密歇根新闻广播 气候变化对森林的影响越来越大

The changing climate the Earth is experiencing is changing the forests in Michigan. Warmer and shorter winters affect trees, pests and the diseases that damage trees.

Stephen Handler is a climate change specialist with the U.S. Forest Service. He’s based in Houghton, in the Upper Peninsula.

Handler described two main changes happening now to Michigan’s climate: Winters are milder and more variable, and more precipitation falls in heavy rainstorms.

In the past, cold winters have kept pest populations in control. Due to fewer cold snaps, certain pests, like the hemlock¹ woolly adelgid, have spread north.

Since trees use carbon dioxide to grow, Handler said increased CO2 in the atmosphere could mean bigger trees. Some growth trials suggested trees grown with more CO2 had 20% to 25% more wood.

“When we grow trees in an atmosphere that is enriched in CO2, that’s like growing them in an all-you-can-eat buffet,” he said.

He said many factors, including water and nutrients², contribute to tree growth, and that it’s an area of active research.

Why is this important? For one thing, the health of Michigan forests impacts the quality of water in Michigan, Handler said. Forests consistently capture, filter and release water through the soil.

“The most important product we get from forests is not wood, it’s water,” he said.

To hear the full conversation about Michigan forests and climate change, listen above.

1 hemlock   

n.毒胡萝卜，铁杉

参考例句：

• He was condemned to drink a cup of hemlock.判处他喝一杯毒汁。
• Here is a beech by the side of a hemlock,with three pines at hand.这儿有株山毛榉和一株铁杉长在一起，旁边还有三株松树。

2 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》