Usually said pine or pine has a broad and narrow sense. Generalized pine includes more than 230 species of pines from 10 families of Pinaceae. There are 10 genera in China, more than 90 kinds, all of which are produced.
The 10 genera of Pinaceae are: Pinus, Larix, Pseudolarix, Cedrus, Peseudotsuga, Keteleeria, Picea, Abies , Cathaya, Tsusago. Simplify them as: pine, fall, gold, snow, yellow, oil, cloud, cold, silver, iron. The first 4 genera have the word "松", and the latter 6 genera have the word "杉", which is easy to remember.
It is not a good idea to call the pine tree "pine". Because of Pinusaceae, Taxodiaceae, they are two different families, Familia, which are different families with different morphological and anatomical features. For example, pine roots, stems, branches, leaves, and skin all secrete cell tissue, which can secrete turpentine, but cedar does not. For historical reasons, in order to pass on the historical customary customary title, they were standardized. However, it must be remembered that the pine with the word "cedar" is still pine in nature, so don't look at the meaning of the text, mistaken for the fir.
Narrow sense pine refers only to the trees of Pinus. About 100 species are distributed in the northern hemisphere. There are 22 species in China, which are widely distributed and spread throughout the east, west, north and south. They are extremely important afforestation and timber species.
According to China's current national timber name standards (domestic and imported materials), narrow pine can be divided into two categories: softwood pine and hardwood pine. The air dry density of 0.4 to 0.5 g/cm3 is cork pine, such as Pinuskoriensis and P. sibilisa. The air dry density of 0.5-0.7 g/cm3 is hardwood pine, such as P. massoniana, P. sylvestris. However, natural products are not as soft and hard as people think, but also intermediate types, such as the most common pine sylvestris (P. sylvestrisvar. mongolica) today, which is soft and not hard pine. Some hardwood pine artificial fast-growing materials, due to the annual ring width, large proportion of early wood, and low density, such as Pinus massoniana and P. radiata fast-growing materials, the density is less than 0.5g/cm3. On the contrary, some cork pines have slow growth, narrow annual rings, large proportion of late wood, and increased density. For example, P. kwangtungensis, which is born on alpine rocky mountains, has a density of 0.5 g/cm3 or more.