There are several theories but the two that seem to stick are that sleep: allows your body to replenish energy stores and repair itself. gives you the chance to save energy. Sleep may also aid learning and give our bodies time to organise all the memories of the hundreds of events we experience every day.
Softwood is also used in the production of paper, and for various types of board such as MDF (medium-density fiberboard). The finer softwoods have many special uses. they are used for making window frames,doors,frames,t.v. stands,flooring and beds.
Wood from all Pinus species is considered a softwood. It is generally fast growing, takes nails well, and is heavily used in construction. Heart pine is a common name for two species of southern yellow pine, the longleaf pine (Pinus palustris) and loblolly pine (P. taeda). Anatomy of a Tree. All wood has an outer sapwood layer and an inner heartwood. The sapwood is the transport system of the tree, moving water and nutrients up from the roots.