OSU scientist leads massive drought research project.
Plants take up a big portion of the CO2 that humans put in the atmosphere.
Therefore, the effect of sudden shifts in plant population at large scales, such as tree die-off observed globally in recent decades, could affect the rate at which climate changes.
Current global vegetation models have a hard time producing consistent estimates of plant CO2 uptake, and their predictions vary widely based on the assumptions they use about how plants respond to climate.
“The discovery of how droughts cause mortality in trees, regardless of the type of tree, allows us to make better regional-scale predictions of droughts’ effects on forests.” Trees and forests are particularly important in this because they take up and store a lot of this CO2 and also affect their environment in other ways.
One idea for improving these models, is to base forest responses on how trees die in response to heat, drought, and other climate stresses.
But progress on this has been limited by disagreement over whether carbon starvation or hydraulic failure, the inability of a plant to move water from roots to leaves, is the true cause of death in trees.
Adams and his fellow researchers found hydraulic failure to be universal when trees died, while carbon starvation was a contributing factor roughly half of the time.
“This research will help us more accurately predict how different plant species respond to different types of environmental stress such as drought, insect damage or disease.” Adams explainED that 99 percent of the water moving through a tree is used to keep stomata open, the pores that let in CO2, allowing it to carry out photosynthesis.
This makes sense, because the stored sugars and starches that could be reduced in carbon starvation are also important for preventing hydraulic failure.