If you ever feel useless, remember the elm tree.

The elm tree is the only natural predator of the elm beetle, which kills most other types of trees by boring into them. It cannot die.<br>The elm tree is the only natural enemy of Dutch elm disease, a fungus that kills almost every type of tree by cutting off its vascular tissue. It cannot die.<br>The elm tree often lives for hundreds of years, sometimes over a thousand, and grows slowly but steadily its entire life. It cannot die.<br>The elm tree is an example of what is known as a keystone species, an ecosystem which cannot function without a particular plant or animal. The elm tree is at the center of its own ecosystem, and countless species of plants and animals rely on it for their very lives. It cannot die.<br>The elm tree grows in even the most inhospitable conditions. It can thrive in standing water, dry sand, and elm trees have even been found growing in the median of the highway. It cannot die.<br>The elm tree is impervious to even the most potent chemical herbicides. They cannot kill the elm tree. It cannot die.<br>If you ever feel useless, remember the elm tree.<br><br>Edit: The elm tree _can_ die - but it is difficult to kill, and it cannot be killed by all of those methods mentioned. It is an incredibly resilient tree, and it is very hard to kill elm trees. It cannot be killed by people, beetles, fungi, or bad conditions, which is part of the reason it is a keystone species - i.e. the center of its own ecosystem.