Still Dry Tree Fall - Why?

102 F at noon.. one of the hottest days days of the year in a string of hottest days.
This morning at 10 I went to the NE Gate of the Woods. I mowed Escarpment and Pipeline Trail. Smell of carrion fairly strong.. not intense maybe 30 m in from gate. Has HK placed new carrion off the trail? or is this some other natural occurrence?

Below escarpment, beside trail descending to the wash and the Elm Bridge, a large 2.5-3 foot DBH hackberry fell. It took down a large 2 ft DBH oak, a couple mid sized and smaller elms and the whole tangle blocked the trail by the wash.

Why did this happen? There has been no wind and no rain for a month or more. Earlier (early July) we had lots of rainstorms. Why did the tree come down now when it was still? Odd.. the hackberry was rooted mid slope on the escarpment and I imagine was suffering from various root decaying fungi. The May 10 tornado would have shaken it pretty strongly most likely.. a few other large trees in the same southeast quarter of the Woods did come down in the May 10 storm.

I cleared the trail through the tangle of boles and branches.. and cleared some logs blocking the EW Fence line Trail and Northern Loop.

Pool near Elm Bridge was dry but pool above Island Crossing was still there.

Quit at 1:00 drenched in sweat and suffering from modest heat exhaustion.

Exiting NE Gate I noticed new aluminum tags on several (7-8?) small diameter trees (hackberry and green ash) labeled TGR CAMBISTAT 2010. Mystified, I looked on web and found discussion of tree growth regulator that interferes with gibberellic acid mediated tree growth. I wonder who is doing that? Probably folks that clear the right of way for power lines.

Need to talk to OU surveying class and see if they want to survey in Woods.