29. Silver Poplar Populus Alba
Also known as a White Poplar, this fast-growing, large tree spreads easily by the cotton-like seed catkins and root sprouts that establish clonal colonies. As such, many municipalities and agencies in the US consider this an invasive tree. In addition to the "cotton" catkins, it is known for its appearance of fluttering in the wind. Each leaf is dark on one side, and light on the other. The construction and shape of the leaves create a flickering effect in a breeze. This is a native to Europe, Africa and Asia but naturalized in nearly every state in the US. It tolerates salt air and pollution. It has a light gray bark and distinctive white down on both the shoots and undersides of leaves.
30. American Chestnut Castane dentata
Horse Chestnuts are deciduous trees native to Europe and are easily propagated from the seeds which are sometimes called "conkers". They appear commonly in New England, but are rarely planted anymore because of a blotch which causes an unsightly browning of the leaves in the fall.
This is a large tree (often growing more than 100') and flowers in big pyramidal clusters of white flowers in May. The fruits are spiny shells that split in October to release one or two nuts. These should not be confused with sweet chestnuts which look similar. Deer and wild boar can eat horse chestnuts, but they are poisonous for humans, dogs, birds and most other mammals. In dire circumstances, squirrels and chipmunks may eat them, but they are not a major food source.
31. Sourwood Oxydendrum arboreum
Sourwood is a native tree that rivals our native dogwood for sheer beauty and three season interest. Young foliage is iridescent green which then turns to a deep green before turning yellow, red and then maroon in the fall. Fragrant white flowers on long panicles blossom in June and July and stay on the stems for three or four weeks. It grows at a medium rate (12-24" per year) to 30' and can tolerate acid soils and partial shade. It is host to many native species of insects, caterpillars, bees and birds. Its name comes from the acidic taste of its foliage, but the honey produced from sourwood nectar is highly prized and sought after by honey and native bees.
32. American Elm Fagus sylvatica
This well-known, native species once lined most main streets across the United States. Majestic, graceful, vase-shaped, these trees are often wider than they are tall. They are fast-growing, often reaching above 100'. Their population has been in steady decline since the introduction of the Dutch elm disease in the early 1930s. Mortality does not occur until the trees are mature. There are hybrids in development that seem to be more resistant to dutch elm disease but currently, American Elm's conservation status is considered endangered.
The inclusion of this American Elm on the tour is two-fold. One, despite its massive cutback about ten years ago, it is still easy to imagine how huge this tree once was. Second, even with the massive cutback (leaving no branches or leaves) the tremendous reserve of energy and food in this tree is resulting now in a second life. Kind of amazing!