A fire and rescue crew from Spalding was called out to a fire in a hollow tree in Station Road, Surfleet.
The alarm was raised at 9.25pm on Monday.
Firefighters used a water backpack to extinguish the blaze. Spalding firefighters were also in action earlier in the day when a skip was on fire in Winsover Road, Spalding. Firefighters used one hose reel jet to put out the fire. The time of call was 1.38pm.
Lincolnshire Fire and Rescue gave no cause for the fires.