Trees produce extensive root systems that spread out and down from the base of the stump. These roots can remain active for long periods of time, causing the stump to produce new shoots with green foliage for several years after you cut down the tree.he exact amount of time it takes a stump to decay varies depending on the species of tree and the conditions in your yard. If you do not want to wait, there are ways you can encourage a stump to break down on your schedule instead of nature's.
1 Materials and installation for a stone retaining wall start around $25-$40 a square face foot and go up depending on materials, site conditions, and other factors. 2  It costs $1,250-$2,000 or more for a wall 30 inches high and 20 feet long.
Retaining Wall Costs. The cost of a retaining wall depends on the material chosen, the overall height of the wall and the length of the wall. Wood retaining walls start at $15 per square foot, while concrete retaining walls start at $20 per square foot.etaining Wall Costs. The cost of a retaining wall depends on the material chosen, the overall height of the wall and the length of the wall. Wood retaining walls start at $15 per square foot, while concrete retaining walls start at $20 per square foot.