There is a great product on the market from a company called Wood Stove Pools. It is a completely stainless steel wood stove pool heater. The main reason it is stainless steel is because of the chemicals used in pools. Chlorine and slat water will corrode mild steel.
A wood-burning pool heater is just a wood-burning water heater. That said, there are a number of different makers out there. Use the link below and begin looking at the different ones. Feel free to refine your search if you wish.
form_title= Pool Heater form_header= Stay warm and swim with a pool heater! What is your budget for a pool heater?*= _  What type of pool do you have?*= () Salt Water () Chlorine What is the size of your pool?*= _ 
What i s the best pool heater
The heater will not operate if the pump is not on.
directions for closing above ground pool with heater
Do you mean a pool that has a salt water generator? If so, any pool heater could be used.
it depends if you have a pool heater
no you need a stronger heater specifically designed for a swimming pool
locate pool in sunny area, use a solar water heater, solar pool cover, pool heater or enclosed sun room
Recommend 400,000 BTU heater
Start with a "maxtemp pool heater" search.