Simple techniques can describe how maple trees are responding to climate change

Posted by Libby Ellwood and Richard B. Primack

“Our life is frittered away by detail. Simplify, simplify.”

-Henry David Thoreau

In a study recently published in a Special Issue of Applications in Plants Sciences, we found that simple annotations of plant specimens are as effective as more detailed ones for phenological research. With climate change increasingly effecting plants and animals around the world, phenology is an important metric for us to readily monitor the extent to which organisms are responding. Plant specimens are a critical resource for this as they record the phenological state of a plant at a specific place and time. Each specimen therefore provides evidence of such events as flowering, leaf out, and even dormancy.

Red maple specimens are evaluated for their
flowering stage, along with information
on where and when collected.

However, is it necessary to record the fine-scale phenology of a specimen, such as flower buds, early flowers, or peak flowers? Or, is simply noting “flowering” enough to see patterns of change? In researching this question, we found that the simpler approach of noting “flowering” was sufficient to see that the phenology of our study species, the red maple, has been advancing by about 2 days for each one degree F of warming temperature. These are the same results we found with a more detailed approached.

We evaluated specimens from across eastern North America.

Detailed phenological information may be necessary for certain research, though our study demonstrates that in many cases a simpler approach is just as effective. This finding is especially important as scientists work with members of the public, citizen scientists, to monitor phenology and annotate specimens. It is much easier to teach an armchair botanist to recognize flowering or non-flowering as opposed to finer phenological details, and now we know that the results will not be comprised with this approach.

Read the full paper here: Ellwood, E. R., R. B. Primack, C. G. Willis, Janneke HilleRisLambers. 2019. Phenology models using herbarium specimens are only slightly improved by using finer-scale stages of reproduction. Applications in Plant Sciences 7(3): e1225