There are eight different kinds of redwood trees that fall into four families, two of those families being conifers and two being broadleaf. The first family of redwood trees that we will cover is the largest family, the Family Cupressaceae. The Family Cupressaceae is populated by conifers and is made up of four distinct trees. The Sequoia sempervirens, also known as the "Coast Redwood;" the Metasequoia glyptostroboides or the "Dawn Redwood;" and the Cryptomeria japonica, which is more commonly called the "Sugi" are all redwood trees in the coniferous Family Cupressaceae. There is a fourth tree in this family. The fourth tree is the Sequoiadendron giganteum, which goes by two different names. It is called both "Giant Sequoia" and "Sierra Redwood."
The second coniferous family of redwood trees is the Family Pinaceae. This family only includes one redwood tree, the Pinus sylvestris. The Pinus sylvestris is called the "Scots Pine." In the timber business, this tree is simply referred to as "redwood."
Now we come to the two broadleaf family of redwood trees, neither of which are as large as the Family Cupressaceae. The Family Fabaceae includes only two redwoods. The Family Sterculiaceae, like the coniferous Family Pinaceae, only includes one redwood. Within the Family Fabaceae are the Caesalpinia sappan, which is also known as the "East Indian Redwood" or "Sapanwood tree," and the Caesalpinia echinata, which is known as both the "South American Redwood" and the "Brazilwood tree." In Europe, the Caesalpinia sappan is also sometimes referred to as "brezel wood." The second broadlead family of trees, the Family Sterculiaceae, includes the Trochetiopsis erythroxylon, which is more commonly known as the St. Helen Redwood.
As you can probably guess by the names, redwood trees are found in many places around the globe. The Brazilwood tree, for example, is native to Brazil. The Giant Sequoia, for another example, grows primarily in California. It is known also as the "Sierra Redwood" because it primarily grows in the western Sierra Nevada mountain range within the state of California. Because the tree is considered to be endangered, it has been cultivated in Europe, Canada, Australia, and New Zealand.
The Sugi tree, however, is native to Japan. Although it is not a member of the cedar family, the Sugi is sometimes called "Japanese Cedar." The Scots Pine can be found in many places around the globe including Ireland, Great Britain, Siberia, and Portugal.