September Visit (9/8/2017)

Early September brought strong winds, which proved too much for some of the oaks in the reserve that had been weakened by fire.  The one below was on the trail just before the actual entrance to the reserve, very near where the new trail access meets the original trailhead at Highway 128.

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Although weakened, this oak had been alive before it fell.  This is post-fire regrowth:

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September Visit (9/29/2016) 2 of 3

It’s oak gall season!  I spotted the leaf below right in the middle of the trail, with galls from two different wasps.  The urchin gall wasp (Antron quercusechinus) makes the spiny pink galls and the crystalline gall wasp (Andricus crystallinus) makes the furry pink galls.  These wasps, in the family Cynipidae, lay their eggs in oak leaves (in this case a blue oak), and the eggs secrete plant hormone mimics which cause the leave to form the spectacular gall.  The larvae grow and feed in the gall for weeks to years, depending on environmental conditions, and then pupate within the gall and emerge as adults.

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Continuing the oak theme, I looked carefully at oak regrowth along Cold Creek.  Interior live oak, an evergreen oak, is generally a more vigorous basal sprouter, as observed below:

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Blue oaks, which are deciduous, generally do not resprout from their bases, but show regrowth in their crowns:

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