Book Excerpt: 'Intelligent Tinkering' By Robert Cabin
The Hawaiians loved these forests and often chose to live in or near them. Because of the hot, dry climate, many of the trees grew extremely slowly and produced some of the world's hardest woods, which the Hawaiians fashioned into buildings, tools, weapons, and musical instruments. They also made exquisite multicolored capes and helmets containing hundreds of thousands of bird feathers and strung elaborate leis using vines and sweet-smelling flowers.
The first time I walked through a patch of native dry forest containing a grove of alahe'e trees in full bloom (Psydrax odorata, a member of the Coffee family), I told my native Hawaiian colleague that the light fragrance of these small white flowers seemed to creep mysteriously in and out of my nostrils. He smiled and explained that the Hawaiian word alahe'e literally means "to move through the forest like an octopus."
Today we can only imagine what these complex ecosystems looked like and guess at how they worked. Tragically, more than 90 percent of Hawai'i's original dry forests have been destroyed, and many of their most ecologically important species are actually or functionally extinct. For example, most of the native birds and insects that once performed such critical services as flower pollination and seed scarification and dispersal are now gone. Many of the once dominant and culturally important canopy trees are also extinct or exist in only a few small populations of scattered and senescent individuals.
The demise of Hawai'i's dry forests began soon after the Polynesian discovery of these islands around AD 400. Like indigenous people throughout the tropics, these early Hawaiians cleared and burned the dry coastal forests and converted them into cultivated grasslands, agricultural plantations, and thickly settled villages. In 1778, Captain James Cook became the first white man to reach Hawai'i when he accidentally discovered the archipelago while searching for a northwest passage between England and the Orient. Cook's arrival set in motion a chain of events that dramatically accelerated the scope and intensity of habitat destruction and species extinctions throughout the Hawaiian Islands. While the Polynesians had deliberately brought many new species to Hawai'i in their double-hulled sailing canoes (and some stowaways, such as the Polynesian rat, geckos, skinks, and various weeds), their impact was trivial compared with that of the ecological bombs dropped by the Europeans. Thinking the islands deprived of some of God's most useful and important species, Cook and his successors, with the best of intentions, set free cows, sheep, deer, goats, horses, and pigs. Over time, foreigners from around the world unleashed a veritable Pandora's box of ecological wrecking machines, including two more rat species, mongooses (in an infamously ill-advised attempt to control the rats), mosquitoes, ants, and a diverse collection of noxious weeds such as fountain grass.
During relatively rainy periods, when fountain grass greens up and is in full bloom, large sections of the leeward side of the Big Island can look like a lush midwestern prairie. But inevitably the merciless Kona sunshine returns, and the rains disappear for months on end. All that fountain grass dries up and changes from bright green to sickly brown, and the whole landscape looks as if it had been sprayed with Agent Orange. Then all it takes for the whole region to burst into flame like a barn full of dry hay is for somebody to park a hot car on a clump of fountain grass or throw a cigarette out the window.
In contrast to most Hawaiian species, fountain grass originated in an ecosystem (North African savannas) that regularly burned, and consequently it has had thousands of years to evolve mechanisms to cope with and even exploit large-scale fires. I have watched fountain grass rise up from its ashes like a smiling green phoenix after seemingly devastating wildfires: vigorous new shoots quickly appear within the old, burned clumps; seeds germinate en masse; and the emerging seedlings rapidly establish themselves in the favorable postfire environment of increased light and nutrients and decreased plant competition.
The net result of these fires is more fountain grass and less native dry forest. More grass means that during ensuing droughts there will be even greater fuel loads, which in turn will lead to more frequent and widespread fires. This cycle of alien grass, fire, more alien grass, more fire has proven to be the nail in the coffin for dry forests on the Big Island and throughout the tropics as a whole. The reason we don't hear about campaigns to save tropical dry forests is that there are now virtually no such forests left to save. If we want at least some semblances of this ecosystem to exist in the future, we'll have to deliberately and painstakingly design, plant, grow, and care for them ourselves.
As I approached the dead trees, I was hot and felt frustrated because I had never seen this forest before it burned. Yet, in a bittersweet way, I was also glad I had not, because even with no personal connection to this place, I found the sight of those scorched trees almost unbearably depressing. This had apparently been one of the best native dry forest remnants left in the entire state, but we would never know which species had lived here or even what the canopy tree, shrub, and understory layers had looked like. We would never be able to collect seeds or cuttings from the gnarled old trees, which had thrived here against all odds for hundreds of years but now were on the very edge of extinction. One more irreplaceable piece of the mysterious Hawaiian dry forest ecosystem puzzle was gone forever, leaving behind only some tantalizing clues in the fading memories of the few remaining people who had seen these trees alive.