Beginning in 2003 in Milton, VT (north of Burlington, Champlain Valley), we measured soil moisture at various depths, and in several locations during the growing season with an Aqua-Pro sensor.  Two locations within a tree root zone, and two in perennial beds were used.  Below are links to graphs of the results for 2003, and discussion of the results.

All locations, 6" depth
front=by spruce, maple=under large sugar maple, wall and back=similar perennial beds in open/no trees

Open perennial beds, all depths.(combined two locations)

Under trees, all depths (combined two locations)

Monthly rainfall.

Discussion of the results