Bonfires are the stuff of life.
From when families had to burn flea-ridden garments etc. to nowadays, when councils charge to carry away garden waste, they are a boon!
As long as the fire doesn't make misery for anyone, like neighbours etc., then shove it all on the flames, use the ash, and get on with your life!
Sterilising soil by burning has been around for ages, it's the cheapest way to get rid of bugs, disease and the rest, so do it and if you just have to say 'save the planet', then get on with it, and don't watch too much BBC.