Red Cedar -  Western Red Cedar is one of the most popular wood species for log homes. Beautiful color, aromatic, red heartwood, white sapwood, soft (low density, lightweight), low strength, low shrinkage, straight grain, easy to work, resistant to weather decay and insects (good for wet climates), low initial moisture content, non-resinous, and excellent thermal performance. It is relatively easy to stain and moderately expensive. In summary, Red Cedar is a good choice for log homes, although somewhat expensive, because it is naturally resistant to water and insects, looks good, smells good, and is easy to work with. It is a very strong resistant to rotting and decay.
(THUJA PLICATA) This species of cedar is found in the Pacific Northwest, Alaska and Western Canada and it is also called Inland Cedar when found in Idaho and Montana.
The Heartwood of Western Red Cedar is found in a wide variety of colors. It can be dark brown, pinkish brown, or reddish brown. This can all be found in a bundle of Cedar lumber. White streaks can appear in the wood as well. The Sapwood is very White.
Western Red Cedar is one of the few wood species that are naturally at home in the outdoors. It is classified as a durable wood by the building codes across North America, which permits the use of its heartwood in exterior applications without preservative treatments. The heartwood contains extractives that are toxic to decay causing fungi. The two principal extractives that are responsible for the decay resistance are Thujaplicans and water soluble Phenolics. The tress's ability to produce these extractives increase with age making the outer regions of heartwood the most durable.
Western Red Cedar is an excellent thermal insulator. The low density and presence of air spaces make it the best insulator. The low density and presence of air spaces make it the best insulator of any available softwood. Its thermal conductivity factor K is 0.74 BTU inch per square feet and its R value is 1.35 per inch of thickness. These exceptional thermal insulating properties protect  a building from the extremes of heat and cold. Cedar sidings provide far superior thermal protection to alternatives such as concrete, brick and stone.
The open cell structure of Western Red Cedar has demonstrated an ability to absorb and dissipate sound energy. The cell structure converts the sound energy into heat by friction and Viscoelastic resistance. The use of Cedar for walls and ceilings provides a level of sound insulation that will quieten rooms.

Western Larch - Grows chiefly in the drainage of the upper Columbia river. Its natural range extends from Southern British Columbia to the Western Slopes of the Continental divide of Northern Montana and to the Eastern slopes of the Cascade mountains of Oregon.
Western Larch is moderately heavy, strong, moderately hard, moderately high in shock resistance, stiff, and has a moderately high shrinkage, it is moderately decay resistant, slightly resinous, has no distinctive odor or taste. The Heartwood is a dark reddish brown and the Sapwood is a light straw color and very narrow. Western Larch ranks high in the compressive strength department.
Western Larch does not mar, dent or scratch readily. It is a hard softwood, the Heartwood of Western Larch is moderately decay, it is used satisfactory without preservative treatment where the decay hazard is not high.