As California nears the end of a devastating wildfire season – one that’s charred more than 1 million acres of private, state and national forests – it’s critical that we understand the importance of whether or not to treat lands after wildfire and how these decisions affect our forested ecosystems.
Although low-severity wildfire has always been an important part of California history, the explosive fires we see today are detrimental. In the past 15 years, we have seen an increase in the number of acres burned, as well as the severity of the burns, which pose a significant threat to public health and safety, air and water quality, and wildlife habitat.
Studies have long shown that these high severity wildfires are burning so hot that they burn all organic matter, kill any available seed source and cause hydrophobic soil, making prompt natural regeneration highly unlikely. Hydrophobic soils lack the ability to absorb water, leading to increased runoff into critical watersheds.
For example, 47 percent of the King Fire that burned in El Dorado County in 2014 was considered high severity. In the first winter after the storm, U.S. Forest Service estimated that 380,000 tons of sediment went into the Rubicon River and Ralston Afterbay – threatening the region’s sole source of water.
In order to facilitate forest recovery, immediate action is needed.
One of the strategies used in post-fire recovery efforts is to remove a proportion of dead and dying trees. This provides benefits for both the environment and the economy, and is the first step toward recovery.
Landowners salvage the burned logs to recoup a fraction of the lost timber value and put the money back into regenerating a thriving forest. Salvage logging is used to improve public safety by reducing the hazard of unstable, dead trees and is just one of the many steps that landowners use to regenerate a burned forest.
Trees begin to decay as soon as they are killed by a fire. Their value for lumber and other wood products begins to decline immediately after the fire. In order to retain any value from the burned trees, salvage logging must begin shortly after the fire and be completed with two-years.
Private landowners are able to salvage timber quickly because of state emergency rules, but federal lands get mired in lengthy environmental approvals resulting in lost timber value – income that would potentially be available to offset the cost of reforestation.
In a carefully planned effort, foresters leave a percentage of standing dead trees — those that are vital to wildlife and do not pose a threat to public safety. To promote forest diversity and protect watersheds some landowners till the forest floor, effectively breaking through the hydrophobic soil layers, to allow for water absorption, reduce surface runoff and prevent soil erosion.
Once chosen dead and dying trees are removed, a mix of natural seeding and planting can then occur. Once canopy closes, newly regenerated forests capture carbon at a faster net rate than older forests. A mixed-species landscape fosters diverse wildlife that meets habitat needs in both the regenerated and adjacent unburnt forest. According to the U.S. Fish & Wildlife Service, the real threat to many wildlife species and ecosystems is the wildfire itself, not the recovery efforts.
While some argue that we should let nature heal itself, in cases of high severity wildfire, if the goal is to rapidly develop forest cover, we can’t. The hydrophobic soil won’t allow for adequate natural forest regeneration. Without restoration efforts, these areas will result in a landscape dominated by shrubs.
In the Sierra, many shrubs sprout or develop from seeds and form a dense layer of cover that prevents conifers from germinating and growing in the sunlight.
In the four years since Yosemite’s Rim Fire, the high-severity burned federal lands are now dominated by cheat grass, chaparral and other invasive plants. Private landowners who pursued wildfire recovery already have a new mixed-species forest growing with shrubs and other ground cover in the understory.
Prompt reforestation is crucial given the fact that 60 percent of the state’s water supply originates in the Sierra Nevada.
With responsibly planned recovery efforts, in 10 years we can once again see a thriving forest, full of various species and age classes that form an ecologically diverse forest that is once again home to a diversity of species. In contrast, a forest that is left untreated turns into a brush field with far less diversity. Which would you prefer?