The
roots of the Gambel oak are very important to the tree and the surrounding
plant communities. The roots contain lignotubules and rhizomes which help
regenerate new trees. Gambel oak regeneration is more dependent on roots
than on seed. They also hold the soil in place reducing erosion. If the
soil were to erode many plants could not grow in areas where soil erosion
would normally occur including the Gambel oak. The roots of the Gambel oak
keep soil in place and allow the plant communities to thrive in City Creek
Canyon. 
Gambel
oak is fire tolerant. Low grade fires can leave openings in the soil for
new tree sprouts to grow from the roots of the old trees. High grade fires
will top-kill the stands. Successive fires are most harmful to the oak,
especially when carbohydrate
reserves are low.
Fire stimulates the
buds on rhizomes found on the roots which produce new sprouts after fire.
These are found between 4 and 20 inches below ground so only severe fires
can harm them. Oaks recover from fire more quickly on south-facing slopes
at low elevations.
Here is a picture of an oak stand two years after a fire. The fire killed all that was above ground, but sprouts were produced by the lignotubers and rhizomes.