(Fagaceae Quercus macrocarpa)
Adopted in 1961.
Although Iowa did not designate a
specific species of oak as its state
tree, many people recognize bur oak,Fagaceae
Quercus macrocarpa, as the state
tree since it is the most widespread
species in the state.
The Oak was designated as the
official state tree in 1961. The Iowa
Legislature chose the Oak because it is
abundant in the state and serves as
shelter, food, and nesting cover for
many animals and birds.
It is difficult to find a tract of
natural woodland in Iowa that does not
harbor at least one species of Oak. No
other group of trees is more important
to people and wildlife. Acorns, the nuts
of Oak trees, are a dietary staple of
many animals and birds. Wild turkeys,
pheasants, quail, wood ducks, raccoons,
squirrels, chipmunks, bluejays,
nuthatches, grackles, and several kinds
of woodpeckers are a few of the species
that depend on acorns for a significant
portion of their diet.
The mighty, majestic oak has,
throughout the centuries, been the
subject of story, song and proverb. More
than 80 species of this beautiful tree
are found in North America. All oaks are
deciduous trees with toothed leaves and
heavy, furrowed bark. The fruit is, of
course, the acorn. Like other deciduous
trees, most oaks shed their leaves in
fall. However, in warmer areas of the
continent, some varieties, the ‘live'
oaks, keep their greenery throughout the
winter. Oaks have always been
economically important for their hard,
strong wood which has a multitude of
purposes including furniture and
flooring. Oaks also have landscape uses
although mature trees can dominate
- Leaf: Alternate, simple,
6 to 12 inches long, roughly obovate
in shape, with many lobes. The two
middle sinuses nearly reach the
midrib. The lobes near the tip
resemble a crown. Pale pubescence is
- Flower: Male flowers are
green, borne in naked catkins, 2 to
4 inches long. Female flowers are
reddish and appear as single spikes.
Appearing shortly after the leaves.
- Fruit: Acorns are quite
large (1 1/2 inches long) and 1/2
enclosed in a warty cap that has a
long-fringed margin. Maturing in one
year, dropping August to November.
- Twig: Quite stout,
yellow-brown in color, with corky
ridges. Multiple terminal buds are
small, round, and may be somewhat
pubescent. Small, horny stipules are
generally present. Laterals are
similar, but smaller.
- Bark: Ashy gray to brown
in color and quite scaly, but
noticeably ridged vertically.
- Form: A medium-sized to
large tree that is very coarse in
appearance. Develops a very
spreading, broad crown.
Plantae -- Plants
Tracheobionta -- Vascular plants
Spermatophyta – Seed plants
Magnoliophyta – Flowering plants
Magnoliopsida – Dicotyledons
Fagaceae – Beech family
Quercus L. – oak
Quercus macrocarpa Michx. – bur oak
Dendrology at Virginia Tech
U.S. Department of Agriculture