With gathering eggs, growing popcorn and learning about the web of life on the agenda, it’s no surprise that this 320-acre overnight camp for kindergarteners through 8th graders is making major efforts to be green. Along with recycling, composting, using CFLs and installing low-flow shower heads, Gwynn Valley serves 70 percent homegrown food from its own farm — including beef — and heats 70 percent of the camp’s hot water with fallen or dead trees found on the property.