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At the same time, the life cycle of the beetle is accelerating. These organisms are thermophilic animals, which means that their function depends on the external temperature. If the temperature rises, they will reach childbearing age faster and produce more and more offspring.
Chris Williams, director of environmental sciences at Clark University in Massachusetts and a researcher on drought, bark beetles and wildfires, said: “Rising temperatures enable bark beetles to go through the maturation stage faster, allowing the population to grow larger and more Explosive size.”. Their larvae live in trees, and when they are big enough, they turn into beetles, and they fly out to find other trees to destroy. Once they begin to invade, they release pheromones, which signals to other beetles that there is more room. (The beetle is also unlikely to die in warm winters, but Robbins said this was not the main factor he studied in California.)
The drought from 2012 to 2016 was particularly harmful because it lasted for a long time. But 2018, 2020 and 2021 are also extremely drought years. Tom Smith, a senior plant pathologist at the California Department of Forestry and Fire Protection, witnessed the effects of the drought. “We are seeing this now, the activity of the western pine bark beetle and the bark beetle of other species around California has increased, and we have entered another year of drought,” Smith said. “My main concern is that because there are a lot of dead trees in the landscape, there is a lot of dry fuel waiting to be burned.” These tree cemeteries act as catalysts. Landscape scale wildfire Those already Trouble California.
The large number of deaths of the 100-year-old Ponderosa pine will increase the risk of wildfires. There is another reason: the bark of the pine tree is very thick, which is a kind of fire-resistant tree. However, after the beetle broke out, the old trees were replaced by younger pine and fragrant cedar trees, which were less resistant. The combination of young trees that are easier to ignite and dead trees that provide fuel is a cause of high-intensity forest fires.
Robbins and his research team were shocked that small changes in the environment (such as a temperature increase of 1 degree Celsius) could have such a lasting effect. “This is one of the examples of climate change, not putting the genie back in the bottle,” Robbins said. “Many of those trees are hundreds of years old, and now they are dead-they won’t come back in 100 years.”
“Climate change is not a future event. We are now experiencing the consequences of climate change,” Robbins continued. “Our ecology is already operating in ways that we cannot predict, and we will have to manage forests and natural resources based on this assumption.”
But what might some of these management decisions be? Robbins believes that increasing forest diversity will become a protective factor against bark beetle attacks. “Not only the species, but also the age,” Robbins said. “We often have trees of the same age, and they are vulnerable to bark beetles at similar times.” Without reforestation efforts, Robbins believes that the forest may be transformed into a jungle shrub.
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