7/8/22: on the trees' schedule

We’ve been patiently waiting on the rain to pass and the roots to root. The sugar maples and star magnolias for our waterlogging project were still not quite ready this week. You can’t rush mother nature, so we wished the trees the best and went on our way. That brings up the unexplored mystery of root phenology. Phenology is the study of life cycles and how they relate to seasonal influences such as climate. When does a flower bloom? When does a tree lose its leaves? When does a bird fly south? These are all questions concerning phenology. Just like all other parts of the tree (leaves, flowers, trunk, and branches), roots display phenological patterns. At certain times during the year, they experience intense growing periods. This is the perfect opportunity to give you a deeper look at the research we do with the minirhizotron scanners. Continue reading to find out how we use these images to tell a story about root life cycles and growth patterns (and some other fun updates from this week)!

Imaged roots with minirhizotron scanners

To give you a refresher, we use the minirhizotrons to see how and when roots grow and die over time. Plastic tubes are placed in permanent locations within the forestry plots, allowing us to scan the same area at 4 different depths. As mentioned above, root phenology is a mystery! Scientists have yet to tie down a clear seasonal pattern for roots, let alone all the variation between species. Luckily for us at the arboretum, our plots allow us to do species comparisons unlike anywhere else in the world.

Why is this important? Root phenology plays a critical role in the life-cycle of plants, and it is very sensitive to climate change. If a plant’s timing is thrown out of whack, it can grow, leaf-out, flower, and fruit at the wrong time. This makes plants vulnerable to the environment. If a tree blooms too early, a late frost event may damage leaves and flowers. If changes in climate cause fine roots (remember, “fine” roots are those cute little dudes responsible for absorption) to get a late start during the growing season, then the trees now have no way of sucking up the water and nutrients they need. To learn more about current research on root phenology and climate change, check out this review authored by our very own Dr. Luke McCormack and others.