Sassafras is an aromatic hardwood native to eastern North America, known for its distinctive spicy scent, often likened to root beer, which is most noticeable when the wood is freshly cut. The wood is relatively lightweight and possesses a straight grain, making it a popular choice for furniture, cabinetry, and decorative items. Its workability also leads to its use in utility applications like fence posts and small boats. The suitability of Sassafras for outdoor projects depends on its natural resistance to decay, which varies depending on the part of the wood used.
Durability Classification of Sassafras Wood
The question of rot resistance in Sassafras wood depends on which part of the tree is used. The inner core, known as the heartwood, is classified by the United States Forest Service as durable to very durable against decay. This high rating places it in the top tier of domestic species for natural rot resistance.
In contrast, the outer layer of the tree, or the sapwood, offers almost no natural protection against decay fungi. Like the sapwood of most wood species, Sassafras sapwood is considered non-resistant or perishable when exposed to conditions that promote rot. Therefore, for long-lasting exterior use, lumber must be milled exclusively from the heartwood section of the tree.
Natural Compounds Providing Resistance
The heartwood’s natural defense against decay is due to fungitoxic compounds called extractives. As the tree grows, non-living sapwood cells convert to heartwood, depositing these compounds into the cell walls. These extractives are the source of the wood’s spicy aroma, which comes from aromatic oil cells.
These natural chemicals inhibit the growth of wood-destroying fungi and deter common wood-boring insects. The presence of these compounds makes the heartwood durable, even though the wood itself is comparatively soft and lightweight. This internal chemical protection allows the heartwood to resist the effects of continuous moisture exposure.
Performance Compared to Alternatives
Sassafras heartwood’s durability compares favorably to other popular outdoor woods, but it is not the most resistant option available. It is superior to the low resistance of untreated pine and common hardwoods like ash or maple. Its resistance is often grouped with other durable species like Black Walnut, Catalpa, and Western Red Cedar heartwood.
It is less durable than the highest-rated woods, such as old-growth redwood or tropical hardwoods like Ipe and Teak. For projects that do not involve ground contact, Sassafras offers good dimensional stability, resisting warping and checking when moisture fluctuates. While pressure-treated pine is chemically enhanced for longevity, Sassafras is a naturally resistant, non-toxic alternative that falls into a similar durability class as cedar heartwood.
Maximizing Sassafras Wood Lifespan
To ensure longevity in outdoor applications, several protective measures should support the wood’s natural resistance. Good ventilation is necessary to allow the wood to dry quickly after rain or high humidity, preventing the conditions fungi need to thrive. Preventing moisture accumulation is the most effective way to extend the lifespan of any wood species.
Applying a high-quality exterior finish, such as a penetrating oil or water repellent preservative, protects the surface from moisture and UV damage. These finishes soak into the wood rather than forming a surface film that can peel, simplifying maintenance. When fastening Sassafras, use corrosion-resistant materials like stainless steel or hot-dipped galvanized fasteners. Standard steel fasteners can react with the wood’s natural extractives and moisture, leading to dark stains and accelerated decay around contact points.