Thursday, August 11

Trees That Survive Droughts May Have Common Characteristics

In southwestern states like Arizona and Utah, trees are particularly at risk for death by drought. In 2002, 225 million trees in the region died in a drought, and 300 million died in Texas in 2011.

These massive die-offs are happening all over the world, and scientists are striving to understand how to better protect trees from drought — or better yet, help them help themselves.

A study led by Princeton University researchers has identified certain traits that protect trees against drought.

The study found that the species most resistant to drought are those that are better at withstanding stress to the xylem, which is a plant’s internal water transport system.

A better understanding of the factors that contribute to a tree’s ability to withstand drought could help forest experts and conservationists to create early warning systems, or take preventative and precautionary measures.

Lead author William Anderegg, an associate research scholar at the Princeton Environmental Institute, said, “We don’t really know the future of the forest in a changing climate. Our results provide a foundation for improving our predictions of drought-induced tree mortality across Earth’s diverse forests.”

Anderegg and his team looked for patterns in previous studies of tree mortality and found common traits uniting trees that lived — and died — during droughts.

Trees are an important part of life, in both big and small ways. Worldwide, they absorb carbon dioxide equivalent to about a quarter of the emissions produced by humans, and at home they can reduce noise pollution by as much as 40%.

Large-scale tree die-offs threaten the world’s safety, especially because they re-release carbon dioxide back into the atmosphere. Indeed, Anderegg notes, “These widespread tree die-offs are a really early and visible sign of climate change already affecting our landscapes.”

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