our reporter, kerstin palzer, went to see it and find out more about the challenges local people are kerstin: arstanali matkadirov tells us this forest is unique, his voice tinged with awe as he says it. he lives in the world's largest walnut forest in the south of kyrgyzstan. the ancient forest has grown to cover 30,000 hectareres. 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 r trees. kerstin: a lack of young trees is a fundamentalal problem of te kyrgyz