Scientists from the University of California in Berkeley have now established that Tropical montane cloud forest trees not only take up water through their roots like other trees but also through their leaves directly from the clouds. Trees growing in arid areas usually find alternative means of survival and this is a classic example of one such strategy in a largely foggy region. However, the after-effect of climate change is beginning to take a toll on these trees because the very clouds they depend on for survival are diminishing.
According to Professor and senior author at the university, Prof. Todd Dawson, the backbone of the study was highlighting the plight of this unique ecosystem brought about by climate change. This study has come up with alarming findings that indicate a decline and in some cases total disappearance of animal life found in the cloud forests. specific examples include salamanders as well as frogs whose population is fast declining. This new study will have its results published in next year’s journal ecology letters but is already accessible this month online.
The leading author of this research, Greg Goldsmith, explains that the trees in the cloud forests are usually immersed in cloud cover and this keeps them constantly wet. When water available in the ground below is just too little to go on, the trees drink up the water from the clouds through their leaves. Greg who is a student in Prof, Dawson’s laboratory explains that during the dry annual season experienced by the cloud forests the primary source of water shifts from being rain water to water available in the clouds.
To simulate what goes in the cloud forests, the researchers set up in Monteverde Costa Rica. They put in place small plastic leaves which were attached to an electrical circuit. These plastic leaves use the changes in the circuit’s voltage to detect the extent of wetness. Sensors were also attached to the branches of actual trees in the cloud forest to detect if there was uptake of water whenever the leaves were wet. All of us are taught that trees take up water through the roots and the water then travels up through the trunks or stems, to the branches, then the leaves and finally out through the leaves. This may be true but Greg Goldsmith of the University of California contests that this is not the only way. Water can as well enter through the leaves, go through the branches and move downwards towards the trunk or stem.
This study is a follow up to a previous study carried out by Prof. Dawson in the redwoods of California. Despite evidence of water entering trees through the leaves, the study unveiled that different trees have different capacities to absorb water in this way. Trees that take up the most water are those that are highly susceptible during the dry season which comes about yearly and renders cloud cover insufficient. Greg Goldsmith received a grant from the National Geographic Society Young Explorers to undertake this research which has established a distinct relationship between cloud cover and plants in the cloud forests. The findings of this research will serve as fundamental elements in future studies carried out in similar ecosystems.