When farmers give up trying to earn a living from farming or herding, trees simply move in.
当农民放弃靠种田或放牧来维持生计，树木就生长起来了。
2
Then, about 7000 B.C., within the space of a few generations, they switched abruptly to herding domesticated goats and sheep and to growing einkorn, pulses, and other cereal grasses.
"Life is very different in Kenya. People live a poor life here on the grasslands. They can't afford TVs, cars or mobile phones. They make a living mainly by herding cows and sheep." Marco says.