Add an on_burn callback.

game_api.txt

@@ -176,6 +176,14 @@ The farming API allows you to easily register plants and hoes.
 		maxlight = default.LIGHT_MAX           -- Maximum light to grow
 	}
 
+Fire API
+--------
+
+`on_burn(pos)`
+
+ * Called when fire attempts to remove a burning node.
+ * `pos` Position of the burning node.
+
 Screwdriver API
 ---------------
 

mods/fire/init.lua

@@ -235,8 +235,14 @@ else
 				-- remove flammable nodes around flame
 				local p = minetest.find_node_near(p0, 1, {"group:flammable"})
 				if p then
-					minetest.remove_node(p)
+					local node = minetest.get_node(p)
-					nodeupdate(p)
+					local def = minetest.registered_nodes[node.name]
+					if def.on_burn then
+						def.on_burn(p)
+					else 
+						minetest.remove_node(p)
+						nodeupdate(p)
+					end
 				end
 			end
 		end,