Old growth timber is a term we hear on occasion but is rarely defined. For a cabinet maker or timber frame carpenter old growth timber is the ideal medium for strong and stable furniture and framing. But what exactly is old growth timber?
Once upon a time in the forest primeval, eastern white pine and other species of trees grew close together in dense stands of timber. Since light was scarce under the thick canopy of leaves and pine boughs, young trees grew slowly but very straight as they strove to reach the sunlight far above them. Since there wasn’t much light near the ground, trees expended little energy growing branches and leaves low on their trunks. As a result, the trunks weren’t covered with knots and produced clear lumber when milled. White pine was especially straight grained with little wane (i.e. the natural taper to a tree trunk) and ideal for framing, millwork and even furniture.
The slow growth also resulted in growth rings that were very thin, meaning the wood was dense and stable. Much of today’s lumber comes trees that are farmed and grow quickly with lots of sunlight. This is great for the lumber company’s profits since they don’t have to wait 200 years for trees to grow and mature, but results in poor lumber for furniture and millwork. Furthermore, slow growth yields a much higher percentage of fine, mineralized heartwood that is harder and resistant to rot and insects.
In comparison to old growth wood, lumber today isn’t as dense, has crooked grain and is much more liable to twist, warp and decay. The picture below shows a cross section of a white pine sill salvaged from an 1882 depot from Chaksa, MN. This example has up to 20 growth rings per inch and is quite hard and dense. Standard pine harvested today often has 6 to 10 rings per inch (sometimes only 2 or 3!!!) and is far less dense in comparison. Anyone who has sorted through a pile of twisted, wracked and warped lumber at a lumberyard or big box store can appreciate the qualities of old growth timber. It is little wonder that even some the most hastily built furniture and millwork from the 19th century survives with little warping, splitting and decay.
Since virtually all of the old growth timber was harvested in the eastern U.S. and most of the remainder is protected, old growth lumber is now salvaged from buildings during demolitions and remodels. Some is also being recovered from lake and river bottoms where logs sank during the 19th century. Unlike the 19th century, when it was used for the most mundane purposes such as framing and sheathing, old growth is scarce, expensive and reserved for special projects.