Mayanmar, Cambodia, Malaysia, Indonesia, Thailand, South Korea, Philippines Laos, Japan. It is also grown in Western Ghats of Karnataka as the climatic conditions and altitude is similar to the above mentioned areas.
Agar plant prefers high humid, sub-tropical climate with rainfall 1800-3500 mm per annum. It grows from sea level up to 500-m altitudes. It is a sun-loving plant and requires lot of sunshine.
When Agarwood trees are damaged either naturally or artificially, fungus enters the tree. As the fungal infection progresses, the tree produces a dark aromatic resin in response to the attack, which results in a very dense, dark, resin embedded heartwood. The resin embedded wood yields agar oil after distillation that has a unique fragrance and is one of perfumery’s oldest and costliest raw material.
When Agar tree is about seven years old, the trunk of the tree is attacked by fungi which enter the tree through naturally formed holes. As the fungi go about injuring the inside of the tree trunk, the tree offers resistance to it and brings the development of the fungi to a standstill. Due to these chemical reactions inside the tree trunk, a white milky substance called ‘oleoresin’ is produced. Finally, a large quantity of dark brown agarwood is produced on the tree trunk.
About 3 – 6 years are needed for the production of resin wood from the tree that undergoes primary infection. Once the production of aromatic trunk or agarwood is complete, the tree slowly starts drying up signaling its readiness to be harvested.
It is a common practice to damage the agarwood tree trunk artificially to allow fungi to infect the tree and reach the inside of the tree trunk. All the trees can be artificially inoculated to produce Agarwood.