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

Tuesday, October 30, 2007

A welcome rain in south central Kentucky

Drought has hurt Kentucky's trees.

It's wonderful to see water in some of the creeks again. We've had a nice rain in south central Kentucky -- a slow rain that took place over several days, fairly typical for this time of year. At our house, we received over 4 inches. We are still 8 or 10 inches below normal, but the precipitation was much needed and very welcome.

Our trees suffered during last summer's extreme drought. Some began dropping leaves in July. Others held their leaves, but the leaf tips and edges are dead, a condition known as "leaf scorch." Branches on some trees appear dead, and some trees appear to have died completely.

Unfortunately, the drought followed a late frost that killed the blossoms and early leaves on many of the trees. The weather has given our trees a "1-2 punch" this year.

The extent of the damage to our trees isn't fully known at this time. We will be seeing the long-term effects of this summer of extreme drought for years.

Related post: How does drought damage trees?

How does drought damage trees?

Some effects of drought on trees

Drought damaged tree Crowns of two trees -- one appears dead.

Some effects of drought on trees are apparent, and other effects are unseen, though just as damaging. Here are three major damages that drought can do.

1. Dead feeder roots
The fine feeder roots that collect moisture and nutrients for most trees are located within the first 15-18 inches of topsoil. If that soil dries out for a long time, the feeder roots will die. Without feeder roots, the tree cannot effectively absorb nutrients and water, even when it rains again.

2. Reduced photosynthesis
Some trees apparently drop leaves as a drought-survival mechanism. Without leaves (or with fewer leaves,) they lose less moisture through evaporation. However, photosynthesis is reduced when leaves fall prematurely, so there are risks as well as benefits to this drought response.

Photosynthesis produces glucose. The cells need glucose as they manufacture a wide range of organic compounds that sustain and regulate every aspect of the tree's life. (Many of these chemicals can be grouped under the term "secondary metabolites.")

Some of the most obvious effects of reduced photosynthesis are a slower growth rate and reduced seed production. In the long term, the tree's lifespan may be shortened.

3. Reduced resistance
In addition, trees are susceptible to invasion by pests or disease, when they lack the normal flow of water, nutrients and secondary metabolites. For example, a tree may be unable to compartmentalize a disease as effectively as normal. Though the disease may not become apparent immediately -- such as root rot -- it can kill the tree over the next decade or two.

Much information about drought damage to trees is available on the internet. Here are some readable and informative articles for non-scientists like me.

The Long-term Effects of Drought
The Effects of Drought on California Oaks
Long-term Drought Effects on Trees and Shrubs
How Drought Affects Trees and Shrubs
Kentucky Forests Respond to the Drought
The Damaging Effects of Drought (pdf)

Wednesday, October 24, 2007

Autumn glory of an old sugar maple

Acer saccharum, with yellow fall color

Maple leaves, with brilliant yellow autumn color

The old sugar maple tree in front of the kitchen door is in glorious fall color right now.

Sugar maples have some of the most brilliant autumn colors of all trees. They can be yellow, orange, or red.

The rest of our old sugar maples grow in a row in front of the site of the old log house. They all turn orange. This one grows in a different area of the yard, near the old garden site, and it's the only one that turns yellow.

Standing beneath this tree and appreciating its rich, beautiful color for a few minutes will make any autumn day better.

Sunday, October 21, 2007

Sumac: Bright red color in autumn

Rhus species

Sumac in a fencerow

The sumac in the image above is growing in a fence row along a road in Christian County, KY. Here in Kentucky, we also see sumacs growing at the edges of forests, in open areas in the woods, on sunny hillsides, and in old fields. They can soak up a lot of sun in such locations (one of the requirements of these small trees.)

Every state in the continental USA has one or more native sumacs. There are 15 or more different native species, not counting poison-ivy, poison-oak, and poison-sumac which are also in the Rhus genus.

I didn't try to identify the sumac in the photo above, but it is probably Rhus glabra (smooth sumac) or Rhus typhinia (staghorn sumac), both of which are common in this area. It's a young tree, judging by the spindly size of its trunk and the lack of fruit.

Sumac seed headThe sumacs I know, staghorn and smooth, produce a large colorful head of berries that holds on through the winter. The small berries don't have much pulp -- they are mostly seed. They are not a "first-choice" wildlife food, but they are important because many birds and animals eat sumac seeds when the supply of more desirable winter food is exhausted.

In the garden, either of these sumacs has year-round visual appeal. Their seedheads are interesting in winter. In the warm months, their long compound leaves have an exotic look. In autumn, they have vivid color. They will grow in almost any soil, even dry, gravelly areas where little else will survive, and they grow very quickly.

Sumac in OctoberTwo warnings about using sumac as an ornamental:

1. Sumacs form a clump by sending up root suckers.
2. Sumacs have weak wood that breaks easily in severe weather.

In my own experience with sumac, these problems haven't been too difficult to deal with. The suckers are controlled easily enough by mowing regularly. Some branches have broken in storms but we don't have the trees near our house, and they aren't very large trees anyway.

Saturday, October 20, 2007

Sycamores in Autumn

Platanus occidentalis: Tall native tree of the Eastern bottomlands

American Planetree (sycamore)

The American sycamore is a common native tree of the eastern United States, easy to recognize even at a distance. Here are some characteristics of the adult Platanus occidentalis:

  • massive trunk and branches
  • great height
  • uniquely mottled bark color on the lower trunks and branches
  • peeling outer bark exposing the light-colored inner bark on younger (upper and outer) branches
  • large leaves
  • dangling ball-shaped fruits, especially visible in winter

Common names for the American sycamore include "buttonball" and "buttonwood", which refer to the sycamore fruit.

Once you learn what a sycamore looks like, you'll notice it in many of the bottomlands of the eastern USA. Its natural range encompasses every state from Maine to Florida and west, as far as eastern Nebraska, Kansas, and Texas.

Sycamore trees of the Mississippi and lower Ohio river valleys are some of the largest of the species. Here are several nice specimens, photographed last week in northeastern Christian County, Kentucky.

In my opinion, sycamores are not suited for the area of your yard that's near the house. They shed large leaves throughout the season, and the fruits are prickly. Also, they have a lot of surface roots that interfere with lawn mowing. However, if you have a remote area that doesn't really need a groomed look, they're beautiful, fast-growing trees. Just make sure you have room for them.

Buttonwood trees in a Kentucky valley
Some nice images of the sycamore
Platanus occidentalis fact sheet
Wikipedia sycamores page

Wednesday, October 17, 2007

Grafted black walnuts vs. seedlings

Is the high price of a grafted black walnut tree worth it?

The two main reasons that people buy grafted black walnut trees are 1) bigger nuts, and 2) easier-to-crack nuts.

About 14 or 15 years ago, we decided to plant some black walnut trees. We bought a couple of grafted trees from a nursery catalog, and they arrived in good shape and we planted them.

That same spring, someone advertised in the newspaper that they had black walnut seedlings to give away to anyone who wanted to transplant them. Supposedly, the mother tree had thin-shelled nuts, so the seedlings were expected to continue this trait.

My husband went dug up several of those seedlings and planted them in the part of our yard that we call "the meadow" because it has to be mowed all the time. His idea is that if we get enough trees there, the grass will quit growing.

From all that planting, we have four black walnut trees today. Two of them are the grafted trees, and two are the seedlings from the newspaper. All of the trees are well over 20 feet tall, and a couple of them are probably close to 30 feet tall.

One of the grafted trees died back so far early in its life that we were afraid it had completely lost its graft and had nothing left but rootstock. It produced the large walnut in the photo below, so apparently it didn't die back as far as we thought. This is the first year it has had walnuts. The other grafted tree has not yet borne nuts, though it is getting fairly big.

The seedlings have borne walnuts for several years now, and each year, they bear a few more nuts. Their nuts are, true to promise, fairly easy to crack (for black walnuts.) They're as easy to crack as the nuts from the grafted tree, but they're much smaller. One of their nuts is pictured at right in the photo above.

I don't know the answer to my question: "Is the high price of a grafted tree worth it?" It probably depends on the tree that you're getting seed from. I have one observation on the topic. If you're going to harvest and use the walnuts, you can crack out a cup of nut meats faster from big walnuts than from small ones.

Monday, October 15, 2007

Twelve native trees with shaggy bark

Eight native deciduous trees and four native evergreens with exfoliating bark

Bark of Shagbark Hickory
Image: U.S. Fish and Wildlife Service
Q. Why would anyone care what kind of bark a tree has?

A. Shaggy (exfoliating) bark adds interest and drama to the winter garden. It draws attention and entertains the eye when there are no leaves on the deciduous trees.

Of course, the bark is attractive at other times of the year as well. It's just more visible in the winter when there's less foliage in the landscape.

Compared to the climate, soil, water, drainage, and space requirements of the tree, the appearance of the bark is a secondary consideration. But when you've narrowed your choice to several trees that should work in your planting spot, then you might research the appearance of the bark.

Common names below are linked to the USDA Plants Database. Visit the linked site for more information about that tree.

Acer rubrum - Red Maple

Acer saccharinum - Silver Maple

Aesculus flava - Yellow Buckeye

Betula alleghaniensis Britt. - Yellow birch

Betula nigra - River birch

Betula papyrifera Marsh - Paper birch

Carya ovata - Shagbark Hickory

Juniperus virginiana - Eastern Redcedar

Picea sitchensis - Sitka Spruce

Platanus occidentalis - Sycamore (American Planetree)

Taxodium distichum - Common Baldcypress

Thuja occidentalis - Eastern Arborvitae

Friday, October 12, 2007

Post oak leaves

Quercus stellata

Post oak leaves

Post Oak leaf

Maltese cross

Many articles that describe post oaks mention their cross-shaped leaves. Often, it's said that the leaf resembles a Maltese cross. Perhaps you can see the resemblance in the shapes of the leaf at left and the Maltese cross at right.

The post oak leaves in the photo above are a bit ragged, but some of them do demonstrate the cross-like shape that is typical of post oaks in this area.

Post oaks are quite drought resistant. This post oak retained its leaves during the past summer of extreme drought, while some drought-sensitive trees in our area dropped a good portion of their leaves or even died.

Post oaks often grow in areas that tend to be dry, such as "rocky or sandy ridges and dry woodlands with a variety of soils" (according to the USDA Forest Service.) True to form, this post oak is growing on a knoll on top of a long, broad ridge. In the fence row between two farms, with a field on one side and a pasture on the other, it gets the full access to sunshine that it needs.

Mature post oaks may reach 50 or more feet in height and about the same distance in spread. They are slow-growing trees, but long-lived, often surviving 300 to 400 years. Their acorns are eaten by a wide variety of birds and animals. (If you look carefully, you can see a few acorns on the branch in the photo.)

Three things that post oaks don't like and may not survive are:
1. Standing in water
2. Trying to grow in shade
3. Having their roots disturbed or their soil compacted.

If you want a post oak in your yard, you'll probably have to plant it yourself. The acorns germinate in the fall, so look for them right now and plant them soon.

If you're building in an area where there are already post oak trees, don't drive on the ground under them. The best way to protect them during construction is to install a fence that encompasses the entire area beneath their canopy.

Images of post oaks

Monday, October 8, 2007

Big Black Oak

Quercus velutina

Big black oak treeThis summer, a tree fell in the yard of a country church in our neighborhood. Since all the church members are elderly, my husband volunteered to clean it up if we could have the firewood. We've gone over there several mornings recently to work on it.

Right away, I noticed a big oak tree growing in the border of trees and brush behind the church. And since I am a little obsessed with identifying trees, I wanted to know what sort of oak it is.

I confess that I usually don't approach tree identification in a logical manner (that is, with a tree identification key.) I pluck a leaf, get out the field guides, and try to match a photo to the leaf in my hand.

Black oak leaves (?)With this oak, I couldn't possibly reach high enough to pick a leaf. The best I could do was zoom in on the foliage with my camera.

Based on the the bark of the tree and the best leaf images from my zoomed-in photo, I think this is a black oak (Quercus velutina Lam.)

The leaves in my photo don't look much like the black oak leaves in some of my books. The books show a leaf that has deeply cut sinuses between the lobes, rather like a pin oak. However, the leaves in my photo look very similar to the black oak leaf in Trees & Shrubs of Kentucky (see info about this book at the bottom of this column.)

Bark of black oakThe Virginia Department of Forestry page about black oaks contains the following explanation about the leaves: "... sun leaves have deep sinuses between lobes, and shade leaves have very shallow sinuses..."

The bark on this tree is dark in color and deeply furrowed as black oak bark is said to be. I could -- but won't -- chip off a piece of bark and see if the inner bark is orange or yellow. That's a distinguishing characteristic for black oaks. The yellow inner bark was once used for dye. I suppose that's why a second common name for the tree is "yellow oak."

After giving this tree a couple of "hugs", I estimate that its trunk is over ten feet in circumference. I am not good at estimating height, so I'll just say that it's a tall tree.

This property has been occupied by a Methodist Church since 1870. The word "Grove" is part of the church's name. It's pleasant to imagine that this tree may be a surviving member of the grove that was here when the church was organized and named.

Saturday, October 6, 2007

Ten native trees with yellow autumn leaves

The foliage of these trees is golden in the fall.

1. American beech — Fagus grandifolia

2. Silver maple - Acer saccharinum

3. Tuliptree (tulip poplar) — Liriodendron tulipifera

4. Eastern larch — Larix laricina

5. Shagbark hickory - Carya ovata

6. Black Walnut - Juglans nigra

7. Honeylocust - Gleditsia triacanthos

8. Eastern poplar - Populus deltoides

9. Bur oak - Quercus macrocarpa

10. White ash — Fraxinus americana L.

Related post: Ten native trees with red autumn leaves

Thursday, October 4, 2007

Dust to Dust, Ashes to Ashes

An old oak tree approaches its end

Old oak

Yesterday, I was sorry to see severe damage to an old oak tree that I like. We had months of extreme drought this summer, and then a windstorm or two when we finally got a few showers.

Besides the large broken branch that left a gaping wound, it looks like some of its other branches have dried out and died back. It will probably still cling to life for a while, but the decline is irreversible.

The broken branch isn't very obvious from the highway, so I didn't notice it until I turned on the side road and drove by the tree yesterday. It was a shock to see.

I've been watching this tree for 15 years. Most of its top has been dead for several years. I think that was caused by a lightning strike. Every spring, I wonder if it will leaf out again.

I think this oak is probably over 200 years old. It has watched the traffic on the "Russellville Road" in Christian County, Kentucky, for a long, long time. I'm glad I've had the chance to enjoy and appreciate it.

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Monday, October 1, 2007

How to grow a black walnut tree from seed

Black walnut fruit and leavesBlack Walnut leaves and nuts
Wikimedia Commons image

Black walnut trees are easy to start from seed. In a favorable site, they often reach 80 to 100 feet in height and their crowns may spread an equal distance.

Choose the planting site carefully

Black walnuts secrete juglone, a chemical that is toxic to many plants. Locate your planting at least 60 feet from any sensitive plants or garden areas.

Black walnut trees will do very well in a moist bottom area that is well drained, or on a moist hillside or upland site. They will tolerate occasional dry spells, and they accept any soil pH from moderately acidic to moderately alkaline.

If you are planting walnuts as garden trees, space the plantings about 60-70 feet apart so their crowns can develop a majestic spread as they mature. However, if you're planting black walnuts for their valuable wood, plant them about 30 feet apart so their trunks will grow long and straight.

Planting the seeds

Gather the nuts as they fall from a tree in your area, and remove the husks. Place half a dozen nuts several inches apart in a cluster, four or five inches deep. If you have squirrels, lay a piece of hardware cloth over the planting spot and pin it to the ground with v-shaped wires. Lay a mulch of straw or leaves over the hardware cloth to reduce the freeze/thaw cycles. Mark the site so you can find it again.

After fall planting and a session of damp, cold weather, the walnut seeds will germinate in the spring. Remove the mulch and hardware cloth from the planting spot in late winter, and mark the spot clearly so you don't accidentally mow over it! After the baby trees have grown for a few months, choose the best one and eliminate the others.

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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