he lives in the world's largest walnut forest in the south of kyrgyzstan. forest has grown to cover 30,000 hectares. arstanali's life is closely entwined with nature. >> i've lived off the walnuts since i was a child. that's how we earn our living in the village. the walnut harvest is extremely important for us. it's our main source of income. kerstin: at sunrise the next day, arstanali and his brother ikram take us up into the hills. walnut trees grow at an elevation of 2000 metres above sea level. we're in the foothills of the tian shan mountains. the two brothers are worried. last year's walnut harvest was the worst in living memory. this year is a little better, but a lot of the trees have taken a battering. >> the wind broke off branches everywhere. the trees are so old. we need younger trees. kerstin: a lack of young trees is a fundamental problem of the kyrgyz walnut forest. there are very few around. the villagers here have been harvesting the walnuts for generations. they lease their plots from the state. but those very people also put their herds

. ♪ >> this week on "global 3000," we head toto kyrgyzstan to the largest walnut forest in the world., changes to this unique area are posing challenges for locals. we go to singapore where foreign domestic workers suffer frequent ill-treatment at the hands of their employers. and life is tough for migrant workers in qatar, too. loneliness, homesickness -- is it really worth it? the world is a global village. goods and data move seamlessly between countries.