Tree of Heaven

Tree of Heaven (Ailanthus altissima) is a ring-porous hardwood cut from a fast-growing deciduous tree native to northern and central China. Widely planted in the 18th and 19th centuries as an ornamental and street tree, it escaped cultivation and is now a notorious invasive across North America, Europe, and Australia. Because it seeds and suckers aggressively, standing timber is common even though it is rarely a deliberate commercial crop.

At a glance the wood is pale cream to tan with a satiny sheen and a bold, open ring-porous grain that reads much like ash or chestnut. On the sample the growth rings are clear and evenly spaced, the color a light straw-to-cream tone throughout.

It is a light-to-medium-weight, moderately soft hardwood that works easily and finishes with a lustrous surface. Historically it saw use in Chinese cabinetry, steamer baskets, and household turnery, and today it is mostly a salvage or hobbyist wood harvested where trees are being cleared.

The wood is pale cream to light tan or yellowish, sometimes with a faint greenish or golden cast when fresh, and there is little visual contrast between heartwood and the paler sapwood. The grain is boldly ring-porous — large earlywood pores concentrated at the start of each growth ring give it an open, ash-like texture — and it carries a distinct satiny to glossy luster on smooth surfaces. On the sample the concentric rings are clear and evenly spaced, producing strong cathedral figure on flatsawn faces.

It is a light-to-medium-density hardwood, typically around 32–36 lb/ft³ dry, with a Janka hardness in the rough neighborhood of 1,300–1,500 lbf — medium by the standards of temperate hardwoods, and noticeably softer and lighter than true ash despite the family resemblance.

Natural durability is low. The heartwood is non-durable and perishable, poorly resistant to decay and insect attack, and unsuited to ground contact or exterior exposure without protection. Fast, wide growth rings can also make some boards prone to movement, so careful drying pays off.

Where it is used at all, Tree of Heaven serves as a light utility and secondary hardwood. Its clean pale color, easy working, and satiny surface suit small furniture, cabinet interiors, drawer parts, boxes, picture frames, and interior millwork. In its native range it has a long history in kitchenware, steamer baskets, and household turnery, and its charcoal and pulp have seen minor use.

The wood turns and carves reasonably well, so it appears in bowls, spindles, and small turned objects, and its ash-like figure makes it an attractive choice for paneling and decorative interior work. It is not a wood for flooring, exterior joinery, or high-wear or structural applications, where its softness and poor durability tell against it.

Tree of Heaven works easily with both hand and machine tools: it cuts, planes, and turns cleanly and takes a bright, satiny surface. The open ring-porous structure means the earlywood pores can tear or fuzz if tools are dull, so sharp edges and light finishing cuts give the crispest results, and open-grain surfaces may want a grain filler for a fully smooth topcoat. It glues, screws, nails, stains, and finishes well.

Caution on handling: the tree is infamous for the foul, rank odor of its leaves and green wood (hence "stinking sumac" and "stink tree"), and freshly cut lumber can carry an unpleasant smell that fades on drying. More importantly, the sap and dust are recognized irritants — contact with sap or heavy exposure to the dust can cause skin, eye, and respiratory irritation and, in sensitive individuals, dermatitis; rare cases of more serious reaction from heavy sap exposure have been reported. Use normal dust protection, ventilation, and gloves when handling green material.

Tree of Heaven is not CITES-listed and carries no conservation concern whatsoever — quite the opposite. It is classified as an invasive species in much of North America, Europe, and Australia, and land managers actively work to remove it, so cutting it is generally encouraged rather than restricted.

As a result it has essentially no commercial timber market. It is not stocked by mainstream lumber dealers and rarely graded or sold as dimensional stock. In practice it is a free or near-free wood obtained through removal, salvage, and hobbyist milling of felled trees. Sustainability and FSC certification are non-issues here: the supply is a byproduct of clearing an aggressive weed tree.