Ecology and Silviculture of Betula Species in the Himalayan Region

Abstract

The genus Betula, commonly known as birch, belongs family Betulaceae. There are approximately 50 recognized species of Betula, all of which are essential ecological components of northern temperate and boreal forests in many parts of the world. The extensive stands of this species have originated on northern and southern slopes and ravines of East Asia (Afghanistan, Pakistan, and India) and South China. The species prefers moist sandy loam soil and can tolerate strong winds and high freezing temperatures but not maritime exposure. Betula's forms tree line vegetation at higher elevations on the northern slopes of the inner Himalayas. The birch seeds are shallow orthodox and exhibit intermediate dormancy. Moist chilling in fully imbibed state usually releases dormancy in birch seeds. The germination of birch seeds is regulated by the interaction of photoperiod and temperature. The bark of birchs was used as paper for writing scriptures and texts in Sanskrit and other scripts. Birches contain various chemical compounds which have valuable medicinal uses those compounds are betulin, lupeol, oleanolic acid, acetyloleanolic acid, betulitc acid, lupenone, sitosterol, methyl betulonate, and methyl betulate which are extracted from bark. The compound betulin shows anticancer, anti-inflammatory, antiviral, anti-HIV and hepato protective properties. Traditionally birch bark has been used to cure rheumatism, gout, malaria