Hardened lava flows of "El Playon"

     The San Salvador Volcano "Quetzaltepec" produced the eruption known as "El Playon" around 1658, which destroyed the town of Nexapa (later relocated & renamed Nejapa).  The picture above is an example of primary succession - the plants that colonized these hardened lava flows have to make do without any soil!  These early pioneer species will eventually prepare a soil matrix that will give way to other successional communities that can't thrive on bare rock - but the process is slooow, the flow picture above is just 354 yr old.  Here's a cool paper on successional "facilitation": Callaway 1995.