Most tree roots are located in the top 6 to 24 inches of the soil???

Asked November 1, 2013, 3:37 PM EDT

"Most tree roots are located in the top 6 to 24 inches of the soil and occupy an area two to four times the diameter of the tree crown." your quote.
Hmmm, then why do we have tree roots, for the first time, invading a cast iron sewer joint AT LEAST TEN feet below grade?
The house is 40+ years old. That's when they put the sewer in and now, 16' from the front porch, on a sewer that starts below the basement floor and pitches down, do we have tree roots?
Thank you so much, David

Arapahoe County Colorado urban forestry

1 Response

David, I said 'most' not all. Roots are used by trees for structure/support and for nutrients. When we look at nutrients, the roots have to separate the useable minerals from the soil. Rain dilutes the minerals, and the roots pick up the moist mineral soup. This action usually occurs in the top 24" of the soil. That is why most of the roots are in this layer. In dry climates, the roots must go deeper to find the moisture. The roots that have attacked your sewer line where probably structure roots. When they found the nutrients in the line, they sent out feeders to use this new food source. Blessings.