California Penal Code section 451 (arson)

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.
 (a) Arson that causes great bodily injury is a felony
punishable by imprisonment in the state prison for five,
seven, or nine years.
 (b) Arson that causes an inhabited structure or
inhabited property to burn is a felony punishable by
imprisonment in the state prison for three, five, or eight
years.
 (c) Arson of a structure or forest land is a felony
punishable by imprisonment in the state prison for two,
four, or six years.
 (d) Arson of property is a felony punishable by
imprisonment in the state prison for 16 months, two, or
three years.  For purposes of this paragraph, arson of
property does not include one burning or causing to be
burned his or her own personal property unless there is
an intent to defraud or there is injury to another person
or another person's structure, forest land, or property.
 (e) In the case of any person convicted of violating
this section while confined in a state prison, prison road
camp, prison forestry camp, or other prison camp or prison
farm, or while confined in a county jail while serving a
term of imprisonment for a felony or misdemeanor conviction,
any sentence imposed shall be consecutive to the sentence
for which the person was then confined.

In California an individual can face serious jail time for
committing arson. Under the code, a person is guilty of arson
if they willfully or maliciously set fire to or burn or cause
to burn or who aids in the process of one of three things:
a structure
a property
a forested land

If great bodily injury occurs the individual is looking at
5,7,9 years. If it is an inhabited structure or property the
individual is looking at 3,5,8 years.
If it is a structure or forest land the individual is
looking at 2,4,6 years.
If it is property the person is looking at 16 months, 2,3 years.

The prosecution will have to prove beyond a reasonable doubt
that the individual set fire or burned the structure/property
intentionally/on purpose or in a manner that was so reckless
that criminal intent can be inferred (e.g. using gasoline to
start a fire on a wooden floor in a home to burn trash).  The
prosecution will also have to prove that there was damage to
the property from the fire, but more than smoke damage.