Aspen is a fast-growing tree, widespread throughout Europe, Russia, Kazakhstan, Ukraine, China and Mongolia.
Because of its prevalence and ease of processing (easily sawn, not split, not crushed) aspen is widely used in ancient times to facing Russian baths. Alas, the original blonde aspen boards, under the influence of moisture and high temperatures quickly darkened, distorted and interior sweating-room required complete replacement after 3-5 years (remember how many movies Russian baths are very different from the traditional Finnish sauna a dark color sweating-room).
Modern woodworking technology have greatly improved the performance of the aspen batten and now aspen upholstery sweating-room is able to serve without losing its characteristics seven to ten years (but it's also a little in comparison with exotic wood, such as cedar or aba-shea).
Given the rate of aspen’s growth (annual growth may reach 3 meters), batten from it is one of the cheapest options upholstery sweating-room. However, due to the high percentage of natural defects (rejected 60-70% of boards), panels of heat-treated aspen are more expensive than popular in Europe Scandinavian spruce.
In general, aspen is economical upholstery sweating-room, widespread in the construction of home saunas "own hands", due to its low cost and ease of processing.
By the way, another "unofficial" feature aspen is its ability to absorb the negative energy. They say that something distressed or angered people visited sweating-room, trimmed with aspen batten, calm and filled with optimism. Although, it can be said of any sauna or bath.