Urban environments depend on maintenance. In intensely used urban settings, the concept of low maintenance is not a practical reality. During the design process, landscape architects must identify the source and capability of that maintenance, and be sure that the maintenance team is informed of specialized requirements and system designs to support the success of the landscape in the long term.
A properly designed landscape should be able to support trees with minimum maintenance. If the tree fails because the level of maintenance available could not provide for its minimum requirements, is the design at fault? Understanding the maintenance capabilities of the client should be a fundamental pre-requisite for informing any successful final design.
Many projects that receive wide acclaim for design success have small armies of maintenance staff who can overcome soil design flaws. When another designer tries to emulate these award-winning projects without the same level of maintenance, plant failure is almost ensured. Sometimes, particularly in cases of poor drainage, the design is simply not maintainable. Design choices do affect the ability to maintain the design and maintenance providers, like designers, must understand soil and tree biology. How soil and trees are treated during maintenance – after the designer considers their job finished – is as crucial as it was during construction.
For example, few people, including landscape maintenance contractors, know that plants look wilted from being either over- or under-watered. Lots of hard work can be undone by overwatering the soil during the first summer after the project is built. Well-developed soil biology can be severely damaged by chemical applications intended to improve plant health. Soil testing, including monitoring of soil biology, should be a regular part of the maintenance process, and soil lab reports should be consulted before deciding on any chemical application. Pruning must be done with the long-term growth goals for the tree and to set up proper branching patterns for the creation of strong branch joints.
While primary designers are rarely part of the ongoing maintenance team, they must set the landscape on an attainable maintenance course and make strong recommendations to influence quality maintenance practices by certified arborists and other providers. This is an essential first step in designing for low-maintenance landscapes that can also thrive in urban environments.
This was adapted from Design Principle 10: Design for Maintenance in “Up By Roots” by James Urban. It is reprinted with permission from its publisher and source, International Society of Arboriculture.
Top image Flickr credit: Mike Smail
Below has no research backing. I have never seen landscape soil biology damaged by properly applied fertilizer or pesticides. Even overapplications have no long term affect on soil biology that I have seen. There are no properly controlled verifications of accuracy or benefits of soil testing for soil biological. On Western woody plant landscapes there is no calibration of chemical soil tests. They are generally useful for pH, soluble salts and B.
“Well-developed soil biology can be severely damaged by chemical applications intended to improve plant health. Soil testing, including monitoring of soil biology, should be a regular part of the maintenance process, and soil lab reports should be consulted before deciding on any chemical application.”
This statement was peer reviewed by a number of scientist during the production of Up By Roots. In one particular conversation I had with with Dr Dan Struve at Ohio State, he reported that when fields are converted from “traditional” agricultural chemical practices to organic farming practices, it generally took about 5 years to restore the soil biology. I know that in our collective science, one can find studies supporting both sides of almost any argument and we often pick studies that support our views. That principle of different outcomes and interpretation is fundamental to good science, and time and the over whelming weight of data generally brings the majority of reasonable people to one conclusion or another. The data on the benefits of reducing chemical applications on soils is in my opinion, convincing that we should reduce chemical applications. The point of the sentence is not to stop adding chemicals but to do so only after proper soil testing shows that a particular chemical is needed and that they are applied in the correct amounts. I would be surprised if you disagreed with the premise that soil testing before application was a good idea.
I would be happy to look over your observations assuming that it is test data with controls. It is absolutely incorrect to say that there are no research backing this statement. There is a considerable amount of work on testing for soil biology. I suggest that you look at the ASLA Sustainable Sites Documents which were widely peer reviewed or talk to T. Fleisher at Battery Park City Conservancy in New York on the benefits of biological soil testing. He is a national leader on this topic and relies heavily on sound science in his work.
Here is an easy to access web literature review paper that has a number of research citations on this topic. This I not a definitive paper but was just one of many that are easily accessible in just a few moment on a web search.
Look at http://www.organiclandcare.org/files/education/pesticides_and_fertilizers/Effects%20of%20some%20synthetic%20fertilizers.pdf
Thank you for your interest.
Jim Urban, FASLA / Urban Trees + Soils
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