It comes despite repeated warnings that fires are banned on Shrewsbury Town Council land and perpetrators could face fines and legal action.
The blaze happened at Rea Valley Nature Reserve in Shrewsbury.
A Shropshire Fire and Rescue spokesman said:"At 4.25pm on Thursday, October 27, SFRS Fire Control received a call reporting a fire in Shrewsbury. Small unattended camp fire extinguished using buckets of water and knapsack sprayer.It comes after repeated warnings that fires are banned on Shrewsbury Town Council land and perpetrators could face fines and legal action.
During the summer, the authority warned people not to hold barbecues on multiple occasions. And this month the council said anyone starting illegal bonfires would face prosecution.