Overplanting of the same species has come to light recently because of the Emerald Ash Borer and the Japanese Beetle. Both insects devastate trees in their path and only by diversifying what we plant can we fix the problem.
The Tree Monopoly, too much of a good thing
Like a coral reef or a forest floor, diversity plays a key role in how ecosystems work and flow. In nature diversity means a healthy environment, where many kinds of species co-exist in harmony and not one single species overpopulates the given area. In our society today, monocultures have taken over most neighborhoods and urban cityscapes. This can cause problems if a certain species of plant is overplanted then falls victim to a disease or pest. We are experiencing this right now in slow motion as both the Japanese Beetle and the Emerald Ash Borer both descend upon the Omaha area.
The overplanting of Ash, Birch, and Linden species of trees starting over 50 years ago has caught up with us as now bugs that once were contained have had a population boom. These insects have been spreading where food is plentiful, and predators are few and far between. There are very few things that we can do to combat the spread of them more, but the best one is also the easiest. If you are in the market to plant a tree, choose varieties that are uncommonly planted and have unique characteristics. No nursery will sell you an Ash tree anymore, but they still sell birches and lindens as fast as they can grow them. This along with oaks and maples make up a large portion of tree market, which should change sooner rather than later.
Some uncommon tree species that are tough as nails in Nebraska weather, easy to maintain, and have unique character include Ginkgo, Kentucky Coffeetree, Tuliptree, Baldcypress, Sycamore, and new varieties of Elm. All of these trees are few and far between when walking through a park, or driving through a neighborhood. Diverse species need to be planted more, and people need to recognize that diversity is good for an ecosystem. Variety in tree plantings, and the use of native species, will help with future problems that may arise from another species of tree being hit with a disease or pest.