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Monday, May 22, 2017




Monday, 8:00 AM,  48 degrees F at the ferry dock, 47 on the back porch.  Wind SW, calm with light gusts.  The sky is overcast, the humidity 87%.  The barometer stands at 29.80".
   The paper birch, Betula papyrifera, in the Birch Family, is a tree of the far north, native in North America from the Great Lakes north to the Tundra and all across Canada and Alaska. It is in flower now, the trees bearing both male and female flowers. The small, wafer-like seeds will mature by fall, and will be gradually dispersed over many months, often seen freshly deposited on new snow and ice in winter, and they will be taken everywhere by wind and the waters of melting snow.
   Used as an ornamental, paper birch trees are usually planted in locations too hot and dry for them to thrive.  The natural habitats of paper birch are stream banks, the edges of swamps, rocky hillsides and wet sands, although they will grow on drier sites in a cool climate.
   The paper birch was, and still is, an important element in traditional American Indian life. The exfoliating bark (skillful removal does little to harm a mature tree) provides a light and durable material for canoes and for wigwams, and is an excellent fire starter. Birch Bark makes good drinking cups and baskets.  Birch wood is light and easily worked, and it makes excellent firewood.
   Native Americans had a number of medicinal uses for paper birch, and in many northern countries birch species are taped like maple trees and the sap fermented to make a birch beer, or boiled down to make sugar, although it is inferior to sugar maple sap in that regard.
   Even in nature, paper birch are short-lived trees, seldom lasting more than forty or fifty years, if that.  They are a pioneer species, requiring full sun, and in nature are shaded out by oaks, maples and fir trees.  Paper birch trees will often stand dead, held together by their bark, until a strong wind or other disturbance sends them crashing in a pile of lumpy sawdust.
   The bronze birch borer often kills whole groves of paper birch trees, even in the best native habitat, and it sneaks up on ornamental plantings and kills trees often before it is detected.  Trying to control the borer in the wild is pretty much impossible, and although it is possible to combat it in the home landscape the effort may not be worth it for what is necessarily an ephemeral tree.
   The bronze birch borer is the larvae of a beetle that inserts its eggs under the bark of the host tree, where the borers feed on the cambium of branches and trunks, eventually girdling and killing the tree.  Their presence is indicated by raised areas on branches that trace their tunneling. If the bark is peeled back with a sharp knife the tunnels and grubs can be seen.  Systemic insecticides can be effective if applied soon enough, but are expensive to use and may not be worth the trouble and environmental hazard.
   To help a paper birch tree live as long as possible in the landscape, it should be planted in good topsoil that is on the sandy side, and it must have good drainage but also adequate moisture, and an acid soil.  The roots must be kept as cool as possible, which means mulching (use oak leaves or conifer needles if possible), or at least not mowing the grass beneath the tree.  Under-planting with compatible native shrubs, grasses and wildflowers is also an option.
   There have been a number of hybrids of the paper birch with the European white birch (the birch genus is circumpolar in the far north) or the eastern gray birch that are more adaptable, and are resistant to borer.  Also, the river birch, B. nigra, has a very ornamental, exfoliating  orange-white bark when young and sometimes is used in place of the paper birch, although it becomes a much larger tree and its bark becomes less attractive with maturity.
   Like many things in life, paper birch trees are a fleeting presence, and are probably best enjoyed when and where nature placed them.

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