In California, arson is defined in Title 13, Chapter 1, section 451:
"A person is guilty of arson when he or she willfully and maliciously sets fire to or burns or causes to be burned or who aids, counsels, or procures the burning of, any structure, forest land, or property..."
(d)Arson of property is a felony punishable by imprisonment in the state prison for 16 months, two, or three years.His lawyer will have to argue "willful and malicious", unless he has some other defense
So if you were to purposely burn one blade of grass of your neighbor's yard it is arson?
A bit extreme...
There needs to be some definition of property with a threshold of value. At some point it is meaningless.