Halmaddi is a fragrant binding ingredient which is used in traditional masala incense. It is an earth coloured liquid resin drawn from the "Ailanthus triphysa" tree; as with other resins, it is a viscous semi-liquid when fresh, it hardens to a brittle solid as it evaporates and ages. Some incense makers mix it with honey in order to keep it pliable. Due to crude extraction methods which resulted in trees dying, by the 1990s the Forest Department in India had banned resin extraction; this forced up the price of halmaddi, so its usage in incense making declined. In 2011, extraction was allowed under leasing agreements, which increased in 2013, though production is still sufficiently limited for the resin to sometimes be stolen via improper extraction to be sold on the black market. Other tree resins or gums are also used as a binding agent, such as amber, myrrh, and frankincense, and these will add their distinctive fragrance to the finished incense; some resins, such as gum arabic, may be used where it is desirable for the binding agent to have no fragrance of its own.