字幕列表 影片播放 列印英文字幕 With California facing a megadrought, many fear that fire season this year will be bigger and more devastating than previous years. But is there a way we could fight forest fires, with fire? Hey guys Julia here for Dnews With drought drying up the west, the threat of wildfires is more dire than ever. In the past five years, many states have seen the biggest fires in 50 years. Previous wildfires have caused millions of dollars in damage to homes and property. Some fires even were deadly. So it's no wonder the US Government spends billions every year to fight them. But unfortunately it's not a simple case as some bear in a hat wants us to believe. Historically, places like California saw big burns every year. But as more and more people moved west, forest fires had to be stopped. But decades of fighting forest fires actually made things worse for a little while. It made some ecosystems less diverse. And suppressing natural fires led to a buildup of debris and clutter on the forest floor, setting the stage for disasters to come. After the Yellowstone fires of 1988 and the fire season of 2000, people began to understand that some ecosystems NEED fire, they've evolved to make use of it. Fire is part of their natural lifecycle. Fire benefits an ecosystem in a few ways. Sometimes it breaks down nutrients in a flash, literally. Nutrients from leaves, logs, and other debris that otherwise would have taken years or decades to break down and return to the soil. Some plants actually need fire and heat to thrive. Like the giant sequoias in Sierra Nevada region in California. They need the heat of fire to reproduce! Sequoias make large cones, that only open and disperse their seeds when they dry up. One of the primary ways they dry out, is from, you guess it kids, the heat of a fire. And they aren't the only ones. In the Pinelands in new jersey, there's several species that need fire to reproduce including the pygmy pitch pine. This small plant evolved a few ways to fight fire. It's got thick bark that protects it from the heat. But if the trunk happens to be damaged by fire, it can regrow sprouts from the wound! Fire doesn't just help things grow, sometimes its powers of destruction, are for good! By clearing out clutter, it can destroy invasive species or harmful insects and can even open up the dense forest canopy to allow sunlight to reach the forest floor, so more things can grow. It also creates new areas of grasslands which some species of animals depend on for shelter or food. so what do we do? is there a way we can protect our homes while still allowing these delicate ecosystems to thrive? Well every year some forestry services practice what's called controlled burn or prescribed fireY. yes there are people whose job it is to set fires. ON PURPOSE. But it's a tricky business. The conditions have to be just right or a fire could quickly get out of control. If conditions are too dry, the fire can get too hot or too big too quickly, and there are a few cases of controlled burns getting out of control. If too damp, well nothing's going to burn. In the Pinelands of New Jersey parameters for burning are tight, like under 55 degrees, wind speeds of 7 to 12 miles per hour and about two or three days since the last rainfall. In some years, they can burn up to 22,000 acres of forest. And this policy seems to be helping. One study published in the journal Ecosphere, found that areas that were purposely burned had twice as many native plant species as nonburned areas after 10 years. And other studies from the Ecological Society of America show that prescribed burns reduce the severity of wildfires. But these are small, very well managed, controlled burns. So it seems it really pays to fight fire with fire. But only if you're a professional with a permit, so still listen to that bear in a hat.