Thursday, December 25, 2008
Fifteen years ago, when a new monthly community paper called Ka'u Landing had just been launched, I helped get it started with a series of articles entitled "Koa: the Struggle for a Forest." At that time, one biologist estimated that only about 15 percent of the islands' original koa forests were still viable as forests. The percentage today is even smaller. I was reminded of that fact last weekend, when I went up with a Sierra Club group to spend a couple of nights at Keanakolu Ranger Cabin on the Mana Road, a public 4WD trail that hangs like a necklace on the windward slopes of Mauna Kea. Most of the land that the Mana Road runs through is officially range land. But it is also a vast koa graveyard: a landscape where a few twisted ancient koa survivors still stand among thousands of rotting fallen trunks.
Koa, for those who don't know, is one of Hawai'i's three major native overstory trees: the big trees that overshadow everything else in the forest and form the backbone of forest ecologies. 'Ohi'a, the most common, tend to dominate the lower-elevation forests and the areas where lava flows are still relatively fresh; Koa prevail in the deep ash soils such as those on the slopes of Mauna Kea at mid-altitude (although some grow at sea level), while the much smaller mamane are the mainstay of the high elevation drylands forest.
Koa, in my opinion, are the most magnificent and unusual of the three. They start out life with delicate, locust-like compound leaves, and later grow large, sickle-shaped "leaves" that technically aren't leaves at all; they evolve out of petioles, the little stems that connect leaves to branches, which in mature Koa elongate and flatten to take over the normal leaf's chlorophyll-making function. But the trunks themselves also undergo a metamorphosis, albeit a slower one. In a healthy forest, young koa sprout from seeds or tree roots wherever sunlight strikes bare soil--a mechanism that evolved so that the forest could replace itself whenever an old tree fell, opening a hole in the forest canopy. In their youth, they grow tall and relatively straight. As the forest ages, however, the old trees grow huge, twisted and gnarled, spreading out their branches to cover more and more area as the trunks around them die.
The surviving trees along the Mana Road are extreme examples of this process, thanks to human interference. When Kamehameha the Great allowed Captain Vancouver to release cattle in Hawai'i, the bovines encountered a landscape that had not evolved with any grazing animals and had no defenses against them. With no native carpet grasses to munch, the cows greedily chomped up young koa and grazed and trampled out the understory plants. The koa seeds that had lain dormant, awaiting their literal chance in the sun, burst forth into the cow-trampled landscape, and were promptly gobbled in their turn. Then, to feed the starving cattle, humans introduced carpet grasses such as kikuyu grass, which had evolved on the African veldt and was programmed to grow faster than the wildebeests and antelopes and cape buffalo could eat it. Kikuyu is so virulent that it can grow atop fence-posts, and completely buries entire fences if it isn't grazed regularly. A koa seed that falls in Kikuyu grass and waits for sun on bare soil to trigger it may face a long hibernation indeed.
So the surviving Koa along the Mana Road have fought a long and losing battle against the cow pastures, falling trunk-by-trunk as they've waited in vain for their replacements to grow. They've grown twisted as giant bonsai, battling the elements to spread their branches as far as possible, producing thousands of seeds in long rattly pods and dumping them into the thick grass without reward.
With a little help, this forest could still grow again. That's obvious if you stroll the public trails around Keanakolu. This area of the forest has been fenced off and the cattle have been evicted. Younger trees appear to be thriving. The grass is still thick underneath them, but wherever there's a bare patch of earth--such as along the edges of the trail -- koa keiki are sprouting up. In fact, a row of young koa is forcing the path itself to visibly shift in places. A few years ago, the remaining koa in this area were being smothered by an invasive vine called banana poka, but biologists introduced a fungus that feeds on poka leaves, thinning the poka enough that the trees can survive. Now poka may even be contributing to the habitat; we saw evidence that native i'iwi and apapane were feeding on the poka blossoms and fruit.
Restoring the native understory could be more of a problem: the grass smothers other plants as well as koa, and may be altering the soil in ways that make it less hospitable to forest plants. But that problem pales, compared to a new threat: the Lingle Administration's drive for energy independence.
I recently reported in the Honolulu Weekly about the efforts of a company called Hawaii Sunfuels to start a plant here that would convert biomass to diesel fuel. To supply that operation, the company wants to plant thousands of acres of non-native eucalyptus trees on current "ranch land" under the DLNR's stewardship. But in two recent public meetings in Hilo and Honoka'a, it became clear that Sunfuels is only one participant in a new land rush: at least five different companies, maybe more, have designs on DLNR lands for biofuel production. Much of that land is currently leased to ranchers and is the same kind of remnant koa forest that I've been describing.
So far, the debate has been mainly between the biofuel companies and the ranchers, who argue that food-raising should also be a priority. But in fact, most of the cattle that are raised on those ranchlands are still being shipped of to the mainland for "finishing" in feedlot--they're an export cash crop, just like sugarcane used to be. Koa itself could be a cash crop. Thousands of fallen logs could probably still be salvaged from those cowpastures, and the rotten part burned for fuel and the good part sold for lumber, and some of the proceeds plowed back into reforestation. Koa could be intercropped with food or fuel crops such as apples or marijuana. There's an orchard at Keanakolu that was planted experimentally in the mid-20th Century and still produces apples and pears, despite decades of neglect. Woodworker Tai Lake and now-Councilman Kelly Greenwell started a project years ago that rotated apple and koa plantings; after salvage logging, apple trees were planted on the lumber mill site, and will produce for a few decades, then can be cut down and reseeded with koa.
Both energy independence and food independence are urgent and worthy goals. But if we allow those grandmother koas to be replaced with eucalyptus, that's the end of any future for the koa forest. As we search for answers to global warming and peak oil, I hope someone will take notice of that.