Andy S said…
I believe the loblolly pine forest is a good indicator of long-term climate trends. They and their long tap roots are sensitive to long term soil moisture levels. The lost pines of Bastrop are there because it’s an island of sandy soil that is permissive so that more of the region’s rainfall is available for tree growth versus becoming surface runoff. Likewise the east Texas pines indicate both sandy soils and greater and more dependable rainfall. There are islands of loblolly forest between Bastrop and Houston whereever sandy soil inclusions exist in what is largely a sea of heavy clays.
How old is the pine forest around Bastrop? I’d guess it’s been there since before the end of the Pleistocene when rainfall was higher than today and temperatures were cooler. Probably the pines were continuous or nearly so between Austin and Houston. I’d also guess that it survived the Holocene optimal as I’ve heard from other biologists that there is significant genetic differences between the Bastrop pines and those of east Texas.
So if the Bastrop pine forest dies before we get rain, then I’d say the drought and high temperatures are unprecendented since at least the last interglacial and that this is no longer weather but climate change that is killing Texas.