorado State Forest Service) 

Take a moment to look at the map. Other than urban cores, most of our communities would have to follow these new tree-clearing rules. This flies in the face of tree retention ordinances in many cities and watershed protection plans such as for Lake Whatcom Watershed. It also conflicts with state goals to capture more carbon and increase climate resiliency. It would increase the likelihood of flooding (less trees means less rain buffer), increase stormwater runoff and subject many residents to more summer heat stress which has been linked to hospitalizations and deaths in our region.

And it will not reduce wildfire potential.

That might seem counterintuitive, but here’s the key fact: wildfire science does not support extensive tree removal. As national wildfire expert Chad Hanson has written, “After building hardening, which is paramount, the second part of the fire-safe home equation is defensible space pruning. … This is not about cutting down trees; in fact, it is important to maintain tree cover for the cooling shade it provides. Defensible space is about reducing the most combustible material immediately adjacent to homes, especially dry grass, seedlings and shrubs, lower limbs (prune them to six feet above the ground), limbs that touch the house or deck (remove these, but not the tree) and dead leaves and pine needles on the ground.”

Even the insurance industry’s Wildfire Prepared website does not recommend wider landscape clearings. The Insurance Institute for Business Home and Safety (IBHS) has funded cutting-edge wildfire research for decades. If anybody would readily call for big buffers, they would. However, they know the science doesn’t support it.

There’s also this reality: Wherever trees are removed, grasses, invasive brush and other vegetation with high flammability will readily grow unless there is annual maintenance by landowners. That often doesn’t occur and is not enforceable.

What can be done to reverse this misguided state tree-removal law that goes into effect March 2024 and would be applied unnecessarily to thousands of homes over time? Whatcom Million Trees Project and Friends of Trees have been working together to build awareness of the problem. The next SBCC meeting (Nov. 17) will be pivotal to get the defensible space rules withdrawn in time.

You can help us accomplish that goal. Please take a moment to do one or both of the following actions:

  • Sign our online petition. Please enter a few heartfelt sentences in the comment field, too. Note that you do not need to be over 18 or a registered voter.
  • Speak at SBCC’s Nov. 17 meeting virtually. Audio-only, you’ll have three minutes. The Zoom link and agenda will be posted five days beforehand. We encourage you to contact us beforehand so we can coordinate comments effectively.

A final thought: Many of us live along the Salish Sea in part because of how trees and forests are integral to our community’s character and quality of life. If science supported well-targeted tree removal to improve our collective wildfire resiliency, then perhaps we’d grudgingly have to accept that as part of a new climate reality. But the science doesn’t support it. SBCC’s defensible space rules are unnecessary, too widely applied, and will be destructive to our communities. Let’s get this changed!

— Contributed by Michael Feerer

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