In California, used and unsold Christmas trees are being recycled by being thrown into lakes to create reefs and fish habitats in otherwise barren lake beds. For over 20 years, trees have been dumped in Quarry Lakes to help create a habitat for the declining fish populations. It is now being done at Carlyle Lake in southern Illinois as well as Lake Havasu in Arizona, using biodegradable sandbags as weights so that everything is biodegradable and helps the fish population over time.
“If you imagine a lake bottom that has no vegetation, is really bare, it’s kind of two dimensional. And by putting these reefs in, you create a kind of three-dimensional habitat for fish,” Joseph Sullivan, the fisheries program manager at East Bay Regional Park District in Oakland, California, told The Verge. “You’re essentially creating a whole ecosystem there.”