How Deep do tree roots grow?

James Urban's 2010 entry on how deep tree roots grow is one of the most popular.There is a need for useful data about this topic.The original post is not as image heavy as we would like.There is a new and improved version of the original post with more pictures and a simplified explanation of how deep tree roots grow.

Three simple factors determine how deep a tree's roots grow.Jim Urban is a noted tree and soil expert.He made a contribution to the post.

Water, oxygen, and soil compaction levels need to be low enough to allow root penetration.The roots can grow to great depths if all these conditions are met.The roots have grown to more than 20 feet (6 meters) deep under ideal soil conditions.

An image of trees with deep roots and root architecture that mimicked the structure of the top tree was presented in early studies of tree roots.The root system for all trees was embedded with the idea of a deeply-rooted tree.The shallow, horizontal root systems of urban trees were found more often in later work.Many tree professionals now believe that deep roots in trees are a myth because urban foresters have spent a lot of energy trying to make people understand that tree roots have a horizontal orientation.There is a truth between deep roots and shallow roots.

The root system was formed on top of the soils.The photo was taken by Miles Barnard.

Jim said that trees are genetically capable of growing deep roots, but root architecture is influenced by soil and climate conditions.

Poor drainage is one of the most common limitations to tree rooting in urban areas.A poorly-draining hard pan is created by a compaction layer.A perched water layer restricts roots.Water tables and hard pans can be found in nature.In clay soils and silty soils, rooting depth is often limited.shallow roots trees are often seen as typical in urban areas.

There are six foot long roots in well-draining soils.There is a remnant of horizontal roots at the trunk flare.The photo was taken by Miles Barnard.

A tree researcher in Sweden studied over 500 trees that had root and utility conflicts.He found roots at depths of 7 to 9 feet and the deepest one was 23 feet.E.L. Stone and P.J. wrote a paper about tree roots.Kalicz summarized previous root depth studies of many genera and species.There are many examples of trees growing roots over 10 meters and one tree that grew roots to a depth of 174 feet.The ability of a tree to grow deep roots is not a significant factor in soil design.

Urban trees need flexible solutions that allow roots to grow out or down because of the unpredictable site constraints.Increasing soil depth is not a problem in some sites.The opposite can also be true.The Silva Cell system is able to respond to different spatial limitations in all three dimensions.

The roots are at least 4 feet deep.The tree fell after the irrigation contractor put a line on the wind side.The photo was taken by James Urban.

The system has a maximum depth of 45 inches.This is a compromise between the system's structural requirements, soil volume, and cost and constructability issues.Because roots will grow to these depths, the Silva Cell was designed to provide a deep soil volume.One- or two-layer systems can provide the same total soil volume across a shallower profile for urban sites where deep excavation is limited.

The ability of roots to grow through the entire soil profile is dependent on two factors: the type of soil that is used and the system to permit adequate water into and to drain out of the soil.The environment in which the Silva Cells are to be placed, the types of soil resources available, and the project performance expectations of trees, soil and water are some of the factors that must be considered when designing these features.

The rooting was done in the soil over the river wash.The photo was taken by James Urban.

Thanks for the article.The situations shown in the photos are major roots, so they are somewhat misleading.I think there are hundreds or thousands of miles of small roots that get left in the ground.How many feet of roots do trees have?

When a tree falls over, many smaller, more delicate roots won't make it out.As an illustration of how deep tree roots will grow under proper conditions, these photos are more useful.I don't know how many cumulative feet of roots trees there are.

As a student in the early 1960s, we never explored the depth of roots, but assumed they were deep.For the last 25 years I have been drilled into the fact that all root systems look like a tip up on a hard pan soil.Science and education are wonderful.

It is true that things change.Too many people are stuck on the old "facts" in the case of how deep tree roots grow.

Excellent article.James Urban has made a name for himself in the tree root world.If species names were attached to the trees in the photos, the article would have been greatly improved.

I have a Norway Maple that is 80 years old.Would anyone know how deep the roots are for this tree?A new water line goes under a tree as I install it.

Is olive trees deep roots or not?A colleague believes that olive trees are deep routed to allow them to grow in dry climates, but my experience has been that they are shallow routed.What is the experts opinion?Thanks.

I don't think I'm an expert on olives because they tend to be shallow roots.I know that roots will grow wherever they can find good conditions.Depending on the planting conditions, trees tend to have certain rooting habits.I can't be more helpful.

Excellent post!Being happy to learn new things about trees.It is amazing how roots can grow so deep.Thanks for sharing!