About Eucommia ulmoides Oliv.
Eucommia ulmoides Oliv. is a deciduous tree that reaches approximately 15 meters in height. Its leaves are arranged alternately along stems, with a simple ovate shape, an acuminate tip, a serrated margin, and a length between 8 and 16 centimeters. If a leaf is torn crosswise, strands of latex released from its leaf veins solidify into rubber that holds the two torn portions of the leaf together. This species flowers between March and May; its flowers are small, greenish, and not prominent. Fruits develop between June and November, taking the form of a winged samara that holds one seed. These fruits measure 2–3 cm long and 1–2 cm broad, and closely resemble elm samaras in appearance. This tree is occasionally planted in botanical gardens and other gardens across Europe, North America, and other regions worldwide. It draws interest because it is the only rubber-producing tree that tolerates cold temperatures, surviving at least -30 °C. Fossils of other Eucommia species have been recovered from 10- to 35-million-year-old brown coal deposits in central Europe, and are widespread across North America. These fossils show that the Eucommia genus had a far wider geographic distribution in the past. In Chinese herbology, Eucommia ulmoides is counted among the 50 fundamental herbs, where it is known as dùzhòng (Chinese: 杜仲). Due to low production and high demand for natural rubber in China, a unique manufacturing process has been developed to create elastic materials using Eucommia ulmoides gum (EUG) as a substitute for natural rubber products. Unlike the latex used to make natural rubber, EUG is the polymer trans-1,4-polyisoprene. As a result, materials produced from EUG can have different properties than natural rubber, including higher elasticity and a lower thermoplastic temperature.
