Trillium grandiflorum flowering in the spring as overstory trees begin leafing out. (Photo: Courtesy of Mason Heberling)

In New England’s forests, wildflowers are some of the first signs of spring – often blooming before trees leaf out and shade the forest floor.

Heberling: “This high light period before the trees leaf out is really critical for how these wildflowers grow.”

That’s Mason Heberling, assistant curator of botany at the Carnegie Museum of Natural History. He says that as the climate warms, this critical period is getting shorter.

He worked with Boston University scientists who studied tree and flower leaf-out dates in Concord, Massachusetts.

They found that, compared to 160 years ago, the trees now produce leaves about two weeks earlier. But wildflowers are only leafing out about one week earlier than before.

Heberling: “Essentially wildflowers have one week less of high light before they’re shaded out by the overstory.”

He says that limits photosynthesis and the flowers’ ability to grow. And if that sun-drenched period continues to shorten …

Heberling: “It makes intuitive sense that that could lead to smaller plants, the flowers might not turn into fruits, and decreases in reproduction in subsequent years.”

So a spring walk in the woods could become a little less colorful.

Reporting credit: Sarah Kennedy/ChavoBart Digital Media.

Topics: Species & Ecosystems