Soft woods grow much faster than hardwoods resulting in a much lighter, less dense piece of wood.
These lightweight woods are typically resinous which allows the wood to light easy and burn hot and fast.
The disadvantage of softwoods is that they don't burn as cleanly as harder woods, and they leave behind a fine ash with little to no coals. Due to the poorer coaling qualities, you will need to add wood more frequently, and they are not suitable for overnight burning because the fire will run out long before the morning.
See our help section on how to make the most out of Hardwoods.