There is more carbon dioxide in the air surrounding plants at night and less during the day. Less Carbon dioxide is used during the winter and the level of carbon dioxide rises. In the summer carbon dioxide levels fall.
Human Activity and the carbon cycle
Buring fossil fuels release carbon dioxide,. Burning trees releases locked carbon compounds. Result is that there is a steady increase of level of carbon dioxide in atmosphere. Lined to Global warming as carbon dioxide is a greenhouse gas.
Argicultral use, mining, timber, room for roads and towns. Nitrogen in soil is lost but ash from trees puts back nutrients. Over times amount of crops decline as nutrients removed with crop, and nutrient leaching.