Black, burnt edges of torn off plants. I found this example in a crop formation at Simonshaven (NL) in 2002.
Another example of traces of heat: these black, burnt carrot plants were discovered by crop circle researcher Dr. Eltjo Haselhoff at Etten-Leur (NL) in 1997.
In 2004 I found this wheat plant in a formation near Pewsey, Wiltshire (UK). The upper half of the seed head had been scorched and shrunk by a heat source:
In 2004 I found this wheat plant in a formation near Wijchen (the Netherlands). The upper half of the seed head had shrunk and the seeds had disappeared: