Page  38 ï~~38 THE MICHIGAN BOTANIST Vol. 43 THE BIG TREES OF MICHIGAN 35. Fraxinus profunda Bush ex Britton Pumpkin Ash Susan Campbell Elwood B. Ehrle Senior Naturalist, Belle Isle Nature Center Department of Biological Sciences Belle Isle Park, Detroit, MI 48207 Western Michigan University Kalamazoo, MI 49008 The largest known Pumpkin Ash in Michigan is located on Belle Isle, an island in the Detroit River, located just south of the city of Detroit in Wayne County of Michigan's lower peninsula. Description of the Species: The Pumpkin Ash is a member of the genus Fraxinus in the family Oleaceae. In some treatments it is known as Fraxinus tomentosa Michaux f., an illegitimate name because the younger Michaux cited previously published names in synonymy-his name was a deliberate substitution. It has opposite, pinnately compound leaves (see Fig. 1). When the young leaves unfold, the blades and petioles are covered with a hoary tomentum. At maturity, the leaflets are covered with a silky pubescence below. The flowers are small and borne in panicles in the spring. Most species of ashes are dioecious. The fruit is a prominently winged samara. Unlike the maples which have double samaras, the fruit of an ash is always single. An outstanding characteristic of the Pumpkin Ash is the large size of its samaras. They are usually several cm long x 10 mm wide, substantially larger than the samaras of other ashes. McCormick, Bissel & Stein (1995) provide an illustration of the gradation from the smallest samara (E americana) through E nigra, E pennsylvanica and E quadrangulata to the largest (F profunda). The samaras of E profunda persist in the leaf litter for more than a year and are usually not difficult to find under the trees. These authors also provided a convincing demonstration that the Pumpkin Ash is more common in Ohio than previously thought. Its range extends along the coastal plain from southern New Jersey south to Florida and west to Louisiana. It is also known in the Mississippi Valley as far north as Illinois and "... along the Ohio and Wabash Rivers to Indiana, Ohio, and southern Michigan." Finally, they cite a specimen collected in Hillsdale County Michigan in 1992. Voss (1996) cites an additional specimen collected in Berrien County, Michigan in 1994. Location of Michigan's Big Tree: The Pumpkin Ash trees on Belle Isle grow in the wooded NE part of the island between the Zoo and the Nature Center. The State Champion tree is in a grove with Shumard Oaks. The grove is located along the Nashua Canal just east of the western bridge of the bicycle trail which runs along the canal. To reach the tree, take 1-75 south through the City of Detroit to 1-375. Follow 1-375 south to Jefferson Ave. Exit 1-375 onto Jefferson Ave. and go east to E.

Page  39 ï~~2004 THE MICHIGAN BOTANIST 39 2004 THE MICHIGAN BOTANIST 39 FIGURE 1. Documented Michigan distribution and characteristics of the Pumpkin Ash. The map is from Voss (1996). The asterisk indicates the location of Michigan's Champion tree. The illustration (x%) is from Sargent 1922. Note that the flower clusters are borne opposite one another, as are the young leaves. Grand Blvd. Turn right and proceed over the McArthur Bridge onto Belle Isle. As soon as you are on the island, the road forks. Take the left fork and proceed along Central Avenue to the intersection with Inselruhe Avenue. Turn right onto Insulruhe Avenue. Go one block and turn left onto Loiter Way. Follow Loiter Way until you come to a curve and then a small bridge. Park on the left and walk down the bike trail over the nearby bridge. Once you have crossed the canal, leave the paved path and turn right along the canal. Proceed about 60 yards. The Champion Pumpkin Ash is on your right about 23 yards back. It is slightly behind and to the right of a large Bur Oak. Description of Michigan's Big Tree: There are a number of Pumpkin Ash growing with Shumard Oaks in what might be described as a Pumpkin Ash-Shumard Oak Association. These trees were previously visited by Herb Wagner, Steve Koblarz, Susan Campbell, and Bill Brodovich who all agreed that they were, indeed, Pumpkin Ash trees. The State Champion tree was measured by Susan Campbell and Elwood B. Ehrle on 10 July 2001. Its girth at 4%' above the

Page  40 ï~~40 THE MICHIGAN BOTANIST Vol. 43 ground was 85" (7'1" or 3.3 m). The tree is 135' high (38 m) and has an average crown spread of 50' (15.2 m). The tree is healthy and has a solid straight trunk. INVITATION TO PARTICIPATE If you would like to join us in extending this series of articles by visiting and describing one or more of Michigan's Champion trees, please contact Elwood B. Ehrle for help with locations, specifications for taking measurements, and assistance with the manuscript. The Michigan Botanical Club encourages your involvement in this activity. Please remember to ask permission before entering private property. LITERATURE CITED Barnes, B. V. and W.H.Wagner, Jr. 1981. Michigan Trees. A guide to the Trees of Michigan and the Great Lakes Region. University of Michigan Press, Ann Arbor. viii + 383 pp. McCormick, J. S., J. K. Bissell, and S. J. Stine, Jr. 1995. The status of Fraxinus tomentosa (Oleaceae) with notes on its occurrence in Michigan and Pennsylvania." Castanea 60(1): 70-78. Sargent, C. P. 1922. (Reprintedl965) Manual of the Trees of North America. 2nd Edition. Volume 2. Dover Publications, N.Y. xvii + 433 pp. Voss, E.G. 1996. Michigan Flora. Part III. Dicots (Pyrolaceae-Compositae) Bulletin of the Cranbrook Institute of Science No. 61 and University of Michigan Herbarium, Ann Arbor, MI. xix + 622 pp.