Silver Linden. A Bee Killer?

Bees are often found dead or stunned underneath the silver linden.

One of the other unique lindens in the park is the Silver Linden (Tilia tomentosa.} This linden, or lime, is native to countries east of the Adriatic Sea, including Albania, Bulgaria,Croatia,Greece,Hungary, North Macedonia,Montenegro,Romania,Serbia, Slovenia,Turkey, and the Ukraine. The tree was introduced into Great Britain where it grows into north Scotland. This source  states the tree was used for lumber in Bulgaria and Romania. Another interesting use of the wood is in carvings found in Orthodox Greek temples.

paper on various species of linden in the Balkans mentions that Tilia tomentosa tends to reproduce via sprouts. This same paper recounts it is possible for some lime trees to live for a thousand years. It does not indicate which of the various species have reached this age, though. The University of Florida suggests propagation of this species is most often accomplished via cuttings as seed germination can take two years.

Oddly, the USDA calls T. tomentosa a native of Ontario. Most likely this is a mistake as most other sources list it as native to Asia and Western Europe exclusively. In North America this variety is hardy in zones 4-7 and was introduced in 1767.

Monumental Trees lists the tallest silver linden, a tree in Belgium, at 121 feet. The US list of Champion trees has no listing for Tilia tomentosa, although many sources, including Dirr and Warren’s The Tree Book:Superior Selections for Landscapes, Streetscapes, and Gardens, say it is an excellent street tree that is more resistant to aphids than other lindens, although other sources dispute this. This may also be true of Japanese beetles. It may be more drought and pollution resistant.This information seems to differ by the state which provides it and leads me to believe its properties vary with the environment it is in.

With the silvery underside to its leaves, many consider this a good shade tree with a shimmery effect in a breeze. Like most other lindens, bees are very attracted to its flowers from late June into July. Dirr and Warren, as well as others, report this might not be a good tree for bees as they are often found dead or stunned underneath them. Bumblebees are more prone to suffer than honey bees. Recently studies have been done to figure out if the problem lies with the biology of the bees or  has to do with the flower nectar. The conclusion reported in a Royal Society (2017) article is that further study is needed to determine the cause of death.

E17 Silver linden specimen Tilia tomentosa in City Park is a smaller tree located along the drive to the golf course parking lot. Part of the fire station can be seen in the background of this photo.

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Tilia tomentosa

 

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.

Lacebark Trees–Species of Similarities and Contrasts

While the lacebark elm is easy to transplant, the lacebark pine requires patience.

Although a tropical tree in Australia is known as the lacebark tree, it appears to only grow in hardiness zones 9 and above, limiting its growth to warm coastal areas in the US. Two other species of tree, both from China, come in a lacebark version, the Lacebark Elm  (Ulmus parvifolia) and the Lacebark Pine (Pinus bungeana).

The elm version, also known as Chinese elm, has been introduced to much of the midsection of the United States. Although it is considered invasive in some areas, it has also been considered a good alternative to Siberian elms, which are more weedy. According to The Tree Book: Superior Selections for Landscapes, Streetscapes and Gardens (Dirr, Michael and Warren, Keith, 2019) this elm is useful in stressed environments and has been planted in parking lots, streets, and in parks. It is resistant to both Dutch elm disease and the elm leaf beetle as well as black leaf spots. Hardy from zones 5 through 10, it doesn’t drop its leaves until well into winter, and as may be expected from its name, its trunk is a major focal point when the bark exfoliates to reveal multiple colors.

Lacebark elm trunk
Lacebark elm trunk

The Tree Book features write-ups on thirteen different cultivars. Another somewhat unusual use of the species is in Bonsai. The leaves may be eaten cooked or raw and are said to have a pleasant taste which imparts freshness to one’s breath.

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The lacebark pine

While Dirr and Warren state the lacebark elm is “easy to transplant and propagate,” they report the lacebark pine grows slowly and requires patience. It was first discovered in China in 1831. Often grown on temple and palace grounds, the tree is revered and in Korea the largest trees are considered national monuments. The species may grow for 200-300 years with the oldest trees closer to 900 years of age. Often in their native habitat they reach heights of 80-100 feet.* In North America this conifer is more likely to grow to 40′ to 50′ and have multiple stems.

This three-needle pine also has bark that exfoliates in irregular pieces, giving it the appearance of a mosaic. It may not start this process until it is ten years old. Colors which may appear include green, purple, white, and grey.

Peeling bark on the lacebark pine

Although it has some resistance to diseases which attack pine trees, its wood is brittle and it may suffer damage in storms. The seeds from this plant are edible but no information has been given on how to prepare them. Turpentine extracted from this species may be used in a number of medicinal remedies, but as this tree is not abundant in the states or easy to grow, it should not be used for these purposes.

E2 Lacebark pine (Pinus bungeana) is located behind the fire station on Bryan Avenue, along the drive to the parking lot for the forestry department, next to the mugo pine.  

To find the lacebark elm (Ulmus parvifolia) E48 head to the parking lot near the ballparks. It is on a peninsula in this parking lot just about halfway between Mountain Ave and Oak Street.

*The Tree Book: Superior Selections for Landscapes, Streetscapes and Gardens (Dirr, Michael and Warren, Keith, 2019)

Mugo Pine–Little Tree, Short Post

Small tree with many names

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Mugo pine in early spring

Mugo pine (Pinus mugo), champion of the landscape? This conifer, especially in the form of its many cultivars, normally appears to be a shrub with its many trunks and shorter stature. Many sources consider it only a shrub for use in the landscape, notably in rock gardens and parks.

Other names this specimen goes by include Dwarf mountain pine, Swiss mountain pine, scrub mountain pine, knee pine (Sibley, 2009*), mugho pine, creeping pine, and all the variations in the languages of Europe.  It was given its scientific name in the 1700s. One website describes the plant growing in its native habitat in the mountains of Europe, where it may grow at heights up to 8000 feet,  by saying, “it grows low to the ground in mounds like a creature huddling against the cold winds.” According to the USDA map, the tree has been introduced to parts of the east and Canada, although its hardiness zone appears to cover most of the North American continent.

The champion tall tree, which grows in Finland, is nearly 80′ tall. This species often has multiple trunks. Monumental Trees does not include the width of more than one trunk. The tree of most girth meeting this requirement resides in the UK and is over eleven feet in circumference. No information is available about the age of mugos.

There is little unique information about this species’ edibility or medicinal use, although mention is made of a delicious Bulgarian tea brewed from the leaves. Other sources says the trees provide shelter for small animals and may help with erosion control.

To find the tall mugo (E 1) on the City Park Self-guided tour, go to the westernmost area of the park behind the fire station and near the Forestry office. This specimen was planted in 1975, making it one of the earliest planted trees on the tour. Pinus mugo is located close to the locked gate to the maintenance lot near the southern boundary to the park. A small map is shown with the mugo represented by the star. Mugo pine mapThanks for Molly T. Roche for the map

*Sibley Guide to Trees (Sibley, David Allen, 2009)

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.