KESQ: Joshua Tree National Park, in all its natural beauty, is in danger. Park rangers have said to visitors that they have seen more of the iconic Joshua trees dying off than ever before, many of which litter the national park There are many theories into what’s causing it. Still, it remains a mystery. One theory: climate change is causing more fires the Joshua trees can’t recover from. Air pollution from Los Angeles may be another cause. The endangered desert tortoise isn’t …