Mass graves are often the result of

local criminals
genocide
world politics
taphonomy

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

2%? i tried finding the exact sorry if it's not 100% correct ; -;