On a beautiful July morning, the Arrowhead Native Plant Explorers met at the White Pine Picnic Area trailhead in the Superior National Forest. This event examining fire-dependent native plant communities was led by Nate Quadhamer of the US Forest Service. At our first stop, we discussed intact fire-dependent woodland forest communities that had not recently been burned. This area had magnificent white pines that were over 300 years old.
Nate read an excerpt out of the Minnesota Department of Natural Resources booklet: Field Guide to the Native Plant Communities of Minnesota – The Laurentian Mixed Forest Province. We discussed indicator species that are present in forests classified as Northern Mesic Mixed Forest (FDn43). This area had an abundance of yellow birch, mountain maple (sometimes colloquially known as “moose maple”), and spotted coralroot.
We observed large colonies of common wood sorrel (Oxalis montana), one of four species of wood sorrel that are found in Minnesota. This species can be distinguished by the hairs on the leaves and the white color of the flower.
Nate also pointed out a slug on a pink slime mold – what a treat!
The white pine picnic area had a diverse understory featuring many different ferns. One of which was the Long Beech Fern (Phegopteris connectilis). Nate pointed out that Phegopteris connectilis can be recognized by its “lawn chair” appearance: the lower pair of pinnae are at an acute angle, making the fern appear like a chair that one could sit in.
On our second stop, we observed a fire-dependent plant community that had been recently burned in the Greenwood Fire in the Superior National Forest in 2021. This area had a lush green understory that was filled with many early-colonizing wildflowers such as pale and golden corydalis (Corydalis sempervirens and C. aurea), American dragonhead (Dracocephalum parviflorum), and geranium (Geranium bicknellii).
We also observed a liverwort bryophyte, which Nate identified as Marchantia polymorpha. Very neat!
What a great day to get out and explore, and a fascinating learning experience to see the differences in plant communities between a recently burned site and an area that was in a later stage of succession. Thanks Nate!