It is fine, he could just ask his dryad waifu to regrow them with his mana as a price.
Although,I think it is possible give them magical stove and heater .He could create those CO detector which is more complex than a stove and heater that just heat up its component .
@Jeirien Passive detection probably requires way less power than active heating. He would probably need some high-grade materials to keep the stoves going for any length of time.
Page 33, that globe ... that's just effing Japan. The top left is Hokkaido, with the southern Sakhalins, and the bottom right is Honshu, Shikoku, and Kyushu. No idea what center left is. Top right might be Okinawa.