Page  59 ï~~1998 THE MICHIGAN BOTANIST 59 THE BIG TREES OF MICHIGAN 21. Castanea dentata (Marsh.) Borkh. American Chestnut Elwood B. Ehrle Dept. of Biological Sciences Western Michigan University Kalamazoo, MI 49008 The largest known American Chestnut in Michigan is located on the Old Mission Peninsula northeast of Traverse City (Grand Traverse County) in the northern part of Michigan's Lower Peninsula. Description of the Species: The American Chestnut is a member of the Beech family (Fagaceae). In this family, members of the genus Quercus (Oaks) have acorns, while those of Fagus (Beech) and Castanea (Chestnut) have a bristly fruit. The Beech fruit divides into two sections at maturity while the fruit of a Chestnut divides into four. Furthermore, Beeches have male flowers in a round pendulous inflorescence, whereas the Chestnuts have male flowers in a more or less erect spike (Fig. 1). Finally, Beech buds are long and pointed, whereas Chestnut and Oak buds are shorter and more ovate. The Chestnut was once a major component of hardwood forests in eastern North America, but was almost completely wiped out by the chestnut blight, a fungal parasite, in the first few decades of the twentieth century. The relatively few trees in northern Lower Michigan survived only by being well outside the main range of the species, which extended only into the southeasternmost part of the state. Location of Michigan's Big Tree: Michigan's largest known American Chestnut is located northeast of Traverse City, Michigan. The tree can be found by taking US 31 in Traverse City north to the first traffic light past the Holiday Inn. Turn north on M37 (Center Rd.) and go about 14.4 miles north on the Old Mission Peninsula to Old Mission Rd. Turn right and go 0.7 miles to the curve, and then 0.4 miles to a yellow house at #18367. The tree is 0.2 miles west up a farm lane through a cherry orchard and stands near the top of a hill. This location is in Sec. 35, T30N R10W. Description of Michigan's Big Tree: The tree has a solid healthy trunk. The first major branch is about 5' above the ground and has a circumference of 64" (163 cm). The circumference of the tree at breast height was measured on July 27, 1995 with John Spencer of Traverse City at 208" (528 cm) [diameter = 66" (168 cm)]. The crown spread was measured at 80' (24 m), substantially less than the 106' (32 m) previously recorded by John Thompson. The height was measured at 64' (20 m), again substantially less than the 110' (34 m) recorded by

Page  60 ï~~60 THE MICHIGAN BOTANIST Vol. 37 60 THE MICHIGAN BOTANIST Vol. 37 FIGURE 1. Documented distribution in Michigan and characteristics of American Chestnut. Map is from Voss (1985). The star indicates the location of Michigan's Big Tree. Illustrations are from Barnes & Wagner (1991). 1. Winter twig, x0.8; 2. Leaf, x0.4; 3. Flowering shoots, x0.4; 4. Male flower, enlarged; 5. Female flower, enlarged; 6. Prickly bur, opened, x0.4; 7. Nut, x0.4. Thompson. Although height and crown size have decreased significantly, its State Champion status remains secure because State Champion trees are determined by the circumference of the trunk at breast height alone. 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 Big Trees, please contact Elwood B. Ehrle

Page  61 ï~~1998 THE MICHIGAN BOTANIST 61 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. DEDICATION This series of articles is dedicated to the memory of Paul Thompson, Michigan's Big Tree Coordinator for over 40 years, who died in 1994. LITERATURE CITED Barnes, B. V., & W. H. Wagner, Jr. 1991. Michigan Trees. A Guide to the Trees of Michigan and the Great Lakes Region. Univ. of Michigan Press, Ann Arbor. viii + 383 pp. Voss, E. G. 1985. Michigan Flora Part II. Dicots. (Saururaceae-Cornaceae). Bull. Cranbrook Inst. Sci. 59 and Univ. Michigan Herbarium. xix + 724 pp.