Variable-Density Thinning Research and Virtual Tour

Kudos to the Stanislaus National Forest for its report that says “science shows that thinning and fuels treatments work” and a virtual tour of the project area on the Stanislaus-Tuolumne Experimental Forest in California. The link is to an press release that explains the science findings on variable-density thinning and provides a link to a virtual tour of the area. Note the warnings about the virtual tour taking a LONG time to load — it does, even with high-speed Internet. They recommend using the Chrome browser, which I did.

I haven’t viewed the entire tour yet, but the opening scenes show a dense stand that is very much in need of treatment — a fire there would be intense. It’ll have to be mechanically thinned before Rx fire can be used. The scene is representative of many, many sites in the Sierras. Similar conditions, with different species, exist across the western US.

Perhaps not coincidentally, the Stanislaus recently released the RoD for the Social and Ecological Resilience Across the Landscape (SERAL) project. A news article on the project explains that “The project is planned on an area that totals 118,808 acres of public and private lands that include 94,823 acres in Forest Service jurisdiction….”

The Stanislaus aims to use variable-density thinning (VDT) in the project area. VDT is controversial in the eyes of some environmental groups. For example, a coalition of groups convinced a federal court that VDT is highly controversial, scientifically, as proposed for the Crystal Clear Restoration Project in Oregon; the court agreed, and ruled that the Mt. Hood NF erred in using an EA. The forest had planned to do an EIS, but the White River Fire burned much of the project area in 2020.

On VDT in the experimental forest, the Stanislaus says, “What they found was that during a recent severe drought that killed over 147 million trees statewide, the two thinned treatments came through relatively unscathed, experiencing far less tree mortality than the adjacent unthinned areas. By reducing competition, the remaining trees had greater access to sunlight, water and the nutrients found in soils. They also found that the addition of prescribed fire is key to a more vibrant and diverse understory plant community, similar to what these forests once contained.”

This photo shows before and after conditions:

It will be interesting to see if enviro groups challenge the SERAL project. The news article says SERAL was “born from an ongoing partnership between the federal Forest Service, the collaborative Yosemite Stanislaus Solutions group, and Tuolumne County. Other partners include Sierra Pacific Industries, the Tuolumne River Trust, and the Central Sierra Environmental Resource Center in Twain Harte.”

In any case, I recommend taking the time to experience the virtual tour.


8 thoughts on “Variable-Density Thinning Research and Virtual Tour”

  1. Environmental groups will likely challenge the SERAL project, but not because of VDT. They will challenge it because it’s a conditions based NEPA project that includes ridding the forest of the 30 inch limit and implementing a new CSO strategy, outside of forest planning, that includes many controversial and not-well-vetted changes to the current strategy.

    The treatments at the Stanislaus Ex Forest included removing trees >30 inches. TPA was targeted to NRV…but when this is done, BA is left well outside of NRV following treatments (it’s the one metric that is currently within NRV in mixed conifer SN forests), this is due to all the missing large trees on the landscape. The only true way to return a SN mixed conifer to NRV is to grow your way NRV over many decades. I would argue that this should be done through multiple entries (fire and/or thinning) designed to maintain all the pieces (i.e., maintain integrity by taking smaller bites). I will also point out that following the treatments, the tpa is so low that those stands will not support a commercial harvest for more than 40 years; therefore, maintenance will require routine Rx fire for a very long time, something the Stan NF has not been shown to be able to accomplish at scale. Numerous studies show that SN mixed con forests return to pre-treatment wildfire risk in 10-20 years following treatment, regardless of the intensity or type of the initial treatment.

    Also, this statement is not true: “It will have to be mechanically thinned before Rx fire can be used.” There are countless examples of Rx fire being used under the right fire weather conditions, without pre-fire thinning, that have turned out well (Caples Rx Fire had wonderful results, was not thinned except for a 10 inch limit in control lines, and was the only place not burned in the Caldor Fire).

    Given that less than 30% of the Stan NF is available for mechanical treatments due to slope constraints and access issues, we need to get over this false idea that it needs to be thinned first, because it is not true and most of it cannot be thinned first. Burn it under the right conditions and accept the results, it will be a hell of a lot better than the alternative and there’s no time to wait. There were just ~40 days straight of no precip in the SN in Jan and Feb (the new CA spring), how many acres did the Stan get Rx burned during that time?

    • While I am in favor of eventually altering the 30 inch diameter limit, now is not the time for that. I don’t really think the courts will support that idea, either, due to the existing Sierra Nevada plans. The areas within the Stanislaus have very high rates of fire return. Some areas have seen up to 14 wildfires in the last 100 years, according to tree core samples. We will have to manage those forests back to a more natural state, the same as the rest of the Sierra Nevada.

      The last timber project I worked (2012) on ended up adjacent to the Caldor fireline. Firefighters used backfires within the thinned areas to stop the fire from spreading more into the Amador Ranger District. I’m sure we will see plenty of examples where thinned stands survived the Caldor Fire quite well, once the Google Maps images are updated. I’ve worked in every corner of the Placerville Ranger District, and I’ll know where to look.

    • Anonymous,
      (1) If you don’t think that forests like the Stanislaus can do pb at scale, what is the alternative?

      (2) It would be helpful if you could say more about the characteristics of stands you think can be burned without thinning.. most of us who have worked in the Sierra have probably have images in our heads of stands with very different conditions.

      • First, don’t think I am opposed to thinning. I am not, but I do think thinning cannot and should not be relied on as the primary tool to increase resilience, which it currently is.

        I want to see fuel treatments done at scale, which I don’t see as possible by relying on mechanical methods due to all of the monetary and logistical constraints. I think it is a disservice to getting things done when someone says we cannot burn without thinning first (you have just doomed us to fail). Any stand in the Sierra can be burned without pre-treatment thinning with decent to glorious effect. In SN mixed con, fire weather and fuel moisture dictate what the effects will be on tree mortality, more than the fuel tonnage and configuration. I have seen it done in some gnarly stands and had FMOs state as much (including a former ELD NF FMO). Yes, trees will die. But hell, chainsaws kill trees too, so let’s not let the idea of killing a tree stop us from burning. By far, more trees we want to keep will die if it burns under the wrong conditions than the right conditions. Again, much of the SN is not accessible or is constrained by access and lack of volume to support a thinning project, so fire is the only tool in the box in these areas. Random acts of thinning isn’t doing it, we need many large (>2,000 acres) contiguous areas with reduced fuels, I see no other option to accomplish this than fire, and the science supports that:

        You have two choices in these areas, burn it under the right conditions and save most of it, or watch it burn under the wrong conditions and fight with Chad about salvage. How’s the latter choice working out for you?

        • I did see in the North paper “Analysis suggests mechanical treatment in most subwatersheds could be more effective if it established a fuel-reduced “anchor” from which prescribed and managed fire could be strategically expanded. “. I think this may be similar to Rocky Mountain PODs. So, don’t thin the whole thing, thin strategically and then use PF and MF.

        • Thinning isn’t the current “primary tool”. Drought is. The trouble is that drought (including high-intensity wildfires) kills trees of all sizes and species. Drought kills trees on lands that wouldn’t be thinned, too.

          If the ‘damage’ from thinning is significant, wouldn’t we be seeing evidence of that, in the projects (30″ diameter limit) that were finished 25 years ago? We should resist comparing the last two fire seasons to anything ‘normal’. Since thinning didn’t stop the Caldor Fire, that doesn’t mean those projects were a failure.

          Of course, every land-use decision should be site-specific. Yes, there are some places that could be burned every 5-10, with minimal pre-burn site prep. There are also places where tree densities (and species compositions) are not safe to burn, without modification. We’ll need creative project design to bundle some non-commercial tasks in with thinning contracts.


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