Hillside Tree Removal in Pittsburgh, PA

Hillside tree removal is its own kind of job in Pittsburgh. The city sits on the dissected Allegheny Plateau, with elevations from about 710 to 1,370 feet inside city limits, and a lot of homes are built into that relief: houses perched above wooded banks, backyards that drop off behind a wall, and garages at street level with the house two flights up. A tree on a 30-degree bank cannot be felled downhill without the trunk sliding, rolling or launching off the slope, and a crew cannot set ladders or a lift on it the way they would on a lawn.

Why slopes change everything

On flat ground, gravity does part of the work. On a slope it works against you. Logs that hit the ground keep moving. Brush cannot be dragged uphill easily. A dropped piece can bounce into the house below, the wall, the road, or the neighbor's back porch. So most hillside removals are climbed and rigged: each piece is cut, held on a rope, and lowered to a spot where it can stop. Sometimes the wood is winched uphill to the street, sometimes cut small enough to carry up the steps, and sometimes left on the slope in short lengths, laid across the hill, where that makes sense.

Soil, roots and landslides

Pittsburgh's steep hills, clay soils and narrow valleys have produced landslides for a long time. 2018 began as the wettest start to a year on record here, and USGS researchers tracked slope failures across the city from late February through September, ending with heavy rain from the remnants of Tropical Storm Gordon. Trees do not cause slides, but a slope that is moving tilts the trees on it, and a tree with a lifted or cracked root plate on a saturated bank is a real hazard. When we remove trees on a slope we generally leave stumps and roots in place to keep holding soil, and we do not run heavy equipment across a wet bank.

Walls and structures below the tree

A tree growing at the top of a retaining wall puts weight and root pressure on it, and its failure can take part of the wall with it. A tree at the bottom of a slope below a house can drop limbs onto the roof from above eye level. We plan these jobs around what is downhill: where each piece will land, what holds the rope, and where the ground crew stands.

Zoning on steep slopes

Pittsburgh's zoning code includes a steep slope overlay and a Hillside District, in Chapters 905 and 906, aimed mainly at development and grading. Removing a hazardous tree from an existing yard is a different matter from clearing a slope for construction, but if your project involves grading, a new structure or clearing a large wooded area, check with the city's zoning office first. Suburban municipalities in Allegheny County have their own steep-slope rules.

Knotweed, locust and tree of heaven

Wooded Pittsburgh slopes are full of fast, weedy growth: black locust, tree of heaven, Norway maple and Japanese knotweed. Clearing a few trees opens light that these species use quickly. If the goal is a clear view or a usable slope, talk with us about what comes back after the cut and how to keep the bank stable while it does.