Our forests are changing

A dead tree, the bark has fallen off and the trunk has been bleached by the sun.

A standing dead tree or snag is habitat for many animals

Forest Service Scientists recommend a broad approach to managing our forests that takes into account many agents including insects, pathogens, and fire; these agents interact to influence the makeup and structure of our forests. Typically, as long as a forest receives adequate rain and/or snow, vast numbers of seeds, seedlings and saplings will grow to replace the mature trees killed by bark beetles, fire, drought or other causes. Isolated patches of forests may not see the regeneration of pine trees, but they will persist in other areas of the forest. The seed stock in the soils and the young seedlings and saplings currently on the forests have the ability to mature and repopulate the forests.

Impacts on trees and wildlife

California's forests are home to many wildlife species. How the changes in the forest structure will impact the animals of the forest is an important question yet to be answered. This drought and bark beetle outbreak, resulting tree mortality and subsequent changes in the forest structure, through both natural means and human intervention, will have long term implications for all of the forest occupants. This includeshumans living in structured communities to the bacteria and fungi occupying the forest floor. Since all forest inhabitants are linked in some way, it is reasonable to speculate they will all be impacted in some way - some species may benefit from the changes while others may suffer.

Consider the factors

A variety of factors have led to the current state of our forests, including stand density, climate change drought and air pollution. Once the beetles have taken advantage of all of the available stressed conifers, the beetle populations will be reduced back to normal levels. Bark beetles are the primary cause of mortality for most pine and fir trees; other trees such as incense cedar and live oak are simply dying from lack of water. Ponderosa pine, Jeffrey pine, and pinyon pines are most impacted by bark beetles. While prolonged drought has an impact on most trees, the most significant mortality due to lack of water has occurred in the following species:

  • Coulter Pine
  • Bishop Pine
  • Monterey Pines
  • Oak trees growing on drier sites
  • Ponderosa Pine
  • Jeffrey Pine
  • Lodgepole Pine
  • Sugar Pine
  • White Fir
  • Incense Cedar