Bennett Valley

Bennett Valley is a northwest- to southeast-trending valley in Sonoma County, California, US, approximately 1 mile (1.6 km) wide in its northwestern portion, where the southeast extremity of Santa Rosa, California is located. The axis of the valley floor slopes 40 feet (12 m) per mile (a gradient of 0.008 or 7.6 m per km) from the pinched central portion of the valley, where knolls divide the northwestern from the southeastern segment of the valley. Bennett Valley is drained by Matanzas Creek which is incised into the valley floor; an unnamed stream and Spring Creek drain into Matanzas Creek from the east side of Bennett Valley below the Matanzas Creek Reservoir. A flood-control reservoir on Matanzas Creek in the central portion of the valley collects water from the drainage of the upper portion of the valley. Precipitation in the valley varies from approximately 35 to 40 inches (90 to 100 cm) per year. The latter amount falls on Taylor Mountain, located immediately above Bennett Valley, in an outlier spur of the Sonoma Mountains sometimes called the Los Gullicos Range. Rainfall occurs primarily during winters (November to April), separated by warm dry summers. Bennett Valley is accessed chiefly via Bennett Valley Road, which traverses the valley floor to connect southeast Santa Rosa with Warm Springs Road in Glen Ellen.

Both the upper southwest and northeast sideslopes of Bennett Valley have significant oak woodland. Both forested areas have dominant trees that include coast live oak. On the lower slopes and northern valley floor there are considerable numbers of valley oak in relict stands, from a previous dominant cover of these lower elevations prior to agricultural development of the valley floor. According to the 1990 report of Earth Metrics, a large percentage of valley oaks near Bennett Valley Road at the northwest end of Bennett Valley were infested with oak apple gall.Gall wasps of the family Cynipidae produce a single sexual generation within a structure that resembles an apple. Some valley oaks on the site are infested with these "fruits," and on first glance appear as apple trees. This infestation is considered mild, and should not affect the oaks' ability to survive. Some valley oaks in this area were also noticeably infested with dwarf mistletoe in the 1990 survey. This facultative epiphytic parasite can lead to the detriment of oak trees if allowed to persist and spread among trees

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