Nesting sites are hollows greater than deep in tree trunks, limbs, and stumps. His initial designs looked like trunks or boxer shorts. Mature trees range from tall with short trunks and round-topped canopies. The floors were supported by slender iron columns like the trunks of trees. This foot arrangement is good for grasping the limbs and trunks of trees. The nests were placed on strong branches close to the tree trunks. They are very good climbers capable of ascending even vertical, branchless tree trunks. There are mosses that preferentially grow on rocks and tree trunks of various chemistries. She generally selects sheltered places such as dark, hollow tree trunks. Many woodpeckers have the habit of tapping noisily on tree trunks with their beaks. Mature specimens can develop sculptural twisted-bark multiple trunks and a distinctive overall form. Some of the earliest wheels were made from horizontal slices of tree trunks. They feed mainly on insects taken from tree trunks. They have even been observed to charge tree trunks and termite mounds. Some snails estivate in groups on tree trunks, posts, or walls.