Learning about fire ecology
I recently went on a Deschutes Land Trust hike just west of Bend, OR to learn about fire ecology. The area we hiked in is known as the Skyline Forest. There were fires in this vicinity in 2010 and 2014 and together they burned about 6,000 acres. The area is currently privately owned but the Deschutes Land Trust has been trying to acquire it.
Our guide, Pete Caligiuri with The Nature Conservancy, informed us that this area has about the steepest environmental gradient in the world. In the Cascade Mountains the precipitation can be as high as 160 inches per year while less than 25 miles away, it can be as low as 10 inches per year. Plants respond to the extreme amount of variability in this gradient. In the past, fire and moisture limited the number of trees in the forest. Now there can be as many as 800-900 trees per acre in this area.
We looked around to see how many large stumps left over from timber harvesting we could see. There weren’t many at all. At one time this forest had the trees much more widely spaced. We noticed the high number of young trees with branches reaching down closer to the ground. There was also a thick growth of underbrush that included bitterbrush and manzanita. The forest floor was covered with pine needles and fallen branches. The closer spacing, higher number of shrubs, and accumulation of litter on the forest floor makes this forest more vulnerable to fire.
Improper management = more fires
Changes have occurred in local forests due to fire management practices, tree harvesting, and grazing of livestock.
- Fires were suppressed instead of being used as a management tool. Every tree that germinated was considered important. In a normal fire cycle here, there are fires every 7-35 years – depending on the moisture gradient.
- This was the area with the highest harvest rate of Ponderosa pine in the country for a while. The largest trees were cut first and the result was that younger, less fire-resistant trees flourished and crowded the landscape.
- About three million sheep grazed in this area until the 1930’s when livestock grazing became a less popular industry. Cattle could graze on Deschutes National Forest lands until the 1990’s.
Five types of plants after fires
After fires, the plants that begin to grow can be broken down into five categories.
- Invaders, such as fireweed, are adaptable and take advantage of the changed environment. We saw fireweed and thistle near the trail.
- Evaders, such as Ceanothus, can burn above ground but be adapted to sprout when the conditions improve. Ceanothus seed can sit dormant for up to 100 years. We saw quite a bit of Ceanothus and manzanita in this fire-affected area.
- Avoiders include plants such as mountain hemlock, Western white pine, and western juniper. They are not well adapted to tolerating a fire but if they avoid the hottest part of a fire, they may survive.
- Resistors, such as Ponderosa pine, have special adaptations such as thick bark that allow them to survive a fire. Ponderosa pine can also cast seeds up to 300 feet away.
- Endurers, like aspen, can sprout from their roots after the fire has passed. The aspen in this area is sprouting like crazy since it no longer has the competition for light that it had before the fire.
Due to long term changes in climate, some areas are changing from forested to non-forested habitats. Some habitats will only become drier over time. The warmer temperatures can also benefit the pine beetle and other insects that can destroy trees. We may experience more precipitation in the form of rain instead of snow and this will have long term consequences.
Deschutes Collaborative Forest Project
Five years ago several people from diverse backgrounds got together to form the Deschutes Collaborative Forest Project. The group is working together to improve the health of local forests in a way that will benefit the needs of the community. For example, a land owner in a forested environment will have different needs than someone who just goes to the forest to recreate. The group is trying to work on active restoration before a fire rather than after it.
There are several ways people are trying to do a better job of managing forested lands. Homeowners that follow some of the guidelines suggested by the Firewise program have a better chance of protecting their homes from wildfires. Development could be limited in forested environments. The acres could be used to preserve and grow trees rather than houses. The Deschutes Land Trust and The Nature Conservancy are a couple of organizations that work towards preserving land in this area.
One of the management tools used today is prescribed, or controlled, burns. Forests used to be “messy” with some areas affected by localized fires, windstorms and other weather events, and insect infestations while other areas remained relatively untouched. The litter layer and understory beneath the trees was managed by these events.
Now, due to fire suppression, too much litter and too many trees and shrubs per acre have accumulated. Remember Smokey the Bear saying, “Only you can prevent forest fires”? Since fires are used as a management tool now, it’s been changed to “Only you can prevent wildfires”. Many people do not understand the concept of prescribed burns and do not like seeing and smelling the smoke from them. Prescribed burns, along with selective cutting and other tools, can reduce the chances of severe fires.
Due to the magnitude of acres burned in recent fires, less money is going into forest management since more is going into fighting fires. It only makes sense to have funds to fight fires come from the same funding source that manages other types of natural disaster events. It also makes sense to put more money into research so that we are better equipped to do what we can to manage wildfires based on the best available data. Okay, I’m jumping off of my soapbox for now.
I visited Yellowstone National Park this summer and try to go there every other year. In 1988, I was saddened to see firsthand the effect the big fires had on the land. The fires burned nearly 800,000 acres – more than a third of the park property. After decades of fire suppression, the area was long past due for fire. The fires burned in a patchy sort of way as a fire would do in nature. The National Park Service was criticized at the time for not putting out all of the fires but fires are a part of the cycle of nature.
I knew the park plants would regenerate eventually and that the habitats would end up being a mosaic rather than a monoculture. Some of the trees in Yellowstone are slow growing so the changes may not be apparent for quite a while. I close this post with a shot-through-the-window-during-a-storm photo from Yellowstone that shows a healthy forest coming back after the fire. Fire equals destruction, but it also equals a new beginning.
2 thoughts on “Forests and Fire: Fire ecology in action”
This was a great article. It reminded me of a book that I read that described the Prescribed Burn that started the larger Wildfire at Cerro Grande which consumed 48,000 Acres and caused 1 Billion dollars in damage.
You might also like “The Big Burn” by Timothy Egan. Very well written book about a devastating fire that occured in 1910.