At approximately 1516 hours, stations 37, 12 & 11 were alerted for a tree on fire then upgraded to a structure assignment due to the involvement of a shed. Lt11 arrived and confirmed a working shed fire. Engine-Tanker 12 & Engine 11 arrived together. 12 assumed first due stretching lines as 11 supplied its tank water. Crews quickly contained the fire and Asst 37-1 placed the fire under control.