Tree of the Month
December 2015 ~ Black Spruce; A Tree of the Far North
Black spruce, Picea mariana, in the Pine Family (Pinaceae), is a tree of the far north, growing from the Canadian Tundra to the Great Lakes states and south at elevation in the eastern mountains. It is a slow growing, relatively short species (30'-40'), often stunted in nature. In its southern range it inhabits cold bogs; farther north, it can occupy drier sites.
This is probably not a practical landscape tree south of the Lake States, although I understand there are some cultivars that are beautiful and take some southern heat. I think black spruce very useful and good looking when used in Northern Wisconsin, in conjunction with other native species. In the far north, black spruce grows in association with white spruce, white pine, balsam fir, paper birch and aspen. Black spruce is available from large northern wholesale nurseries that do their own propagating. The species does need full sun, so black spruce is most appropriate for planting in sunny, cold, moist or even wet, locations. November 2015 ~ Basswood
Basswood, Tilia americana, also know as American linden, in the Linden Family (Tiliaceae)is a normal component of the great eastern deciduous forest of North America. It is a shade tolerant species found in association with sugar maple, red oak and ironwood. It has good potential as a street tree, along with its counterpart, the European little-leaf linden, which is probably used to a greater extent.
Tilia americana has a very formal, pyramidal shape when young, becoming large and spreading at maturity. The two trees are quite similar, the European tree having much smaller leaves. The "little leaf" leaf is generally 3" or less in length and mostly heart-shaped ; the American species more than that in length, up to 4.5", and in shade can be very large. It is not heart-shaped, but is rather irregular at the base of the leaf. The branches lack a true terminal bud, the dormant winter bud being slightly offset, in the axil of a terminal leaf. The trees have toothed, simple leaves and alternate leaves and branches. Both trees provide heavy shade. Both have a yellow fall color, the basswood being quite nice some years. An often overlooked aspect of the lindens is their sweetly scented flowers. While not showy, the blossoms are heavily scented and a large tree will be render a considerable area fragrant. There are a few other, less well known and less frequently used lindens, some hardy north, some not, but they are not as likely to be planted as street trees as the European and the American species. The tree pictured is on the north side of Manypenny Ave., between Fourth and Fifth Streets. Growth rate is moderate to fast, with few disease or insect problems. October 2014 ~ Honey Locust
The thorn less honey locust, Gleditsia triacanthos var. inermis, in the legume family (Leguminosae), has been used, perhaps overused, as a street and landscape tree ever since the onslaught of Dutch elm disease a generation ago. Native to rich forests of the central and southern Midwest, it has very small compound leaflets and therefore is easier to clean up after in the fall. Although it grows to be quite large, it yields a more dappled and lighter shade than other trees so has its uses, but can be a misshapen and not particularly pleasing tree if not pruned properly. It does have a bright golden fall leaf color that can make a nice statement, and since it is a legume and fixes nitrogen it is also a good tree for sandy and poor soil conditions. The species itself is far too thorny for any practical ornamental use (the species name refers to the vicious three-pronged thorns, the variety name to the lack thereof). There have been many patented trees produced by nurseries over the years from the thorn less variety, some of which, such as 'Moraine' are superior for street tree and landscape use. The "honey" of the common name refers to the sweet, gummy, edible substance surrounding the seeds inside the large, long pods that this leguminous tree produces. Many modern varieties do not produce seed pods. October 2014 ~ Ohio buckeye
The Ohio buckeye, Aesculus glabra, on Manypenny Ave. between 4th and 5th Streets, had turned its bronzy fall leaf color.
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August 2013
A white pine has been declining for several years on S Ninth St., and the property owner recently had it cut down. It was for all intents and purposes dead. I counted the growth rings of the stump and they indicate the tree was about forty-five years old, probably the same age as the house on the property. I had been observing the tree, and was eager to examine it once it was on the ground.
I found that an infestation of bark beetles had finished the tree off, but they seldom attack healthy trees, and my assumption is that this tree was badly damaged by the drought of recent summers and that it had outgrown its environment as well. Poor soils, drought and other environmental factors weakened the tree and made it a target for the tiny beetles, the adult males of which excavate chambers in which the males and females mate, and in which eggs are laid. When the eggs hatch the larvae feed under the bark, creating tunnels that girdle branches and eventually the entire tree. The infestation begins at the top of the tree and proceeds downward over several growing seasons. In the above photo of the galleries the larvae have pupated into adults and left the tree to attack another weakened pine tree. The photo of the branch with the bark still intact shows the very small (smaller than a pin head) exit holes produced by the emerging young adult beetles. Red pine plantations are sometimes seriously damaged by bark beetles, but the insects are probably only a secondary threat in ornamental pines, and once the bark falls off the dead trees and their branches the beetles are gone and the tree is no longer a source of infection. There are two species of pine bark beetles in Wisconsin, and they often are both present in infected trees. For further information on pine beetle life cycles, their biology and control, visit the WDNR web site. July 2013
The Japanese tree lilac, Syringia reticulate, in the olive family (Oleaceae) is a small tree lilac that blooms later than the common lilac and is very useful as an ornamental street tree, growing to a maximum of thirty feet or so. Its blooms are large and beautiful but lack the appealing scent of the common lilac. It is hardy to zone three, and is usually quite trouble free, so it has become very popular. The hazard of courseis that if it becomes over-used it is bound to develop problems, such as borer, mildew and scale insects which are common to other members of the genus. We have used it a lot along Bayfield streets, mostly the variety 'Ivory Silk.'
April 2013
American Chestnut (Castanea dentata) on S. Seventh St and Manypenny Ave. It is 50" in diameter at breast hieght (DBH) but unforturately has a large cavity which renders it quite unsafe. Condition is poor, value $1,500.
February 2013
Red Oak (Quercus rubra) on S. Second St., age about 175 years. Probably planted when street was built. Condition is good, value over $23,000.
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