Effectiveness of Fuel Treatments at the Landscape Scale: Jain et al. 2022

I was looking for a “Scientist of the Week” to honor and ran across this JFSP report. I’d like to give a vote of appreciation to these authors, and to the folks at JFSP for funding a useful synthesis of the research.

What I think it interesting about this paper is that the authors used different forms of knowledge (empirical, simulation, and case studies) to look at the question.   I also like that they separated out (1) direct wildfire effects, (2) impacts to suppression strategies and tactics, and (3) opportunities for BWU. Some studies only talk about (1) or, in some cases,  it’s not clear what exactly they are talking about. Here’s one chart.

I particularly liked the section “Identified management and policy considerations and research gaps” on page 25.

Here is an interesting section of that:

Our synthesis focused primarily on how fuel treatments performed in the event of large wildfires, rather than the effect of fuel treatments at keeping wildfires small. Treatments offer suppression opportunities and subsequently influence how many fires are being extinguished in fuel treatments. In the case studies, there were comments that the wildfires ignited outside the fuel treatments and therefore when fuel treatments were burned by wildfires, the wildfires were already large. If fuel treatments allow for effective wildfire management, including successful full suppression compared to untreated areas, our focus may have undervalued their suppression benefit.

Longevity of fuel treatments was mentioned in all three synthesis types. In most cases fuel treatments were shortlived from 1 year to 20 years; however, in most cases the longevity of fuels was focused on surface fuels. Future studies should focus on the longevity of treatment effects in each relevant fuel stratum to test the following hypotheses: 1) surface fuels have the shortest fuel treatment longevity; 2) crown fuels have the longest fuel treatment longevity; 3) ladder fuels longevity decreases when crown fuels are separated creating growing space for latter fuels to flourish. Studies that focus on fuel strata longevity can inform managers when is it necessary to conduct maintenance treatments and choose a method of treatment that extends treatment longevity.

A discussion of research gaps in empirically based studies is premature given the current state of knowledge. Empirical approaches to understanding landscapelevel fuel treatment effectiveness are in their infancy. Indeed, the field is at a point where clear and precise terms and concepts are not broadly recognized. The fundamental issue is the varied and  imprecise use of the term ‘landscape.’ Wildfire is a landscapelevel process. Fuel treatment effectiveness should be evaluated by how it affects that process, functionally, from a landscape perspective. The terms landscape scale and landscape size have little generalizable meaning. Large wildfires and or large treatments may be called ‘landscape’, but our inference on treatment effectiveness will remain constrained to withinsite (i.e., within treatment) effects if the sampling design and analysis are sitelevel and not also measuring effects outside the treatment footprint. Therefore, instead of identifying gaps in understanding, there should be 1) broad recognition of what is meant by landscapelevel fuel treatment effectiveness and how the characteristics of fuel treatments affect wildfire activity outside of treatment boundaries, and 2) longterm commitment to designing and implementing research projects at the landscape level over large areas that can inform questions and test hypotheses about the type, size, density, and configuration of fuel treatments that best affect subsequent wildfire in desirable directions.

The authors say “Wildfire is a landscape-level process. Fuel treatment effectiveness should be evaluated by how it affects that process, functionally, from a landscape perspective.” It seems to me that effectiveness would be measured as “do these treatments make wildfires easier to manage, with management including protecting communities, water and other infrastructure, and protecting species and watersheds from excessively negative impacts.” And I don’t really care about defining “landscape scale” except for the idea that say if you are planning PODs, you obviously have to think at the appropriate scale. But perhaps we all have different definitions. That could certainly make researchers’ lives difficult if we are all operating from different definitions and thinking we mean the same thing.

9 thoughts on “Effectiveness of Fuel Treatments at the Landscape Scale: Jain et al. 2022”

  1. I agree that the definition of the term landscape-scale should not be an issue. The author defined it. Seems to me they did expressly identify a gap in understanding, i.e. long term effects and treatment effectiveness. So that can help guide long term research, that’s obvious. That’s kinda the heart of the matter. Should we treat? If yes, how?

    But now I gotta read more than page 1…. dang it.

    • Hi Albert: I agree that wildfire mitigation plans (and most other forest management plans), are best considered at a “landscape scale.” As a reforestation contractor for a little over 20 years and more than 85,000 acres of successful forestry projects completed during that time, I began early on maintaining maps, contracts, production records, aerials, etc. on a subbasin-scale — that is, individual named creeks, ridgeline to ridgeline; from the mouth to the ridgeline above the initial source of water.

      Fires move from subbasin to subbasin; most plants and animals spend their entire lives within a subbasin. Also, the creeks have a name and perhaps endemic populations that should be monitored. From a ridgeline, from the right viewpoints, most or all of the creek’s landscape can often be viewed. Here is a recent article I wrote on this topic: http://nwmapsco.com/ZybachB/Articles/Magazines/Oregon_Fish_&_Wildlife_Journal/20220101_Umpqua_Reforestation/Zybach_20220101.pdf

      • I imagine fire research would probably show fire boundaries tend to follow watershed boundaries more than anything else. Watersheds are also the basis for “watershed management” for aquatic species and other beneficial water uses. So this approach to defining “landscapes” makes sense. But we should work with the existing terminology hierarchy for “hydrologic unit codes,” where “individual named creeks” would not be subbasins, but probably watersheds or subwatersheds. The level of HUC to use should depend on the expected scale of fires for the particular ecosystems. (The table here provides a summary of HUC scales: https://en.wikipedia.org/wiki/Hydrological_code)

        • Hi Jon: My own research and experiences through the years has shown — and documented — that fire is typically defined by watershed boundaries. The link I included shows a photograph and has some discussion on this point. So far as to whether to used “subbasin,” “sub-watershed,” or “watershed,” I think the situation is the same as creek, stream, or tributary — all work, are accurate, and it depends on context. In my opinion, all are greatly preferable to “HUC” government-speak!

        • I was reading on “Pre-European Fire Regimes and Vegetation of Big South Fork, KY and TN” last night and found this passage interesting related to fire frequency and behavior:

          “Actual fire frequency, regardless of ignition source was driven more by fire compartment size than by ignition frequency. A landscape with few ignitions but with large, unbroken fire compartments with long runs of fire in grassy fuels can experience nearly annual fire frequency from lightning alone. The larger the fire compartment the higher the fire frequency regardless of who or what was doing the igniting. In this regard it is landscape that drives fire frequency, not lightning, not Indians (Frost 1998).”

          I think watershed boundaries can be fire boundaries to the extent that there are fire breaks, natural or artificial, at watershed boundaries.

          • Josh: I did my graduate research on the Oregon Coast Range, which rarely ever has lightning strikes, and then usually accompanied by drenching rains. All major fires that I documented for the past 200+ years were caused by people. And while it is true that ridgeline travel routes typically create firebreaks and fire suppression access, it is also true that ridgelines typically form fire boundaries with or without firebreaks or suppression. That is largely a function of updrafts created by fires burning uphill and pulling air (and oxygen) from adjacent subbasins.

            • The Coast Range of Oregon is a great example (North of the Rogue River) of an area with naturally low ignitions, fire retardant vegetation, a highly corrugated landscape, and small fire compartments, all of which mitigate against frequent fires.

              • Josh: The Coast Range is also the location of some of the largest forest fires in history, despite having “small fire compartments.” When the Forest Service listed the 15 “Great Fires” of the US in Bulletin 117 in 1912, three of the 15 largest fires had taken place on the Oregon Coast Range. Fire frequency, as with everywhere people live, is daily and constant. Lightning fires rarely ever occur, and there is no record of volcanic fires. I did my PhD research on this topic: https://www.amazon.com/Great-Fires-Catastrophic-Patterns-1491-1951/dp/1732127603

                • That’s also classic for low-fire-frequency areas. Longer return intervals lead to more intense and severe fires when they do occur. Doug fir fire ecology is a great example. I’ll have to check out your research. Thanks for the link.


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