Largely because of their extremely thick bark that enables them to survive moderate fires, the Douglas Firs are able to live for thousands of years.
(their extremely thick bark; enables; them; to survive moderate fires) (them; to survive; moderate fires) (the Douglas Firs; are; able to live for thousands of years) (the Douglas Firs; to live; for thousands of years)
their extremely thick bark them the Douglas Firs the Douglas Firs
enables to survive are to live
them to survive moderate fires
moderate fires
able to live for thousands of years
for thousands of years