Silver maples are blooming

Blossoms of Acer saccharinum

It's early spring in south central Kentucky, and the silver maples are blooming (a state that is called "inflorescence". Silver maple (Acer saccharinum) flowers are small, but they're noticeable because they don't have much visual competition this time of the year.

The blossoms in these photos would fall on the "spectacular" end of the silver maple blossom spectrum. This tree has large, brilliantly red flowers. In full bloom, it's a joy to the eyes in a landscape that is still wearing winter's drab colors.

The silver maple flowers in Steven J. Baskauf's photo on the Vanderbilt University website have a more subdued, more typical, reddish tone. Normal colors of silver maple flowers include shades of greenish-yellow.

I think the flowers in my photos are females. Flikr user Gavatron has a good photo of the male silver maple flower. Both male and female flowers may be borne on the same tree -- but not always. The U.S. Forest Service Sylvics Manual explains:

Four types of trees, with respect to sex expression, have been observed: all male flowers; all female flowers but with rudimentary pistils; mostly male with a few females; and mostly male with a few females and a scattering of hermaphroditic flowers. (Source)

Of course, the male flowers produce pollen, and that means that some people are having allergy problems, even though it's just mid-March.

The flowers are a food source for various songbirds, squirrels, and other wildlife. I was reminded of this last year after our big ice storm, when I watched a tiny chickadee land on a broken silver maple branch in our yard, peck the ice off a flower bud, and eat it.

Silver maples have their faults, but we won't go into all that today. Today, we'll just enjoy the blossoms.

The very best firewoods

Six excellent woods for heat

Here's a list of six of the best firewoods. (The number in parenthesis is millions of BTUs produced by a cord of this wood under optimal conditions.)

• Sugar maple (25.0)
• Red oak (25.3)
• White oak (27.0)
• Black locust (28.1)
• Shagbark hickory (29.1)
• Osage orange (30.7)

(Source: Wood Fuel for Heating, a University of Missouri extension service publication)

A few years ago, I did a lot of research on wood stoves as we prepared to buy a new one. In one online forum, I read an interchange between a New Englander and a Midwesterner. The Midwesterner wondered whether a certain brand of wood stove would withstand the hot fires he liked to made with hedge (Osage orange) firewood.

The New Englander replied that he made hot white oak fires all the time in his wood stove of that brand. He said with considerable scorn that he doubted if hedge could burn as hot as the fine white oak of the East Coast. He should have done a little research because, according to the University of Missouri publication linked above, he was mistaken.

What kind of a maple is it?

Hybridization of maple species

Usually, a positive identification of a maple tree can be made with a tree field guide and a close look at the bark and leaves of the tree.

However, if you're really perplexed about the identification, you might be looking at a hybrid maple, a cross between two different maple species. This can happen in areas where two maples species bloom simultaneously. It occurs commonly enough that an entire chapter of the book, Maples of the World, is devoted to hybrid maples.

Black and sugar maple hybrids

In the eastern United States, hybrids of black maple (Acer nigrum) and sugar maple (Acer saccharum) are common, according to the U.S. Forest Service Sylvics Manual and other sources.

The black and sugar maples have crossed and backcrossed so many times that the two species are nearly indistinguishable in some areas. In other areas, the black maple still retains its own unique characteristics.

There appear to be two broad populations of black maple with respect to its hybridizing with sugar maple. One is in the western part of its range, where it maintains its identity and shows little tendency to cross with sugar maple. The second population is in the eastern section, where it hybridizes readily with sugar maple. (Source: U.S. Forestry Sylvics Manual)

Red and silver maple hybrids

George Ware of the Morton Arboretum writes "Natural hybridization between red and silver maples is fairly common in the swamp and streamside forests of eastern Wisconsin and eastwood to New England " (source: pdf). Hybridization is also reported in southern Canada. In these regions, red and silver maples bloom at the same time, and the trees grow in similar habitats.

Because the blooming periods of silver and red maple overlap, there is a possibility of natural hybridization between them. Under controlled artificial conditions, the two species hybridize easily, producing prolific seed sets. The hybrids are intermediate between their parents in leaf characters. Their growth was much faster than that of red maple seedlings but did not equal that of silver maple. Source: U.S. Forest Service Sylvics Manual

In fact, red/silver hybrids have a name -- Acer x freemanii or Freeman maple -- and a number of named cultivars, including  Jeffersred (patented as "Autumn Blaze"), Armstrong, Celzam (patented as "Celebration:), and others. The name Acer x freemanii is pronounced "Acer hybrid freemanii".

Related: A comparison of the leaves of red, silver, and Freeman maples

Weak branches are a problem with silver maples

Don't plant silver maples too close to your house.

During the recent devastating ice storm in Kentucky, we heard tree branches breaking all night, with terrible pops that sounded like gunshots. Limbs hit our roof with tremendous thumps. Daylight revealed an incredible scene of natural destruction in our yard.

The photo below was taken through the living room window the morning after the storm. This photo shows only a portion of the branches that broke from a large silver maple (Acer saccharinum), about 15 feet from the window. We have dents and a puncture in our metal roof as a result of the falling branches.

This big silver maple tree was planted by the original owner of our house in about 1960. At about 50 years of age now, it's in its maturity. It provides a lot of shade, but it's dangerous because its weak, brittle branches break easily. This is the great flaw of silver maples (also known as water maples or soft maples.)

The tree's main trunk ends at about ten feet. It has five long, massive limbs growing upward from the trunk, and each limb has smaller branches, of course. One of those limbs poses an ongoing (and increasing) threat to our house. I'm afraid that we need to completely remove that limb. It will be hard on the tree to lose it, but we don't have much choice.

Two more silver maples are planted too close to our house. They are younger trees, planted about 1980. One of them is even closer to the house than the tree outside our living room window.

I understand what the planter wanted -- afternoon shade -- and he would be happy to know that his trees provide that. However, as years pass, both those trees are going to be major problems. To prevent large branches from falling on the roof, we'll have to remove whole sections of the trees. It's very sad.

Silver maples have their merits. They aren't very fussy about where they're planted. They grow well in urban conditions. They will grow in compacted soil. They tolerate short spells of standing in shallow water. They are a valuable tree for wildlife -- especially in late winter and spring when their buds, blooms, and seeds provide food at a time that other food supplies are limited. They have a small-but-noticable, red blossom in early spring when not much else is blooming. They withstand drought and heat, and of course, they do grow very fast.

Unfortunately, silver maples also have a very undesirable characteristic -- weak branches that break in every ice or wind storm that occurs.

If you are willing to deal with the broken branches, silver maples will serve as a fast-growing, short-term (50 to 100 year) tree. They grow up to 100 feet in height with 100-foot canopies. You should plant them at least 50 feet away from anything that could be damaged by falling limbs. Consider power lines, roads, and driveways, as well as your house and other buildings when you select the planting site.

Take my advice and you won't ever have a story to tell about broken silver maple branches making dents in your roof.

Tar Spot on Maples

Maple fungus

I've been studying about tar spot, a fungus on maples, this evening, after reading an article in the Detroit Free Press. It seems that tar spot is a bigger problem recently in Michigan and throughout the Midwest. The article includes a really ugly photo of maple leaves with big black blotches on them. Tar spot was also a problem in heavily-mapled Massachusetts a couple of years ago.

Tar spot is caused by Rhytisma fungi. (There are a couple of types.) The fungus actually starts growing on the leaf early in the growing season, but it's a pale yellow then and not too noticable. In late summer, the fungus darkens to the tar-like color for which it is named and becomes a raised-up spot on the leaf.

The affected leaves usually fall from the trees early. After overwintering on the leaf, the fungus finally releases its spores in the spring -- just at the right time for the wind to carry the spores to an emerging tree leaf.

To interrupt the cycle, rake and remove the infected leaves as they fall in the late summer. Cornell University's fact sheet on tar spot says that composting the leaves will kill most of the fungus, but to be safe, cover or turn over the compost before the trees begin getting their leaves in spring.

We have quite a few maples on our little rural property, so I hope the fungus doesn't get started here. However, it's more of a disfiguration and inconvenience than a lethal threat. Healthy unstressed trees can withstand an infection of tar spot.

Related:
Images of tar spot

Tiny insect is big problem for Louisville Slugger

Ash baseball bats threatened by emerald ash borer

The Louisville Slugger is a baseball bat that has been manufactured in Louisville, KY, since 1884. Though also available in aluminum and maple, the traditional Louisville Slugger is made of white ash -- and not just any white ash.

The process of making a Louisville Slugger begins with selecting the timber itself. Although maple is rapidly gaining in popularity among today’s pros, the majority of bats are made from white ash. However, not just any white ash can become a Louisville Slugger. In fact, the only ash up to Louisville Slugger standards grows along a 200-mile stretch of land on the New York-Pennsylvania border. The soil, rain, sun – everything is just right there. That’s where the best bats in the world, Louisville Slugger bats, come from.

Source: Slugger Magazine

As you might imagine, the Louisville Slugger Company is concerned about the emerald ash borer, an Asian insect that has been wreaking havoc among North America ash trees. The emerald ash borer has spread through parts of Canada, Pennsylvania, Ohio, West Virginia, Maryland, llinois, Michigan, and Indiana. As of yet, the insect has not reached the area where the ash timber for Louisville Sluggers is produced.

Emerald ash borer tunnels under an ash tree's bark. Photo by National Park Service

The Louisville Slugger company is bracing itself for the possibility that the emerald ash borer will reach and destroy the ash forests that produce Slugger lumber. Company labs are conducting research on other woods for bats, especially beech.

In a press release about the Emerald Ash, the Louisville Slugger company urges the public to avoid transporting firewood. When firewood is moved out of the area where it was cut, the emerald ash borer may ride along, expanding its range far more rapidly than the insect could do without human assistance.

Only time can tell what will happen to America's ash trees. We certainly hope for a solution to the emerald ash borer problem, but you might want to buy an ash Louisville Slugger bat (link opens a PDF) while you still can.

Technorati tags: Louisville Slugger, emerald ash borer, white ash

Tall trees that resist wind and ice damage

23 tall-growing native trees that resist wind and ice damage

Updated, 3/6/10.

All of these trees can reach 75-100 feet in height or more when mature. All are native trees of North America with moderate to good resistance to damage by wind and ice.

Trees marked with an asterisk below should be considered moderately resistant. A general rule to remember is that strong evergreens are not as resistant to wind and ice damage as strong deciduous trees. Because of their foliage, they tend to catch more winter wind, snow, and ice. (That's why evergreen trees are often planted in windbreaks.)

1. Acer nigrum -- Black maple
2. Acer saccharum -- Sugar maple*
3. Carya cordiformis -- Bitternut hickory
4. Carya glabra -- Pignut hickory
5. Carya illinoensis -- Pecan
6. Carya ovata -- Shagbark hickory
7. Carya tomentosa -- Mockernut hickory
8. Fagus grandifolia -- American beech
9. Gymnocladus dioicus -- Kentucky coffeetree
10. Juglans nigra -- Eastern black walnut
11. Liquidambar styraciflua -- American Sweetgum
12. Magnolia acuminata -- Cucumbertree magnolia
13. Picea pungens -- Colorado spruce
14. Pinus ponderosa -- Ponderosa pine*
15. Pinus resinosa -- Red pine*
16. Platanus occidentalis -- Sycamore, American planetree*
17. Quercus alba -- White oak
18. Quercus bicolor -- Swamp white oak
19. Quercus borealis -- Northern red oak
20. Quercus macrocarpa -- Bur oak*
21. Quercus velutina -- Black oak
22. Taxodium distichum -- Common baldcypress
23. Tsuga canadensis -- Canada hemlock*

Remember -- if the weather is bad enough, any tree can lose branches, snap its trunk, or even lose its grip and fall over. You should use good judgment about keeping your home safe. It's not wise to have big trees next to your house, no matter what kind of trees they are. 

For a (usually) safe distance between house and tree, allow half of the mature tree's spread (half of the diameter of its crown). If the mature tree will have a spread of 70 feet, it should be planted at least 35 feet from any buildings. This does mean that many suburban properties are too small for large trees.

If you want a guarantee that you will never have to cope with fallen branches or storm-damaged trees, simply remove all trees from your property. That should eliminate the problem.

Sources for the above list include:

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

Ice Storm Damage to Urban Trees, an article in the appendix of Storms Over the Urban Forest, a publication of the USDA Forest Service. (This article's table, "Ice storm susceptibility of tree species commonly planted in urban areas" is reprinted in many reputable articles about ice damage susceptibility on the internet.)

Trees For Nebraska Ice Storm Recovery and Susceptibility of Trees to Ice Storm Damage in the Great Plains, published by the Nebraska Statewide Arboreum

Autumn glory of an old sugar maple

Acer saccharum, with yellow fall 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.

Two examples of shaggy bark

Young shagbark hickories and an old silver maple

These two young shagbark hickories are growing in a road ditch. To be completely honest, I call all shaggy-barked hickories "shagbarks", but some of them could be shellbarks. I don't have a clue how to tell the difference between shagbark and shellbark hickories from the bark. There are some minor differences in their leaves and nuts -- enough to make them two separate members of the walnut family.

Here is another shaggy-barked tree -- an aged silver maple. Old silver maples develop long scales of bark that are loose at the ends. This sort of bark on any species of tree is called "exfoliating."

It would be difficult to confuse a shaggy-barked silver maple with a shaggy-barked hickory, though, even in winter when no leaves are present. Silver maple trees have a broad, spreading crown with the central trunk breaking into massive branches. The crown's width may even be more than the tree's height! Shagbark/shellbark hickories generally have a much narrower crown, about half as wide as they are tall, and their strong central trunk persists high into the tree.

Red Blossoms of Silver Maple

Acer saccharinum, water maple, soft maple

Flower of silver maple

Silver maple is one of the first trees to bloom in springtime. Its bright red blossoms are small, but they are a welcome spark of color in the landscape.

The flower buds and flowers of the silver maple are eaten by squirrels in early spring when food is scarce.

Silver maple blossoms

The silver maple's seeds are the largest of all the maple seeds, and are an important food source for squirrels as well as a large number of songbirds, gamebirds, and wild animals . Even bears, deer, elk, moose, and mountain sheep will feast on silver maple seeds. The seeds appear in spring at about the same time the leaves do.

In nature, the silver maple often chooses to grow in moist bottom lands or at the edges of rivers and lakes. In Kentucky it may be found growing with willows, sycamores, hackberries, cottonwoods and river birch.

The silver maple in the photo below is growing near Kentucky Lake in western Kentucky. In this location, the tree probably stands in water occasionally, but the silver maple can survive some flooding.

Silver maples are often sold in garden centers as a fast-growing shade tree. They are prone to storm damage because of their weak, brittle branches, and they are a short-lived tree that will mature at 50 to 75 years and slip into decline soon thereafter. The silver maple is well-known for clogging drains with its water-seeking roots.

Think carefully about where you want to plant this tree! We have three silver maples near our house, planted by a former owner. We've seen some severe storm damage in them several times. Fortunately -- so far! -- none of the large limbs have hit the house.

One of the trees is very large and probably at full maturity. When its health begins to decline (which will be soon,) we will be forced to remove it because of its proximity to the house.

Silver maple flowering at Kentucky Lake, near Fenton