Just read, "Whole Tree Construction Creates Unique Interiors" in Farm Show, Vol 34, No 5, 2010. The company Whole
Trees Architecture uses who trees for structural components, as well as interior decorating, and they say it competes with steel and
concrete. "Whole trees are 50% stronger in axial loading and bending than milled lumber of comparable size. Milling, they found, removes the strongest and outermost layers of the tree that are pretensioned and resist wind shear." When trees are chosen, they are girdles, bark-peeled, and allowed to dry in place for 6 months+. By then it will lose up to 50% of its weight in
water.
Trees lost to insect infestation are just fine to use--it doesn't matter how the tree dies, just how long it has rotted since it died.
This is also cool because when people clear trees in order to build a house in a wooded area, they can use the very trees they cut down.