VIEWPOINT: Maui has a tree landscape of six continents

In the 1970s on Maui, I remember how unique it seemed to have South American vines climbing up Australian trees. This international mix of flora posed some attraction, but I had to wonder, “Where are the original Hawaiian plants?”

Many folks ask this same question because, the sad truth is, Maui’s landscape is dominated by trees and shrubs from every continent except Antarctica. Australian trees are the most common at various elevations, most of these being invasive and dominating one’s view.

While it might make us feel cosmopolitan to see trees from all over the world, it does beg the larger question: Where are the original native trees and why are they no longer in view during our daily commutes?

Those trees, such as culturally important koa and ohia that sustained the host culture with their many uses, can still be seen in montane natural areas that have not been converted into introduced forests.

The diversity of our native trees and shrubs goes beyond the variety of non-native trees that are naturalizing (spreading) in our wild landscape. But historical large-scale clearing and territorial forestry plantings have shrunk the ranges of our native trees to places that are mostly remote and inaccessible to the general public.

A visit to Haleakala National Park, Waikamoi Preserve or Polipoli State Park can help to invigorate appreciation for our ancient native trees.

Research indicates that some of our largest ohia could be more than 1,000 years old.

Each spring, Upcountry Maui witnesses the annual colorful mix of purple Brazilian jacaranda flowers with orange Australian silk oak. Many of the trees lining the highways were intentionally planted to beautify these drives. But foreign trees have also been escaping from these plantings and tend to dominate in the wildlands, where they have no natural enemies to keep them in check.

While the various banyans and ironwoods may provide shade, they are modifying our natural landscape, even to the point of altering historic landmarks. The famed Iao Needle is now looking like an elk head, with escaped ironwood trees flaring out from its top like antlers. Many ancient Hawaiian archaeological sites have their rocks being shifted by banyan roots spreading them apart.

As tourists take the scenic Hana Highway to rural East Maui, many stop to take photos of the masses of blooming African tulips, despite the fact that most Hana residents consider this tree to be invasive. The most recent alarm in this spread of continental trees is the invasion of Haleakala Crater by pine trees, a prospect that could have devastating impacts on what makes this international biosphere reserve so globally unique. Most of us would prefer to see the moonscape of Haleakala Crater rather than a sea of pines that could easily be found in other parts of the world.

And that is simply the point. Regardless of the cosmopolitan inclusion of trees and shrubs from six of the world’s continents, Maui should be noted as exceptional for its own unique native-forested landscape of trees found only in Hawaii.

* Pat Bily has worked as the invasive plant specialist for The Nature Conservancy’s Maui Program since 1990. He is an active member of the Maui Invasive Species Committee, recently serving three years as chairman.