The VFTs I've seen in the field grow mostly under light to heavy grass
cover. The grass shelters the VFTs from a lot of direct sun and wind. Jeff
Welch has pointed out to me that there's a good chance that there's a
microclimate at VFT level that's pretty different than the climate 24
inches above the soil. I'm not sure what the differences would be, but I
expect that more moderate temperatures and higher humidity would be among
them.
Phil