Friday, March 12, 2010


Contributing Writer - Matt Freeman, Intern

The city can be a tough place for a tree. They not only get knocked into repeatedly by car doors and get over pruned to accommodate overhead power lines but they must deal with a long list of other hazards that their country cousins do not.

So before you think of what type of tree to plant you should make yourself aware of what potential dangers your tree might encounter in the location you plant it. By knowing what your tree will be up against you can select the most appropriate tree for that space.

While you are sitting outside enjoying your iced no whip latte here are a few things your trees are putting up with:

  • Restricted root zones – The city is a crowded place and more often than not we do not give trees the space they need to grow healthy and reach their full size. Many urban trees are placed in "tree coffins" which while not a proper technical term accurately describes what happens to trees with too small of a space for their roots to spread - they die.
  • Soil compaction – Walking instead of driving is great but trees located in heavily trafficked areas can get the short end the of the stick. Compaction can cut off water and oxygen to the tree roots.
  • High soil alkalinity from cement leaching – Cement is an amazing building material that has allowed us to make metropolises such as the District but the cement can lead to the soil being too alkaline for some trees.
  • Low soil fertility – Without a forest growing above it can be difficult to replenish the nutrients soil naturally loses over time.
  • Pollution and toxins – With all of the cars driving around the air quality in cities is usually not as nice as it should be. Trees also have to deal with these pollutants in the air and any liquid toxins that may get into their soil.
  • Vandalism – Carving the initials of your loved one into the bark of a tree may seem terribly romantic but it does absolutely nothing for the tree. Cutting into the tree can damage the phloem, xylem and cambium, compromising the tree's ability to transport nutrients and expose it to infections.
  • High winds – Paved roads and steel buildings can serve as wind tunnels making it easier for storms to fall trees if they do not have a strong root structure.
So what trees can not only survive the challenges of city life but flourish. Here is a short list:
  • Thornless Honey Locust –It is a fast growing tree that will be able to mature fast enough to protect itself from the different elements.
  • Littleleaf Linden - Unlike me it is great at tolerating the stresses of living in the city and can grow to fairly impressive size giving off plenty of shade.
  • Ginkgo biloba - Some people dislike it because of how the fruit smell, but if you get them before they fall the fruits have great health benefits. This tree handles the stresses of the city very well and the trees also turn a beautiful bright yellow in the fall.
  • European Hornbeam - It is able to withstand the different hazards and responds well to pruning.
  • Willow Oak - It is tolerant of wet and dry conditions which is good for people who forget to water their plants and then over water them.
  • Nuttall Oak - This tree is good at handling the switch from our hot summers to cool winters. It is also well equipped to handle the alkaline soil from cement leaching.
This is just a short, short list. Click here for a list of trees that we plant and do well in the City.

No comments: