Planting a tree too deep is the single biggest mistake that is made when planting. It is also the most common. Soil and/or turf around the trunk of a tree restricts uptake and over time is extremely detrimental. Turf and trees are not truly compatible and a barrier of mulch should ideally separate the two.
The parallel often use to describe the issue is putting a tight rubber band around your arm. While it may not be immediately terminal, it is certainly restrictive and causes stress to the tree. Stressed trees are more susceptible to insects and disease. Soil leveling is a process by which we remove the turf and soil down to the “root crown” or “root flare”. We then replace the material removed with organic matter and/or mulch to provide the tree a more conducive growing environment.