Researchers have found a way to predict whether or not a forest will survive based on drought conditions 鈥� information that can help forest managers deal with climate change.
The researchers from the University of California Davis in the Sierra Nevada forest from 2012 to 2015. In the early years, the trees were doing fine, despite drought conditions. But by 2015, 80% of them were essentially dead.
鈥淲e could see how the drought was causing changes in its (the Sierra Nevada forest鈥檚) behavior鈥攁nd actually, how it could lead to the collapse of the ecosystem,鈥� Jessie Au, a researcher on the study and a postdoctoral scholar in the university鈥檚 department of plant sciences, said.
If there鈥檚 a drought 鈥� much like when someone forgets to water a plant 鈥� trees will stop growing leaves. Without those leaves, it becomes harder and harder for photosynthesis to occur 鈥� until there鈥檚 a tipping point when the trees lose their ability to store and convert carbon dioxide.
鈥淓ven when the rains come back, if you don't have any reserves to even perform the basic functions, your (trees) are effectively dead,鈥� Au said. 鈥淭he water stress depletes your carbon reserves.鈥�
These changes can be hard to see at first. Au compared drought to hunger 鈥� if a human goes two or three days without food, they will be very hungry, but won鈥檛 die. After a few weeks without food 鈥� or in the case of trees, without water 鈥� death can quickly set in.
鈥淚t takes a while for all these reserves to break down,鈥� she said. 鈥淚t highlights that drought has a delayed effect and you don't necessarily see it instantly.鈥�
Now, the researchers have come up with CARDAMOM, a system that shows in real time the point past which a forest becomes so water-stressed that photosynthesis stops. The system's spice-inspired nickname is a mashed-up version of the phrase "Carbon Data Model."
The model relies on the historical climate data of a particular forest, like the Sierra Nevadas, to make geographically-specific predictions. And it鈥檚 applicable to all types of ecosystems 鈥� not just forests. Once researchers have a dataset to work with, they can see how much photosynthesis is going on that ecosystem given the current amounts of carbon dioxide, water and sunlight there 鈥� and see how it would change if a drought started and/or continued.
Au said it鈥檚 unlikely that researchers can save threatened trees with this method or get more water to dying forests. Still, understanding a forest鈥檚 stress level can help land managers direct their resources to forests that have a better chance of survival.
鈥淚t's to help us better manage or assess the vulnerability of forests to then think about, 鈥極K, well, how best can we use the various lands that we have?鈥欌�� she said.
From an industry standpoint, this information is important as .
鈥淚f you suddenly lose a lot of trees, you lose your ability to take in that atmospheric carbon dioxide, which is going to have really big implications if you are hoping to combat some of these emission problems,鈥� she said.
The researchers hope to apply this to other forests to determine their vulnerability to drought, especially in places like Colorado that receive significant levels of precipitation and snowpack.
For the climate鈥檚 sake, Au hopes more forests can avoid getting to that tipping point when photosynthesis fails.
鈥淭rees would be one of the biggest absorbers of carbon dioxide from the atmosphere given the size of them, the lifetimes that they live. They can store things,鈥� she said. 鈥淧hotosynthesis is like the driving force behind our ability to tackle any type of carbon emissions.鈥�
This story was produced by the Mountain West 暗黑爆料 Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, KUNC in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West 暗黑爆料 Bureau is provided in part by the .
