为什么树会让附近的树桩存活?
为什么树会让附近的树桩存活?
A tree stump without leaves shouldn't be able to survive on its own. In a New Zealand forest, however, two researchers recently found a leafless stump defying death.
一个没有叶子的树桩是不可能独立生存的。然而，在新西兰的一个森林里，两位研究人员最近发现了一个没有叶子的树桩。
The stump had callus tissue growing over its wounds, and it was also producing resin, a sign of living tissue. While this might leave a casual observer feeling ... stumped, Bader and Leuzinger are ecologists, and they quickly figured out what was going on.
树桩的伤口上长着愈伤组织，它还在分泌树脂，这是活组织的迹象。虽然这可能会让一个不经意的观察者觉得……贝德和鲁泽格是生态学家，他们被难住了，但很快就弄明白了发生了什么。
This stump wasn't surviving on its own; it was surviving with help from nearby trees.
这个树桩不是靠自己存活的;它是在附近树木的帮助下存活下来的。
This image shows the Kauri tree stump from the new study. (Photo: Sebastian Leuzinger/iScience)
Trees in a forest are often connected by vast underground networks of symbiotic soil fungi, whose subterranean internet helps the trees exchange nutrients and information. Trees of the same species also sometimes physically graft their roots together, blurring the line between individual trees to the point that an entire forest could be considered a "superorganism," sort of like an ant colony.
森林中的树木通常由庞大的地下共生土壤真菌网络连接，其地下互联网帮助树木交换营养和信息。同一物种的树木有时也会把它们的根嫁接在一起，模糊了单个树木之间的界限，以至于整片森林都可以被视为“超有机体”，有点像蚁群。
Linking with neighbors lets trees expand their root systems, providing more stability when growing on a slope — which could be a significant perk for a species known to grow more than 50 meters (164 feet) tall. The stump may be a shadow of its former self aboveground, but it presumably still has a substantial root system underground, and can thus offer some additional stability to its neighbors.
与邻居的联系可以让树木扩展它们的根系，在斜坡上生长时提供更多的稳定性——这对于一个已知能长到50米(164英尺)高的物种来说可能是一个显著的优势。树桩可能是它以前在地面上的影子，但它可能仍然有一个坚实的地下根系，因此可以为它的邻居提供一些额外的稳定性。
Kauri trees tower above the ground in Waipoua Forest on New Zealand's North Island. (Photo: riekephotos/Shutterstock)
Plus, because a combined root network lets trees exchange water as well as nutrients, a tree with poor access to water could boost its chances of survival in a drought by withdrawing water from the community's shared roots. Yet there could also be drawbacks to that, the researchers point out, since it might enable the spread of diseases like kauri dieback, a mounting problem for this species in New Zealand.
此外，由于一个联合的根系网络可以让树木交换水和营养物质，一棵无法获得水的树可以通过从社区共享的根系抽离水来提高其在干旱中生存的机会。然而，研究人员指出，这种方法也可能存在缺陷，因为它可能会导致kauri dieback等疾病的传播，kauri dieback在新西兰是一个日益严重的问题。
Leuzinger plans to look for more kauri stumps in this kind of situation, hoping to reveal new details about the roles they play. "This has far-reaching consequences for our perception of trees," he says. "Possibly we are not really dealing with trees as individuals, but with the forest as a superorganism."
Leuzinger计划在这种情况下寻找更多的kauri树桩，希望揭示它们所扮演角色的新细节。“这对我们对树木的感知有着深远的影响，”他说。“也许我们并不是把树木当作个体来对待，而是把森林当作一个超有机体来对待。”
Ferns grow on the forest floor beneath kauri trees in New Zealand. (Photo: Bildagentur Zoonar/Shutterstock)
"This is a call for more research in this area, particularly in a changing climate and a risk of more frequent and more severe droughts," he adds. "This changes the way we look at the survival of trees and the ecology of forests."
他补充说:“这是对这一领域进行更多研究的呼吁，特别是在气候变化和更频繁、更严重干旱的风险下。这改变了我们看待树木生存和森林生态的方式。”
