Environmental Factors

NPS Photo

What factors affect life in these parks? Large drivers of change like climate and fire affect where wildlife and plants can live. Climate, or long-term patterns of temperature and precipitation, shape habitats across park landscapes. Fire-dependent species can only thrive in locations where periodic low to moderate intensity fires continue to occur. Air quality and water quality are critical to supporting healthy ecosystems as well as rural and urban communities.

These parks are among many throughout the country experiencing negative impacts from climate change. Climate affects everything from snowpack and water availability, to fire occurrence and severity, and the health of plants, animals, and other organisms in these parks. Learn more by visiting our climate change page.

 

A firefighter uses a drip torch to ignite portions of a prescribed burn in Giant Forest, Sequoia National Park, June 2022.

NPS Photo - Tony Caprio

Fire

In the past, the landscapes of these parks were regularly shaped by fire. The positive results benefited both plants and animals, such as encouraging the regeneration of plants, which in turn can benefit wildlife. After decades of fire suppression the landscape has severely changed, but efforts are on-going to reduce fuels through prescribed burning and manual thinning. Fire is a critical process for restoring forests to a healthier, more resilient condition.

 

An air quality monitoring site in Sequoia National Park.

NPS Photo

Air Quality

Geography and air flow patterns contribute to air quality problems in these parks. An air flow eddy circles around the neighboring San Joaquin Valley and carries air pollution from human activity and industry into the parks. This affects visibility, the health of people and natural resources in the parks. Air quality monitoring in the parks is making a difference by providing important data to notify the public of health hazards on “bad air” days and to help both state and federal agencies in their efforts to improve air quality. This program also monitors smoke from fires and issues advisories when conditions are unhealthy.

 

A MacGillivray's Warbler perches on a tree branch. Birdsong or bird calls are important aspects of bird territory identification, and other communications. For people, birdsong is an often-appreciated sound in park landscapes.

Photo courtesy of Gary Lindquist.

Night Sky and Natural Sounds

As the population of the state continues to increase and urban areas grow, so does the use of outdoor lighting. This has an environmental impact on dark skies. Where once dark skies provided the perfect backdrop to distant stars and planets, they now glow more from the lights of urban areas. By recording these changes and providing education, park staff can increase appreciation of the night skies and suggest ways that we all can take a more active role returning a natural glow to our night skies. Learn more about National Park Service efforts to monitor and protect the night sky.

People come to parks to experience the variety of landscapes, but may also appreciate the “soundscapes” of places far from the noises of cities and freeways. Explore park sounds on our Natural Sounds page, where you can watch a video, visit a park sound library, and explore a story map of sounds across park elevations.

 

Because of the extreme elevation range in the parks, weather conditions vary widely between areas. In summer, the sequoia groves have comfortable temperatures and the foothills are hot and dry. Snow lingers on high-mountain passes well into summer. In fall, conditions can range from summer-like to winter-like. Winter brings snow to sequoia groves and rain to the foothills. Be prepared for tire chain requirements. Spring is a great time to hike in the foothills and snow begins to melt at higher elevations.

Weather Details