|MadSci Network: Botany|
Moss needs two main things for growth that it often gets from the surface it grows on, water and anchorage. Plastic is not good at providing either. Most plastics don't hold water well, and they have smooth surfaces that do not provide good anchorage. However, if the environment was very moist and the plastic surface was flat, moss would probably be able to grow on it if provided with adequate mineral nutrients and light. Wood is usually rough and holds water because it has cracks and its dead cells absorb water. Wood used in playground equipment might be treated with preservatives that will prevent moss growth however. Rubber is a natural product from plants. If the rubber was cracked so it provided water and anchorage, it should be able to support moss growth. Some metals are toxic to plant growth, such as copper and zinc. Moss on roof shingles is a common homeowner concern but that is usually wood and asphalt shingles. I think I have seen moss growing on iron railings however. Moss often grows on standing tree trunks. One factor there is the stability of the bark. Some tree barks, such as birch and sycamore, peel off. That would displace the moss every so often. Trees with nonpeeling barks might be better for long term moss growth. I'm not aware of any experiments to test what kinds of wood moss grows best on but you probably can find differences because different mosses have different growth requirements, particularly soil pH. Perhaps you can do some experiments. Mosses are considered pioneer species because they can grow on bare rocks and help form soil. I often see moss growing in sidewalk cracks, even in fairly sunny places. Many mosses are quite resistant to drying out. There are many fascinating websites on mosses you may wish to consult. The study of mosses is called bryology. Scientists who study mosses are called bryologists. References Roof Moss Problems Mosses as pioneer species and indicators Bryophytes The Bryophytes
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