Hazard reduction burns increase risk of severe bushfires, report finds
February 17, 2024 9:35 PM   Subscribe

Hazard reduction burns increase risk of severe bushfires (forest fires), report finds. Traditional fire management strategies such as hazard reduction burns, logging, and the thinning of undergrowth have increased the flammability of forests, new research has found.
posted by chariot pulled by cassowaries (9 comments total) 10 users marked this as a favorite
This seems to be specifically about forest fires in areas where there might (eventually) be tall trees.

I assume it's not relevant to shrub land, fynbos, or any other area where the vegetation won't eventually be tall trees with high crowns?
posted by Zumbador at 10:01 PM on February 17 [1 favorite]

A different scientific article, "Fire management in Mediterranean-climate shrublands: a case study from the Cape fynbos, South Africa"


"Recurrent wildfires, and not prescribed burning, are providing sufficient opportunities for fire-stimulated regeneration in fynbos ecosystems. Because of this, and because burning to reduce fuel loads is unlikely to prevent wildfires, there should be less pressure to conduct prescribed burning. The predicted growth in human populations in all areas is expected to increase the number of ignition opportunities and the frequency of fires, with detrimental consequences for biodiversity conservation and the control of invasive alien trees. Fire frequency should thus be monitored and steps should be taken to protect areas that burn too frequently."
posted by chariot pulled by cassowaries at 10:08 PM on February 17 [4 favorites]

chariot pulled by cassowaries, so this South African paper seems to be saying that human encroachment (with resultant increase in ignition events) and alien vegetation are causing the fires, and that controlled burns will make little difference to the severity of those?
posted by Zumbador at 11:00 PM on February 17 [1 favorite]

Face it folks, nature, that is, reality, is going to get us one way or the other.
posted by njohnson23 at 8:23 AM on February 18 [1 favorite]

I glanced at the study being reviewed in this article: it appears that the hazard reduction burns they look at are associated with conventional fire management. The source study doesn't mention cultural burning / Aboriginal practices.

At the very end of this article cultural burning is mentioned, but briefly, by a scientist rebutting the study's findings.

Recent research in Australia suggests that cultural burning practices create very different circumstances on the ground than conventional fire management does - and that such practices can effectively reduce the intensity of wildfires. This is a whole different approach to burning - centuries-old indigenous practices involving setting many small fires over time, in different ways and under different weather conditions, with specific cultivation aims in mind. The complexity and subtlety of cultural burning practices are at a whole different level compared to conventional practices. These practices were increasingly limited and eventually banned by the Australian settlers/government starting in the late 18th century; they have only recently been allowed by the government.

With this in mind, I'd like to encourage folks to read this article as a critique of conventional burning practices, with an understanding that, based on emerging data, Aboriginal burning is increasingly supported by forest service agencies as a better way to burn.
posted by marlys at 12:02 PM on February 18 [9 favorites]

Oh I should add, given this article's location... cultural burning practices are getting increasing study and support in Canada and in California too. I don't know what the conversation is in South Africa though.
posted by marlys at 12:08 PM on February 18 [2 favorites]

FWIW, US Forest Service, Pacific Southwest, just issued a press release this week for a relevant paper (which I have not read): Forest thinning and prescribed burning treatments reduce wildfire severity and buffer the impacts of severe fire weather

There's usually a cycle of critique / pushback on these studies. (A summary of a significant previous example, featuring many of the 'big names' in North American wildfire science, here.)

Agree with marlys that cultural burning is a thing apart from conventional practices; it's been good to see more government agencies take it seriously and understand that it's necessary to have indigenous projects take the lead.
posted by to wound the autumnal city at 3:35 PM on February 18 [4 favorites]

Aaaah, the author of this paper... He has, erm, strong opinions, but I would advise caution - his work is very focused around a very specific vegetation type (tall, wet eucalyptus forests, rather than dry eucalyptus forests where the efficacy of planned burning is much clearer), and he has long been an opponent of native forest logging. Which is fine by me, so am I, but in his continued quest to prove the evil of logging operations, he has started to make some claims in the field of fire ecology that are a bit simplistic.

There are a few premises this is being argued from. One is that forests are dense, moist, and therefore have some natural in-built fire protection. Now, yes wet forests are, most of the time, except under extreme conditions, very difficult to burn. The idea is, if you log these forests, or do conduct hazard reduction burning in them, it opens them up, allows more light and wind in, dries them out, and increases fire risk.

This is not an unreasonable concept, broadly - but it really only applies in my opinion to forests that are on the very wettest end, very close to rainforests. These are the sorts of environments the author mainly studies, but that isn't the sort of environment you find across the vast majority of the flammable eucalyptus forests in Australia.

The other premise that is problematic, is that this author and some of his associated collaborators have come to the conclusion that Indigenous people never went into wet eucalyptus forests - did not utilize them, did not burn them. This is highly questionable and relies on anecdotes from a few individuals, and many other individuals would strongly disagree.

I will note, a study I was involved in of the 2019/2020 black summer fires in Australia, using a lot of data, found no strong evidence for the sorts of land management effects the authors propose. These effects were totally overwritten by extreme fire weather. The weather was a much, much more important driver of fire intensity/severity than whether an area had been logged or had hazard reduction burning (which only has a short-term impact).

As I said on Mastodon the other week, when this paper appeared; imagine if in 2024 a bunch of physicists were still publishing papers saying "light is a wave!" and a bunch of other physicists were publishing papers saying "no way man, light is a particle!". Australian fire ecology feels a bit like that at some times... the answer is both, and it's complicated! In this case, in fire ecology (and this is echoed in the western US as well), we have the "Leaving forests alone prevents dangerous fires" camp, and the "Actively managing forests, as they have been for millennia, prevents dangerous fires!". In reality, it's complicated, it's context-specific, and popular press articles declaring that "Severe bushfire risk increased by hazard reduction burns" are really, really not helpful.
posted by Jimbob at 8:13 PM on February 18 [13 favorites]

Paging Jimb… oh, cool.
posted by pompomtom at 1:32 AM on February 23

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