Trees cannot heal a physical wound like a human does. In order to remain healthy and alive, a tree needs to be energy-efficient, and recovery is just an unaffordable drain on resources. Instead of applying a Band-Aid and mustering up some healing, the plant blocks off all life to the injured part, effectively abandoning it. The benefits of this are twofold. Not only does this shut the door solidly in the face of nasties that could further infect the entire tree, but it can now spend its valuable energy on new growth somewhere else.
However, amputation is not a fail-safe survival switch. Sometimes, a wound is just too large or infected, and sickness and rot eventually kill off the tree. But when it does work, the damaged cells start the process through leaking their contents which then oxidize and form the lifesaving barrier. As time passes, the wound will eventually close up as every year's new growth forms around it.
4.They Have Audible Angst
French scientists have recorded a sound trees make when they undergo drought stress. They don't ask for a cup of tea in a parched voice—oh, no—trees get weird. They bubble. But by the time they're bloop-blooping somewhere in the ultrasonic range, a dangerous process is already occurring that can prove fatal to the unlucky bubbler.
To get water to all of their extremities, trees suck the lifesaving liquid—under the pressure of several atmospheres—through special tubes called xylem. During a drought, the plant must increase this pressure but, in doing so, air bubbles form that can interfere with the water flow, and these are the stress sounds now audible to the right microphone. Scientists call the phenomena "cavitations" and, since too many cavitations can kill trees—sometimes endangering valuable plantations—it's crucial to know when they start. The French scientists are aiming to eventually create a device that can capture this ultrasonic noise in order to alert forest managers when a tree needs an emergency watering or even automatically activate a watering device.
During a study of genetically identical poplar trees, researchers found that the specimens responded to their present environment based on what individuals had gone through in the past, pointing to some sort of memory at a molecular level. Researchers took stem cuttings from poplars and, apart from the fact that the cuttings came from two different nurseries, everything else about the experiment that followed was identical. The genes of the cuttings, species, and environment in which they were raised were all the same to allow researchers to notice any difference in reaction. And they got it.
Simulating drought for some while watering the rest, the scientists expected the poplars to all react the same since they were in effect genetic clones. But the trees from Alberta activated a different group of genes in response to the "drought" than the poplars obtained from Saskatchewan. This pointed to the plants "remembering" where they came from.
Perhaps "leaves" is the wrong word here. Trees do not use sign language with their foliage to greet each other in the morning—that would just freak everybody out. Communication between trees happens subtly and below ground. Suzanne Simard, a forest ecologist, has made the unprecedented discovery that forest trees communicate and share resources with each other via their roots. With the help of symbiotic fungi, trees can actually feed seedlings with the nutrients the youngsters need to survive.
This fungal network also allows bigger trees the opportunity to swap necessities like water and carbon with other trees, depending on their needs. Simard also identified the phenomenon of "mother trees"—the really old and massive trees in a forest. Not only are mother trees connected to all the other trees, but they seem to be the heartbeat of the woodland. They control and dispense resources through the massive fungal web and, when such a matriarch is chopped down, younger trees face a reduced survival rate.
1.Arson As A Competitive Edge
Wryly nicknamed "gasoline trees," the popular eucalyptus tree is almost designed to prepare the groundwork for a devastating bush fire. Their broad ribbons of dry, peeling bark create tinder all over the place, made even more dangerous by the extremely flammable oil it produces.
This combination is what makes this tree the firefighter's archenemy because it can turn a manageable ground fire into an uncontrollable firestorm in minutes. In 1991, over 3,000 homes and 25 lives were lost after eucalyptus trees caught fire throughout the Oakland Hills of California. After such sweeping wildfires, eucalyptus babies thrive without a problem. During their first couple of years, the young trees will grow intensively, sometimes at the cost of other species that can't keep up. Despite their arsonist nature, eucalyptus trees remain coveted for their strange beauty, fast growth, and prized essential oil.