Standardized gum tapping techniques to maximize yield from high-value Indian tree, Sterculia urens

Industrial applications of natural gums have been expanding tremendously, so gum collection from trees provides an important livelihood for local dwellers in drought-prone Rajasthan and its surroundings states. Traditional gum tapping is crude and unscientific; deep incision, untimely extraction and high concentration of chemicals in gum have affected Sterculia urens species in its natural habitat. In studies 2 years on trees having diameter at breast height >40 cm from natural stands to maximize gum collection and standardize the tapping method (bore holes vs. V blazes), tapping season, chemical and concentration, different tapping techniques were tested. For tapping maximum gum was collected using bore hole. Ethephon was better as extraction chemical than sulphuric acid. Bore-hole tapping with a 5-cm hole and ethephon at 300 mg/mL yielded the most gum (135.20 g/tree). Ethephon at 300 mg/mL yielded the most gum. Ethephon induced gummosis without affecting the health of tree. Tapping seasons also significantly affected the gum yield; the most gum was obtained in April–June.