2005 THE MICHIGAN BOTANIST 109
THE BIG TREES AND SHRUBS OF MICHIGAN 46. Pseudotsuga menziesii (Mirbel) Franco Douglas-fir
Elwood B. Ehrle Department of Biological Sciences Western Michigan University Kalamazoo, MI 49008 [email protected]
The largest known Douglas-fir tree in Michigan is located on the North Cam- pus of the University of Michigan in Ann Arbor, MI, in Washtenaw County in the southeastern part of Michigan’s Lower Peninsula. Description of the Species: The Douglas-fir is an evergreen tree with a usu- ally straight trunk and conical crown. The soft, flexible leaves are 2–2.5 cm long, somewhat 2-ranked, and have constricted bases. The branchlets are mostly smooth and exhibit oval scars where leaves have been removed. The cones have conspicuous three-lobed bracts extending beyond the cone scales, with the mid- dle lobe long and narrow. This species is native to the Rocky Mountains and the North American Pacific Northwest coast, where it forms extensive forests of large trees. It is an important lumber tree in the northwest. In Michigan, it is fre- quently planted as a park or lawn tree and is grown as a Christmas tree which holds its needles better than Balsam Firs or Spruces. The common name honors David Douglas, 1799–1834. Location of Michigan’s Big Tree: The North Campus of the University of Michigan is located on the north side of Ann Arbor, MI. It can be reached by tak- ing exit 180 off of I-94 and going north on Rt. 23 through Ann Arbor to Ply- mouth Road (exit 41). Take Plymouth Road east to Beal Road and turn right into the University of Michigan’s North Campus. Go a short distance and turn left onto McIntyre Street. Follow McIntyre Street to parking lot NW23. Walk up the slope about 150′ into a grove of trees. This was formerly the site of a cemetery. The Douglas-fir stands next to a Norway Maple at 42° 17.954′ N and 83° 42.851′ W. Description of Michigan’s Big Tree: The tree has a straight solid trunk. Its girth was measured at 86″ on 23 August 2003, by Gail McPherson of Global Re- Leaf of Michigan, Richard Pomorski, noted Ann Arbor area Big Tree hunter who discovered the tree, and Elwood B. Ehrle. The height was 90′ and the crown 1 spread 40′. The total number of points (Girth +Height + ⁄4 of the crown spread) 1 for this tree is, therefore, 86 + 90 + ⁄4 × 40 = 186. 110 THE MICHIGAN BOTANIST Vol. 44
FIGURE 1. Location of Michigan’s Champion tree and characteristics of Douglas-fir. The asterisk on the map indicates the location. Illustrations are from Barnes and Wagner (1981). 1. Winter shoot, ×2. 2. Winter buds (leaves removed), ×2. 3. Leaf, ×2. 4. Cross section of leaf, ×10. 5. Opened cone, ×1. 6. Cone scale with seeds, ×1.
INVITATION TO PARTICIPATE
If you would like to join in extending this series of articles by visiting and de- scribing one or more of Michigan’s Big Trees, please contact Elwood B. Ehrle ([email protected]) for help with locations, specifications for tak- ing measurements, and assistance with the manuscript. The Michigan Botanical Club encourages your involvement with this activity. Please remember to ask permission before entering private property.
LITERATURE CITED Barnes, B. V. & 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, MI. viii + 383 pp.