If you spend any time in the reclaimed lumber world, you will hear the term "old-growth" used frequently — and reverently. Old-growth lumber is one of the primary reasons that reclaimed wood commands premium prices and outperforms modern equivalents. But what exactly makes old-growth different, why is it superior, and how can you identify it? This article explains.
Old-growth refers to trees that grew in virgin forests — forests that had never been commercially logged. In the Eastern US, old-growth forests were largely cleared by the early 1900s. In the Pacific Northwest, significant old-growth logging continued into the 1970s and 1980s before environmental protections were established. The key characteristic of old-growth trees is that they grew slowly and for a very long time: 100 to 500+ years in many cases. This slow growth in mature, dense forest canopy produced wood with dramatically different properties than modern plantation timber.
The most visible difference is grain density. Old-growth wood has extremely tight, even growth rings — typically 15 to 30 or more rings per inch for species like longleaf pine, Douglas fir, and redwood. Modern plantation timber of the same species has 3 to 8 rings per inch. This is because plantation trees grow in open conditions with abundant sunlight, water, and often fertilization, producing fast, wide growth rings. Old-growth trees competed for light in dense canopy, growing slowly and producing narrow, closely spaced rings.
Grain density directly determines wood density, which in turn determines strength, hardness, and durability. A reclaimed old-growth Douglas fir timber with 25 rings per inch can weigh 35-40 pounds per cubic foot, while a modern Doug fir with 6 rings per inch weighs 28-32 pounds per cubic foot. That 20-30% density advantage translates to proportionally higher bending strength, compression strength, and stiffness. In structural applications, old-growth wood provides a meaningful safety margin over modern lumber of the same nominal dimensions.
Hardness follows the same pattern. Old-growth heart pine (longleaf pine) has a Janka hardness of 1,225 lbf — comparable to red oak and suitable for high-traffic flooring. Modern Southern yellow pine from plantation stock has a Janka hardness of only 690 lbf — barely half as hard and prone to denting from foot traffic, dropped objects, and furniture movement. This is why reclaimed heart pine flooring commands premium prices and is sought after by architects and homeowners who want a pine floor that actually holds up to daily life.
Dimensional stability is another significant advantage. Old-growth wood moves less in response to humidity changes than new-growth wood of the same species. This is partly due to higher density (denser wood absorbs and releases moisture more slowly) and partly due to the more uniform cell structure of slow-grown timber. A floor made from old-growth oak will develop fewer gaps and less cupping over seasonal humidity cycles than a floor from plantation oak.
Heartwood percentage is dramatically different between old-growth and new-growth timber. In an old-growth tree that has been growing for 200+ years, the heartwood (the darker, denser, more rot-resistant center of the trunk) comprises 80-90% of the cross-section. In a plantation tree harvested at 25-40 years, heartwood may be only 30-50% of the cross-section. Heartwood contains natural extractives (tannins, resins, and other chemicals) that resist decay and insects. This is why reclaimed old-growth redwood heartwood can last decades outdoors without treatment, while new-growth redwood (which is mostly sapwood) requires protection.
How to identify old-growth wood: count the growth rings. If you can see the end grain, count the rings per inch. Fifteen or more rings per inch strongly suggests old-growth origin. Ten to fifteen rings per inch is transitional. Under ten rings per inch is almost certainly new-growth plantation timber. The rings should be even and consistent — old-growth trees grew at a steady rate in stable forest conditions. New-growth plantation trees show wide variation in ring width from year to year as conditions changed.
Other identification clues: old-growth heartwood is typically darker and more richly colored than new-growth. Old-growth boards tend to be heavier for their size. The grain pattern is tighter and more uniform. In species like Douglas fir, the contrast between early wood and late wood is more pronounced in old-growth. And of course, if the wood is reclaimed from a structure built before 1940, there is a high probability that it is old-growth — virtually all commercial lumber in America was old-growth until the mid-20th century.
Today, old-growth timber is available almost exclusively as reclaimed material. Harvesting old-growth forests is prohibited or severely restricted throughout the United States. This means that the supply of old-growth wood is finite and irreplaceable: what exists in old structures is all there will ever be. As these structures are demolished, the wood is either rescued for reuse or lost to landfills forever. This fundamental scarcity is what makes reclaimed old-growth lumber so valuable — and why companies like LA Lumber are committed to rescuing every board we can.