A fire believed to have been started by illegal marijuana farmers is threatening tens of thousands of hectares of bamboo forest in Mount Kenya. It has already destroyed 80 square kilometres of moorland and is now threatening indigenous forests. East Africa is home to the largest natural bamboo forests in Africa. According to the CGIAR (Consultative Group for International Agricultural Research), it accounts for around 3-4% of the world's total known bamboo coverage. The fire, blamed on farmers clearing an area to plant marijuana, threatens one of the five highland areas known as Kenya's "water towers", which feed the rivers and provide three-quarters of the country's freshwater. A second front of the fire threatens 40,000 hectares of bamboo forest and its vital ecosystem.