I was just playing Uprising again this evening, and I noticed that the plants growing in the outdoor areas looked familiar. After taking a closer look, I found that they're plants native to the Pacific Northwest, where Bungie is headquartered. Take a look and compare the next time you're playing that level:
Sword fern: large plant, small plant
Alder (generic): general shape (these are very large as alder trees go), leaf shape
Western red cedar: general shape, bark
It's fun to see renditions of real Earth plants in the game, and in fact the whole area looks like it could have been lifted straight from the Pacific Northwest coast. It makes me wonder -- were the artists just copying what they saw out the window, or are there story implications here?