The city of Mt. Lebanon, Pa., has a verdant landscape of tree-lined streets. But lush growth on top means deep root growth below the soil, and older clay sewer lines are coming under attack. A consistent and assertive program of annual chemical foam root-control treatments over the past decade has helped the city tame its root problem to manageable proportions, as the worst lines are repaired and replaced. As a smaller community (population 33,000), the city finds that farming out the service to specialized contractors helps keep it affordable and on budget.Attacking the culpritIn 1850, the Rev. Joseph Clokey imported
