I collected phenological data from 5 trees on April 7, 2025. The species included red oak, sugar maple, white oak, red maple, and Norway maple. I noticed that generally, the buds on the selected trees hadn’t quite broken. The only changes of phenological significance were a few broken buds on the sugar maple, and dead leaves on the white oak remaining from the fall. I didn’t see any flowers, pollen, or expanded leaves because it was too early in the season to view these changes. Due to my observations, I can determine that all five trees were in a similar phenophase: either close to budding or starting to bud. When walking around campus in the following weeks, I noticed the test trees starting to bud around 2 weeks later.
When exploring NPN’s website, I found an article titled “Are plant and animal species responding differently to climate change?” derived from the study “Phenological divergence between plants and animals under climate change” from Nature Ecology & Evolution. In this study, they collected an extensive dataset of phenological observations from other peer reviewed literature and networks including the USA-NPN. They estimated whether the average time that a life cycle stage occurs has shifted since 1980, and evaluated the role of temperature and precipitation in discovered changes. Furthermore, they researched how climate change may increase the likelihood of phenological mismatches for species in the same location to assess risks to ecosystem dynamics.
The authors found that spring and summer phenological processes for plants like leaf out, flowering, and fruiting are happening earlier than 40 years ago. This advance is likely the effect of rising temperatures. Contrastingly, leaf fall has not shifted over time. Additionally, climate change has had a much weaker effect on the timing in animal life cycles. The differences in responses contribute to the evidence of emerging mismatches between interacting species.
An example of an emerging concern of phenological mismatch is how plants that rely on insect pollination are flowering earlier, however, the insect pollinators are not emerging earlier in the year. If this pattern continues and their seasonal timing further diverges, the pollination process may be disrupted in future and have detrimental impacts on the ecosystem and food web.
The data we are collecting on campus may contribute to the development of this study and other similar research projects to determine how tree phenology is changing in Vermont in relation to climate change, and potential consequences for species dynamics.
