US-Parks.com: America's National Parks and Road Trip Planning Find Your Park Road Trip Activities Nature

Yosemite National Park Tree Hazard

Diseases, insects, soil moisture, wind, fire, and snow combine with human activities to create tree hazards, especially in natural areas like Yosemite. The National Park Service defines tree hazard as any tree, either alive or dead, which due to outwardly visible defects could fall down (in part or entirety) and strike a person or property within any designated portion of a development zone.

Forestry workers in Yosemite balance protecting people and property with conserving unimpaired the natural and cultural resources of the park. Crews accomplish this through regularly scheduled surveillance and special surveys after severe storms, fires, or other disturbances. At that time, trees requiring hazard abatement are identified. Crews then post warnings or site closures, or proceed with hazard mitigation by pruning or tree removal. Tree debris is left on the ground in places where practicable, but often must be removed. Forestry workers remove a tree hazard in Yosemite National Park.

Unfortunately, trees without apparent defects also fail, and tree hazards cannot always be immediately identified and abated or mitigated. Catastrophic tree failures in Yosemite have killed eight people since 1963, seriously injured many more, and caused $1 million worth of property damage.

Additional Nature and Science Topics for Yosemite

Featured Outdoor Gear

$142.33 58% off
The Juneau is one of Level Six's top-level dry tops for paddling in cold weather. It combines superior waterproofing...
Price subject to change | Available through Backcountry.com

National Park Spotlight
Bryce Canyon National Park
Bryce Canyon National Park
Featured Wildlife
Maine Puffins
Maine Puffins


Maine ocean islands provide the only nesting sites for Atlantic puffins in the United States. Eastern Egg Rock in the midcoast region, Seal Island and Matinicus Rock at the mouth of Penobscot Bay, and Machias Seal Island and Petit Manan Island off the downeast coast provide habitat for more than 4,000 puffins each summer.

Currently Viewing
Yosemite National Park Tree Hazard
Outdoor Gear
Featured National Parks
Popular Activities