Kauri trees are a group of about 21 species that form the genus Agathis. Native to the South Pacific region, various representatives of the genus occur in Australia, New Zealand, Indonesia, Philippines and New Guinea. The biodiversity of the genus reaches its peak on the island of Borneo, where up to five species may occur in the same area.
Most kauris are large trees, but some are truly massive, with nearly as much volume as the largest redwoods. The largest species within the genus are emergent trees that push through the forest canopy to reach the sunlight above.
Ancient Trees
Kauris are ancient trees, who, along with the other members of the family Araucariaceae, were quite common during the Jurassic Period. However, angiosperms (flowering plants), which began taking center stage in the Cretaceous Period, eventually outcompeted most conifer lineages. Nevertheless, a few members of the family managed to survive the angiosperm onslaught, and retain their role in their native habitats. Many of these continue to serve important roles in their native ecosystems. Currently, most members of the family – including the Kauris – are restricted to the southern hemisphere.
Survival Strategies
Most kauris are residents of lowland rainforests, although a few grow in other habitats, such as cloud forests. To survive in such competitive habitats, kauris have developed a number of important adaptations. For example, many species possess smooth, gray, peeling bark, which helps them to shed parasitic plants and fungi before they can gain a foothold. Additionally, as the trees grow, they jettison their lowest branches, which helps prevent vines from colonizing the limbs, and ultimately stressing the trees.
Kauri trees also engage in chemical warfare with their competitors. The acidic leaves and shed bark alter the soil chemistry near the base of the area. As rain falls on the debris, the nutrients in the soil percolate down to deeper layers of soil, making them unavailable to seedlings that may compete with the kauri tree.
Despite their climax-species-like lifespans, these trees produce seeds like a pioneer species. Many begin producing seeds at a relatively young 50 years of age. Upon reaching maturity, the female cones release the winged seeds, which disperse across the area, buoyed by gentle air currents.
Commercial Use
Historically, kauri conifers were important timber trees, often used in marine applications, courtesy of the wood’s natural resistance to rot. However, timber harvests are greatly restricted in the modern world, and the tree is of lesser commercial importance.
Currently, most of the harvested lumber is ultimately utilized in niche markets. For example, many of the wood’s characteristics – including an attractive grain pattern and very light weight – make it an attractive material for the construction of guitars, flutes, drums and other musical instruments.
California Cultivation
Many kauri conifers are poorly known and unavailable commercially; additionally, many are threatened species, whose future is in doubt. In fact, scientists suspect that only 1,000 or so mature Agathis flavescens exist within the remote Malaysian wilderness. Additionally, as most members of the genus quickly grow into truly massive trees, they are simply inappropriate for most lots.
Nevertheless, a few species are occasionally planted successfully in southern California. While most members of the genus are vulnerable to frost damage and require very warm climates, Queensland kauris (Agathis robusta) are suitable for much of the West Coast. Hardy down to about 20 degrees Fahrenheit, Queensland kauris usually grow to about 80 feet in height, although wild specimens may exceed 150 feet. Additionally, bull kauris (Agathis microstachya), from the Atherton Tableland region of Queensland, may thrive in Southern California.