Many years ago when I lived in Chicago, the Silver Maple in front of the house had a cracked limb. I decided to remove the limb and was using a bow saw to cut it off.
These two girls were walking past and remarked, "He's killing the tree."
Little did they know I was saving the tree by removing the cracked limb to keep out insects and disease.
While I was living there I took a mail order course about natural resource conservation (National School of Conservation). It ended with a trip to Eagle River, Wisconsin to the Trees for Tomorrow camp. It might still be there. That was back in the mid 70s.