That is a great offer for people in Tucson who need wood chips---the best mulch there is. And 1-3 cu yds. is not that much. Half a cubic yard will do a new tree 4 feet in diameter and 8" deep (it will rapidly settle to 4" in 2 weeks due to settling and water loss). In PHX it is 20 cu yds, maybe half if you request it and they happen to be in the area. The variable size of the chips helps lock them in. Besides a somewhat pointed shovel the best method of transfer into a wheelbarrel is with a pitchfork. Besides landscapers or arborists who often have to pay to dump in landfills, Tuscon Electric, Tucson and Pima County waste disposal depts. are good places to inquire as well.

Here is a link that might be useful: Wood Chip Mulches

Thanks, there should be plenty of Chilean Mesquite mulch to go around after the monsoon.

Are you supposed to remove the mulch in winter, to let the sun warm the bare soil? (I've just been leaving mine in place.)

You can rake it out in a ring leaving a 4 foot dirt area if you want the roots to warm up faster in the day (or the dirt to warm up for heat storage if you are tossing frost cloth over it later in the day) or leave it in place. If you run drip emitters under the mulch you should rake out and inspect every winter. In some areas it is possible that rodents will overwinter in the mulch so pulling well away from the trunk can be advantageous.

One last caveat: There is actually a playground grade of wood chip mulch safe for playing upon. Mulch with palo verde or mesquite in it may contain cultivars that have enormous spines that will go through work boot soles and should either be inspected before applying or applied to areas not expected to be trafficked.