Trees and their Cycles: Water and Carbon
If overworked farmland gets dried and caked, effectively reverting to inert dirt, heavy rainwater can compound the problem. The water either runs off, causing flooding and havoc downstream, or pools on top of the field and destroys the crops. And with it a whole season’s, or year’s, worth of income for the local community is wiped out. Then there’s also the public health risk, since mosquitoes, who thrive in wet sunlit areas, are commonly known to transmit malaria.
Meanwhile, extreme weather swings, i.e. rapid change from drought to deluge, are becoming more common as a result of climate instabilities.
In a water-scarce region, where people are digging their wells ever deeper because the groundwater is disappearing, some believe that there’s a trade-off between planting trees and the availability of drinking water for people. Some officials have avoided supporting tree-planting in arid or semi-arid regions because of the perceived conflict.
The accepted orthodoxy is that trees remove water from catchments, and that planting trees reduces water availability for local people. However, research conducted by a team from the Swedish University of Agricultural Sciences has shown that in dry landscapes, trees (at some densities) can actually increase the availability of water during dry months. Tree roots – and the animals they attract (e.g. ants, termites, worms) – help to create holes in the soil for the water to flow through…in either direction.
These same roots also increase the soil’s ability to absorb huge amounts of water when heavy rains do come, and also channel excess rainwater into underground aquifers. In this manner, the trees do ‘double duty’ to keep water in the soil where it can stimulate microbial growth and create a nourishing environment for agricultural activity.
In some circles, the water-management capabilities of trees are considered to be more important than the carbon capture behavior. The good news is that this dynamic is becoming better understood, and new trees are getting planted. Here at ForestPlanet…it’s all good!