Some wetlands are easy to identify. A pond is not land, but it is wet, and so it is a wetland. Sometimes wetlands are defined by their hydrology or soils.
Red maple is one indicator.
To find out whether a particular site is classified as a wetland, you can get help from the Conservation Commission. A representative of the Commission should be able to help you determine which areas are wetlands and advise you on how to proceed. Sometimes the identification of affected land becomes technical. Land that may appear to be dry may, in fact, be in a floodplain. When a peak storm arrives, that land may be under water.