Tree Body of Palos Park
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PROVENANCE IS IMPORTANT

For years, the Palos Park Tree Body has advocated the planting of native species of trees, using the logic that species native to our area have a proven ability to exist here, with our cold winter temperatures and unpredictable summer rainfall. While getting the species correct is a big first step in tree selection, that wonít do you much good if you donít get the provenance right as well. Provenance is a fancy way to say "place of origin." Where the treeís ancestors evolved determines many of its genetic characteristics. A tree grown here from a Bur oak acorn picked up in Texas has a Texas provenance because its heredity was determined there. Heredity is important because many subtle mutations develop through the years, as the trees with the gene and the appropriate trait survive.

When we talk about the provenance of a tree, we are not talking about the species as a whole, we are talking about the specific tree. Before you purchase that tree, ask about where the tree was grown, its place of origin. If it was locally grown from local seed, it would be from the same latitude, the same relation to Lake Michigan, and similar soil characteristics as where you plan to plant it, so your chance for success would be good. Experts say that up to one hundred miles is an acceptable distance; however, trees from Northern Michigan sometimes have a problem on this side of the lake. Obviously, if your new tree is from South Carolina or Georgia, it probably will not make it through a winter freeze or a summer drought here.

The effect of provenance is easily illustrated by experience with the planting of the sugar maple, Acer saccharum. A sugar maple with a northern provenance will show low drought resistance, susceptibility to leaf injury, but have high resistance to winter injury. A tree with a southern provenance will show high resistance to drought and leaf scorch, and have a low resistance to winter injury. A tree with a central provenance will show a high resistance to drought, a moderate resistance to leaf scorch, and high resistance to winter injury. Obviously, this would be most appropriate for our cold winter temperatures and unpredictable summer rainfall.

For several years, the trees planted by the Village have been purchased from a grower who collects seeds locally and raises them nearby. As a result, there has been a very high survival rate of these trees planted on Village property.