This week will be the hottest yet of 2020. The heat can trap pollutants and create smog. This is especially dangerous for the elderly, and people with breathing difficulties. Coupled with the rising rates of Covid-19 infections, high temperatures are more dangerous than ever before.

However, even as our climate changes, conserving forests has the ability to mitigate the impact of severe heat waves. A study at the National Oceanic and Atmospheric Association was conducted to assess the consequences of converting forests to pastures on the frequency of heat waves. “We found that, all other things being equal, the conversion of forests to crops and pastures leads to a two-to-four fold increase in the occurrence of hot, dry summers in these altered regions,” said lead author Kirsten L. Findell, a climate scientist at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL). “Instead of hot and dry summers happening once a decade, these regions with forest converted to cropland experience hot-dry extremes every two to three years.”

12 years of global land cover humidity and temperature data were compared to results from the study at the GFDL’s Earth System Model, resulting with consistent findings. “Getting similar results from our model provides us with greater confidence that the model can be used to predict future impacts of forest conversion,” said Findell. 

One way this is done is through ‘transpiration cooling’. This is the process in which the leaves release water into the air via transpiration, cooling the air. Another is ‘evapotranspiration’, which is the total amount of evaporation and plant transpiration from land and ocean surfaces to the atmosphere. Evaporation allows for the movement of water to the air from sources such as the soil, canopy interception, and water bodies. “Shaded surfaces, for example, may be 20–45°F (11–25°C) cooler than the peak temperatures of unshaded materials. Evapotranspiration, alone or in combination with shading, can help reduce peak summer temperatures by 2–9°F (1–5°C),” according to climate researcher H. Akbari.

Urban cities especially benefit from having trees and plant vegetation in the area. Including educed energy use, an increased quality of air, water and flood management. These benefits may vary but are usually well worth the cost. A five-city study published in the Journal of Forestry, “discussed above found that, on a per-tree basis, the cities accrued benefits ranging from about $1.50–$3.00 for every dollar invested. These cities spent roughly $15–$65 annually per tree, with net annual benefits ranging from approximately $30–$90 per tree.”

Heat wave reduction is one of the many reasons forested lands must be protected. Volunteering and donating to land trusts and other forest conservation organizations ensure that this continues. As Franklin D. Roosevelt once said,

  “A nation that destroys its soils destroys itself. Forests are the lungs of our land, purifying the air and giving fresh strength to our people.” 

~Ada Snodgrass