Many people still live by subsistence agriculture, on a small farm. They can only grow enough food to feed the farmer, his family, and his animals. The yield is the amount of food grown on a given amount of land, and it is often low. This is because subsistence farmers are generally less educated, and they have less money to buy equipment. Drought and other problems sometimes cause famines. Where yields are low, deforestation can provide new land to grow more food. This provides more nutrition for the farmer's family, but can be bad for the country and the surrounding environment over many years.