This is about equipment for the downstream part of woodland ownership, but it may be useful for anyone who burns wood for hot water.
I used to have a little solar powered digital thermometer with a three meter flex which just about stretched from my loft-mounted hot water tank to my bathroom. It died. Now that I have a large, powerful back-boiler woodstove, I really miss that little gadget. I started Googling round for a replacement, preferably one with at least a 10m flex. Stovesonline.co.uk have a nice one, but £136 is an eye-watering price. There are lots of cheapie ones on EBay, but none with a long flex. And then I discovered the Voltcraft TM-500RF Digital Radio Thermometer from Conrad Electronics. Two days later it arrived and five minutes later I had it working. There's a little sensor which you have to buy separately. I chose the snappily named B & B Thermotechnik Folienfühler; plug one end into the radio transmitter unit and wedge the other end between your tank and the tank's foam insulation; put the display unit anywhere you like in your house, and away you go. Now I can easily tell when the tank's getting cold and I need to visit the log-store. Total price, including delivery from Germany, £50. Not bad, compared to the stovesonline price, for a much more flexible and easily installed piece of kit.