I think that I shall never see a poem lovely as a tree. Joyce Kilmer
In 1918, Joyce Kilmer wrote “I think that I shall never see a poem lovely as a tree”. Today we know that trees are necessary for life on earth. Our urban trees provide the oxygen we breathe, improve air quality, reduce air pollution and air temperature, absorb UV radiation, improve water quality, reduce storm water and serve as a buffer to street noise. Trees make life more pleasant and provide us comfort. Trees create a common space for neighborhoods, thus bringing about opportunities for informal social interaction and growing bonds between neighbors.
Note that in the diagram below, the feeder roots extend far out from the drip line of the tree and are more shallow than might be assumed.
Why plant native trees
A native tree is a species that was growing here before the arrival of Europeans. Native trees generally leaf out later and drop leaves sooner than non-native species. This enables sunlight to reach the understory of the tree for a longer period, allowing low growing plants to perform better and reduces the risk of frost damage to the tree. Because native trees developed in this region, they are very well suited to our climate, soil types and better equipped to adapt to the hot dry summers that lie ahead. Once established they require much less water than non-native species. For a complete list of native trees for Tennessee, download this PDF from The Agricultural Extension Service at The University of Tennessee.
Why oak trees are valuable
Oak trees are a keystone species, meaning they are trees that entire ecosystems depend on for survival and habitat. Doug Tallamy, professor of entomology at Delaware University and author of the groundbreaking gardening book Bringing Nature Home, noted that over 500 species of Lepidoptera caterpillars (butterflies and moths) are supported by native oaks— more than any other tree species. Insects play a crucial role in the food web, acting as a food source for birds and their young, as well as many other species of animals. Caterpillars are high in protein and soft, thus the perfect food for a baby bird. Baby birds can’t digest seeds at this most critical point of survival. When we look up into the canopy of our oaks, we do not see any damage from the caterpillars. Oaks and caterpillars have co-existed for millions of years.