As much as cattle have helped to destroy much of the native vegetation at Pu`uwa`awa`a, they now play an important – if limited — role in its restoration. Everyone familiar with the issues at Pu`uwa`awa`a agrees that some degree of grazing will be needed to control the growth of grasses. The non-native grasses fuel fires and prevent natural regeneration of native trees. Chris Yuen, a Hilo lawyer who has been closely involved with the development of plans for alternative management of the area, anticipates the need for a small herd of “lawn-mower” cows that can be moved from area to area to keep down the fuel load of grasses.
Miki Kato has been working at Pu`uwa`awa`a for the last 40 years. To him, grazing is absolutely essential, not just for the control of weeds, but even more for restoration of the forest. Over the last five years, he has been keeping a paddock of some 700 acres adjacent to the state’s own Pu`uwa`awa`a Wildlife Sanctuary lightly grazed. The result is that some of the native trees, especially koa, are beginning to regenerate. “There’s a seed bank there. Reforestation through paddock management will work,” Kato says. “There are lots of critics of cattle, but to me, the reason we have what we do is cattle.”
Kato has used his cattle to help out with managing the sanctuary when, at the request of the state Department of Land and Natural Resources’ Division of Forestry and Wildlife, he moved some of his herd into fenced areas and let the cattle munch down the weeds. The cattle may take a few young trees as well, but, says Kato, “it’s better to lose a few trees to grazing than to lose everything to fire.”
Jon Giffin, head of the Big Island district of the DLNR’s Division of Forestry and Wildlife, elaborated on the use of cattle as a conservation tool. “We put cattle on about 800 acres of the west side of the sanctuary,” he said, in an area that has no endangered plants. “They were there about three months, and pretty much took care of all the banana poka on the ground and pulled some out of the trees.”
The watering trough was at the lower elevation of the land grazed, Giffin said, “so the cattle never got to the upper elevation. But the lower two-thirds was pretty well cleared out of banana poka and the grass was cut down. They were just starting to trample the ferns and I began to see some dieback” when the decision was made to pull the cattle out of the area.
The use of cattle is “real promising,” he said, mainly for keeping the banana poka in check on the sanctuary’s western side. The east side “is a lot drier,” he explained. “Banana poka is there, but it grows much more slowly.” Grazing is also useful around the sanctuary’s lower-elevation boundary as a fire-break and buffer against encroaching weeds.
Eventually, Giffin hopes that a fungus recently introduced to the area will kill the banana poka. “We’re hoping that will take the place of the cattle,” he said.
Overall, Giffin judges the experiment to have been “quite successful” and anticipates using them again, perhaps in another three years.
“Really dense grasses are a fire hazard,” he said. “You try to balance everything. You can take out the grasses and weeds, but that sets back native trees as well.
“There’s no right answer. Probably do a little of what you can, graze as much as you can with as little damage as possible. When you start grazing enough to reduce the fire hazard, you’ll probably start losing the natives. It’s a real fine line.”
And cattle are only a short-term remedy. “If you can just graze lightly, keep the poka out and not have the place burn down, it’s a temporary measure. In the long term, you have to get the animals out. The forest will have to make it on its own. We’ve already noticed that as the koa canopy gets thick, grass dies out and ferns replace it.”
Collateral Damage
The injury cattle and other browsers inflict on native plants is just one aspect of the harm they cause. Another was recently brought out by Burt Smith, a University of Hawai`i expert in pasture and livestock management. Smith studied Pu`uwa`awa`a soils in February 2000 for Ka `Ahahui `O Pu`uwa`awa`a. He found the soil nutrient content to have declined over the last century, as a result of ranching.
“Cattle have been grazing at Pu`uwa`awa`a for well over a hundred years,” Smith wrote. “While the actual amounts [of nutrients] lost on a per acre basis (5 to 12 pounds) may seem insignificant, it is a cost that a marginal, semi-arid ecosystem can ill afford. Trace minerals are presently being fed, but this practice has only been in effect for the last 30 or so years. It takes 50 pounds of a total mineralized supplement (which trace minerals are not) to replace the annual loss of one calf sold.”
He continued: “Pu`uwa`awa`a is a marginal ranch. Most marginal ranches É are capable of providing a living or paying off the mortgage, but not both. However, while doing one or the other the ranch is being degraded to where there is a decline in carrying capacity, which appears to be on the order of one quarter to one third loss every 50 years.”
Livestock may be used as a tool for fire suppression and weed control, Smith said, but this “is not a normal part of production practices. Anything that interferes with day-to-day operations results in something else not occurring or happening sooner or later than it should have occurred. This in turn affects something else and on and on. This is no different than at any other ranch, however, marginal ranches have precious little buffering capacity compared to those in benevolent environments. Events that would barely make a ripple on, say, Kahua Ranch [owned by Monty Richards in Kohala] might well result in a tsunami on Pu`uwa`awa`a.”
— Patricia Tummons
Volume 11, Number 3 September 2000
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