Envirothon at the Hadwen Arboretum

On Tuesday, I toured the Hadwen Arboretum with a group of students from Doherty High School, and their teacher, Stacey Hill. The students are participating in the Massachusetts Envirothon, which is a statewide environmental education program that encourages students to get outdoors and experience local ecosystems. This year’s Envirothon theme is “Trees, Forests, and Sustainability in Massachusetts”. The Hadwen Arboretum is hardly a natural forest, but it is a good place to visit and think about the history of land use and human impacts on plant communities. Excellent photographs of some of the trees of the Hadwen Arboretum have been posted on James Hunt’s blog.

Stacey Hill, Nicole Phan, Anna Figueroa and Samantha Openshaw in the Hadwen Arboretum. The tree behind them is Sciadopitys verticillata, the "Japanese umbrella pine".

Stacey Hill, Nicole Phan, Anna Figueroa and Samantha Openshaw in the Hadwen Arboretum. The conifer behind them is Sciadopitys verticillata, the “Japanese umbrella pine”. This is, in fact, not a pine at all. Pines are members of the family Pinaceae, while S. verticillata is the sole species of the family Sciadopityaceae.

Obadiah Hadwen was a farmer, horticulturist and Commissioner of Parks in Worcester, who died in 1907. In 2006, the Clark University Outing Club compiled biographical notes on Hadwen and a brief history of the Arboretum, based on records in the Archives of the Goddard Library. Hadwen bequeathed his Arboretum to Clark University for educational purposes, along with a sum of money intended to support ornamental plantings on campus. Today, the Arboretum remains a pleasant green space in the middle of a Worcester neighborhood, but it has not been maintained to the standards of an arborist like Hadwen. The grounds are overrun with invasive plants, including Japanese Knotweed (Fallopia japonica) and Burning Bush (Euonymus alatus), and the Physical Plant has used the Arboretum as a place to dump yard waste from the main campus. Some of the invasives may derive from Hadwen’s original plantings, including Norway Maple (Acer platanoides; native to Europe) and the Amur Cork Tree (Phellodendron amurense; Asia), recognizable by its deeply furrowed bark. The Amur Cork Tree is a member of the citrus family, Rutaceae, and is known for a tendency to self-seed. Numerous medium sized individuals of this species occur in the Hadwen.

Included in the Outing Club notes is a reproduction of a map of the trees of the Hadwen Arboretum that was drawn by Clark students in 1978. I used the map to guide walks in the Arboretum as part of my Botanical Diversity class in 2011 and 2012. The 1978 map lists 40 species by common name. There are several ornamental species listed that I have not seen, such as the “Chinese Cork Oak” (Quercus variabilis), Sweet Gum (Liquidambar styraciflua; native to the southeastern US—the northern limit in the wild is in Connecticut) and Katsura Tree (Cercidiphyllum japonicum; Asia). I plan to look for these on future walks. One species that is present but is not on the map is the Dawn Redwood, Metasequoia glyptostroboides, a “living fossil” that is native to China. It is surprising that the makers of the 1978 map overlooked this striking tree, particularly because they did record the presence of a Japanese Umbrella Pine (Sciadopitys verticillata; endemic to Japan) that is only a few feet from the Metasequoia.

Trees of the Hadwen Arboretum prepared by Clark students in 1978 and annotated by me in 2011-12.

Trees of the Hadwen Arboretum prepared by Clark students in 1978 and annotated by me in 2011-12.

I have to confess that I find the Hadwen Arboretum slightly depressing. It is frustrating to think what the Arboretum could be today if Clark had been able to honor Hadwen’s wishes in full. Nonetheless, I am grateful that the University has not sold the land (as has apparently been proposed at various points), and the Arboretum is not unused. My colleague Todd Livdahl conducts research on tree-hole mosquitoes there, and I have visited with my own students. The Outing Club has led walks and produced a trail map, and there is a community garden at the top of the hill. Evidently, some people have cared for the trees over the years; a number have been labeled (when? by whom?), and the Sciadopitys has been staked to keep it upright (see the photo above). Some of Hadwen’s original trees survive and are magnificent, such as the massive Cucumbertree (Magnolia acuminata) just inside the Lovell Street gate (number 25 on the map). Obadiah Hadwen might be dismayed by the current condition of his Arboretum, but it is still used for the purposes he intended, and one imagines he would be proud of the trees.