Tree Notes is about trees -- especially native trees, trees for wildlife, and trees in history.

Monday, November 26, 2007

The corkwood tree

Leitneria floridana

The Florida corkwood (Leitneria floridana) is an interesting and rare North American tree. I'm calling it a tree, but sources disagree whether it is a tree or a shrub. Many compromise by calling it a "shrub or small tree."

As you might suspect, the corkwood is a tree with very light wood. In fact, its wood is about 13 pounds per cubic foot, even lighter than cork. In the areas where it grows, it has been often been used for corks and fishing floats by the local residents.

I don't think I've ever seen corkwood, or if I have, I didn't know what it was. If you look at the photos at the USDA Plants database, you'll know as much as I do about its appearance.

I'll suspect that it might be corkwood if I ever happen upon a dense thicket of smooth-barked woody tree-shrubs in the swamp, 12 to 20 feet in height, with long stems, very short branches, and shiny, thick leaves that have reddish stems.

Corkwood is not often seen. "It occurs rarely and locally along tidewater river and in swamps from southeastern Georgia and western Florida to southeastern Texas; and also in parts of Arkansas and Missouri." (from William Carey Grimm's Book of Trees -- see bibliographic info at bottom of the column.)

The Center for Plant Conservation describes the corkwood's range as "scattered ... freshwater swamps, wetland thickets, pond habitats, brackish tidal streams and brackish marshes of coastal southeast Texas, the central Gulf coast of Florida, extreme southeast Missouri, northeast and east-central Arkansas and southwest Georgia."

One might search for the ivory-billed woodpecker in similar places. And, like the ivory-billed woodpecker, corkwood was once far more common in the southeastern U.S. As wetlands have been drained and stream banks bulldozed, corkwood has died out. It is considered a threatened plant in Florida and Texas, and rare in Georgia, Arkansas,and Missouri,

Where the corkwood grows, it is often found in thickets because it spreads by root suckers. It is unusually tolerant of flooding, and it can live in a submerged state for long periods of time. This makes it a valuable tree for controlling erosion along stream banks.

Florida CorkwoodCorkwood. Image courtesy of USDA-NRCS PLANTS Database /
Britton, N.L., and A. Brown. 1913.

An illustrated flora of the northern United States,
Canada and the British Possessions
. Vol. 1: 586.

Images of corkwood (Leitneria floridana) on Flickr
Corkwood article in Trees of Georgia

Sunday, November 25, 2007

"Green" Christmas trees

The usual Christmas tree debate with a new green twist

Every Christmas, there's discussion about the pros and cons of real and artificial Christmas trees.

Environmental costs of artificial trees include the air pollutants that may be emitted from the factory. Fossil fuels are consumed in their manufacture and delivery, especially if the factory is in China. Artificial trees usually contain PVC, a type of plastic which is hard to recycle. Another item of concern: some artificial trees contain lead.

Real Christmas trees have environmental costs as well. Tree farm runoff from fertilizers, pesticides, and herbicides can degrade water quality, disrupt natural ecosystems, and even endanger wildlife and other life forms. Soil erosion may occur. Fossil fuels are consumed in harvesting the trees, bringing them to market, and in many cases, in disposal. In addition, they can be a fire hazard in the home if they are not properly tended.

Environmentally friendly growing practices

This year, the Christmas tree market will include 200,000 trees grown by members of the Coalition of Environmentally-Conscious Growers. These tree growers have met certain standards in order to join the group and use the label:

To pass muster, a farm must be inspected to ensure that it meets certain standards for managing wetlands, nutrients and pests. Water and soil conservation measures are reviewed, and biodiversity and worker safety are also considered.

Source: Ore. Growers Promote "Green" Xmas Trees, by Sarah Skidmore, AP writer

More tree growers are expected to join the coalition in the future. Many are just waiting to be certified.

This marketing strategy targets consumers who worry about the environment. The "sustainable" practices on these tree farms will indeed be better for the environment. We can hope that, as a result of the coalition, all Christmas tree growers will feel pressured to improve soil and water conservation efforts and practice "greener" chemical use, even if they don't attempt certification.


We got our last real Christmas tree when we lived in Berlin, Germany. It cost about $70, a considerable sum in 1990. We followed all the rules to keep it fresh, but its needles began falling immediately, and it was such a mess that I took it down the day after Christmas.

The next year, we bought a little artificial tree which we used for the next 14 years. I finally advertised it in the newspaper and sold it to a young family who intended to continue using it. I purchased another, slightly larger, artificial tree, and it is now in its 4th year of use.

Most of those years, we put our tree up the day after Thanksgiving and didn't take it down until well after New Year's Day.

I don't know how the environmental cost of that little artificial tree compares to 14 real trees, but we did enjoy it for many, many days. A year and a half of total use is a conservative estimate!

Tuesday, November 20, 2007

Redbud tree in autumn

Cercis canadensis

Redbud in autumn foliage

This nice little redbud tree grows in front of the Christian County Water District office in Hopkinsville, KY. The building shelters it a little from the weather, so that's probably why it still has so many of its leaves in the middle of November.

The white building provides a dramatic backdrop to the redbud when it blooms. Sometimes people plant redbuds against a background of evergreen trees to showcase the bright lavender blossoms. These strategies highlight the autumn color of the redbud as well as its spring blooms.

The golden yellow of this tree's leaves is the typical fall color of the species. If you could look up into this tree's branches, you'd probably see some of its seed pods. The redbud is a legume and it produces a "bean pod." The pods are brown, flat, and up to four inches long.

The branches of redbud trees are usually more sprawling and widespread than this. I suspect that this tree has been pruned or topped to keep it away from the electric wire at the upper left of the photo. Redbuds can grow up to 35 feet in height, so they're not a good tree to plant under power lines.

I suppose you could plant a redbud seed, but it's easier to transplant a little tree that has sprouted in the wild. Move them in spring or in autumn, keeping as much dirt as possible around the roots by using the ball and burlap technique.

Or buy a young tree from a nursery. Various cultivars are available. Some even have white or pink blooms rather than the lavender that is usually seen in the wild redbuds.

Related posts:
Native beauties: Redbud and dogwood
Eastern redbud: A tree I love

Thursday, November 15, 2007

A Handsome White Oak

One of my favorite trees in our neighborhood

Large white oak growing in a front yard

One of our neighbors has a beautiful, big white oak in his front yard. He didn't plant it. It has been growing for many, many years.

I knew an old man who was born in this house. He has passed away now, but if he were living, he would be about 90. He told me that the tree was there when he was a child, and it was a big tree then (at least to his little eyes.)

I took this photograph about ten years ago. Since then, our neighbor has torn down the old house and built a new house.

I was a little worried that the tree might be hurt during the construction, but I think it's going to be all right. It probably didn't have many roots where the new house was built, directly behind the site of the old house.

This is one of my favorite trees. Even though I don't own it, I enjoy seeing it and I have an affectionate concern for it.

According to Gary Hightshoe's Native Trees, Shrubs, and Vines for Urban and Rural America (see book info at the bottom of this column), one of the sites that the white oak (Quercus alba) likes is "moist, warm, south, or west facing slopes."

The white oak in the photo grows on a gentle slope that faces south, just above a river. In fact, the river is about 100 yards from the sign in the foreground of the photo. White oaks can't tolerate flooding, but even on the rare occasion that the river is out of its banks, this tree is far enough up the slope that it won't stand in water.

It's hard to guess how old it might be. White oaks are very slow growing , but they are very long-lived. They usually live 350 to 400 years, and they often live 500 years or more. Truly, when you plant a white oak, you plant it for your grandchildren and their grandchildren.

You could also say that you plant it for the birds and animals. White oak acorns are the least bitter of all the oak mast. They are a valuable food for a wide range of birds and animals. Even bears will eat white oak acorns.

Quercus alba info in the USDA Plants database
White oak info at the Virginia Tech. Dept of Forestry website

Tuesday, November 13, 2007

Sycamore leaves in autumn

Platanus occidentalis, American planetree

Sycamore leaves in the fall

I like sycamore trees in the fall when their leaves begin to change color. They look like someone has tied colored handkerchiefs to all the branches -- or so it seems to me. Each leaf is so large that it makes its own splash of color.

I found this sycamore growing in my garden one wet spring about a dozen years ago. It was just a seedling. Sycamore seeds like to fall onto mud flats and take root, and "mud flat" describes my garden that spring. We dug the little tree up and planted it on the far end of our little acreage.

(The rainy season that year was interesting. A killdeer made its nest in my muddy washed-out garden, and she had a hissy-fit every time I came anywhere near it. I felt bad about making her fake a broken wing all the time so I just let her have that end of the garden for a while. But now, back to the sycamore tree...)

I estimate the current height of the sycamore tree at 35-40 feet. I'm not real good at estimating height, but it's a good 15-20 feet above the power lines.

Ah, yes, the power lines. They are going to be a problem. We underestimated the spread that the tree would develop and the power company will want to trim back its branches on that side. We'll have to let them do it. One good thing about it -- sycamores aren't a densely branched tree.

Sycamores may grow up to 70 feet in 20 years. They are long-lived trees, often living over 300 years. They often reach 100 feet in height and they may be even wider than they are tall!

Monday, November 12, 2007

November Night

With faint dry sound,
Like steps of passing ghosts,
The leaves, frost-crisp'd, break from the trees
And fall.

Poem by Adelaide Crapsey. Rrom The New Poetry: An Anthology,
edited by Harriet Monroe and Alice Corbin Henderson.
Published in New York by The Macmillan Company in 1917.

morgueFile photo by S. Whitmore

Thursday, November 8, 2007

Champion white oaks

Kentucky's champion white oak compared to past and present national champions

The current champion white oak for the state of Kentucky grows in Logan County, a couple counties east of where I live. It is 270 inches in circumference (about 22.5 feet.) It's height is 94 feet and the spread of its crown is 104 feet. With 390 points, it ranks as one of the biggest trees in my state -- a "monster" of a white oak in our day!

I'm a bit disappointed that no photograph of this champion white oak is available on the Kentucky's Big Tree Program website.

Wye OakThe Wye Oak of Maryland was the champion white oak of the nation for many years. A windstorm took it down in 2002. Its circumference was well over 31 feet. It was 96 feet in height and the spread of its crown was 115 feet. It was awarded an amazing 508 points for its overall size. At the time of its demise, it was estimated to be over 450 years old.

The photograph of the Wye Oak at right was taken by E.H. Pickering, in December of 1936. The image is part of the Historic American Buildings Survey on the Library of Congress website.

The current champion white oak for the nation grows in the Lawrenceville, Virginia, area. It has been awarded 427 points. It is 86 feet tall and 32 feet in diameter. If there's a photograph of it on the internet, I haven't found it yet.

The Wye Oak Gallery

Wednesday, November 7, 2007

White oak bark and leaves

Quercus alba, foliage and trunk

Quercus alba bark and leavesOne of the most helpful tree-identification things I've learned lately is that the sinuses of oak leaves at the top of the tree will be more deeply cut than those at the bottom of the tree. (Sinuses are the indentations between the lobes.) Apparently, a leaf that is getting plenty of sunshine doesn't need as much surface area as a leaf that is growing in the shade.

The white oak leaves in the image above are a good example. The leaves at the top of the tree (in the background at the top of the photo) have much deeper sinuses than those at the bottom of the tree (foreground.)

Bark of quercus albaWhite oak bark is quite distinctive in color. It's actually a light gray, not white, but it's lighter in color than many tree barks. It's often a bit scaly. You can see some scales on the trunk in the above photo at upper left.

Recently, I happened to find a great image of white oak leaves and acorns from the early 1900s in the Kentucky Virtual Library. Its caption mentions that they came from "a monster white oak near Persimmon." Persimmon is a small settlement in Monroe County, Kentucky (north of Tompkinsville, in south central Kentucky.)

Sunday, November 4, 2007

Hawthorn trees and wildlife

Berries of the Washington hawthorn, Crataegus phaenopyrum

These cheery red berries are the autumn fruit of a thorny little Washington hawthorn tree I planted about a dozen years ago. I got it in a bundle of ten free ornamental trees from Arbor Day Foundation.

Washington Hawthorns bloom late in spring, so this tree's blossoms were not affected by the late freeze last spring. It's loaded with berries. In fact, I think it has the most fruit of any tree I've seen this fall. Many of the fall-fruiting trees and shrubs have nothing at all because their blossoms were frozen.

American Wildlife and Plants (see bibliographic info at the bottom of this page) has the following comment about hawthorn berries:

The small apple-like fruits are not used by wildlife to nearly so great an extent as might be anticipated. Fox sparrows and cedar waxwings are the principal songbird users.

The authors note that up to 25% of the diets of fox sparrows and cedar waxwings may consist of hawthorn berries, in areas where hawthorns are common. They also list about a dozen birds and over a dozen small and large animals that include small amounts of hawthorn berries in their diets (up to 2% of their total diet.)

In a winter of scarce food, I suspect those birds and animals would be glad enough to find a hawthorn tree full of berries.

Hawthorns belong to the rose family, as you might guess when you experience their long, sharp thorns. They are a favorite nesting place for birds. The mockingbirds have a nest in this tree every year.

Saturday, November 3, 2007

Two borers that attack persimmon trees

Agrilus fuscipennis (persimmon agrilus) and Sannina uroceriformis (persimmon borer)

It doesn't take a rocket scientist (or an arborist) to see that the young persimmon tree at left probably has been invaded by borers. Two holes are clearly marked by the blackened gum around them. I think these are entry holes, but I suppose they also could be holes left by a woodpecker going after the borers.

After seeing the holes in this tree's trunk, I did a little reading about tree borers and learned that two types attack persimmons: Agrilus fuscipennis or persimmon agrilus, and Sannina uroceriformis or persimmon borer

These holes are located at about 4 or 5 feet above ground level. That makes me think that persimmon agrilus is at work.

Persimmon agrilus

The persimmon agrilus is active in the lower trunk of the persimmon tree as well as the taproot. offers this:

Dissections [of persimmons infected with agrilus] reveal that galleries [long holes made by the borers] are most prevalent around the root collar and commonly occur 1.2 m up into trunks and 0.5 , down into roots. However, a few galleries have been found in trunks to 2 m and in roots to 1 m.

The adult persimmon agrilus is a beetle, and it apparently lays its eggs on the trunks of persimmon trees near the ground. Damage to persimmon trees by the agrilus larvae usually does not endanger the tree's life, but it does decrease the value of its wood as lumber.

Sannina uroceriformis

The adult persimmon borer moth usually lays its eggs on the lowest portion of the persimmon trunk, rarely over 60 cm from the ground and usually much closer to ground level. She may lay eggs on the ground around the persimmon as well.

The egg-laying sites are near the ground because the freshly hatched persimmon borer larvae need to find their way to the persimmon's root system. They will spend the next year or two eating their way through the roots and creating tunnels as they go --hence their name, "borer".

The persimmon's roots can become so weak from the activity of persimmon borers that the tree falls over.

Tree borers

Don't dismiss persimmon trees just because they sometimes get borers. Many trees are attacked by borers.

If you think your persimmon or any other tree has borers, your county extension agent or university extension service is one of the best sources of specific information, available without charge.

Read more:
More about persimmon trees
More about persimmon agrilus
More about persimmon borer
Damage to persimmon roots from persimmon borer
Tree borers of the world

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Enrich your life with the study of trees.

"The power to recognize trees at a glance without examining their leaves or flowers or fruit as they are seen, for example, from the car-window during a railroad journey, can only be acquired by studying them as they grow under all possible conditions over wide areas of territory. Such an attainment may not have much practical value, but once acquired it gives to the possessor a good deal of pleasure which is denied to less fortunate travelers."

Charles Sprague Sargent (1841-1927)

Print references I frequently consult

Benvie, Sam. Encyclopedia of North American Trees. Buffalo, NY: Firefly, 2000.

Brockman, C. Frank. Trees of North America: A Guide to Field Identification. Ed. Herbert S. Zim. New York: Golden, 1986.

Cliburn, Jerry, and Ginny Clomps. A Key to Missouri Trees in Winter: An Identification Guide. Conservation Commission of the State of Missouri, 1980.

Collingwood, G. H., Warren David Brush, and Devereux Butcher. Knowing Your Trees. Washington: American Forestry Association, 1978.

Dirr, Michael. Dirr's Hardy Trees and Shrubs: an Illustrated Encyclopedia. Portland, Or.: Timber, 1997.

Elias, Thomas S. The Complete Trees of North America; Field Guide and Natural History. New York: Book Division, Times Mirror Magazines, 1980.

Grimm, William Carey. The Book of Trees;. Harrisburg, PA: Stackpole, 1962.

Hightshoe, Gary L. Native Trees, Shrubs, and Vines for Urban and Rural America: a Planting Design Manual for Environmental Designers. New York: Van Nostrand Reinhold, 1988.

Little, Elbert L. National Audubon Society Field Guide to North American Trees. New York: Chanticleer, 1996.

Martin, Alexander C., Herbert S. Zim, and Arnold L. Nelson. American Wildlife and Plants. New York: McGraw Hill, 1951.

Mitchell, Alan F., and David More. The Trees of North America. New York, NY: Facts On File Publications, 1987.

Randall, Charles E. Enjoying Our Trees. Washington: American Forestry Association, 1969.

Settergren, Carl D., and R. E. McDermott. Trees of Missouri. Columbia: University Extension, 1995.

Sternberg, Guy, and James W. Wilson. Native Trees for North American Landscapes: from the Atlantic to the Rockies. Portland: Timber, 2004.

Wharton, Mary E., and Roger W. Barbour. Trees and Shrubs of Kentucky. Lexington: University of Kentucky, 1973.

Wyman, Donald. Trees for American Gardens. New York: Macmillan, 1965.

Photos and text copyright © 2006-2010 by Genevieve L. Netz. All rights reserved. Do not republish without written permission. My e-mail address is