|I need to replace a willow tree that was drenched with alot of rain. and went thru a strong wind storm. In 2006 we received alot more rain than usual for Washington, hard to believe I know. Anyway the wind storm blew the 35' willow tree down. I've been told they're a low rooted tree. I would like to find a deep rooted tree to replace the willow tree. It would sit not to far from house. A nice looking, but sturdy tree.|
|I do not know of any source that lists trees categorized by rooting depth. I think the reason for this is that tree rooting depth depends a lot on the nature of the soil. In a deep, sandy soil such as in a river bottom, roots of some trees like oaks can go 10 feet deep. However, in most suburban landscapes, the topsoil may be only a few inches deep, overlaying a dense soil with very high clay content. Even tree species that normally have tap roots will generally be unable to grow roots deeper than 12 to 18 inches in such a soil because there is insufficient oxygen to support root growth deeper than that. This is the basis for the commonly made statement that all trees are shallow rooted.
There are certain tree species that are notorious, however, for producing surface roots that may buckle sidewalks and cause pedestrian tripping hazard. Sweetgum and silver maple (maples in general) are usually at the top of the list. Ash, tuliptree, pin oak, cottonwood, poplar, willow and elm are also commonly mentioned as being shallow rooted. You might check the fourth edition of Arboriculture by Richard Harris ISBN 0-13-088882-6 . In Chapter 10, there is a section on root-pavement conflicts with a table that lists tree species observed to have caused pavement damage and species unlikely to damage pavement. On the latter list you will find Turkish hazelnut (Corylus colurna), red buckeye, black gum, Shumard oak, Regent scholar tree (Sophora japonica) and Redmond linden. All of these can be grown successfully in western Washington.