Growing a Forest
The definition of a Forest is a set of domain trees that shares a common schema and Global Catalog (GC) but does not share a common namespace. For example, the root domain of one tree might be Wadeware.net and the root of another tree might be wadewarewidgets.net. The two trees share a common schema and GC as long as the second tree was initially created by joining the Wadeware.net Forest (see Figure 11.5).
Figure 11.5. A Forest consists of two separate domain trees, which share a common schema, GC, and security context. The two trees do not share a common namespace. In the preceding example, Wadeware.net and wadewarewidgets.net are separate trees that are part of the same Forest.
Keeping in mind the definition of a Forest, it is a straightforward process to identify whether you should grow a Forest rather than a domain tree. You grow a Forest if you have a requirement to add a discontiguous namespace and yet you want to maintain a contiguous and continuous security context. If there is no need for a unified security context, it is possible to build new Forests when developing new namespaces. There is no transitive trust security between trees in different Forests.