Alders, for example, happily drop bright-green leaves onto the ground as though there were no tomorrow. Alders, however, usually grow in swampy, nutrient-rich soil and can, apparently, afford the luxury of producing new chlorophyll every year. Fungi and bacteria at the base of the trees recycle the discarded leaves to produce the raw materials the alders need to build chlorophyll, and all the trees need to do is take these building blocks up through their roots. They don’t even have to worry about recycling nitrogen, thanks to the symbiotic relationship they have with bacteria in nodules on
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