2007_Volume14_Issue3

Tre e C are Ad v i s o r New s l e t t e r http:// www.mntca.org

Dave Hanson and Gary Johnson, Managing Editors

Inside This Issue:

Autumn is upon us once again! It is time to start thinking about your trees and the long winter months ahead. Water adequately right up to the time that the

More Invasive Than Buckthorn!

1 ground freezes, consider stem protection and think about calling in an arborist to

handle pruning chores.

By: Dave Hanson Putting Down Roots

By Cliff Johnson

Volume 14 Number 3 Autumn 2007

Being the tree person that everyone turns to for answers - be prepared to 2

handle questions on the above topics and the ever popular query: “Why do trees change colors?” For information on these and other topics - turn to the web: http://fr.cfans.umn.edu/extension/SeasonalCare/WickedWinters.pdf http://www.na.fs.fed.us/spfo/pubs/misc/autumn/autumn_colors.htm

Chestnut Tree Poised for Comeback?

4

So, study up, get ready—because those questions are coming!

By Mark Clayton

And, keep up the good work out there!

Contacts And

8

See page 8 for information on this plant!

The Story Terminator

More Invasive than Buckthorn!

This plant is taking over our woodlot and we need to get rid of it all! It is more invasive than buckthorn! So it was reported, and the story continued without proper identification of the shrub even though several sources were checked.

Well, the photos of the plant in question made it to my e-mail late on a Friday. I studied them on Monday morning as I perused e-mail, the photos left no doubt in my mind and the identification was quick. In order to stave off the senseless elimination of this plant, I quickly replied with the proper identity and supporting information. Occasionally, members of this genus are considered aggressive or opportunistic in an open understory, but not one of the species has yet been listed as invasive.

Invasive?

Seldom are species native to a region considered “invasive.” Two typical definitions of an invasive species follow: Continued on Page 6

Page 2

Putting Down Roots By Cliff Johnson, Carver/Scott Master Gardener

Ash Trees Facing Growing List

I was golfing with a friend recently on Dahlgreen Golf Course. His attempt to draw a ball around an ash tree using a 3-wood failed and the ball smacked the 3-inch-diameter trunk square in the middle, knocking a piece of bark off in the process. The ball ricocheted back nearly to its original position.

of Threats

“Jim,” I exclaimed, “ash trees have enough problems without you removing their bark with a golf ball.”

Most readers should be aware by this time that a dreaded green bug named the emerald ash borer is headed towards Minnesota via Michigan, where it began destroying ash trees in 2002.

Although Minnesota has a lot of ash trees – 872 million according to one estimate – the emerald ash borer has the potential to kill every one of them. Experts estimate that emerald ash borers have already killed more than 20 million ash trees, primarily in southeast Michigan.

Emerald ash borer-infested trees die fairly quickly, according to Jeff Hahn, University of Minnesota Extension entomologist. Most trees are killed in three years. No ash is safe from this insect, including green, black, and white ash.

At this time, emerald ash borers have not been reported in Minnesota.

The state received a scare in April, however, when inspectors discovered that firewood distributed by Taylors Wood Products was transported from Illinois into Minnesota and sold at Menards stores. Ash wood cannot be moved from quarantine areas unless it has been treated or the bark has been removed (the emerald ash borer lives under the bark until it turns into an adult beetle). This firewood, however, was brought into Minnesota with the bark intact and some of the firewood was sold before the violation was discovered.

For more information about emerald ash borer go to the Minnesota Department of Agriculture’s site, (http://www.mda.state.mn.us/plants/ pestmanagement/eab.htm). You can also visit a national web page on this insect, http://emeraldashborer.info/.

Ash trees face other threats, as well. In mid May I visited a landowner’s property where a row of stately 20-year-old green ash trees along the driveway failed to leaf out this spring. As we walked along the driveway, we talked about the various possible causes for the trees’ demise. All of the trees looked beautiful through leaf drop last fall, she said. This spring, a dozen trees completely failed to leaf out.

Putting Down Roots By Cliff Johnson, Carver/Scott Master Gardener

Page 3

Was the cause of decline and death the dreaded emerald ash borer? Not likely, since the insect hasn’t been reported locally, and because there were no telltale bullet-shaped exit holes in the bark of the trunks.

Later I inspected some similar-size ash trees on the golf course that I had noticed were having difficulty leafing out. Many ash trees on the course were fully leafed out and growing vigorously, while others were only sparsely leafed out with meager tufts of leaves at the ends of branches.

I called Patrick Weicherding, University of Minnesota extension arborist, and he said, “We've noticed the same thing (ash trees failing to leaf out) over the last few years, particularly with ash planted as boulevard trees. Like you, I doubt that it is EAB or ash yellows, and verticillium is really hard to confirm in ash for some reason.

“The short answer is that nobody seems to know what is going on and they are simply referring to it as ash decline.”

Follow-up conversations with the landowner revealed a possible other cause for her ash trees dying. Last fall, a pesticide applicator sprayed chemicals on the turf grass under the ash trees to control broadleaf weeds in the lawn. He admitted to the landowner that he had some mechanical problems with the sprayer and chemical could have been misapplied in the area and, as a result, damaged the shallow roots of the ash trees.

At this writing, the cause of death of the driveway row of ash trees has not been determined, although the property owner suspects chemical contamination. A private tree service and a DNR forester have inspected trees.

If there’s a lesson in this discussion of ash tree problems, it may be to “not put all your eggs in one basket” when it comes to planting trees. In this world that we like to describe as “getting smaller and smaller,” exotic diseases and pests seem to arrive on a regular timetable from other parts of the world.

The emerald ash borer is an import from China and Japan.

While disease and insect attacks on plants are inevitable, many diseases and insects attack only a single species of plant and ignore others. When trouble strikes, it can be reassuring to know that, while one or two of your plants may be vulnerable, other plants in your landscape may be resistant or immune to attack.

More than 200 previous Putting Down Roots columns can be viewed at Cliff Johnson’s website: www.puttingdow nroots.net.

The Master Gardener program is a part of the University of Minnesota Extension Service. For more information, or to ask a gardening question, call 952-466-5300.

Page 4

Chestnut Tree Poised for Comeback (MA) Tromping through a Massachusetts state forest, Brad Smith spots an old stump

Christian Science Monitor August 9, 2007

By Mark Clayton

with dead shoots and one lone, green sprout – a sad but not uncommon remnant of a once-proud species – the American chestnut tree.

Except for a few mature trees, the species has struggled for 50 years to survive. It does that in the same way: Stumps send up sprouts that are quickly attacked by the same invasive blight that wiped out about 3.5 billion chestnut trees between 1904 and 1950.

"What you're seeing is the former king of the forest reduced to surviving as a mere shrub," says Mr. Smith, president of the Massachusetts chapter of the American Chestnut Foundation (ACF).

Now, however, an American chestnut revival may be imminent. Scientists using traditional plant breeding techniques are on the verge of a breakthrough. In fact, Smith smiles and shares a little secret: the "holy grail" of American chestnut trees – a hybrid supertree fully resistant to the blight – is alive and growing down south.

Hidden on a country road that winds through rural Meadowview, Va., is a 93-acre plot of ground that holds the future of the American chestnut: about 120 hybrid saplings.

The trees – going on two years old and four feet tall – are considered "fully blight resistant" and are thriving.

Above: Leaves of Castanea dentate Below: The spiny fruit husks

At this rate, by 2010 there should be enough "holy grail" nuts to begin planting in selected test sites in national forests. By 2015, production from such plots is expected to grow exponentially – yielding enough nuts to allow for full-blown replanting – if everything goes well.

Cross-breeding American chestnut trees is a challenge because they do not produce fruit until their sixth year. Researchers have spent 25 years breeding resistant Chinese varieties of chestnut with nonresistant American versions – then "back-crossing" or breeding resistant American chestnuts with one another. It's a difficult project that the US government attempted but dropped long ago.

Restoring the species to its former glory has been the life's work of Fred Hebard, whom some regard as the American chestnut tree's Johnny Appleseed. What he's growing on his research farm in Meadowview is a tree now 15/16ths American chestnut that will grow tall and true, with 1/16 Chinese chestnut resistance.

"We're starting to produce the critical generation of fully resistant chestnut, the one we intend to release into the woods," he says. "Within three to five years we hope to begin putting out large numbers of trees, maybe 10,000 of them."

Known as the "sequoia of the East," the American chestnut was once dominant in forests from Maine to Florida, a majestic giant that easily grew four feet across, 120 feet high and lived for centuries. Its nuts were an important source of food for animals and hu-

Page 5

Chestnut Tree Poised for Comeback (MA) mans and its rot-resistant wood prized by timber and furniture companies.

It's taken Dr. Hebard 18 years of painstaking hybridization to get to this point of having several hundred fully blight-resistant trees. Before him, predecessor Charles Burnham began the work in 1983.

Earlier this year, about 2,000 partially blight-resistant American chestnuts were planted on reclaimed mine land. Those trees may not survive beyond about six or seven years because they are not blight resistant. Even so, the effort will enable researchers to better understand growing conditions on such land.

Trials of the fully resistant American chestnut are expected within three years, when the ACF and the US Forest Service expect to plant thousands of the best of the "holy grail" seeds in two forests – in Kentucky and West Virginia – the heart of the chest-

NOTICE: In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving this information for research and educational purposes.

nut's domain. About that same time, members of the ACF will also begin receiving seeds for planting.

Indeed, 13 state ACF chapters, whose orchards maintain about 40,000 partially resistant chestnut trees, will play a vital role in the chestnut restoration. Smith's Massachusetts chapter, like the others, is growing small orchards of the trees, slowly doing their own hybridization programs. Pollen from the best trees will be sent from Virginia to ACF chapters to accelerate development of varieties well-suited to regional weather and soil.

One new problem the foundation is facing isn't blight, but keeping the seeds from being sold on eBay for fat profits.

"Everybody and his cousin wants these seeds, but we've got to be real careful about naming it and what we're going to claim about [the trees' capabilities]," says Paul Sisco, a co-architect of the recovery plan with Hebard. "We won't really know how good it's going to be until about five years from now."

In fact, a tree labeled "fully blight resistant" may still contract the blight, but it should be able to ward off the fungus altogether.

Other groups, such as the American Chestnut Cooperators Foundation, are taking different approaches to breeding. Some hold out hope for a direct genetic-engineering fix, although that task is daunting because the tree's genes have not been sequenced.

"We are planting the hope, and making a commitment, that this noble hardwood will be restored to the American landscape and its vital ecological role in our nation's forests," Dirk Kempthorne, US Secretary of the Interior, said on July 26.

Today when consumers buy chestnuts for "roasting by an open fire" during the holiday season, they come from the Asian chestnut and other varieties that resist blight. But now it looks as if the American version could return one day. "I'm looking forward to growing a really big one in my backyard," Smith says.

The flower of American Chestnut.

Photos: Dave Hanson.

Page 6

More Invasive ...

Continued from page 1

A species is regarded as invasive if it has been introduced by human action to a location, area, or region where it did not previously occur naturally (i.e., is not native), becomes capable of establishing a breeding population in the new location without further intervention by humans, and becomes a pest in the new location, threatening the local biodiversity. en.wikipedia.org/wiki/Invasive_species An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health, as defined by the Department of Agriculture. www.tlcfortrees.info/glossary.htm So, Sambucus canadensis (American elderberry) and S. pubens (American red elderberry) would not fit these definitions since they are native plants to Minnesota.

However, depending on your sources S. racemosa (European elderberry) might be considered a non-native plant. According to Earl Rook, S. racemosa is a circumboreal species including the North American plants S. pubens or S. racemosa susp. pubens. Some taxonimists do not separate S. pubens but instead list it as a sub-species of S. racemosa.

Above is a heavy flattened umbel

Let’s discuss each of these in a little more detail:

of purple fruit found on Ameri-

S. canadensis, American elderberry is listed as attaining heights of 5-12 feet. The

can elder.

plants produce white flower heads (umbels or flat cymes) that are rather flat in profile and

Below are the red berries of red

similarly, the dark purple berries will also be arranged in a flattened cluster (umbel or

elder. Note the pyramidal panicle structure.

Both are readily eaten by wildlife!

All Photos: Dave Hanson.

cyme). The berries of this species are edible. Opposite branching, and compound leaves with 5-9 leaflets are characteristics common to these species. Another characteristic to note, the color of the rachis of the compound leaf is greenish on S. canadensis. For further verification check the pith of the older growth, probably 1 year old growth, it should be white and spongy.

S. pubens or S. racemosa subsp pubens, American red elder is listed as attaining heights of 12-25 feet. It is also has white flowers but in a pyramidal structure or panicle. The red or dark red fruits are not edible and the panicle structure is maintained. The rachis of the compound leaf is described to be reddish and the pith of the older growth will also be spongy, but reddish to brown in color.

If a text or identification description separates S. racemosa from S. pubens, one or the other is often simply described as ‘very similar in appearance’ to the other.

While S. canadensis is reported to tolerate saturated soils, the other elderberries prefer well drained soils with adequate moisture and will tolerate Ph ranges of the soils from 5 to 8. Listed as an understory species elderberry are shade tolerant or at least partially shade tolerant as those plants in heavy shade are noted to be stunted and to flower

More Invasive ...

Page 7

Continued from page 1

and fruit sparingly.

Amazingly, for a circumboreal species, Sambucus are often affected by cold weather. Entire shrubs or individual stems will be killed by winter cold forcing sprouting to occur from the root systems. If you want to see freeze damage or frost damage on foliage, keep your eye on Sambucus. Elderberry shrubs leaf out very early, typically mid-April, and frequently suffer from late spring freezing temperatures or late spring frosts.

In most forested settings elderberries are widely scattered in the understory. Under the right conditions larger ‘stands’ can form thus making it appear aggressive; however, elderberries do not threaten local biodiversity nor do they present a harmful threat. So, neither the Minnesota DNR nor the Minnesota Department of Agriculture has listed any Sambucus species as invasive.

Mid-April bud break, leafing out well ahead of other species.

For More Information: Minnesota Department of Agriculture Invasive Species List: http://www.mda.state.mn.us/plants/pestmanagement/misac/profiles.htm Online 9/13/07.

Minnesota Department of Natural Resources invasive species list: http://www.dnr.state.mn.us/invasives/index.html Online 9/13/07.

Rook, Earl, J.S. Flora, Fauna, Earth, and Sky: The Natural History of the Northwoods.

Available. http://www.rook.org/earl/bwca/nature/index.html Online 9/13/07.

This photo illustrates the color difference of the piths.

Red elder (top) and American elder (bottom).

Compund leaf of American red elderberry

Flower panicles of red elderberry.

Contact Phone Numbers

TCAAG Members:

Program Contacts:

Bob Condon – 952-890-1228

Mimi Hottinger – 507-388-4838

Gary Johnson – 612-625-3765 or grjonson@.umn.edu Dave Hanson – 612-624-1226 or dlhanson@umn.edu Mailing Address: 115 Green Hall, 1530 Cleveland Ave. North, St. Paul, MN 55108

Paula Denman – 612-338-1871

Lisa McDonald - 612-721-2672,

Laurie Drolson – 651-464-9829

Betsy McDonough - 651-779-0437

Bruce Granos – 952-423-5211,

Lu Schmidtke - 651-455-6125

Contacts: Regional Extension Educators: Bob Mugaas – 651-480-7706 Patrick Weicherding, – 763-767-3836 or weich002@umn.edu Gary Wyatt, 507-389-8325 or wyatt@umn.edu County Contacts: Carver County (Jackie Smith) - 952-466-5309 or smith515@umn.edu Dakota County (Barb Stendahl) – 952-463-8002 or stend004@umn.edu Olmstead County – 507-285-8250 Ramsey County – 651-777-8156 Scott County (Jackie Smith) - (952) 492-5410 or smith515@umn.edu St. Louis County (Bob Olen) – 218-726-7512

Additional Reference Contacts: Debby Newman (Info-U) – 612-624-3263 Don Mueller, DNR Forestry – 651-772-6148 don.mueller@dnr.state.mn.us Ken Holman, DNR Forestry – 651-296-9110 ken.holman@dnr.state.mn.us Paul Walvatne MNDOT – 651-284-3793 Paul.Walvatne@dot.state.mn.us Great River Greening – 651-665-9500 Tree Trust – 651-644-5800

Story Terminator: Is it wild grape (Vitis riparia) (a.k.a. riverbank grape)? Or something else?

It is Menispermum canadense or common moonseed, an interesting vine native to Minnesota’s riverbottoms. The fruit resembles a cluster of grapes.

Wild grape Moonseed

Moonseed

M. canadense to the left and a combination of Vitis riparia, wild grape and

Wild grape

moonseed to the right.