While, in the Rocky Mountains (shown here), groves of quaking aspen frequently grow relatively undisturbed by humans, in other parts of the country the species is intensively managed for pulp. The fast growing aspen was originally thought to be "useless" because the wood is not appropriate for structural timber. The wood of most aspens begins to degrade from heartrot before it reaches saw-log size, and even that which does not, is generally too weak for most uses. Fortunately the fibers of the tree, although short, can be mixed with pulp from other species to produce high quality book and magazine papers. The demand for pulp, as well as products from the tree such as excelsior (a shredded packing material), and increased use of aspen as flakeboard and paneling, has warranted its commercial production in easily managed stands.