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The Morton Arboretum accession tag for this tree
BUR OAK
Quercus macrocarpa
138-U-15 unkn T N-73/25-46
and the online catalog lists it as being in in
the Forestry Plot Area, but you'll find
it near the Magnolias and Relatives, just west
of Crowley Marsh. The old oak tree next to the marsh
and nearest the road is a Shingle Oak, beyond
that is a Sweet Gum and beyond that is this wonderful
old Bur Oak.
Picture taken April 17, 2004
The pictures on the left showing newly emerged leaves
and catkins of Bur oak. These pictures are of different
branches and were taken on the same day.
Bur oak flowers shortly after leaves develop, but prior to or early in
the period of major stem expansion. Initiation of flowers and
leaves in the spring is not closely related to temperature.
Flowering usually begins in April in the South, but may not begin until
June in the North [2].
Pictures taken April
17, 2004.
Bur
oaks bear seed up to an age of 400 years, older than reported for any other American
oak. The minimum seed-bearing age is about 35 years, and the optimum is 75 to 150 years.
Good seed crops occur every 2 to 3 years, with no crops or light crops in intervening
years. The acorns are disseminated by gravity, by squirrels, and to a limited extent
by water. (1)
Many birds and mammals eat bur oak acorns including squirrels, deer, wood ducks, blue jays, and cows. Rodents and blue jays frequently cache the acorns for later use, thereby facilitating seed dispersal. (2)
Photo taken in mid-August 2009
The
lowest branches of this Bur oak rest on the ground,
but others reach to the sky. Leaves are dark green
on top, but a much lighter color on the bottom. Click
on the middle photo to see how the sun on the undersides
of leaves gives the appearance that the tree is filled
with doves. 
Standing
under this Bur oak and looking upwards gives you an
appreciation for the strength of the trunk of this
older tree. The shade was a welcome relief from the
hot sun on this 90 degree day. 1 - USDAFS Silvics of North America
2 - Tirmenstein, D. 1988. Quercus
macrocarpa. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: http://www.fs.fed.us/database/feis/ [2009, August 21].
Karren Wcisel © copyright 2004 - 2009
Please ask for permission before using my photographs. Larger sizes and additional photographs of the tree are usually available.