Definition: A shallow stretch of a river or stream, where the current is above the average stream velocity and where the water forms small rippled waves as a result. It often consists of a rocky bed of gravels or other small stones.
Definition: Forested peatlands including both rain- and groundwater-fed types, commonly recorded in tropical regions with high rainfall. This type of peatland covers around 350,000 km2, primarily in south-east Asia but also occurring in the Everglades in Florida.
Definition: a plant that produces wood as its structural tissue. Wood is a structural cellular adaptation that allows woody plants to grow from above ground stems year after year, thus making some woody plants the largest and tallest terrestrial plants. Wood is usually primarily composed of xylem cells with cell walls made of cellulose and lignin