Related to this, I still remember reading about how the smell of grass that has been freshly-cut is due to the chemicals released by the grass due to suffering damage. Supposedly, the grass being damaged causes it to release a chemical "distress signal" which draws insects to it such as wasps that can help attack what is "harming" it, as well other insects that can help with sealing off and repairing the damage. What we smell is the tears of billions of blades of grass as it cries out for aid.