Trust properties totalling 1,148 acres (465 hectares) lie on the Oak Ridges Moraine. The hardwood and mixed forests of the 161-acre (65-hectare) Bullen property lie adjacent to the Ganaraska Forest, a significant natural area on the Moraine. The property was donated in 1980 by Robert and Dorothy Bullen.

Perched on the "shoulders" of the Oak Ridges Moraine, the Fleetwood Creek Natural Area protects the forests and swamps in the headwaters of Fleetwood Creek. This 910-acre (365-hectare) site – home to 268 species of flora and 44 species of breeding birds – was purchased by the Trust with the help of the Pangnam family in the mid-1980s. The Kawartha Region Conservation and the Trust work in partnership to preserve the property.

The 173-acre (70-hectare) Walker property, donated in 1978 by Mr. and Mrs. James Walker, is located near Uxbridge and is linked to the Glen Major Forests, owned by the Toronto and Region Conservation. This natural area forms part of the headwaters of Duffin Creek.

Sheppard's Bush and the Smith property lie within the Town of Aurora. The forests at Sheppard's Bush were donated in 1972 by E. Reginald Sheppard. The Smith property was donated in 1992 by the late Anne Bartley Smith.

The Wright and Blair properties fall within the Humber River watershed. Both are small but play an important role in conserving the headwaters of the Humber River. The Wright property, one of the early natural heritage acquisitions of the Trust, was donated by Justice Peter Wright in 1970. The Blair property was donated by Sydney M. Blair in 1981.