Crown lifting is the process of removing the lower branches on a tree. This allows for a higher clearance from the ground, a building, or road/driveway.
Crown thinning is the process of systematically removing branches throughout the canopy to create a thinner appearance. This reduces wind surface area thereby reducing the stress on the tree during high winds. It can also allow more light to penetrate through the tree brightening up the area. We usually do this by climbing in through the canopy.