Classification of trees

Bailey’s records are kept in a series of waterproof yellow notebooks. It uses a system that has to be done on the fly by a scientist from the Forest Service; Look at a tree and give it a number from one to four.

“It is a four summer situation. “That’s when the leaves fully photosynthesize and become completely green,” he said.

As the trees change with the seasons, the numbers move further down the scale. At three o’clock the trees begin to turn. When they reach two, they are mostly colored. At one point about half of the leaves fell and at zero they were all gone.

Bailey says the number 2.5, which he frequently uses, is not technically in the criteria table. We can call this peak decline.

Throughout the day, Bailey records the condition of sugar maples, yellow birch and American beech trees in three areas. Classifying a tree turns out to be surprisingly difficult; especially if it’s not healthy.

“It’s the classic thing where you look up and see all the switchbacks at the top, but here you see the green leaves,” he said. “I have to adjust to the death there and all the leaf loss. And even though it’s still green here, I’m going to call it 2.5.”

Bailey has a relationship with these trees. He knows their history. During our walk, he visits a tattered-looking maple tree that he has been observing for 30 years. He says he was very sad when he died. But death and decay; it’s all part of the job.

“That’s part of the whole forest story; You need spaces to let new things in. Now we’re excited to see what’s coming. What will happen?

Climate change and autumn colors

As humans burn fossil fuels and warm the atmosphere, Bailey and his colleagues have seen data from forest change: average annual air temperatures are warming, cold winter nights and snowdrifts are disappearing.

As Bailey watches the leaves each season, he notices the changes around him. September and October are warmer and trees stay green longer. This year was no different: There was no frost in mid-October.

“Trees really need the cold to express fall color,” he said.

Scientists still have big questions about how climate change affects the behavior of forests in the fall. Northern Arizona University professor Andrew Richardson looks to Hubbard Brook’s data for clues.

He uses Bailey’s observations to model what might happen during leaf-peeping season and study how climate change is changing the way forests store carbon.

Richardson says there are several signals that the leaves will begin to change in the fall. What matters is the length of the day. This is some kind of security measure.

“Even in a very warm fall, plants will be able to tell that the days are getting shorter and we’re heading into winter, and they need to start preparing for that,” he said.

Cold temperatures are another signal. But warmer precipitation appears to extend the time trees stay green.

As trees stop photosynthesizing, they reveal other colors (orange and yellow). The Reds are a different story; Scientists think they are created by leaves and are probably a type of sunscreen. New Hampshire’s waterfalls become less common during cold nights, which make this color more vibrant and awe-inspiring to visitors from around the country.

“It seems pretty clear in recent years that the end of the growing season or the beginning of the leaf peeping season has been gradually pushed back every decade,” Richardson said.

But Richardson says there’s a lot of variability from year to year, and the trend for leaves to change later in the fall isn’t very strong.

Yes many factors Colors that influence autumn colors and interact in complex ways. species Number of trees in New England forests is changing. Extreme heat in summer can stress trees, so their leaves die before they can show their colors. Some research suggests that an early spring may cause leaves to turn earlier in the fall. Severe storms can defoliate trees, so they won’t even be able to change color come autumn.

These nuances, he says, are part of why having long-term data is so important.

At Hubbard Brook, Bailey says he knows how important his job is. Observation gives him some peace of mind as he watches a forest he has known for half his life warm up with climate change.

“I’ve seen a lot of changes happen over the years and things grow again. “And the forest is resilient,” he said. “I think one of the things I’ve really come to respect in this area is that these soils want to support plants.”

These may not be the same plants that once grew here. For Bailey, sugar maples It would be a big loss. But he says change is constant in the forest. It may be sad, but it’s more than that.

“The soil will do its thing. And we’ve changed what it will be, but it will support life,” he said. “We may all have a hard time living in this landscape that faces a lot of flooding or something like that, but the trees will survive one way or another.”

This fall, Bailey will watch all the leaves in the forest fall to the ground. In the spring, he will stand in the same spots with his notebook to record when the first new buds appear.

This story is a production of the New England News Collaborative. In the beginning it was It was published By New Hampshire Public Radio.