ï~~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 Campus 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 usually 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 middle 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 frequently 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 taking exit 180 off of 1-94 and going north on Rt. 23 through Ann Arbor to Plymouth 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 42Â~ 17.954' N and 83Â~
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 ReLeaf 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
spread 40'. The total number of points (Girth +Height + Y of the crown spread)
for this tree is, therefore, 86 + 90 + Y x 40 = 186.
