American Trees Are Moving West, and No One Knows Why
Climate change explains only 20 percent of the movement.
As the consequences of climate change strike across the United States, ecologists have a guiding principle about how they think plants will respond. Cold-adapted plants will survive if they move “up”—that is, as they move further north (away from the tropics) and higher in elevation (away from the warm ground).
A new survey of how tree populations have shifted over the past three decades finds that this effect is already in action. But there’s a twist: Even more than moving poleward, trees are moving west.
About three-quarters of tree species common to eastern American forests—including white oaks, sugar maples, and American hollies—have shifted their population center west since 1980. More than half of the species studied also moved northward during the same period.
These results, among the first to use empirical data to look at how climate change is shaping eastern forests, were published in Science Advances on Wednesday.
Trees, of course, don’t move themselves. But their populations can shift over time, and saplings can expand into a new region while older growth dies in another. The research team compared a tree population to a line of people stretching from Atlanta to Indianapolis: Even if everyone in the line stood still, if you added new people to the end of the line in Indiana and asked others in Georgia to leave, then the center of the line would move nonetheless.
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Worst invasion of locusts in 60 years hits Sardinia
The plague has been described as the worst of its kind in six decades. Vegetation has been severely hit and the industry fears it may be too late to save this year's crop.
Millions of locusts have invaded the Italian island of Sardinia, seriously affecting farmers' livestock and crop production.
Italian agricultural organization Coldiretti has pleaded for government assistance in fighting the plague.
"We are walking on locust carpets," Coldiretti said in a statement.
The locusts have destroyed 2,500 hectares (6,200 acres) of agricultural land in the province of Nuoro, between the towns of Ottana and Orani.
Coldiretti fears it may be too late for this year's crop, but preventative measures should be put in place for next year.
"We had droughts in 2017 and a lot of rain in 2018, the ideal climate for locusts to emerge from fallow land and then move to cultivated fields to eat," Michele Arbau from the lobby group said. "There is nothing we can do about it this year."