Arizona loves its pine forests. But we’re losing them – and some aren’t coming back
20 October 2023
Published by: https://www.azcentral.com
USA – Opinion: When ponderosa pine forests burn, they don’t always come back. And that has major implications for Arizona.
It’s hard to believe that what we now call the Dude Fire burn scar once was a ponderosa pine forest.
Thousands of acres at the edge of the Mogollon Rim northeast of Payson were decimated in the deadly 1990 fire.
What grew back in the three decades since is tangle of scrub brush so thick that even wildlife has trouble traversing it.
Even worse, the manzanita and juniper that now dominate its vistas are not adapted for periodic, lower-intensity fire — the kind that once helped prune the ponderosas and clear the way for beneficial ferns and grasses to grow underneath.
This new landscape burns hot and quick, making the area even more dangerous for people and infrastructure should it ever burn again.
It is Arizona’s cautionary tale.
Why Arizona can’t just let forests burn
We suppressed low-intensity forest fires for decades and killed off a functional logging industry, creating a ponderosa pine forest so full of fuel that any spark can quickly kill everything in its path, burning so hot that even the soil turns to glass.
Arizona has been working for years to rectify this problem, though efforts to thin millions of acres of overgrown forests remain woefully small-scale and behind schedule.
The logging industry we need to help return the forests to their previous health is barely hanging on, even with unprecedented federal funding now in the pipeline.
There simply aren’t enough bodies to do the work, both within the industry and in the overwhelmed U.S. Forest Service that must offer up acreage each year for cutting.
Some folks argue that we should just let it burn. A giant fire would at least clear out the overgrown parts and give us a clean slate to start again.
But that’s not what we’re seeing in places like Dude.
Ponderosa pines don’t always come back
The cautionary tale from this area is that when ponderosa pines burn, they don’t always come back.
It’s hotter and drier now, and that makes it tough for pines to dominate the landscape like they once did.
Quicker-growing brush that flourishes in these conditions — but that also is not as well-adapted to fire — is crowding out the few slower-growing trees that remain.
On southern facing slopes, the change is permanent: Precipitation doesn’t stick around long enough to nourish new pines. Even if we were to plant trees in these places, they’d be unlikely to survive.
Thankfully, workers have begun to clear the overgrown brush that grew back after the Dude Fire.
Giant machines pulverize most of the scrub into mulch that will dry for a few years until it can be cleared with a controlled burn. They leave any spindly ponderosa they can find, as well as a variety of oak tree with acorns that are special to local tribes.
The hope is that will buy time for the ponderosa to grow before the scrub moves back in.
But even still, the landscape will never return to how it was before that fateful day in 1990 when a lightning bolt changed everything.
Problems after a fire can last for years
There are a lot more reasons to thin the forest before it burns in a cataclysmic blaze.
Ponderosa pine are a keystone species, for example, one on which the entire ecosystem relies. Lose too many and one day it will reach a tipping point.
We also know that massive fires send ash and debris careening downhill with the melting snowpack that becomes our drinking water, causing dangerous flooding, cutting short the life of our reservoirs and degrading water quality so much that treatment plants can’t accept it, because the crud in the water will tear up their pumps.
This cycle can continue for years in areas that have been severely burned.
Salt River Project deserves major props for its efforts to thin thousands of acres across the Mogollon Rim, including the Dude Fire area.
Because juniper and manzanita have no logging value, these acres probably would have never been thinned without the utility and its partners — including corporate sponsors — underwriting the effort.
We’ll still have losses, but let’s limit them
SRP also is doing a ton of science in the burn scar, not only to model how much additional water can be produced in healthier, thinned areas, but to determine how far it flows.
That’s critical, because the more we can quantify the benefits of forest thinning — beyond saving the landscape for future generations — the better chance we have of gaining more partners to accelerate the work.
As it is, SRP is being strategic on where it thins, using prevailing winds to choose areas that have the best chance of de-escalating a fire when it starts.
This is both necessary and realistic. Even if we can find more bodies to do the work, we’re never going to thin every inch of overgrown forest.
There will probably be swaths of ponderosa that we lose forever, replaced by areas of juniper and manzanita that act like tinder boxes.
But the more we can limit these losses, the better off all of Arizona will be.