Question

1. Explain why roots of urban trees typically do not grow as near to the surface as trees roots in a typical landscape soil.

2. Explain why urban tree roots don’t grow as deep as trees roots in a typical landscape soil.

Answer 1

Deep soils deeper roots do occur, but that's infrequent. In the urban landscape related to road, building, structures and utility line construction, soil compaction instead of looseness is more common leading shallower instead of deeper root growth.

The reason woody plants roots grow within the top few feet of soil is primarily that the air required for internal respiration isn't available at greater soil depths. Roots reside plant organs that need oxygen. The deeper into the soil roots goes, the less oxygen is present there. Roots even have evolved to grow near the soil surface because within the wildlife, plant nutrients from decomposing organic matter also are found near the soil surface.