what is the root system for redwoods and sequoia? - Ask Extension
Hi-
We are thinking about building auxiliary dwelling units on space that we own on the lot next to our house. There are two large trees in the yard....
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what is the root system for redwoods and sequoia? #876518
Asked July 09, 2024, 2:12 PM EDT
Hi-
We are thinking about building auxiliary dwelling units on space that we own on the lot next to our house. There are two large trees in the yard. One is a sequoia and the other a redwood. We are worried that the part of the foundation that will be closest to the trees might impact the roots. We are trying to find out if the root system will come into play when the foundation is constructed. Hoping that you can possibly assist with answering that for us.
Thanks for your help.
Washington County Oregon
Expert Response
Root systems of both redwood and giant sequoia are often very widespread and shallow. You can expect their roots to extend 2 to 4 times the width of their canopy, depending on soil conditions. So the key question is how close to these trees are you thinking of locating the buildings?
The extent to which the roots and the building foundations may impose on each other also depends on your soil type. If the soil is shallow, all of the roots are concentrated in the top layer, so excavation may have greater impact on the overall root system. If the soil is deep, there is more room for roots to grow below the layers impacted by construction.
One way to look at it is to sketch out a plan view of the building footprint and the mature-tree canopy and root zone. See how the percentage of the root zone impacted by the building changes as you move the building farther away. You could consult with an arborist or landscape design professional to evaluate this.
The extent to which the roots and the building foundations may impose on each other also depends on your soil type. If the soil is shallow, all of the roots are concentrated in the top layer, so excavation may have greater impact on the overall root system. If the soil is deep, there is more room for roots to grow below the layers impacted by construction.
One way to look at it is to sketch out a plan view of the building footprint and the mature-tree canopy and root zone. See how the percentage of the root zone impacted by the building changes as you move the building farther away. You could consult with an arborist or landscape design professional to evaluate this.
