When a forest burns, the aftermath is a post-apocalyptic landscape of smoldering black trunks. The forest’s managers, whether they work for the U.S. Forest Service or for private companies, sometimes send in heavy machinery to harvest the dead trees in a process called salvage logging, to turn them into boards or other products. The idea is that since the trees are already toast, the responsible thing is to get a little more value out of them before they start to rot, as well as to remove fuel for a future fire from the area.
But salvage logging can be controversial. It churns up the fire-damaged soil. It may introduce seeds from invasive species, carried by the machinery. And dead trees, known as snags, are habitats for woodpeckers and other wildlife. Does removing them hamper the long-term recovery of the forest? More than 10 years ago, researchers from of the Forest Service’s Pacific Southwest Research Station decided to take advantage of a fire in the national forest near Mount Lassen, in Northern California, to study this question, and recently published their surprising results: At least on plant life, salvage logging did not have as much of an effect as one might expect.
At the beginning of the study, the researchers laid out 15 plots in the area burned by the Cone Fire, an accidental blaze that swept through the park’s dry pines in 2002. They directed salvage logging efforts of varying intensity in some plots and left others untouched. Then, every two years, they returned to the plots to count the number of plants and plant species that had sprouted, keeping track of which were natives, which were invasive, and whether they were weedy plants or shrubs, among other factors. Interestingly, the weedy plants that grew over the years were the same whether the plot had been logged or left to its own devices. The disturbance of the machinery did not appear to affect what grew, and didn’t seem to tip the scales to favor invasive species. Even cheatgrass, an invasive legendary in the West for its aggressive spread and alarming flammability, showed up in similar amounts regardless of the plots’ treatment.