Wildfires have spread dramatically—and some forests may not recover. An explosion in the frequency and extent of wildfires worldwide is hindering recovery even in ecosystems that rely on natural blazes to survive. https://www.nationalgeographic.com/science/2020/01/extreme-wildfires-reshaping-forests-worldwide-recovery-australia-climate/
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BY JOHN PICKRELL, JANUARY 30, 2020, Pungent and damp, the so-called tall, wet forests of southeastern Australia are home to the tallest flowering plants on Earth. Eucalyptus regnans, the Latin name of the mountain ash, means “ruler of the gum trees”—which is fitting, given these giants can reach more than 300 feet high.
Many of Australia’s gum trees, particularly those in drier forest types, are famously able to tolerate fire, throwing out new buds and shoots within weeks of being engulfed in flames. But even these tenacious species have their limits. Old-growth forests of the mountain ash and a related species, the alpine ash, are among the gum trees that are less tolerant of intense blazes. In the state of Victoria, these trees had already been severely depleted by logging and land clearing. Now, the bushfires that have burned more than 26 million acres of eastern Australia in recent months are putting the forests at even greater risk. Some of the forests razed this year have experienced four bushfires in the past 25 years, meaning they’ve had no chance to recover, says David Lindenmayer, an ecologist at the Australian National University in Canberra. “They should be burning no more than every 75 to 125 years, so that’s just an extraordinary change to fire regimes,” he says. “Mountain ash need to be about 15 to 30 years old before they can produce viable amounts of seed to replace themselves following fire.” The loss of these dominant trees is a significant problem, since they provide vital habitat for threatened animal species such as the sooty owl, the giant burrowing frog, and a fluffy arboreal marsupial called the greater glider. (Also find out how Australia’s fires can create big problems for freshwater supplies.) |
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