The largest fungus

The largest fungus found so far is a honey fungus in the Malheur National Forest in Oregon. Spread over three-and-a-half square miles (nearly one thousand hectares) and weighing somewhere between 7,500 and 35,000 tons, it is the largest known living organism on Earth estimated to be many thousands of years old.

Hidden Connections

Nature is complicated. To understand how populations of predators and prey affects each other, we can look to Isle Royale, an island in Lake Superior in the state of Michigan. Here, Nature started a unique experiment, one that researchers have been observing since 1958.

First, moose arrived on the island over the frozen lake. The lake thawed, the moose were stranded, and their population exploded. They are their way through the underbrush and destroyed most of the young trees. Then, during another harsh winter, a wolf pack settled on the island and set about reducing the moose population. The remoteness of the island was a gift for the researchers. With both populations more or less trapped, they could study the interconnection in a relatively small area(more than five hundred square kilometers).

The researchers expected that if the number of wolves rose, moose numbers would fall because the wolves would catch and eat more of them. Eventually, wolf numbers would fall because it would take the wolves longer to find the moose and hunt them down, so more wolves would starve. Moose numbers would then start to rise.

But you could look at this dynamic completely differently. When the moose have a lot to eat, they reproduce so the wolves have lots of moose to catch. The more moose are killed by wolves, the more the wolves reproduce. And yet, a larger populations of wolves means more stress on the predators because they must now put more energy into defending their territories from other wolves.

The fluctuations in the moose population, therefore, depend more on the condition of their habitat than on the presence of wolves – unless a particularly harsh winter comes along. In a harsh winter, food becomes so scarce that many moose die of starvation. If the wolves now hunt the remaining animals more vigorously, it can cause the moose population to collapse. Are you completely confused?

Interdependencies in nature are often not as obvious as we once thought.

Perhaps the connections will be easier to understand if we pay less attention to the fluctuations in the size of the herbivore population and more on the changes in their behavior.

There were way too many herbivores(mostly elk) in Yellowstone National Park. These large deer drastically reduced tree cover until they’d stripped extensive areas of the landscape bare.

Park rangers exacerbated the problem by feeding the elk in winter, which allowed the herds to continue increasing in size. The turning point came in 1995, when the ranges, together with scientists, released wolves into the park. By 1996, ranges had introduced a total of thirty-one animals. The wolves set about steadily increasing their numbers and did one thing above all others; they ate elk.

So, the number of elk declined steadily from 1995(16,791) to 2004(8,335) to settle at a lower level. The number of wolves rose to 174 in 2003 before declining to a sustainable level of about 100.

But more important than the decline in the number of herbivores was the change in their behavior. In earlier times, the elk had enjoyed browsing along the riverbanks, destroying the vegetation that protected the river from erosion. Rivers and streams began to cut into the land and carry off valuable soil. The sediment in the water affected fish and other aquatic organisms, and in some places the park became little more than an elk zoo.

With the return of the wolves, elk began to avoid the riverbanks, where they were particularly easy prey. Shrubs and trees soon began to grow once again and line the banks.

Now beavers came back as well, because they had access to the trees they used to build their dams and the branches they relied on for food. The rivers began to meander through the valleys once again. The bends slowed the rate at which the water flowed and therefore the rate at which the water eroded the banks. All this happened thanks to the reintroduction of a top predator.

드디어 이 책의 끝을 마주하게 되었다. 비교적 쉽게 읽히는 책이다. 숲과 관련된 전반적인 얘기들을 다룬다. 숲 해설가 과정을 배우면서 마주했던 많은 내용들도 포함한다. 이렇게 보면 언어와 지역이 달라도 숲을 주제로 한 내용은 동서고금을 막라하고 비슷한 내용으로 채워진다는 것을 알 수 있다.

책 저자인 피터도 말했듯이 이 책은 다른 숲해설과 관련된 전문적인 내용을 파고들기 전에 한 번 쭉 훑어 볼 것을 권고한다. 이 책을 읽고 나면 특정 주제를 만날 때 서로 연관련 주제들을 쉽게 떠올릴 수 있게 만든다.

개인적으로 비교적 와 닿은 부분은 숲을 인간과 공존하게 만들 수 있다는 것이다. 우리 나라에서도 있듯이 숲을 수목장으로 활용함으로써 숲과 인간을 좀 더 가깝게 만들고 인간도 자연의 일부임을 깨닿게 하고 숲에서 평온함을 찾을 수 있도록 만드는 생각을 하고 있다. 우리 나라에는 그리 보편적이지는 못하지만 숲이 정말 잘 가꿔지고 태초의 숲으로 유지될 수 있다면 새로운 문화공간으로 만들 수 있겠다는 생각이 든다.

2024.10.20