On a recent trip to Fort Collins, Colorado, sponsored by Anheuser-Bush, I got to see what the 163-year-old Budweiser beer company is doing with regional watershed cleanup. Our group was transported from Fort Collins through a light fall snow to the Ben Delatour Scott Ranch for a look at the Cache la Poudre River watershed. We were an hour away from Anheuser-Busch's Fort Collins brewery, and I was curious how the brewery, a Boy Scout ranch and forest management all fit together.

There's a strong link between forest health and a clean water supply. The biggest risk to the Poudre watershed is fire. When a catastrophic fire ravages the local forests, the ash can wash into the Poudre River, contaminating the water. In the summer of 2012, the High Park Fire that eventually destroyed at least 248 homes and burned more than 82,000 acres left behind ash that rolled into the river when the rains came, turning the river black and making the water undrinkable for a time. About $25 million was spent to dredge out the reservoir. After that fire, Anheuser-Busch partnered with The Nature Conservancy and the Coalition for the Pourdre River Watershed (CPRW) to keep the forests healthy.

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Our trip to the Boy Scout-run Ben Delatour Scott Ranch demonstrated one way this partnership is working. In an effort to try to get ahead of the next catastrophic fire, they are proactively cutting down trees on the ranch and using controlled burns. The Nature Conservancy has created a "prescription" for cutting down trees that thins the forest, making it less dense and less likely to succumb to devastating fires.

Fire is a good thing for the forest, but it's dangerous and inconvenient for people who live nearby and need the natural resources that forest fires can destroy or temporarily contaminate. Before humans suppressed forest fires, forests took care of that thinning themselves. When fire suppression became a common practice, forests grew unnaturally dense. Now, forest fires that used to burn themselves out become catastrophic blazes because there's so much fuel for them to consume.

The Nature Conservancy's prescription instructs those who wield the chainsaws on which trees to leave untouched and which trees to cut down. For example, old trees, trees with flat tops, and those that have visual nesting cavities or favorable conditions for nesting are left alone. Old species are left untouched, too. Trees are left in small clusters to give safe haven to squirrels who might become prey if they came down on the ground to get to their next tree.

cluster-of-treesThe trees around this small cluster have been cut down, but the cluster has been left standing as a safe haven for squirrels. (Photo: Robin Shreeves)
The trees that are the most undesirable are Douglas firs. The prescription calls for removing 90 percent of them that are less than 10 inches in diameter. Why do Douglas firs get the chainsaw? The same thing that makes the species great-looking Christmas trees also makes them "ladder fuels" in the forest. They carry fire from the grass into the treetops via their low branches. Once the fire gets up into a tree, it then gets into other trees, even those that are adapted to fire with a lack of low branches and thicker bark. Before humans started suppressing forest fires, Douglas firs would be taken out in natural low-intensity fires and the more fire-intolerant trees would often remain. But now, it's not unusual for all trees to burn in a forest that has become overly dense.

Once workers cut down the trees, they remove and find use for as much of the cut wood as they can. Other wood is put into piles and burned with caution in later winter or early spring when there's snow on the ground. The prescribed fires clean up needles and any remaining biomass on the ground. The fire doesn't just remove the biomass; it plays a role in rejuvenating soil nutrients, the grass ecology and seeds. While the mechanical thinning of the trees is very important, the prescribed burns ensure that the ecological role of fire isn't lost in the process.

Of course, it benefits Anheuser-Busch to have a clean water supply where one of its breweries is located, but the benefits of the partnership that protects the local watershed clean are far-reaching. The residents and businesses of the region have their drinking water supply protected. Anheuser-Busch is not the only brewery in Fort Collins. The town has more than 15 craft breweries according to the Coloradoan, and all of those breweries benefit from an uncontaminated watershed.

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.