Having survived the passing of a dune, a witness tree has three huge advantages: it is bigger so it can grow more cones each year; it has another century or two of seed production before another dune comes upon it; and, most importantly of all, its seeds are likely to inherit its fast rate of growth. (A Day in Doñana Martin Jacoby) 
Cross the grain of the land
until you come to the first dune.
Watch as wind ripples sand 
into ridges where red crystals gather, 
shadows on a miniature Sahara.

At the crest you may find the scales of pine cones,
bits of bark. Twigs that jut out of the ground 
like gnarled fingers and claw the air; 
these are the ghosts of trees, drowned 
in the sands of a passing dune.

From here, the eye can drift across an ocean 
of wind-sifted tides that blow in 
and in again, a slow-motion tsunami.
Marshes succumb, pine groves are besieged,
defiance mapped by odd island-clumps of green.

Like old souls the witness trees endure.
They reach down into unsuspected sources
and root, stretch towards an intuited light.
As the sand rises they keep their heads above land
and remember to grow. 

Each domed pine seems to hunker down
and raise a shield against aeolian advance,
joining the ranks of those who survive
against the odds, against the elements, 
marking time in rings deep inside. 
*Witness Trees or Testigos, are umbrella pines that survive the passing of sand dunes in the Doñana Nature Reserve, in the south-western Spanish province of Huelva.