Many thanks to folks in Forest Service Research at the Rocky Mountain Station, who reached out with a few more studies… below are some photo series I lifted from the studies..
Other Stations are invited to submit their relevant thinning literature! In their words,
For Western dry, historically frequent fire forests. From the TAMM Review (second link) “There is overwhelming evidence that reducing tree density and returning low severity fire to dry mixed conifer forests reduces the severity of subsequent wildfires” and from the Alchemy of Addition piece: “It’s important to use both cutting and burning together when possible. The mechanical- and process-based (i.e., prescribed fire) approaches work together to quickly and reliably produce good results for restoration and fire hazard reduction”
What do we know about forest treatments and fire? Photos and long-term studies help us understand
The below link is based on work in Montana
The Lubrecht Fire & Fire Surrogate study shows that fuel and restoration treatments in ponderosa pine forests of the Northern Rockies can bolster resilience to multiple
disturbances, while buffering risk of high carbon losses.
● The findings of this study support thinning and prescribed fire to increase ponderosa pine forest resilience to both wildfire and bark beetles for up to 20 years, but efficacy decreases over time and additional fuel treatments are needed to maintain forest resilience.
● However, these treatments can increase the number of nonnative species, which may require additional mitigation measures.
● As the site is re-treated, long-term monitoring is planned to document cumulative effects of multiple treatments to inform future management decisions.
We havent needed science in Western FS forest management for quite some time – forests are overcrowded from fire suppression and public forestry castration since the early 90s, plus a warming climate, etc etc. We owe env and forestry science a tremendous debt of gratitude. But their most useful use now is to declare We did our job, and pass the mic to managers whenever possible to spotlight it is Time to Act.
Well toyon, there is that; however, I don’t have a clue in what you are trying to say! Can you elaborate and help this old forester understand where you are heading with your response, please? You’ve picked a long row to hoe and I don’t see the crop……👍
The cartoon sketch you included from the Tamm review is interesting. I don’t see any difference post-wildfire between “thin and rx burn” and “rx burn only”, and indeed, their figure 4 confirms this. It shows–for interior mixed conifer forests, the low-mid elevation Rocky Mountain forests–essentially the same reduction in fire severity for “rx burn only” as for “thin and pile burn”. It shows that “thin and rx burn” offers only slightly more reduction in severity. “Thin only” treatments, without any burning, did not have nearly the benefit of the other treatments that included burns. It begs the question of why bother with the thinning? The Tamm review suggests that the slightly greater benefit from “thinning and rx burn” over “rx burn only” likely results from ladder fuel removal. OK, then, so why do commercial thinning?
Unfortunately, here in Bitterroot National Forest, so called “fuel reduction” and “forest health” projects always come with large commercial logging components, which are also the parts of the projects prioritized for completion. The non-commercial work is often incomplete (usually “subject to funding availability”); this includes the restoration work and the follow-up prescribed fire. How can anyone not think that “fuel reduction”, “thinning”, and “restoration” are just smokescreens for commercial logging?
Also, “thinning” seems to have different meanings. Commercial thinning that removes large trees is much different than non-commercial thinning of smaller diameter trees and brush. Again, here in Region 1, commercial “thinning” often leads to things that look a lot like clearcuts, and are hot, dry places filled with invasive weeds and crisscrossed by roads. I live near what I call a knapweed savannah created by commercial thinning 15-20 years ago. Maybe it is less likely to burn (knapweed stays green until late summer), but it does not have many other ecological attributes.
A thorough examination of fuel reduction and wildfire is the Graham et al 2012 report on the Fourmile Canyon fire in Colorado:
https://www.fs.usda.gov/rm/pubs/rmrs_gtr289.pdf
It’s rarely cited by the USFS, even though it is one of their own publications!
I forgot to mention that the Tamm study found that 40% of “thin only” treatments actually increased wildfire severity.
Jake, the “thin only” concept is about as worthless as it can be, and why would anyone do a “thinning only”, except for some sort of silly research document?
I have personally never seen one in production forestry, except some pre-commercial thinning in the South, that has only a one-year effective fuels buildup, due to rapid decay processes not found in the West!
This research paper examined “thin only” projects that had already been done and their effects on subsequent wildfires. The “thin only” projects were not done for the “silly research project”.
On Bitterroot National Forest there have been many commercial “thin only” projects. Some had planned follow-up prescribed burns that never got done.
Any thin only is silly! What knot-head would approve a project that needs a second entry, later on, to do anything other than pour gasoline on a fire? I always tried to address the “do no harm” adage of management. Of course my comments are aimed for those west of “the hundredth”……
We have lots of thin-only around subdivisions because people don’t tend to want broadcast around their homes and sometimes the openings are not large enough for (safe for the trees) pile-burning. This is on private land.
There are any number of ways to reduce/remove thinning slash; mastication, chipping, whole tree removal, jackpot burning, etc. Evergreen had/still has a system of slash removal to a central point and then it was chipped into biomass for mulch – that was all private land. Subdivisions on the A-S didn’t have anything but stumps and memories of slash from those thinkings. Of course, having a biomass energy plant within the circle of affordability was certainly a gift for disposal.
It is a different world in the West, compared to the East/South, just leaving the slash on the ground outside these dry-site forests is no concern whatsoever. In Oregon, we always took care of the thinning, as well as created slash within timber sales. How many times have you seen enviros accuse the FS of “too clean” of a site, and the division over residual vs activity concept? But that was back in the day before all the smart folks started the “isolation” option of fuels management……tic!
https://methowvalleynews.com/2026/03/12/my-turn-what-youre-not-being-told-about-forest-thinning/
For a different take on thinning. And, yes, I know this guy is considered a “radical environmentalist”. But I admit to being swayed by his arguments.