By Ann Robinson and Annie Vernon
We’ve mentioned several times that your landscaping can take a beating during remodeling. At best you’ll lose a few flowers and at worst you’ll have to start from scratch. But there is one aspect of your landscaping you should seriously consider and even plan around when remodeling: mature trees.
If you are considering an addition to your home, existing trees should be a factor from the start of the design process. Trees are the most valuable part of your landscaping and the hardest to replace. According to Sunset magazine (where we found many of the tips for this column), homes landscaped with mature trees have values 5 to 20 percent higher than homes without them.
Mature trees add charm to a neighborhood, and homes landscaped with mature trees have values 5 percent to 20 percent higher than homes without them. Mature trees can also lower cooling costs.
Mature trees can also lower cooling costs 10 to 40 percent as they provide shade and help keep homes cool. Mature trees are also a valuable resource to the community. The most desirable neighborhoods often consist of tree-lined streets and tree-filled yards that are beautiful and practical in their shade, cooling and renewal of oxygen.
When working on a home remodel that will impact your trees, there are several things to consider. Building an addition too close to a tree is unwise for the health of the tree and the safety of the structure. If you decide to remove a mature tree, it is usually better to grind out the stump rather than pulling it out with the roots, which can damage the root systems of other nearby trees. You may also consider moving the tree. But this needs to be done carefully and is not a do-it-yourself project if the tree is of any substantial size.
If you plan to keep a mature tree, remember that half of the tree is below the ground, so you must protect the root system. In general, the root system extends to the edge of the leaf canopy. Ideally you should avoid building in this area. If you have to use this area, a maximum of one-third of a healthy tree’s roots can be removed without severely harming the tree.
On a construction site, the leading causes of root damage include:
1. Trenching (usually for utilities) too close to the trunk, which can injure tree roots.
2. Laying solid, non-porous paving under the leaf canopy, which can prevent water and air from reaching the roots.
3. Poor drainage caused by changes in grade, which can smother roots.
4. Soil contamination within the root zone caused by spills of paint, solvents or concrete, which can poison a tree.
5. Soil compaction as a result of heavy equipment or materials, which can damage a tree’s shallow surface roots.
If branches need to be trimmed or the height of the tree needs to be reduced to accommodate your remodeling project, it is best to hire an arborist to do it correctly. You can also protect your tree by propping hay bales against the trunk to keep the bark from being damaged, fencing off the area around the tree and root system, and asking the contractor to use tarps to prevent soil contamination.
Most importantly, make sure you discuss your landscaping with your architect and contractor at the outset of your project. If they are aware of your concerns, you’ll have a better chance of saving your trees. As always, we welcome your home architect design questions at firstname.lastname@example.org.