Tree Rings

By Coggin Heeringa, Interpretive Naturalist, Crossroads at Big Creek, Inc.

This weekend, Crossroads will ring in the New Year! Appropriate to the celebration, our Saturday Science Program will feature “Annual Rings,” and at 4:15 p.m. on Sunday, we host the Wild Ones/Master Gardener Last Sunset of 2023 Hike, which will start from the Collins Learning Center.

Several years ago, when a school field trip program featured the annual rings of trees, one of the fifth-grade students wanted to know whether it was on New Year’s Eve or New Year’s Day that the trees added their annual rings.

Actually, making that dark ring takes several months.

A tree will increase in circumference each year. Come to think of it, this holiday time of year, some humans increase in circumference, too. But in nature, the opposite is true. While we humans tend to put on girth in winter, trees grow very little, if at all, this time of year.

Trees do most of their growing during the summer season, when the weather is warm and nourishment is available. During the growing season, trees develop new wood. Large light-colored cells are formed during late spring and summer, especially during years of abundant rain.

As summer turns into autumn, production of new wood slows considerably. The cells produced in the dry season (and into winter) are quite small. The smaller cells appear to the naked eye like a narrow dark band or ring.

The so-called annual ring of a tree truck is actually a layer of small cells. In most years, seasons alternate between warm and cold. Consequently, a light-colored ring and a slim dark ring are formed annually. The number of dark rings indicates the age of a tree, or more accurately, the number of winters survived.

There is a field of botany called dendrology. Scientists can not only determine the ages of trees; they can also learn about short and long-term climate changes based on the spaces between the dark rings. In drought years, for example, the rings of trees are very close together. When growing conditions were good, the spaces between the dark rings are significantly wider, indicating that the tree was thriving.

What if Crossroads at Big Creek had annual rings? 2023 would definitely have a wide growth ring.

It’s fun to imagine scientists, years and years from now, looking at tree rings and realizing that literally thousands of trees have been planted in the past few years as a part of our restoration efforts.

Many of those trees, shrubs and wildflowers were planted by our volunteers, to whom we give the appropriate names of Habitat Healers and Pollinator Pals. But many trees were planted by school groups, Boys and Girls Club groups, and YMCA Summer Camp participants, as a part of our efforts to “get kids outdoors.”

And those kids love our bridges! In 2023, we installed our third and final pedestrian bridge. The bridge is beautiful, and it also protects the wetlands and flood plains of Big Creek.

If you haven’t crossed our new bridges, you can see images on our new website, also launched in 2023, under the Explore tab. Be sure to check out the Activities Calendar, because we’ve planned a variety of events for learners of all ages in the coming months. The website is also the place to go to find out when our Ski-for Free program will be open and to learn of current hiking or skiing trail conditions.

During the summer, we again hosted researchers from the Environmental Research and Innovation Center of the University of Wisconsin-Oshkosh, and several community science projects got underway.

On Utah Street, we began work converting the historic barn at the Hanson Homestead into a research field station and classroom, and during both our Spring and Fall Archaeological Digs, we opened the 1852 Hans and Bertha Hanson House for tours.

Other 2023 initivates included a soil restoration project in which we removed contaminated soil from two former orchard chemical mixing site locations. And last summer, we began developing a Management Plan for our beautiful Ida Bay Preserve.

Traditional programs continued in 2023, as well. A highlight was hosting an Earth Day Festival in April that included a premiere showing of Peninsula Filmworks’ new “Ridges and Swales” documentary.

In May, it indeed seemed like every day was Earth Day as students from area schools participated in activities designed to inspire environmental stewardship. And in June, the Crossroads Trail Run was a glorious success.

This was a very good growth year for Crossroads. To grow, not unlike a tree which needs moisture and nutrients and warmth, Crossroads grew thanks to donor support and with the efforts of our board, staff and volunteers. And the warmth? That is the joy we feel when we see Door County residents and visitors enjoying our three beautiful preserves. 

Happy New Year, and remember, in 2024, our preserves will be open 366 days, free of charge.