Distribution: Primarily occurring tropical regions worldwide; many species are found in the Pacific Islands
Genus Size: Just over 40 species
Mechanical Characteristics: Most species are very lightweight and soft (one exemption is A. spectabilis, hard milkwood). Strength properties are low.
Visual Characteristics: Generally golden brown, with heartwood not clearly differentiated from sapwood. Some species have intermittent latex canals which appear as horizontal slits in the wood.
Identification: Wood is diffuse porous, typically with large pores arranged in radial multiples. Parenchyma tends to be in a reticulate pattern with the narrow rays. Bears a close resemblance to Dyera species, also in the Apocynaceae family.
Comments: Despite a worldwide distrubtion, commerical timber from the Alstonia genus comes from two primary sources. The first is pulai (or blackboard tree)—primarily from Southeast Asia. The second source is centered in Africa, and is sometimes called emien, or more often in a commercial setting, cheesewood.