Pain in the Grass

The smell of a fresh cut lawn is the spoor of pain -- the silent scream of a living thing hacked by a spinning blade as poisonous gases are spewed on it from above.

Or, to put it another way, the scent of of a new cut law is the smell of volatile organic compounds called green leaf volatiles (GLVs) which are emitted when a plant is injured.  It is, quite literally, the pain in the grass.