Protecting Land Development

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Site Productivity
Undisturbed land has a natural capacity to support living systems. This capacity to support life is known as productivity, and it depends directly on the health of the soil.

Land development causes two major, long term impediments to productivity. First, large portions of land are eliminated permanently from productivity by paving and building over them. Second, land development activities (grading, installation of utilities, paving, changing natural drainage patterns) permanently damage the soil. Frequently, the land resources are so degraded that an extraordinary amount of operating expense (water, fertilizer, maintenance, and replacement) must be budgeted annually just so the installed landscape will survive. It seems ridiculous that such a significant expense is also one that could be avoided or at least minimized, with careful planning.

In the short view, the quickest, easiest, and "most economical" way to develop land is to clear away the vegetation, grade the site, utilize engineered systems to satisfy storm water regulations, and build to suit. These activities cause soil erosion, loss of topsoil and organic matter, compaction of the remaining poorer lower soil layers, and sometimes chemical pollution. The end result is the permanent degradation of the soil (and therefore, the site). The short view (that "quick and easy" equates to "more economical" development) ignores the very real long term expense of site degradation.

With planning and effort, developers can take steps to minimize soil degradation and protect the productivity of a site. In the long term, the effort will pay for itself in reduced costs of landscape maintenance. In the short term, it adds significant value to the final product, particularly if there are nice existing trees that can be left undisturbed. It takes a strong desire and unwavering diligence to design and execute the project so that the land is disturbed as little as possible. There are so many different people and activities involved in land development, and it only takes one equipment operator to undo all the planning and work that has gone into preserving a nice stand of trees.

The major obstacles to conserving site productivity are 1) how to reconcile the topography with storm water management regulations, and 2) how to maximize the economic return on the investment. There are tradeoffs at every turn. Conserving productivity is not easy, but it is often possible, and profitable. Developers must face the difficult choices from a long term perspective.

Assess the Site
The first step in conserving natural resources is to know what is there. Some sites have much more to work with than others. Just having a "wooded site" could mean anything, from high quality bottomland hardwoods to overcrowded, poor quality pines, sweetgums or cedars. An accurate assessment is critical to successful protection of site productivity. Trees, indicator species, soils, and drainage patterns should be assessed and evaluated. Important features (areas of productive soils, groups of significant trees, and drainage patterns) should be delineated on the plat. land development issues can then be reconciled with natural resource conservation issues during the conceptual design phase of the project.

Which site has higher value if the land (and trees) are successfully protected?

Isolate and Protect
Undisturbed land has a natural capacity to support living systems. This capacity to support life is known as productivity, and it depends directly on the health of the soil. If there are trees worth protecting on the site, the entire process hinges on protecting the soil where they are growing. It is as simple as that - protect the land and the trees will take care of themselves.

Usually it is most effective to protect trees in groups or stands. Once the stands are identified, they should be isolated from all land development activities on the site. The goal is to keep the soil completely undisturbed. Generally a barrier is erected at the perimeter of the area encircling the protected stand. This barrier could be orange plastic construction fencing or something as substantial as a chain link fence (for high-value stands or individual trees). Contractors should be made aware of all tree/soil protection zones, and construction contracts should contain penalties for violating these non-disturbance areas. Adding a 2 inch layer of mulch inside the barrier, such as composted or even fresh wood chips, is a cheap and effective way to promote tree health and longevity. Severing the roots around the perimeter with a trencher or cable plow can help prevent or minimize damage to the root systems from clearing and grading operations and chemical spills.

Follow Through
To do the job right, it is critical that everyone who steps onto the site is aware of the tree protection measures. Because of the number of contractors and subcontractors and utilities involved in a typical project, this presents a considerable challenge. It is often accomplished by utilizing several overlapping strategies: dissemination of the message through the primary contractors, signage, verbal reminders, and frequent site checks.

During the summer, supplemental watering can provide substantial benefits in tree/soil protection zones. A simple soaker hose trickling slowly for several hours once a week during dry periods would be a typical low cost, high impact measure. Periodically, look over the tree/soil protection zone for violations, and check the trees for signs of stress or insect infestation. Remember to stay updated on any drought conditions that may exist and take care to adhere to any water restrictions that may be in place.

Although the trunk scrape looks bad, the real damage to this tree occurred underground, before the mulch was spread to help mitigate it.