Frequently Asked Questions About Yosemite

FIRE MANAGEMENT

Why are fires sometimes allowed to burn in Yosemite?
Are fires ever purposefully set by the NPS?
Doesn't smoke obscure the great views?
Why are all the trees dying?
How big was the Ackerson Complex Fire of 1996?
What's the difference between the Forest Service and the National Park Service?

Why are fires sometimes allowed to burn in Yosemite?
In previous years, the NPS and other agencies thought fire damaged resources and consequently suppressed all fires. Through research and experience it has been learned that fire is a necessary part of healthy ecosystems. The current Fire Management Policy allows some natural fires to burn and calls for ignition of prescribed fires in certain areas under specific conditions. Fire provides numerous resource benefits:

• Reduces excessive amounts of dead vegetation. Without natural fire, such materials build up to levels high enough that eventually a fire would burn through with unnaturally high intensity that would seriously harm the forest ecosystem.
• Exposes mineral soil, which many plants (including giant sequoias) need for reproductive success.
• Opens up the forest so that sunlight can reach the ground, which many small plants need for reproductive success.
• Recycles nutrients into the soil.
• Helps control diseases and insects in both soil and plants.

Are fires ever purposefully set by the NPS?
Fires intentionally ignited under very careful conditions are called prescribed fires. Such areas as the forests and meadows of Yosemite Valley, sequoia groves, and the overgrown forests in the western portions of the park are carefully burned. In some of these areas, natural fires are suppressed for safety concerns.

Doesn't smoke obscure the great views?
Yes. However, the tremendous benefits of fire to the ecosystem outweigh temporary inconveniences.

Why are all the trees dying?
Dead trees have a beneficial role in the life cycle of a forest. Here is some information on different areas where people commonly see dead or dying trees:

Along the Wawona (Hwy 41), Big Oak Flat (Hwy 120 West), and El Portal (Hwy 140) Roads in the park: Signs of crown fires from August 1990, are very evident along the Wawona and Big Oak Flat Roads. The fire was ignited by lightning. Due to fire suppression over the years, there was a high accumulation of forest fuels and the fires spread rapidly. These fires were fought from the time of their ignition but were not under control for more than a week. These areas now present an opportunity for visitors to witness forest succession following such an intense event. Natural processes will be allowed to proceed. To ensure visitor safety, hazard trees along roads were removed.

Along the Glacier Point and Tioga Roads (Hwy 120 East) in the park: In most cases, the browning appearance of trees along various sections on these roads is the result of
natural and management-contained fires from 1987-88. A significant portion of the understory trees were scorched and died, as well as a few portions of the more mature overstory level of the forests. Since then, needle accumulation on the ground gives the appearance that fire was not involved. However, you can suggest that visitors look for tree trunk scorching.

Outside the park on Highways 41 and 120 West: The general appearance of patchy, brown, dying trees in the middle elevation forests (the yellow pine belt) throughout California is directly a result of a dramatic increase in pine bark beetles since 1990. The drought of 1986-1992 created tree stress which made large numbers of trees vulnerable to beetle attacks. In general, current tree mortality is somewhat making up for postponed mortality over the past few decades, when fire suppression and forest pathogen controls interrupted natural processes which would have created a less-dense forest better able to withstand the drought/beetle situation.

Inside the park, hazardous trees within falling range of roads, buildings, campgrounds and picnic areas are removed to ensure visitor safety. Elsewhere in the park, natural processes are allowed to continue without disturbance.

How big was the Ackerson Complex Fire of 1996?
The Ackerson Complex Fire is the biggest fire on record in Yosemite. It started as 13 separate wildfires burning in adjacent areas of Yosemite National Park and the Stanislaus National Forest. The National Park Service joined the Forest Service in managing the fires on August 15, 1996, when the fires totaled 1,602 acres. The fires burned for almost a month, with many of the individual fires coalescing into one large fire. Final acreage was estimated at over 59,000 acres. Smoke was thick all over the park at times and many visitors left due to poor visibility and air quality.

What's the difference between the Forest Service and the National Park Service?
The Forest Service is administered by the U.S. Department of Agriculture. The Forest Service's management of national forest resources encompasses the concept of "multiple use." The Forest Service allows logging, mining, grazing, water development (e.g. reservoirs), hunting, camping, recreational opportunities and wilderness preservation.

The National Park Service is administered by the U.S. Department of the Interior. The National Park Service's mission is to preserve natural and cultural resources and provide for the enjoyment of visitors. The National Park Service preserves the natural processes which shape a natural area. Nothing can be taken from national parks.