by Sean Halloran, Plant Propagator, The Arnold Arboretum of Harvard University
In September, the Arnold Arboretum once again visited Southern Highlands Reserve as part of a 3-week long plant collections trip, continuing our on-going partnership for plant conservation started in 2016. All seven 2019 North American-China Plant Exploration Consortium (NACPEC) scientists were graciously hosted by Lauren Garcia Chance, Kelly Holdbrooks, and Eric Kimbrel during one very important stop on our plant collecting expedition. This trip was special for us because we were hosting three Chinese plant scientists from Beijing, Chengdu, and Kunming who aided us in our study and collection of Southeastern U.S. flora. During the trip we made 100 collections in Ohio, Kentucky, Tennessee, North Carolina, and Georgia.
The SHR crew led us on a wonderful tour of the gardens where we marveled at the plantings, including the native wildflower labyrinth, to name just one of my favorite parts of the gardens. I really wish we had more time to explore the gardens before we were off wild collecting in the conserved sections of the Reserve!
Thanks to role of past ice ages, Southern Highlands Reserve is particularly desirable for collecting wild plants. The unique combination of high elevation plant communities and incredible biodiversity of the region mean there are many native plants that are also cold hardy and appropriate here in Boston. In particular, we seek out wild protected areas to collect plants, like those stewarded by Southern Highlands Reserve. Wild plants are important to collect because these existing natural plants often represent a wider gene pool than cultivated plants (think plant nurseries versus your local forest). For example, genes for disease resistance might exist in a single group of plants in the wild, which is why representing as many of these wild groups, or populations as possible in public and private gardens is so important.
When we collect a plant, our procedures include extensive collection of data, including size and visual description of individual plants, density of the plant species in the area, the other plant species that are in the area, habitat descriptions, location information such as GPS coordinates, soil type, and much more. We typically seek out only seeds, but sometimes cuttings or even seedlings are desired based on the time of year. Along with this data and our plant collection, we also collect representative samples of the plants – called herbarium vouchers.
Herbarium vouchers are pressed and dried plant samples that are a record of the plant form and structure (morphology) used for future study. Plant taxonomists, botanists, and other plant scientists use herbarium specimens to make determinations about differences in plant species. For each collection we made on this trip, we prepared between 4 and 7 herbarium vouchers. These vouchers will go to herbaria around the world where current and future researchers can study them, even if a plant is lost to extinction in the wild. Herbaria are large repositories of plant specimens, almost like plant libraries, where specific plant groups can be studied.
The data and plant material we collect is shared with other institutions whose missions align with the conservation or protection of plants. The plant material that we gathered is divided based upon institutional interest and distributed appropriately. For example, at the Arnold Arboretum, we focus on propagation and growth of woody trees and shrubs cold hardy to zone 6. The seeds from a Magnolia that we collected at SHR will be grown in our greenhouses and nurseries before being planted out in our collections; a small piece of SHR growing in Boston. These Magnolia trees can then be studied by researchers or the public for many years to come!
I know that the future of plant conservation in Eastern North America is dependent upon partnerships like these, and we hope to continue collaborating with Southern Highlands Reserve in the future. We can’t thank the Southern Highlands Reserve community enough for allowing us access to the wonderful lands you steward!
Sean Halloran is the Plant Propagator at the Arnold Arboretum of Harvard University. Sean received a Bachelor’s in Horticulture and a Master’s degree in Plant & Environmental Science from Clemson University where he focused on nutrient media in tissue culture propagation. His professional background includes private residential horticulture, greenhouse and nursery production, plant nutrient management in soil-less media, and temperate woody plant propagation and conservation. As the Arnold Arboretum’s Plant Propagator, Sean continues a 150 year tradition of growing trees from seed, cuttings, grafts, layers, and more; as well as being given the honor to travel and wild collect plants for the Arnold Arboretum in Boston, Massachusetts.