Thanks for the response but I still need a better explanation. Trees consume CO2 and produce oxygen (in the process called photsynthesis); the carbon is used to build the cell walls of a growing tree. Can you tell me how something that doesn’t consume oxygen can be oxygen-starved? Thanks!
The air we breathe is made up of several different gases. Two of those being, oxygen and CO2. It is the ratio of these gases in parts per million (PPM) that determines whether the CO2 is good for us or bad. When CO2 increases in relation to the other gases in the air we breath it creates the problem. The CO2, being a heavier gas, displaces the oxygen — people have been killed because of this. This is only my opinion and I have no scientific background, just an interest in the subject.