1. Storms make a tree's roots grow deeper. A rainstorm usually leaves lots of water on the ground, making the soil erode. Therefore, the roots have to grow deeper into the soil. Storms also bring strong winds, which can stimulate the growth of the tree.
2. Most tree roots do not grow more than 12 inches into the soil, but can grow as much as 20 feet deep.
3. Tree roots often extend two to three times the width of the tree's crown.
4. Roots, unlike leaves, do not have green chlorophyll.
5. Roots do not have a central pith (soft central tissue) like the trunk.
6. Roots store more starch than the trunk.
7. Roots anchor the tree, take in water and nutrients from the soil and keep the tree stable.
8. Damaging the roots of a tree causes damage to the branches.
9. An apple tree can have as many as 17 million root hairs.
10. Tap roots (very deep roots) generally do not form on trees in urban landscapes.