Can broken glass start wildfires?...

yep. not to mention discarded cigarettes...but that's another story.

 

When you find trash along the roadways, or in areas it shouldnt be, please make an effort to help clean it up (carefully, use gloves if possible!). Broken glass, when sunlight shines through it at certain angles, can ignite fuel near to it, and start a wildfire.   This area is already very dry, and being able to lower the risk for fires to start can be as easy as picking up trash...

http://www.london-fire.gov.uk/GrassFires.asp