When comes the end of winter’s cold,
squeezed-up tiny leaves unfold,
push back their wraps, enlarge, become
factories powered by the sun:
chlorophyll catalyst, green, is made
(a lovely colour, welcome shade!),
the tree, and flowers it may bear,
are fed by what’s constructed there.
In each leaf axil then there grows
a tiny new bud, slowly shows,
protected, ready for next year,
to swell when leaves must reappear
to replace those dropped in the fall:
’til then they’re immature and small.
The cooling of late summer air
activity triggers to prepare;
– resources now the tree retrieves
to be reused for future leaves
in coming warmth of spring –
cascade reactions so begin
withdrawal, before the frosty day
when fragile growth will die away.
Dismantling also of the green,
so other pigments soon are seen:
such fiery beautiful displays
on stunning, sunny autumn days.
The tree these skeletons can shed
their stores now in the tree instead.
At every leaf stalk’s base they form
a narrow band, th’abscission zone;
in a line across, between each cell
the glue dissolves, cells fill and swell,
their walls are weakened, in the breeze
the stalk will break, cause fluttering leaves.
Meanwhile, the next cells on the tree
became, by further chemistry
a ‘scar’-like layer which protects
from cold, and from disease and pests.
When comes the end of winter’s cold …