USA — A new publication titled Post Fire logging reduces surface woody fuels up to four decades following wildfire was published in Forest Ecology and Management this week. You can find the article here:
The research will undoubtedly be used by pro logging advocates to justify more post fire logging under the guise that it will prevent or reduce future severe fireswhich is the conclusion of the study for a specific short period of perhaps 10-20 years.
A couple of points to keep in mind.
Keep in mind this study was done by the Forest Service researchers and have failed to put their research into an ecological context.
Their starting assumption is that Post-fire logging may provide an economical way to expand the scope of restoration-based fuel reduction treatments, reduce the threat of future high-severity wildfires, and improve future forest resiliency to fire in dry coniferous forests.
This assumption is not necessarily a given in my view. I do not want to improve forest resilience to fire because I do not want to reduce future high severity fires and I believe we already have too few fires, and not enough large fires burning. And we definitely do not have enough snags, down wood, etc. in our forested ecosystems due to past logging practices. So the starting goal of this paper, I believe is not ecologically valid.
It is like reading a paper by a Fish and Game department saying we can reduce the impact of wolves on elk populations by shooting wolves. I would not want to reduce the impact of wolves. And if wolves cause elk numbers to drop, then so be it. Who am I to say what the right number of elk or wolves is?
First, and most important thing to remember is fuel loads does not equal a fire. Many people are going to use this study to justify post fire logging, but fires require far more than fuel. And in particular, the kinds of conditions that will burn snags and down logs after a fire are extremely rare.
Furthermore, post fire logging, even according to this study, INCREASES fuels for five years or more. Weve known this for a long time because it puts more fuels on the ground. But these fuels tend to be the smaller more burnable branches, and other things like flashy fuels like needles. In other words they are the fuels that sustain most fires.
So while small fuels are increased by logging, the larger fuels which would result if left unlogged are far more difficult to ignite.
Then over time you have snags falling over. These tend to be the larger fuelswhat they call the 1000 hour fuels. These are the bigger trees. These do not burn readily. They can only burn under the most intense severe fire conditions. Even in most fires, you will find that the majority of these larger fuels do not burn much at all. That is why you have a lot of burnt logs in a post fire situation. The larger logs require smaller fuels under them to sustain a burning logs. Think of a campfireif you try to ignite a large log, you cant get it to burn under you push small fuels under it and get it to burn. And once those small fuels are gone, the larger log tends to stop burning.
It only under severe fire conditions that you can get logs to burn. Under such conditions, wind, etc. negates the influence of fuels on fire spread. It becomes a climate driven fire. However, these conditions are rare. This brings up the second point.
Second, what this study measures is fuels on the ground. However, just because you have fuels doesnt mean you will have a fire.
There is no attempt to determine the probability when a fire will encounter the logged area. The window, according to this study is about years 10-20. During that time the unlogged forest has slightly more likelihood of burning. But what are the chances or probability that a fire (burning under severe fire conditions) will encounter that logged area.
Remember it takes severe fire conditions to ignite and sustain a fire in larger fuels. Well the probability is almost zero. Not quite, but very low.
The point that this reported marginal decline in probability of reburn is measured during the post-fire window when the probability of fire reoccurring is already the absolute lowest it will be at any time in the fire cycle. So its a tiny reduction in what is already a negligible probability event
Third this study acknowledges the importance of down wood/dead tree pulses created by large wildfires. That is a critical idea to keep in mind. We need these pulses of wood for the forest ecosystem health.
Post fire logging contributes to a loss of biomass and woody debris and its ecological importance. The premise again is the FS knee jerk reaction to fires. Oh, we dont want big fires. When in fact we need the larger fires to create lots of wood debris for ecosystem purposes. Removal of all these snags has significant ecological negative effects. It removes the current stand of snags (woodpecker/cavity nesting habitat) and future down wood for amphibians, insects, etc. They dont evaluate this or give any serious discussion to the importance of woody debris to forest ecosystems.
For instance, I know of one study which showed that fallen logs concentrated water at the ends of the logs. This increased the survival and growth of seedlings. Therefore, helped in the restoration of the green forest. Logs and snags also act as snow fences slowing wind-blown snow and allowing more moisture in the forest. Snags also provide shade. These help to moderate the site conditions which after a fire are typically harsh. This allows for better forest regeneration.
The study of course is only about fuels. But fuels are not the only thing to consider. We know the second highest biodiversity is found in severe wildfires. Eliminating or reducing the opportunities for future fires is not good for the forest ecosystem. There are many species that live in fear of green forests. They are recovering from forest fire protection and green forests. They need the post fire environment.
Fourth, bear in mind that these results were only for dry forest ecosystems dominated by Doug fir and ponderosa pine. You need to keep in mind that the majority of mixed and high severity fires occur in the higher elevation forests and/or shrub ecosystems dominated by lodgepole pine, subalpine fir, aspen, western larch, chaparral, etc.
Even within the Doug fir and ponderosa pine forests there is growing evidence that mixed and high severity fires occur and may even be the norm in some places (for instance that has been demonstrated in the Front Range of Colorado). So what we have is a study that does not apply to most of the forested/shrub ecosystems of the West. But I am certain that people who are logging advocates will try to suggest it should apply everywhere.
Firth, post fire logging loses even more money than green tree logging because the FS assumes the trees have lower value. As a result, the taxpayer is funding all these logging projects. The question becomes is it a wise use of funding.
In short be prepared to hear logging advocates suggest that post fire logging will benefit the forest ecosystem. In reality logging degrades forests. Unfortunately this paper may provide support for the continued impoverishment of our forested ecosystems.