Woods Flashcards
There are two basic types of natural wood. What are they?
Hardwoods and softwoods
Softwoods generally come from which type of tree?
Softwoods generally come from **coniferous **evergreen trees.
Hardwoods generally come from which type of tree?
Hardwoods generally come from deciduous broad leafed trees.
List as many popular softwoods as possible.
Softwoods include:
Scots pine, spruce, douglas fir, larch
List as many popular hardwoods as possible.
Hardwoods include:
Oak, ash, walnut, yew, beech, teak, sycamore, willow, cedar and mahogany
Where does 90% of the UK’s softwood come from?
Scandanavia (Norway, Sweden etc)
What is wood grain?
Wood grain is the visual effect of the flow of tracheids (cells mainly of cellulose supported by lignin resin).
What are trees made of?
Approximately 55% of a tree is cellulose, 28% is lignin resin and the rest is carbohydrates, like sugars. Wood can therefore be thought of a natural composite.
In which direction does wood have its greatest strength?
Wood is strongest in the direction of the grain. If wood is put under tension along the grain it will support a greater load than if tension was applied across the grain (this would result in splitting)..
What defects can occur in wood?
Wood defects include:
Knots, splits, twisting, warping
What are knots in wood?
Knots are natural defects caused by the start of the branches from the trunk.
What are splits in wood and how are they created?
Splits are cracks in the wood grain caused by the material drying out or natural events including lightning strikes.
What is warping and how is it caused?
