The practice of agriculture for thousands of years in the New Guinea highlands led to significant problems with deforestation in more heavily populated areas. How has the casuarina tree proved to be an important part of their efforts to deal with this problem? What are its advantages?

Casuarina is a genus of tree that contains various species of evergreen shrubs and trees. Some of these species have become very useful in the New Guinea highlands. These trees were first introduced there in the 1950s; since then, the people have continued to grow the plants in an attempt to cultivate landscapes affected by deforestation. The locals also use casuarinas to provide shade and rejuvenate soils for their coffee plants, which are extremely important as they are a valuable source of income.
The advantages of casuarinas are numerous. This is a plant that is resilient to heat, pests, diseases, moderate drought conditions, and low soil fertility. As stated above, casuarinas can repair soil (because they are nitrogen-fixing); additionally, they can stabilize areas susceptible to erosion (dunes or hill slopes) and aid in the remediation of marshy areas affected by increased salinity or waterlogging. Moreover, these plants are good colonizers and able to withstand and actually thrive in areas that are overgrown with invasive grasses, like Imperata, which can cause economic and environmental damage. Ultimately, because of their hardy physiology, which allows them to grow and flourish in unfavorable conditions, casuarinas are good candidates for restoring barren areas like those created by deforestation.