Tree of heaven trees (Ailanthus altissima) were imported from China and widely planted in urban environments all over the US because they tolerate poor air and soil conditions, thriving even in mine spoils. Now they're considered invasive. They reproduce both by root suckering and by seed. The trees can grow to 70 feet tall and have a life span of 30-50 years. They have a long taproot and creeping roots that can grow out 50 feet in all directions from the trunk and that sucker freely.

There are several methods to control young trees. Tree roots are extensive and store nutrients, so they can go from a lifeless-looking skeleton in winter to a full leafy plant in summer. When you cut a tree off the stored nutrients allow the tree to send up new shoots. One strategy is to keep cutting down the shoots until the roots have exhausted their nutrients. Mowing frequently does the same thing. Very small trees are relatively easy to pull.

Chemical control will also work, but must be done repeatedly. One good way is to cut off them off at the base and immediately (within 5 minutes) coat the stump with undiluted brush killer (trichlopyr). A paint brush works well. Follow the directions for proper handling on the herbicide container. Using disposable gloves is a good idea. One good thing about trees of heaven is that their seeds are only viable for about a year. Some plants have seeds that remain viable for years.

Young trees produced from either seeds or suckers do not do well in shaded conditions. So keeping the area planted with desirable shrubs and plants can help. Planting with grass and mowing frequently can keep the trees mown down.

This article, IPM Tree of Heavenhttp://wric.ucdavis.edu/information/natural%20areas/wr_A/Ailanthus.pdf has additional information.