Stimulation or Simulation?

As a short follow-up from last month’s newsletter… I went to Chicago to visit family and boyhood friends, and you guessed it, there were mom and dad as we got out of the car, clicking off pictures like I was Mayor Daley. My dad loved the guy, you know. It’s good to be home and back to this weather. Can you believe this is summer in Northern Virginia? Sorta makes everything I’ve written the last 2 years a great big lie!

Who cares, it’s been wonderful and our trees will love it for the next year to come.

Fall is upon us and our minds shift quickly to nutrients and elements, both micro and macro. Never mind the micro, we can do those later, but for now the macro elements,

N-P-K. It’s time for fall fertilization! Trees and Shrubs.

Do trees need to be fertilized? In the urban forest some trees do need fertilization. In the natural forest, trees survive in a self-perpetuating system; trees die so others can live. When trees die in the urban forest they can become hazards that must be removed. In essence, we remove organic matter that is critical to a tree’s success. So, all trees need organic matter but not all trees need to be fertilized. We have discussed mulch and its value in the past. It is, I believe, the best way to fertilize because it is so “root zone encompassing”. This is fine when the situation or environment allows. We are in the process of assisting one of our communities in mulching their entire natural buffer strip between houses and street. It is a wonderful project and each and every homeowner deserves applause.

Do we artificially fertilize trees in a natural area? Rarely, but when trees endure the onslaught of our urban wishes, fertilization can be invaluable. When trees are in turf or re-bounding from a construction situation, augmenting nitrogen in the soil can be just what a tree requires. If the soil has been compacted, high-pressure fertilization programs can breakup that soil and assist in stimulating the non-woody roots that absorb those macro elements, Nitrogen, Phosphorus, and Potassium.

The goal of fertilization is to copy or simulate the natural forest floor in which your trees once existed. We try to introduce elements that are most like the one’s found in the natural humus or duff the forest floor provides. Fertilization is not voodoo, magic or hocus-pocus and each tree’s needs should be carefully scrutinized before application begins.

Do your trees need fertilization? There are some things that need review before a decision can be made, but may certainly be an important part of your annual tree maintenance program. I hope you have enjoyed this summer’s weather as much as I have. I feel good for all my plants and look forward to watching the good it brings us next year. Be happy, go out and touch your plants and please call with any questions.

Copyright 2005 by Peter Deahl. All rights reserved.

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