Last week, nearly 60 community members filled Mather Auditorium to learn from visiting speaker Dr. Drew Barton, professor of biology at the University of Maine at Farmington. He used his new award-winning book, The Changing Nature of the Maine Woods, as a platform to speak about how Maine's forests have changed over time and how they are predicted to change into the future with global warming. Below are some highlights from my notes!

• The Maine forest is a unique mixing of northern and southern ecological elements. The St. John River Forest Preserve in northern Maine is dominated by conifers, the Coplin Plantation in Franklin County is more of a northern hardwood forest, and Mt. Agamenticus in York is a temperate hardwood forest that is completely different from forests in the rest of the state.
• Tree species migrate north over thousands of years. They are able to travel long distances and are very sensitive to climate changes. Each species moves at its own rate.
• Scientists gather data on tree species over time by taking core samples from bogs. Pollen from plants collect in the sediments of lakes and bogs. They don't decompose, but rather accumulate layer by layer over time. The pollen becomes fossilized and highly resistant to decay. Scientists can detect different species of trees present over time by looking at the different types of pollen in the core samples.
• Scientists have found pollen from spruce forests that were present 14,000 years ago. Starting 11,000 years ago, white pine and birch pollen is detected. The spruce forests disappeared until their return 1,400 years ago due to a slight cooling of temperatures.
• Big Reed Forest Reserve, located north of Baxter State Park, is a rare old growth forest landscape with no evidence of any large disturbance over the past several thousand years. Visiting this forest provides a fascinating window into what the presettlement Maine forest looked like. It was a mostly shade tolerant forest, with 20% spruce, 12% beech, and 10% balsam fir. Humans have changed Maine's forests so that shade intolerant species like birch and poplar now dominate many areas.
• Into the future, changes in our climate will bring more non-native insects into Maine. The hemlock woolly adelgid is already here and the emerald ash borer is on its way from New Hampshire. Lake ice-out is now earlier due to climate changes, as well. Scientists predict that the future Maine forest will be less spruce-fir and more oak-hickory.
• Some Maine species expected to decrease in number with climate change include: Moose, loon, lynx, marten, chickadee, paper birch, yellow-bellied sapsucker, spruce, and firs.
• Some Maine species expected to increase in number with climate change include: White oak, Carolina wren, red-bellied woodpecker, flowering dogwood, bobcat, fisher, pignut hickory, mallard duck, and white-tailed deer.