This is Scientific American 60 Second Science.

I'm Cynthia Graber.

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In autumn, New England foliage turns vibrant shades of red, yellow, and orange, which brings in lots of green, as in the money spent by

tourists who flock to the region to witness the explosion of color.

Because of Falls economic implications, exactly when the leaf peeping season will begin is thus a source of

constant speculation. Scientists know that factors including frost, heat, rain, and

drought all affect the timing, but the whole colorful picture is still difficult to accurately predict.

Now scientists have picked apart satellite imagery from two New England forest ecosystems

collected from 2001 to 2012 to try to get a better handle on exactly what factors influence the autumn leaves.

The scientists looked at Northeastern Highlands and Coastal Zones.

They incorporated available data on chills, frosts, and heat, and rain, drought, and flooding.

In general, cold, wet, and extreme heat made leaves change color sooner, while moderate heat and low rainfall delayed the coloration.

But the different ecosystems behave

differently. Forests in the highlands reacted to frosts both in spring and in the

fall, while the coast only responded to fall frosts. The coastal regions

forests were also particularly sensitive to rain and flooding.

Incorporating climate change predictions for the next century, the researchers propose that the

highlands will change color later in the fall while the coast may start to turn earlier.

The study is in the proceedings of the National Academy of Sciences.

The researchers note that more data, such as for extreme weather events and flooding,

need to be incorporated into future models, which could help

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