木材是三大建筑材料之一,不论建筑、交通、工业、农业以及人民生活等都需要大量的木材。木材产自树木,各种树木的构造、性质差异很大,郎使同一树种也有差别。如果拿木材和钢铁水泥比较,有它固有的优点和缺点,在使用时,我们必须掌握它的性能,做到合理利用。木材的尤点是:分布广阔,便于采伐运输;容乃加工结合;“强重比”(强度和重量的比值)较高;绝缘性好,对电热的传导性很小,热胀冷缩不显;天生有各种美丽花纹;通过人工培植,能够源源供应,取之不尽。木材的缺点是:有“吸湿性”,随着湿度变化,尺寸不稳定,干燥时发生开裂翘曲;有“向异性“,它的构造和性质三个方向都不同;有“变异性”,同 Timber is one of the three major building materials that require a great deal of wood, regardless of construction, transportation, industry, agriculture and people’s lives. Wood produced from trees, a variety of tree structure, the nature of the very different, Lang also makes the same tree species are also different. If you take the wood and steel cement, it has its inherent advantages and disadvantages, in use, we must grasp its performance, so that rational use. Timber is characterized by: a wide distribution for easy cutting and transportation; capacity is the combination of processing; “weight ratio” (the ratio of strength and weight) higher; insulation is good, the conduction of electric heat is small, thermal expansion and contraction is not Was born with a variety of beautiful patterns; through artificial cultivation, able to source supply, inexhaustible. The shortcomings of wood are: “hygroscopicity”, with the humidity changes, the size of instability, cracking occurs when dry warp; “anisotropic”, its structure and properties of three different directions; a “variability” with