You can't just huck this into a forest fire but it might be an option worth exploring:

https://www.amazon.com/BioLite-BL-CSA-Wood-Burning-Campstove/dp/B00BQHET9O

Or combine a solar charger with your existing power bank:

https://www.amazon.com/PowerGreen-Folding-Charger-Mobile-Devices/dp/B01E6Q4BY4/ref=sr_1_5?s=sporting-goods&ie=UTF8&qid=1482706443&sr=1-5&keywords=solar+power+bank