This spring we’ve begun a first-of-its-kind project—one that will have wide-reaching implications for the future of Southeastern forests. Partnering with HudsonAlpha Institute of Biotechnology through an ADECA grant, we’re developing full DNA sequences for multiple species of trees common on the 150-acre Paint Rock Forest Dynamics Plot.
An ecosystem catastrophe has made our work even more timely and important. Emerald ash borers have infiltrated the Paint Rock Valley, and in many areas that has meant the loss of more than 95% of ash trees. In Paint Rock, ash trees number among the top 5 groups of trees, and their loss will be a blow to the forest.
There’s reason to believe that Paint Rock’s unusually diverse ash populations may have a bit more fighting power than ash in many places. So we’ve focused this season on collecting DNA from as many trees as possible in the ash genus (Fraxinus), which will allow researchers to dig into the genetics between the population of trees succumbing and those surviving this threat. We may also be able for the first time to accurately identify some “hidden” ash species that are difficult to distinguish by leaves alone.
We’re not looking at just a dozen or so samples either. We’re sequencing 700 to 800 samples before June. We have our work cut out for us.
What collection means for our team at Paint Rock these coming weeks is many hours in the plot, navigating a rocky terrain and the inherent hazards of being in the brush in the springtime when other life is bursting forth.
Our task comes with a timeline, too: We must gather samples of fresh growth from the tops of trees as soon as possible after they emerge to protect the genetic integrity of the leaves. Some of these collections are straightforward. We can pluck samples with a Hastings pole (a long 30-foot pole used by utility crews)—or a massive “slingshot” designed to carry lines over limbs. Trees with leaves only in the crown, often a hundred feet in the air, dominating the overstory, will require some creativity and cutting-edge technology—such as sending a robot into the sky (we’ll share more on that later this month). After we’ve collected the branches, we freeze the leaf samples in liquid nitrogen and place the tubes on dry ice to keep them frozen until we can deliver them to HudsonAlpha.
We’re just getting started here too. This will be an ongoing project for the next several springs as we continue to work through the species list. Our ambitious plans for a DNA census in our forest dynamics plot will be critically important to the future of trees facing fast-paced threats and environmental changes.
By Landon Rakestraw, Research Staff & Aquatics Coordinator