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，美国出口下降了25%，尽管黄杨和桦出口量同比有所升。

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

桦醇、桦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病毒活性，它们的衍生物也有较高的生物活性。