Spring forest phenology update: community scientists help Holden researchers study the effects of climate warming on forest plants.

Each year at the Holden Arboretum, volunteers team up with members of the Stuble lab to survey spring ephemeral wildflower phenology. Phenology is the study of the timing of life history events like emergence, flowering, and seed production. We track spring ephemerals common to Northeast Ohio like trout lily, trillium, squirrel corn, and dutchman’s breeches.

We also monitor the forest canopy to see when and how quickly the canopy closes. Spring wildflowers emerge and gather most of their resources early in the spring while the canopy is still open and there is lots of light, and small changes in the timing of canopy leaf out could have big consequences for spring ephemeral growth and survival. Plant phenology is very responsive to temperature, and monitoring spring wildflowers and the forest canopy can help us understand how plant communities are changing with global warming. We are curious to see how well both the spring ephemerals and the forest canopy can track warming. If one is better than the other, we could be seeing what is known as a “phenological mismatch” between the forest canopy and the understory plants.

This spring has been rather warm, and our spring ephemerals have emerged and flowered earlier than in years past. Trout lily was leading the pack this year, with the first emergence recorded on March 24^th. That’s about 10 days earlier than when we started this survey back in 2018. Too, we saw our first flowering dutchman’s breeches on April 5^th this year, about 18 days earlier than in 2018.

Our volunteer group, the “Phenology Phenoms,” will continue to monitor these plots through June, when our canopy will be fully leafed out and most of the spring ephemerals’ life cycle will be over for the season. We expect this weekend will be great to get out in the woods and see some beautiful blooming trout lily, squirrel corn, dutchman’s breeches, and trillium, among other early spring plants!