The word sere (meaning dry, withered, or barren) comes from the Middle English sere, which derives from the Old English sēar ("dry, withered").  It comes from the Proto-Germanic *sauzaz (“dry, parched”) and the Proto-Indo-European *h₂sews- or *saus- (“to be dry”).  It is linked to Ancient Greek aûos (dry), Lithuanian sausas (dry), Dutch zoor (dry and coarse), and Old Church Slavonic suχŭ and shares a common root with the verb and noun sear (to scorch or burn), as well as the adjective austere.  It is documented in literature before the 12th century, with figurative extensions appearing in the 1530s (such as referring to aging or barren life stages). "Sere-month" was also an old historical name for August.  

The earliest recorded use of sere in English according to the Oxford English Dictionary (OED) dates to around 1175 in Middle English, appearing in the Ormulum (for the adverb/adjective sense).  The adjective/adverb first appeared around 1175 in the Ormulum (Middle English period, 1150–1500).  The noun (meaning a withered state or aged stage first appeared in the early 1600s, with earliest evidence from 1606 in a translation by Joshua Sylvester.  The noun referring to an ecological community sequence, from series didn't appear until the 1910s, with earliest evidence from 1916 in the writings of Frederic Edward Clements.  The adjective sere-ish showed up in the mid-1600s, with earliest evidence from 1648 in the work of Henry Hexham.  

The primary meaning of sere means dried up, withered, shriveled, or barren (most commonly applied to vegetation or landscapes).  Its definition expanded into broader figurative descriptions by the 1530s, such as the old poetic term "sere month" for August.

41 minutes ago, drpaladin said:

When I see sere, I think of SERE training (Survival, Evasion, Resistance, Escape.)

 

 

That's the military acronym initialism that is a 20th-century development first established during World War II by the British military.