One of the largest organisms in the world, a Utah forest of genetically identical trees, is slowly being devoured by deer.

　　世界上最大的生物之一——犹他州的一片基因完全相同的树林，正慢慢被鹿啃光。

　　The Pando quaking aspen colony, also known as the "Trembling Giant," has likely survived for thousands of years. But about 80 percent of it is in a perilous state, according to a new paper published today (Oct. 17) in the journal PLOS One.

　　这个“潘多”颤杨群(也被称为“颤抖的巨人”)可能已生存了数千年。但17日发表在美国《科学公共图书馆·综合》杂志上的一篇最新论文称，其大约80%的树木处于危险之中。

　　The trembling giant, weighing 13 million lbs. (5.9 million kilograms) and covering 106 acres (0.42 square kilometers) of Utah’s Fishlake National Forest, consists of over 47,000 genetically identical stems that grow from a single underground parent clone.

　　这个“颤抖的巨人”位于犹他州鱼湖国家森林公园，重约1300万磅(约590万千克)，占地约106英亩(0.42平方千米)。它由一个地下无性繁殖根系上长出的4.7万株基因一模一样的树干组成。

　　In this new study, a group of researchers measured the health of various parts of the forest, such as by counting the number of living versus dead trees, counting the number of new stems and tracking the feces of animals that dropped in for a bite. They found that the biggest obstacle to the strongest indicator of the forest’s health — whether new sprouts could survive — was mule deer.

　　在这项最新研究中，几个研究人员衡量了树林不同部位的健康状况，比如数一数活树与死树的数量和新长出树干的数量并追踪啃树动物的排泄物。他们发现，树林健康状况最有分量的指标就是新芽能否存活，而它的最大障碍是骡鹿。

　　It’s natural that the older stems are dying off, lead author Paul Rogers, the director of the Western Aspen Alliance and adjunct associate professor at Utah State University,told Live Science. What’s unnatural is that new stems aren’t growing, he said. For the past couple of decades, mule deer and cattle have been eating all the new stems that sprout from the underground mama aspen. In most areas, there’s no "young or middle-aged trees at all," he said. So the forest, to use human terms, is made up "entirely of very elderly senior citizens," Rogers said.

　　论文第一作者、美国西部颤杨联盟负责人、犹他州立大学兼任副教授保罗·罗杰斯在接受美国趣味科学网站采访时称，老树干枯死是自然而然的。他说，违反自然规律的是，新树干长不出来。在过去几十年里，骡鹿和牛一直在吃掉从地下颤杨母根上发芽的所有新树苗。他说，大多数区域没有“中青年树”。罗杰斯表示，用拟人词语来说，这片树林“完全由老年人”组成。

　　Rogers and his team also compared aerial photographs of the area that spanned 72 years and found that the aspen forest has been thinning. Back in 1939, the tree crowns all touched, but starting in the 1970s, "you see a lot of spaces between the trees," he said. This means that the old trees are dying and new ones aren’t coming in to fill in the gaps.

　　罗杰斯和他的团队还对比了该地区72年来的航拍照片，发现这片颤杨林日益稀疏。他说，在1939年时，树冠连成一片，但从上世纪70年代开始，“可以看到树与树之间有很大空隙”。这就是说，老树渐渐枯死，而新树没有长出来填补空缺。

　　Part of the problem is that game such as mule deer do not have natural predators in the area anymore. In the early 1900s, humans killed off most natural predators, such as wolves and grizzly bears, Rogers said. Now, most of the grounds in Pando are set aside for recreational uses like camping, where the browsers are protected from hunting. "The deer know that very early on, and they find it a safe harbor."

　　问题的部分症结在于，该地区的骡鹿等动物不再有天敌。罗杰斯说，在20世纪初，人类杀死了它们的大多数天敌，比如狼和灰熊。现在，“潘多”的大部分地面被用于休闲活动，比如野营，啃食嫩枝的动物是受到保护不得猎杀的。罗杰斯说：“骡鹿很早就知道这一点，它们发现这里很安全。”

　　But really, "Pando is failing because of human decisions," Rogers said. "Humans control wild animals, particularly wild-game species like deer and elk."

　　不过，“潘多的失败，是由于人类的决策，”罗杰斯说。“人类控制着野生动物，特别是像鹿和麋鹿这样的野生动物。”

　　There is one part of the trembling giant that is thriving. This area was fenced in around 2013 and within five years, thousands of stems — some 12 to 15 feet (3.6 to 4.5 m) tall — have been growing per acre, Rogers said. Here, the fence seems to be working. Half of the area that the aspen clone takes up is unfenced and easily accessible by the mule deer and cattle. Around 30 percent of the area is fenced in with an 8-foot-tall (2.4 meters) fence, Rogers said. But "the fence is not doing its job, so it’s also in a poor state," he said. "Somehow, the animals are still getting in — it’s a bit of a mystery to us," he said. He thinks the mule deer (not the cattle) are jumping it.

　　不过，“颤抖的巨人”有一部分繁盛兴旺。罗杰斯说，这块地区在2013年左右被圈起来，五年内平均每英亩长出了数千株树木，高约12到15英尺(3.6米到4.5米)。在这里，围栏似乎发挥着作用。这个颤杨根系所及的区域有一半没有围栏保护，很容易有骡鹿和牛进入。罗杰斯说，大约有30%的区域用8英尺高(2.4米)的围栏围着，但他表示:“围栏没有发挥作用，因此仍然很糟糕。”不知怎么的，动物们还是可以进来——这对我们来说可能有点神秘。”他认为骡鹿(不是牛)跳过了围栏。

　　"We need to help control the animals — both deer and cattle — and give Pando a break so that it can recover," Rogers said. This can be done by culling their numbers, restricting them with properly working fences or keeping them moving out of the area, as predators traditionally did, he said.

　　罗杰斯说：“我们需要帮助控制这些动物——无论是鹿还是牛——让‘潘多’有机会喘口气以便复原。” 他说，这可以通过减少它们的数量，用合适的围栏限制它们的活动，或者像传统的捕食者那样，让它们远离这个区域来实现。

　　"We’re not talking about just the tree, but we’re talking about all the plants and animals dependent on it," Rogers said. "We can’t manage wildlife and forest independently, we have to manage them in concert and in coordination with each other."

　　罗杰斯表示，“我们所谈论的不只是树，而是所有依赖于树生存的动植物。”“我们无法独立管理野生动物和森林，我们必须协调一致。”

　　And the approaches that work to protect Pando could be extended to aspens around the world, he said.

　　并且他说，保护潘多的这片树林的方法可以在全世界发扬。