Total U.S. hardwood log exports were down 25% through July despite modest year-on-year increases in Yellow Poplar (Tulipwood) and Birch shipments.

在7月，美国硬木原木出口下降了25%，尽管黄杨木和桦木出口量有所上升。

Betulin and betulinic acid, the triterpenes of the lupane family, are considered to be potential agents against tumoral cancer and HIV .

桦木醇、桦木酸是具有羽扇烷结构的三萜合物，目前的研究发现，它们具有较高的抗肿瘤、抗HIV性，它们的衍生物也有较高的生物性。