invasive species – What Tree Where

The Invasive Christmas Tree–the Scotch Pine

A Scotch Pine has never been used as the Capitol Christmas tree.

Every list of tree species used as Christmas trees seems to include the Scotch or Scots Pine, latin name Pinus sylvestris. At least one list considers it the most popular tree in the States, while others list it as the most popular pine but 8th most popular conifer overall. The National Christmas Tree Association does say it is the most popular tree for the holiday season.

OLYMPUS DIGITAL CAMERA — The distinctive two needle packets of the Scotch pine.

The Scots pine is the most widely distributed pine in the world, with its range stretching across Europe and into Asia, or as many sources say, from the Arctic to the Mediterranean. Although not often used as lumber in the US, that is a common use throughout Europe.

The species was introduced into North America in the 17th century. It has naturalized throughout most of Canada and the northeast United States. In fact, it has been so successful in some areas, it is considered invasive. Wisconsin considers it such but currently does not regulate it. The Ontario Parks blog has a headline “Don’t Deck the Halls with Scots Pine for Christmas”.

According to the gymnosperm website, the use of this variety of pine as a Christmas tree is mostly a custom in the United States. This same site says the Scots pine is the second most common conifer world-wide after the common juniper. To sell as a Christmas tree, the Scots pine is grown on tree farms for six to eight years before reaching a height of 7-8 feet. The trees normally last for three or four weeks and even when not watered, they usually don’t drop their needles. More than one source says this conifer accounts for 10% of Christmas tree sales. Although these are popular in the home, a Scotch pine has never been used as the Capitol Christmas tree.

While parts of the tree are edible and can be ground down to a meal to add to oatmeal or flour, it is considered a food of last resort. Like many other plants, it has a long list of conditions for which it is reputed to have a medicinal effect, including respiratory problems. Not surprisingly, the leaves have been used as an antiseptic.

The Scots pine is the national tree of Scotland. Although many will tell of the days when Scotland was covered by the Caledonian forest, made up of Pinus sylvestris, this version is disputed by the Scottish historian Christopher Smout. Still, as the only native pine in the UK, it has many uses, including telephone poles, source of turpentine, and fencing. A large stand of the pines was used for WWII commando training as well as in a Harry Potter movie. This group of Scots Pine has recently been saved by the Scottish Land Trust and local residents, hoping to use it as a tourist site. There are about 77 remnants of the Caledonian forest, with about nine of them easily accessible.

Many sources say these trees can live to 700 years. The oldest known tree is in Finland and dates back 764 years. The tallest tree is about half the height of an average Redwood.

To find (E55) Scotch Pine (Pinus sylvestris) on the Fort Collins City Park self-guided tour, head to the intersection of Bryan and Oak Streets. The large conifer is on the east side of the ditch, directly behind the speed limit sign. See the photo above.

Bees at the Bee-Bee Tree

Hundreds of saplings may grow under a female tree.

The Korean Evodia is another tree with a checkered history in North America. The Latin name for this tree included on the City Park Tree Guide is given as Evodia danielli but it appears Tetradium danielli is also used. Other names include Bee tree, Bee-bee tree or bebe tree. Other sources include the name Honey tree and One Hundred Thousand Flower tree. The current USDA map shows it naturalized in Pennsylvania and Ohio, yet many other states are reporting it as having escaped.

Although Pennsylvania has this species on its watch list for invasive potential, at this point it is not known how it might damage the environment. A four-acre patch of escaped trees has been reported in Maryland. A short article published in 2017 gives more information about the nature of this tree and its invasive nature, stating that hundreds of saplings grow under a female tree and it has been seen outcompeting other invasive species such as the tree of heaven and Japanese stilt grass.

First brought to the United States in the early nineteen hundreds, this specimen is native to the Koreas, northwest China and other parts of Asia. Why is it given its various monikers?

Although the many small blooms, in clusters that resemble poorly formed cauliflower heads, are rather high up and hard to see, bees swarm these late bloomers. It is the second week in September here in Colorado and the flowers are still blooming. Purportedly female flowers will turn to stunning red seed pods.

This propensity for late blooming makes the tree popular with both bees and possibly beekeepers. Although many sites mention this as a nectar source, the references I found date to the 1970s with few current citations. One website suggests a substance made from the seeds is used as both a cooking and hair oil!

In the 1990s the US Forest Service lamented this tree was not used more often for ornamental purposes and suggested it would be a good street tree. Similar to the Amur cork tree, parts of Korean evodia have been used in Chinese medicine for 2000 years. It has been used to treat arthritis, headaches, gastric upset, and other ailments. Both WebMD and RxList suggest there is not enough evidence to show if any parts of the plant are effective.WebMD includes a number of drugs with which evodia may interact and cautions pregnant and breastfeeding women from using it. Surgical patients should also use caution as it might interfere with blood clotting.

C185 Korean Evodia (Evodia danielii) is either no longer tagged or the tag is nearly impossible to find when the tree is blooming. At the right time of year, though, it is fairly easy to identify by the many bees buzzing around its flowers and its somewhat unusual shape. If you found the Amur Cork, walk slightly south and west from there. Although not perfectly aligned with Olive Street, you can also start from where Olive Street tees into Jackson and walk west and slightly south across the park to find it. It is near a large evergreen tree.

Amur Cork—Landscape Lovely or Harmful Invader?

First brought to the United States in 1856

Amur cork tree (Phellodendron amurenses) is native to China, Korea, and other areas of Asia. It was first brought to the United States in 1856 and grown in the Harvard Botanic gardens as early as 1908. From 1933 it has been reported to have naturalized in New York. Currently it is considered an invasive plant in a number of states. As an invasive plant it crowds out native trees and produces berries which are less nutritious than the nuts of native trees; its berries do not have the same essential fats needed for wildlife to survive through the winter.

Some of the sources referenced above speculate that the trees were brought from Asia by railroad workers. The trees’ growth patterns have contributed to its “success” in crowding out native specie. By suppressing the growth of canopy trees, it has become one of the dominate trees in eastern states. Although many states warn against planting Amur cork, others suggest Phellodendron amurenses is a good landscape variety. A few suggest only male trees be considered. This might be a reasonable solution in areas were there are no others, but in areas where the trees have naturalized, the male tree may still fertilize female trees and add to the problem.

Possibly one of the reasons Amur Corks were originally brought to North America is that it is considered to be one of the fifty most important herbs used in Chinese medicine. Some of its compounds have been used to treat meningitis, arthritis, cancers, and diseases of the lungs. The Ainu population of Japan also used parts of this tree as a painkiller.

WebMD mentions most of the uses above. It also states some of the trees’ compounds, such as berberine, might lower blood sugar and LDL cholesterol. At the same time they include warnings about possible harmful effects. There is limited scientific research to support usage.

Other non-medicinal uses have been mentioned; older literature suggests the bark as a substitute for cork.

It may be used for cork in Russia. An oil made from seeds may have insecticidal properties. A yellow dye obtained from inner layers of bark, was used to produce yellow-tinted paper, useful in distinguishing the important of various Chinese documents.

The Amur cork tree (C138) may be found in City Park where Olive Street intersects with Jackson Street. As can be seen in the photo at the beginning of this post, the tree is almost directly across from Olive Street street.

Mayday tree: Inadvertent Meaning to a Name?

In Scotland this was once known as the Witches’ Tree

The Mayday tree is a member of the rose family, in the same genus as cherries and plums. Another common name for it is European Bird Cherry. This name gives a clue as to its origin. According to a Canadian website, it grows in countries near the Arctic but is native throughout Europe where its berries attract birds. It has been introduced in the US and is most prevalent in Alaska and parts of the east, including Canada.

The tree is grown as an ornamental in the states. It is on more than one list of preferred trees for Colorado and is included as a good choice for the Front Range by the Colorado Tree Coalition.

There is no doubt that it is a gorgeous tree when it blooms. It also has a distinctive, spicy smell which wafts over large areas.

The lovely scented flowers of this tree become dark colored “cherries,” also called

P5080079_1 — Flower Clusters of the Mayday Tree

chokecherries, although the berries usually eaten in the US with that name are from the same genus but a different species. These are said to be very bitter, but may still be made into jams and jellies. One source says they can be used to make cherry brandy. Mention is made that Koreans eat the boiled leaves.

The various parts of the tree have been used for the usual medicinal remedies for internal problems such as gall stones; colds, and fevers. A more unusual mention is a concoction of an eyewash for conjunctivitis. The leaves and berries may be made into green dyes, as well as a reddish dye for fishing nets. Some sources say the lumber is prized in woodworking, but the Wood Database doesn’t list it.

Although this tree does not currently appear to pose a threat to the lower 48, it has become invasive in Alaska. It may cause difficulty in growing other shade trees as well as adversely affect the willow population. Moose often feed on willow trees, possibly decreasing a food source. The leaves, twigs, and drupes contain hydrogen cyanide and can be deadly for horses and other large animals. Recently this has caused problems for moose. Eaten in small amounts, humans normally will not be harmed by the hydrogen cyanide in the berry’s seeds.

A photo of the trunk of the tree is included to help in identification.

D74 May Day Tree (Prunus padus) is located on S. Bryan Drive between Oak Street and City Park Drive. It is very close to the street, across from the playground. This specimen was planted in 1993.

As indicated, this tree is called variously the May Day Tree, Mayday tree, European Bird Cherry, Cluster Cherry, and Hagberry. (The Sibley Guide to Trees.) At first I thought it was named the May Day tree as the flowers bloomed around the beginning of May. After reading of the danger to native trees in Alaska and the poisoning of large mammals, I wonder of it was inadvertently given a name mimicking a call for help!

The R2D2 Prototype–Weeping Mulberry Trees

The mulberry fruit might be considered a nutritional powerhouse.

P9250007 — Great backyard tree for hide and seek.

I ate mulberries for the first time three or four years ago. When I first saw them at the farmers’ market, I thought they were blackberries, which is pretty much what they taste like. I’ve looked every year since, but the person who was selling them hasn’t been back. The truth is, I didn’t even know they grew on trees. When I mentioned I’d love to have a tree, people in the know gave me horrified looks. “They’re messy.” “They stain everything,” were common refrains.

There are ten species of mulberry tree, with three native to parts of North America. Although I have memories of purple-black splots on sidewalks under trees, I don’t believe I knew these were from a fruit bearing tree. White Mulberries (Morus alba) were originally brought to this continent from China with the intent to start a silkworm industry. According to the USDA, the white tree has been introduced and grown in all of the lower 48 states except Nevada. The red mulberry (Morus rubra) is native to the eastern half of this continent. In some areas, the white mulberry may be considered invasive. One way to tell the two species apart is by the shiny leaves of the white mulberry.

Not only are mulberries yummy, they could be considered a nutritional powerhouse as they are relatively high in protein, contain high levels of Vitamin C and iron, as well as numerous other potentially beneficial nutrients. Compounds such as anthocyanins, may exhibit cholesterol lowering properties. Rutin, an antioxidant, may help guard against heart disease, diabetes, and some cancers. Myricetin, too, may play a role fighting some cancers. Other websites attribute even more wondrous properties to the mulberry fruit, such as an aid in weight loss, vision improvement, and bone building. Although this might be a property of a different variety of Morus tree, another source mentions the fruit is a source of resveratrol, that miracle compound of red wine much ballyhooed a few years ago.

The weeping mulberry tree, Morus alba Pendula, is a dwarf variety of the Chinese tree. Some of the gardening sites on the web discuss this tree as a good provider of shade, but except for fighting your way through the branches–which you might have to do to find the identifying tag–the versions in the park wouldn’t seem to provide much shade. Although I had not been paying close attention to the two specimens during the spring when they would have fruited, I have stopped and looked at these trees over the years and have never seen flowers or fruit. I suspect they may both be male specimens of the tree. Next year I will be sure to confirm the absence of the fruit.

To view the two in the park go to C190. If you spent time at the Tulip Tree, keep walking west along the diagonal. The two stubby trees are on the south side of City Park Drive, not far from the intersection with Sheldon Drive. If you are driving to the park, turn N off Mulberry onto Sheldon Drive and at the intersection of the two streets, take a right turn along the diagonal. The trees are West of Field 4 and across from the “permanent” latrine.

As an ornamental tree, the weeping mulberry is visually interesting without its leaves. If you are looking for this tree in late fall or winter, look for a form like an open umbrella with too many twisted spines and no cloth covering.

PA180016 — What shapes can you see in the trunk?