I’m somebody who has food stamps. It’s like a debit card that the government will load with money monthly. You can only use it to purchase food items. If your total bill at the store is $40, $20 of food and $20 of other household goods, then paying with the food stamps card will pay for the $20 of food. You’ll still have to pay the $20 of other goods with your own money.
Maybe it can like store a little energy or water or smth to try to have a better shot at survival?
Edit: after a quick googling, they do this when an animal starts eating their leaves. Trees that have been warned will increase tannin production to toxic levels, making their leaves less than palatable.