Cutting the incense trees reveals the white sap (Arabic luban) which drips to the ground where it crystallizes. Harvesting of the incense crystals takes place two weeks after the cuts. How many harvests and how often the cuts are made has been only studied recently (Morris 1992). Other questions which arise include who owns the trees and how extensive were the groves in antiquity compared to their present distribution. Modern day production figures from Southern Arabia and northern Somalia suggest each region produces 2500 annual tons.