Abstract: The thermal energy on the earth’s surface mainly comes from the sun. As green plants produce organic matter, it store up energy. A green plant is not only "a factory of organic matter, " but also "a storehouse of energy". According to the law of conservation of energy, the value oi’ stored the energy of a green plant is equal to the thermal energy it releases through combustion. In light of this theory, we measured the calorific values of 104 species of bamboos and timbers (61 species of bamboos and 43 species of timbers) with a caloriemeter. The samples were collected from 17 areas of 10 provinces in China from 1972 to 1978.This paper consists of three parts: the collection and preparation of the samples, the methods of measurements and the results.The results of the measurements show:1. Calorific values differ with various parts of the bamboo, and its age has nothing to do with calorie values. The calorie values stored in different organs of the plant are as follows: culm 4532 cal./g., branch 4719 ca]./g., leaf 4203 cal./g., rhizome and root 4286 cal./g.2. Calorie values also vary with different genera; Phyllostachys 4680 cal./g., Bambusa 4544 cal./g., Sinocalamus 4554 cal./g., Lingnania 4612 cal./g., Indosasa 4640 cal./g., Sinobambusa 4595 cal./g., Arundinaria 4671 cal./g., Scliizostachyum 4478 cal./g., Chimonobambusa 4457 cal./g., and Melocanna 4562 cal./g.3. The amount of thermal energy per unit mass is influenced by the locality where the bamboo grow. Generally, bamboos growing at higher altitudes contain more thermal energy than those growing at lower altitudes.4. The average calorie value of 61 bamboo species is 4603 cal./g. The average calorie value of 43 timber species is 4775 cal./g., conifers being 4949 cal./g. and broadleaved trees being 4750 cal./g.