Grasslands higher evap rate than forests

unexpected

http://phys.org/news/2012-07-local-factors-important-availability.html

ah food forest gardening proven right again.

one thing I discovered this year..we lost several trees to the emerald ash borer, and when we removed them all of a sudden we had a drought..the grass in our paths and trails all over where the trees had been removed..dried up and turned to straw !!! The trees were holding that much moisture in the area..hopefully the area will recover..but we are still loosing trees to the emerald ash borer...thankfully ash is coppice-able..and some of the stumps are sending up new shoots of baby ash..so it may help to quickly reforest the area, although the baby ash may also die.

I don't know - if they were talking about evaporation from the soil (as opposed to transpiration from plants) then I would think that the presence of trees would shield the ground from wind so having less evaporation from wooded areas makes perfect sense to me.

In general, yes, trees retain soil moisture.  One of the driving reasons I planted trees in my pasture was water retention.  However, a few tree species are known for robbing other plants of water.  Willows, eucalyptus, and poplar are a few.  

I did not click the link, especially since it is from 2012.

To me, soil drys out more on grasslands because the are no trees to block the wind, plus forests are shady thus allowing for more moisture in the soil.

How does a Rain Forest fit in the picture? It is all the moisture from the trees that with the hot sun make the near daily rain. A native grassland is in fact quite moisture efficient and will do much better in a drought than a disturbed landscape.

I don't know if the following comparison was included in the study but the central historic grasslands of the US are now largely cropped.....with abundant humidity being ascribed to crop plant transpiration along with the moisture that moves northward from the Gulf of Mexico.  While I've seen mention that this rise in humidity is due to annual crops versus native prairie species covering this region, I don't know if that's been established for sure.

John,

This is what is said about "corn sweat". It is thought that how we have changed the US landscape with monoculture contributes to severe weather.


AI Overview
"Corn sweat" is the rapid release of moisture (transpiration) by corn plants, releasing thousands of gallons of water per acre daily, which significantly increases humidity and elevates dew points in the Midwest. This localized atmospheric moisture intensifies heat waves, boosting the heat index, and provides fuel for severe, isolated thunderstorms.
OSU Extension