Tamarix aphylla (athel tamarisk). No question on the genus but a big maybe on the species. Tamarix ramosissima (salt cedar) is also in the park and is more common. I didn't get a close-in enough picture to see the truly distinguishing characteristics. The shape, however, looks a bit more athel-like.
From Arroyo Salado & the 17 Palms Oasis