I visited the park on my road trip to Truckee in May of 2006 and took these photos. I recently found some cool facts about the park and the trees that I wanted to share.
The higher, drier, and slightly cooler Mojave Desert is where you can find the Joshua trees. The name Joshua tree was given by a group of Mormon settlers who crossed the Mojave Desert in the mid-19th century. The tree's unique shape reminded them of a Biblical story in which Joshua reaches his hands up to the sky in prayer.