Question
We have a large ash tree in our backyard here in SLC, UT.  The diameter is about 3 ft.  We love it!  Anyhow, we are tearing down our house and rebuilding on the same land and do not want to lose the tree.  Right now, our house is about 19 feet away from the tree.  2 questions:  1) What is the best way to make sure we keep the tree?  I'm worried about disturbing the root system...  2) Are we safe to build at least 19 feet away again?
Thank you!

Answer
If I am reading this correct the house that is being torn down is about 19 feet from the tree and the new house will be located the same (19 feet). If so if you need to protect the area under and around the tree. The roots of a tree that have grown over the years near a house will be adapted to this situation and most of the roots will be away from the house. The 19 feet is really inside the critical root zone but should be ok if protected. Ash trees are some what tolerant to root cutting and compaction compared to other species. But this does not mean that you cut roots but keep damage to a very minimum.

You'll save time and money if you develop a landscape protection plan before construction begins. Careful planning will help you avoid the expense and heartache of later repairing or removing trees located too close to construction activities.

Mark construction zone boundaries. Obtain a complete set of site development plans, including the proposed location of buildings, drive-ways, sidewalks, and utility lines. Ask the builder or architect to mark areas where heavy equipment will be used, where soil will be permanently added or removed and to what depth, and where fill and building materials will be temporarily stockpiled. Use a measuring tape, stakes, and string to temporarily mark the boundaries of construction activities on the site.

Develop a map with the builder or architect showing the location of trees to be protected and the safest route for access to the building zone. Then install bright orange polypropylene fencing and post "Off Limits" signs at the root zone of the trees you plan to save. Put up fences and signs around trees you want to save to alert construction workers to damage potential. Your primary objective is to protect delicate root systems, so provide your trees with as much space as possible. Make sure all construction workers know that nothing inside this area is to be raked, cut, stored, or otherwise disturbed. Do not drive any machinery in the root zone. A landscape protection contract signed by the builder and all contractors will help ensure compliance. Take several photographs of the site before construction begins to document the protection methods used and the condition of individual trees.

Visit the site periodically and inspect the trees.  Your presence alerts workers of your concern for the careful treatment of the trees. Should damage occur, begin repairs as soon as possible. Immediately inform the builder of any violations in the landscape protection contract and photograph the damage. Insist that protective fences remain in place until all construction workers have left the site.

Soil compaction is the single largest killer of urban trees. Tree roots need loose soil to grow, obtain oxygen, and absorb water and nutrients. Stockpiled building materials, heavy machinery, and excessive foot traffic all damage soil structure. Lacking good soil aeration, roots suffocate and tree health declines.

Improper handling or disposal of materials used during construction also can harm roots. For example, wood products treated with pentachlorophenol and creosote can be deadly to tree roots; CCA-treated timber (greenish color) is a better alternative. Ask the builder about the materials to be used on the site and read product labels. Chemical spill damage can be prevented by filling gas tanks, cleaning paintbrushes and tools, and repairing mechanical equipment well outside tree root zone. Insist that all building debris and chemical wastes be hauled away for proper disposal, and not burned or buried on the site.

Do not dig or add fill soil to the root zone. Moving large amounts of soil within the root zone usually kills a tree.

Here is a couple of web link to more information with pictures on trees and construction.

http://www.ci.minnetonka.mn.us/public_works/natural_resources/construction_proje...