The population of valley oak trees in the Los Vaqueros watershed has been on a noticeable decline in the last century due to farming and cattle raising. Many of the surviving trees are old and diseased. But with the establishment of the Los Vaqueros watershed, the valley oak population is protected and thousands of new trees have been planted.
As the Los Vaqueros Reservoir was filled, 976 valley oak trees were inundated (on 174 acres), as well as 2.8 acres of riparian woodland habitat. The District has implemented an extensive replacement planting and monitoring program. More than 9,000 valley and blue oak seedlings have been planted within the watershed. Local students planted many of those trees.
Within 75 years, these actions will restore existing values of these valley oak habitats, and in subsequent years will exceed these values. A total of 394 acres of valley oak woodland and valley oak savanna have been created or enhanced, a small amount of blue oak woodland habitat has also been created.