The Iconic American Elm is Still Hanging Around

An elm which had survived 14 bouts of Dutch Elm Disease was cut down while the 101 year old warden who had cared for it looked on.

The American Elm in Winter

The American elm (Ulmus americana), native to about two-thirds of North America, is an iconic tree and was one of the nominees for the National Tree. Although the oak received this honor, both Massachusetts and North Dakota call American elms their state tree. In the past, elms lined the streets of midwestern cities, college campuses, and the National Mall. The Oval at Colorado State University is still lined with American elms, some of which were planted in the 1880s. Elms dotted the upstate New York campus where I attended undergraduate school. I remember Dr. William Huntley lamenting the death of elms around campus, which might have been brought about by a more deadly strain of Dutch elm disease in the 1960s.*

Autumn color of an American Elm

I’m lucky to have three large elms on my property as the one on the southside tends to keep the house cool in the summer. Once a friend mentioned she considered elms the scrounge of the earth. I was surprised but then remembered the multitudinous seeds, more properly referred to as samaras, covering our sidewalk and how many seedlings I routinely yank out of flowerbeds. Without a doubt they are tenacious trees with a number of deficits, including that surfeit of seed production. 

Elms may also harbor aphids which produce “honeydew,” nearly painting my white house a sticky black. European elm scale also contributes to the annoying honeydew and can debilitate a tree. Another pest, which chews holes through elm leaves, giving them a lacy look, is the elm leaf beetle. My house is now 102 years old, so I assume the trees are about the same age. I would not consider cutting them down unless they were rotten or became infected with Dutch elm disease. According to numerous sources, elms can live up to 175-200 years with an outside age of 300 years. The current oldest tree in the US listed on Monumental Trees, though, is estimated to be no older than 151 years. 

Dutch elm disease started devastating stands of elms in the 1930s after the disease was carried to North America by European furniture makers in the 1920s. Known as a vascular wilt disease it can be transferred in one of two ways. First, native elm bark beetles, as well as European bark beetles, carry the disease-causing fungus. Dutch Elm Disease (DED) can also spread from the roots of closely planted trees. World-wide there are up to forty members of the Ulmaceae family but only six species are native to North America. All are susceptible to Dutch Elm Disease, but American elms are affected in the greatest numbers. Estimates are that 77 million trees  were lost to the disease between its introduction and 1970. Current estimates of loss are closer to 300 million.

American elms (Ulmus americana) do still exist. Plant geneticists have created both American elm clones more resistant to DED, as well as cultivars which may prove to be less susceptible. Possibly the most famous elm tree was one which survived 14 bouts with the disease, thanks to Frank Knight, the tree warden of Yarmouth, Maine. According to the Liberty Tree Society, this elm was planted in the 1770s. Mr. Knight spent fifty years tending to Herbie, which was cut down in 2010 while the 101-year-old tree warden watched. You are able to join the Liberty Tree Society and purchase clones of Herbie, as well as support their research into viable cultivars. This site also has a timeline of the fight to save the elms 

The study of DED tolerant elms continues. A cultivar developed in 1927, the Augustine Ascending elm, was once thought to have some resistance to the disease, although this has proven untrue. Of the 550 elms on the National Mall, a few of them are the Augustine Ascending cultivar. This variety may be noticeable due to its more upright nature. A specimen of Ulmus americana Augustine Ascending(B99) can be seen across the street from the tennis courts in City Park. 

The upright Augustine Ascending elm
The Augustine Ascending elm’s bark

Another cultivar with properties beneficial to fighting scale was discovered by Fort Collins’ own Tim Buchanan, then City Forester. Scale buster American Elm (Ulmus americana Scale Buster) is located near the trolley station. 

Although there is NO American elm listed on the current version of the Self-Guided Tree Tour, I have a sneaking suspicion this tree with its wooden American Elm sign is the same as the scale buster elm as a photo in the talk referenced above looks nearly exactly like the tree. This specimen is located behind the trolley station on the west side of the street. Before the leaves have bloomed it is quite easy to see its wooden sign if you are looking northeast.

The old marker designating the American Elm

*Sibley, David Allen. the Sibley Guide to Trees. 2015, Alfred Knopf.

Tea and Chocolate–Products of the Linden?

Honey from linden flowers is said to be some of the lightest and best available.

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Profusions of yellowish white linden flowers

By far the easiest way to find linden trees is during and immediately after they bloom as the clusters of flowers (cymes) give the whole tree a distinctive look, as if the undersides of the leaves have been painted a lighter color. The flowers also give off a fragrance that can be discerned from a distance. Most of the trees are quite tall and if they are tagged, it may be difficult to find the tag, but there is little mistaking a linden in bloom. Also helpful in identification when they aren’t blooming are the heart-shaped, but saw-tooth-edged leaves. The straight trunk and bark also help identify the genus.

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Grooved bark of the American linden

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Cymes of the linden with a single bract

Lindens bloom between May and July, although many sources mention June as the primary bloom time. The very fragrant blossoms come with a single bract and hang down like lacy umbrellas. Others have described them as “fireworks.”

In the US the American linden (Tilia americana) is also know as American basswood or just basswood. The range of this native tree in North America is the East and Midwest. In England, its European relative (Tilia cordata) is known as a Lime tree or little leaf linden.

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Tilia americana in bloom

Most sources state our native tree grows to a height of around 70′. The National Champion tree in a Kentucky cemetery, crowned in 2017, has a height of 102′. There is a tie for the largest American Linden in Colorado, with one tree in Fort Collins and the other in Denver. Both are listed at a height of 92′. Monumental Trees lists the tallest American Linden in Europe at 101 feet and the oldest specimen in the Netherlands as about 138 years old. Other sources have suggested the species can live for a thousand years!

Monumental Trees lists the tallest Tilia Cordata at 132.87 feet. This tree resides in the United Kingdom. One source states a tree in Britain is over 2000 years old, but Monumental Trees lists the oldest as a mere 820 years. In North America, the little leaf has been introduced in the most northeastern parts of the continent, where the normal height is said to be 50 to 60 feet. The US champion (height plus girth plus branch spread) is in the state of Maryland and only towers 83 feet. Colorado’s champion can be found in Denver at 89 feet, with the second place tree, 72′, found in Fort Collins.

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Tilia cordata

Native Americans made rope, netting, and baskets out of the inner bark, or bast, of the basswood tree. The wood is used for lightweight projects such as guitars and other instruments, carvings, yardsticks, and veneer. At one time basswood was the prime material for prosthetic limbs. The Iroquois carved the bark for ceremonial masks. The wood of the tree, being lightweight and fast-burning, may not be the best choice for heating.

According to the Kentucky Department of Horticulture, the American Linden was first cultivated in 1752. An oil derived from its seed pods was used as a replacement for olive oil, while the sap can be made into a drink or boiled into a syrup. Honey from linden flowers is said to be some of the lightest and best available. The preponderance of bees around the trees give rise to another of its nicknames, the bee tree, not to be confused with the Korean bee tree.

An usual product first made in the 19th century from the dried flowers and nutlets

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Nutlets on the little leaf linden

was a chocolate-like substance. Unfortunately this concoction did not keep well and production ceased. In a short article discussing this “chocolate” the author says it is still possible to make some for immediate consumption or to freeze and includes a recipe.

The flowers of the tree especially have many uses. In France the leaves were made into a tea (tilleul) and used as a mild sedative.

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Blooms on comes with a single bract

Cup of Linden tea
Cup of Linden tea. The tea bags are slimy but the taste is pleasant.

Since the middle ages, the tea has been used to cure headaches. Alternatively the flowers could be added to a hot bath to help insomnia. Even today the flowers may be used in the making of perfume, As an early variation of “forest bathing,” sitting under the trees was thought to be helpful to epileptics.

Usually made from the European species, Tilia Cordata, linden tea is a well known use of the trees’ flowers, leaves, and bark. Unlike many medicinal uses of plants, linden tea has had a number of scientific studies conducted and papers written. Many benefits, such as relieving hypertension, stomach issues, and pain, helping you sleep, and a reduction of inflammation are reported in alternative medicine articles. Along with benefits, most of these articles mention a few drawbacks, such as possible heart problems and drowsiness.

To find the trees in City Park, follow your nose! The American Linden (Tilia americanapictured in this blog is B98, which is across from the trolley station on S. Roosevelt Ave. There is another American Linden on the tree map at B101, which is located on north side of City Park Drive between fields 1 and 2. Tilia cordata, or the Little Leaf Linden (A 88), is also on the north side City Park Drive. It is the fourth stem in from the northwest corner of Roosevelt and City Park Drive, two down from the light post and near the little kids’ playground. These three trees almost form the points of an equilateral triangle.

By the Beech

An unusual use of the buds in the spring is as a toothpick.

When interviewing Molly T. Roche, Senior Forestry Coordinator for the City of Fort Collins, back in 2018, I suggested we take her photo near one of her favorite trees. She selected the European Beech. We took the photo that summer, but I was hoping to include another when its leaves had turned. A cold spell and snow ensured the leaves on most trees crinkled up and turned brown. I waited through this fall but once again, didn’t get a photo.

Molly by the Beech
Molly by the beech, summer 2018.

Although there is an American Beech (Fagus grandifolia) which is native to the East and Utah, the tagged tree in City Park is a European Beech (Fagus sylvatica.) This species has been introduced to North America and similar to the native Fagus, grows in the east and Utah. Beeches belong to the Beech, or Fagaceae family, which includes the oaks, chestnuts, chinquapins, and two other genera that grow mostly in Asia.

The young leaves of the European beech are edible. Some say they haveSunlight through the beech leaves a taste somewhat like sorrel, which if you’ve never eaten it, has a lemony flavor. The leaves can be steeped in gin to create an alcoholic drink or made into a tea. And although this is NOT mentioned often, at least one company in the US makes a syrupBeech syrup from the American beech (Fagus grandifolia) sap. Granted this is not the same type of beech as in the park, but it is still interesting. A study done in Maine has cited a change in Northern forests from maples to beeches due to climate warming. Possibly a switch to Beech syrup can help save some of the current maple sugaring jobs.

Beech seeds, also known as beech nuts, according to most sources are quite tasty, although they may take a bit of work to prepare. Some may roast and grind seeds as a coffee substitute. Although a few seeds may be produced by the time the tree is 10 years old, trees do not fully produce nuts until they are 40 to 80 years old. An unusual use of dried beech buds is as toothpicks in the winter!

According to Monumental Trees, the beech tree trunk with the most girth, over 28′, can be found in Germany as can the tallest (>161 feet). According to the Sibley Guide to Trees (Sibley, 2009), a more usual height for a tree planted in North America is 50-70 feet. The internet site lists the oldest known Fagus sylvatica as a tree in Italy of 520 years. A “tree” planted around 1850 in Massachusetts is listed as the oldest known European beech in the US.

Sources vary on how useful the wood of a beech is for woodworkers. Most mention some furniture making as well as use in parts of instruments such as drums. Beeches in Europe have been used to construct cabins and furniture. Logs are used as firewood. They split easily and burn well. They may also be turned into charcoal or used to manufacture creosote.

The verdict seems to be out on using beech wood or chips for smoking foods. Most lists on the internet leave it off. One says it is long burning but has a strong flavor. Another says it is mild, similar to apple or pecan. This last mentions it is popular in Germany and used to smoke dishes such as Nuremburg bratwurst.

Beech trunk
The gnarly, elephant look of the beech trunk

There is controversy about the medicinal use of the beech, too. Although many sites mention some uses for its oil, leaves, and bark, most warn about toxicity or difficulty in procuring enough seeds or oil to be of much use. Other sources suggest even the bark may be ingested to improve digestion, and decoctions of seeds have been used to improve kidney function. Poultices made of the leaves have been used for headache relief and a tar made from the beech may be considered an antiseptic and has been applied for toothache relief.

A bestseller written in 2015, The Hidden Life of Trees: What they Feel, How they Communicate–Discoveries of a Secret World by Peter Wohlleben, which has received many good reviews, talks about the life of various trees but features beeches. The book isn’t without controversy, though, as seen in this article from The Guardian. The book almost reads like a novel but is backed up with scientific studies. It will certainly change how you look and think about trees.

To find Fagus sylvatica, go to the section of the park bordered by Oak Street,  Roosevelt and City Park Drive. The tree is somewhat in the center of the corner of Oak and Roosevelt. Currently it also sports a bright green box that might look something like a birdhouse but is actually a trap for some sort of bug. A second tagged beech in the park may be found along the lot line with the golf course.

 

According to The Tree Book ( Dirr and Warren, 2019,) the first cultivar of a European Beech was developed in 1770. Fagus sylvatica, Dawyck Purple is of the fastigate type and according to Dirr and Warren may grow to a height of 40-50′ (p.353.) This specimen has lovely, purplish-red leaves.

The Purple European Beech may be viewed along Jackson Ave, almost across from the intersection of West Olive Street.

 

 

 

 

 

The Tree the British Play With: Horsechestnut

The World Conker Championships have been held since 1965.

Horsechestnuts (Aesculus hippocastanum), also known as Conker Tree in England, are in the same genus as Buckeyes. Both are part of the same order as the Soapberry tree.P5180061

These trees are planted as street trees for ornamentation as well as shade. Both the National Audubon Society Field Guide to North American Trees and North American Trees (Preston and Braham, 2002) report them as “escaped.” The USDA maps show them as introduced in both the East and the Northwest. The tree originated in the Balkans but has been planted widely throughout Europe and other parts of the world. They may have been introduced in the United States as early as 1576.

Monumental trees lists the widest trunked tree in England, the tallest at over 120 feet in the Netherlands, and the oldest as a specimen in France, which might be as old as 500 years. The leaves are palmate, radiating out from a central point. This species isn’t listed in the National Forest Registry, but the Colorado Tree Coalition lists the largest and tallest tree in the state as one in Cedaredge. The largest Red Horsechestnut can be found in Denver.

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The leaflets radiate from a central post

The trees flower in May in what look like cones of white flowers. P5180054Sibley reports the interior yellow spots turn red when fertilized. The fertilized flowers produce what are known as conkers, or the “nut.” This is NOT the same as a sweet chestnut, and the outer casings look quite different. The two should not be confused as conkers are considered poisonous to humans, although they may be edible once boiled. Sweet chestnuts are encased in a spiny looking ball while the outer coating of a horse chestnut looks like bumpy leather. The interior “nuts” look similar but the edible version has a discernible and palpable point while the poisonous conkers are flat. Horsechestnuts are edible for many animals and are fed to horses and other livestock.

Apparently horsechestnuts are used in homeopathy. They are touted as useful for various circulatory problems such as venous insufficiency, phlebitis, and varicose veins when properly prepared. The leaves and bark may also be useful in a number of other conditions. Lupus is mentioned.

As they are not native to North America or The British Isles, there aren’t many myths associated with them. There is a game played in England called Conkers. This game is reported to have been a favorite of Roald Dahl. Currently, Britain’s trees are threatened by a combination of moths and disease. The loss of the trees may impact the World Conker Championship, which has been held in Northampton since 1965.

A notable characteristic of the Horsechestnut are the distinctive winter buds, which are large and sticky. P4120076

 

 

 

Below is a short video about the Horse Chestnut in the United States.

 

The Red Horse Chestnut (Aesculus x carnea Briottii) is a cross between a Red Buckeye and the common Horsechestnut.P5180013

The flowers are red or pink and it is the most common large red-flowering tree in temperate zones (The Sibley Guide to Trees). The flowers are quite stunning. P5180006

City Park’s  Horsechestnut (Aesculus hippocastanum) (B115) can be found just west of the intersection of Jackson and Oak streets, across from 1312 W. Oak. This tree was planted in 1997 and had a diameter of about 3.5″

To locate the Red Horse Chestnut (Aesculus x crane Briotii) (A93), continue west on Oak Street to the first turn into the park. This street is a continuation of Roosevelt Avenue.  The tree is one of the few deciduous trees in the NE triangle formed by Roosevelt and Sheldon Drive.

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Close up of the Red Horse Chestnut blossoms.

A Champion Larch in City Park

The Colorado Tree Coalition publishes a list of state championship trees. It also has a map of a tree tour of notable Ft. Collins trees.http://coloradotrees.org/wp-content/uploads/2016/06/Notable_FtCollins.pdf

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The Championship Larch on Jackson Street, November 2017

Yes, we have a State Champion tree in City Park. The European Larch is an impressive tree and once you know what it looks like, easy to find. This particular tree is hidden in with a bunch of conifers. What distinguishes a larch from other conifers? It’s deciduous and loses it leaves, which the uninitiated would call needles. The big tree isn’t the only example of a larch in the park. There is a recently planted–in the last ten or fifteen years—larch just behind the Kentucky Coffeetree. This second tree is tall and spindly while the champion tree is tall, sturdy, and spooky looking.

The distribution of the European larch, which is an introduced, non-native tree, is, as you may have guessed, the eastern part of the US and Canada. Its range is less than the many other trees reported on so far. North American Trees reports European Larch “is planted and sometimes escapes”! According to the 1932 pamphlet European Larch in the Northeastern United States by Stuart Hunt, larch was introduced into England in 1629 and into the US in the mid 1800s, in both cases for lumber.  If you are a fan of the Great British Bake-off, you might have noticed a larch outside the baking tent. The largest larch in the world may be one in Switzerland which also may be 900 years old! It makes our larch look like an anemic relative by comparison.

Many authors report larch wood is fire resistant and was used in Roman ship and bridge building for that reason. Current uses include utility poles, veneer,  boat building, furniture, and fencing. The pitch can be tapped to be used as a varnish and for waterproofing boats and roofs. The bark has been used medicinally or ground and added to flour.  Another source mentions Siberians collected the leaves, fermented them and used them as a salad in winter.

The larch also has a place in mythology and pagan rituals, as well wand material in Harry Potter. Larches may be planted for cremation ceremonies, used to ward off evil spirits or burned to inhale the smoke and promote visions.

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Looking up through the branches the tree truly does look magical.

To find our champion Larix decidua (E117) park near the corner of Jackson and Oak. The five-way corner at the NE entrance to the park forms a triangle on the S side of the stone entrance with the row of trees being one side. In the center of these conifers is the Larch. It is probably easiest to locate when its leaves are yellowed and before they all fall, making it a good tree to find in the late fall/early winter.  The tree is across from 210 Jackson.