Plant assets are long-lived assets used in a company's operations. They include land, buildings, equipment, and natural resources. Land is not depreciated as it has an unlimited useful life. Other plant assets are depreciated over their estimated useful lives using methods like straight-line or units of production. Intangible assets lack physical form and include patents, trademarks, copyrights, and goodwill. They are amortized over their useful lives, except for goodwill which is tested annually for impairment. Long-term assets are reported on the balance sheet net of any accumulated depreciation, depletion or amortization.