Fall Foliage Timing Comes into Clearer Focus

秋天来了，什么时候去赏叶呢？

Researchers picked apart satellite imagery from two New England forest ecosystems to get a better handle on exactly what factors influence the timing of the color changes of the autumn leaves

——让科学家告诉你。科学家们选取了两张新英格兰森林生态系统的卫星图片，来明确究竟是哪些因素影响了秋叶变色的时间。

撰文/播音  Cynthia Graber

翻译  王娇娇

审校  邰伦玥

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.

当秋天来临时，新英格兰森林层林尽染，叶片呈现出红、黄、橙等生机勃勃的色调。这样的色彩盛宴当然会吸引来成批涌入的观赏者们。而他们则带来了一片绿色——那是大把大把绿色美钞的颜色。

Because of fall’s economic implications, exactly when the leaf-peeping season will begin is thus a source of constant speculation.

由于秋天美景的良好经济效益，赏叶期的开始就预示着一场持续的投机活动。

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.

科学家已经知道秋叶变色时间的影响因素包括霜降、高温、降雨和干旱，但是要要准确预测秋叶大片变色的准确时间仍是比较困难的。

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.

现在，科学家们选取了两个新英格兰森林生态系统的卫星图片（从2001年至2012年），希望能更好地掌握影响秋季叶片变色的因素。

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.

科学家分析了东北部高地和滨海地区。他们将低温、霜降、高温、降雨、干旱和洪涝的数据与卫星图片进行整合，发现在总体上，低温、潮湿和极端高温使叶片变色期提前，而相对温和的高温和较少的降雨则延迟了变色期。

But the different ecosystems behaved 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 region’s forests were also particularly sensitive to rain and flooding.

但是不同的生态系统其表现是不同的。对于霜降，高地森林在秋天和春天都会有变色反应，而滨海森林则仅仅在秋天有所响应，同时滨海森林对于降雨和洪涝十分敏感。

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. [Yingying Xie, Xiaojing Wang and John A. Silander, Jr., Deciduous forest responses to temperature, precipitation, and drought imply complex climate change impacts]

结合对下个世纪的气候预测，研究者们推测，在未来的秋天，高地森林的变色期将延后，而滨海森林的变色期可能提前。相关研究结果已发表于the Proceedings of the National Academy of Sciences。[Yingying Xie, Xiaojing Wang and John A. Silander, Jr., Deciduous forest responses to temperature, precipitation, and drought imply complex climate change impacts]

The researchers note that more data, such as for extreme weather events and flooding, need to be incorporated into future models. Which could help New England states maximize fall’s economic windfall.

科学家指出，在未来的预测模型中，需要进行更多的数据整合，比如加入极端气候和洪涝的数据。精准的预测将有助于新英格兰各州实现“秋叶经济”的最大化。

（题图来源：carlagasser.com）