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plant community was once locally ubiquitous, but is now uncommon as the savannas adjacent to Buckeye Ranch have been deforested since 1963. The oak-buckeye savanna occurs on the northern and western portions of Buckeye Ranch and occupies about 300 acres. Three and perhaps four species of oaks populate the savanna: interior live oak(Quercus wislizenii), valley oak (Q. lobata), and blue oak (Q. douglasii), and possibly a few coast live oaks (Q. agrifolia) . Individual and clusters of buckeye (Aesculus californica) grow by themselves, in groups and also interspersed with oaks. In a 1940 air photo, savanna tree densities are estimated at 5.4 trees per acre, however this pattern in quite variable. In some areas there are large, grassy openings with only one or two trees per acre. Nearby, there may be as many as 10 or eleven trees per acre. Tree density generally increases near lake margins. It is difficult to define an exact boundary between the savanna and the woody lake margin vegetation because savanna species grow to the lakes' edges. The blurred margin is probably due in part to the historic, seasonal nature of the lakes. More typical wetland species such as cottonwood, willow, and buttonbush occur in a narrow, discontinuous band along the lake margin. Many of the trees of the savanna are in poor health, evidently the result of drought and the indirect impacts from grazing such as soil compaction. The understory vegetation consists almost entirely of annual grassland However, the effect of the canopy cover not only provides a cooler environment, it also attracts cattle in the summer months. The immediate understory habitat, therefore, sometimes has a higher populations of broad-leaved forbs. Typically,valley oak woodlands show little recruitment of new individuals. This is also true of the Buckeye Ranch site. The lack of regeneration appears related to a combination Buckeye Ranch Resource Plan (November, 1993) 36