On the towering mountains in Tibet are endless stretches of primitive forests. On the northern slopes of the mountains, there is luxuriant growth even though the soil is frozen all year long. The average yield per hectare is one thousand and two hundred cubic meters of dragon spruce and fir, and in some cases even three thousand cubic meters. Some of the trees are over five hundred years old and more than one meter in diameter. The southern slopes of the mountains are the home of larch and some herbal plants, such as saffron and Chinese caterpillar fungus.
