Thursday, June 30, 2016

Time and Chance Happeneth to Them All

 I returned, and saw under the sun, that the race is not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favour to men of skill; but time and chance happeneth to them all.   Ecclesiastes 9.11  KJV

To maintain a stable population, an individual needs to have, on, average, one child.  This is no less true for oak trees than for humans.  But it is an axiom of nature that individuals of every species have more offspring than that--very often enormously more.  The house sparrows nesting in the old maple in my front yard will have a little brood in their nest by now--and house sparrows can have several broods per year.  A female mosquito can lay hundred of eggs at a time, and thousands over her life.  And an oak tree?

A big oak tree can pave the ground so thickly with acorns that your feet won't touch the ground as you walk.  Though the tree will have lean years as well, it will produce crops like this many times over its long life.  All of this takes enormous expenditure of resources.  And why?

Life's a crap shoot.  Any given offspring faces very long odds of surviving to have its own brood.  Predators,** disease, competition, starvation, drought, cold--there are any number of dangers and forces at work.  We forget this sometimes because we have so modified our environment* that nearly all of our children (in the first world, at least) grow to adulthood.  But for every other species enormous fecundity is necessary for most individuals just to get a foot in the door of the next generation.  

(And any genetic trait that increases your ability to survive and get more offspring to adulthood will subtly change the genetic make-up of that next generation--which is natural selection, the chief mechanism of evolution!)

 Gray birch seeds (light brown with translucent wings), the scales that 
accompany them (dark brown fleur-di-lis), and sprouts (top left, bottom right)

 More gray birch sprouts.

Pitch pine sprouts.

I had special reason to ponder this chanciness after my little winter project.  Having collected seeds of many native trees last fall, it occurred to me to plant some in my yard in the spring.  I carefully wrapped seeds of nearly a dozen species in moist paper towels, bagged them in plastic, and kept them cold over the winter to break their dormancy.***  Those that had not gotten moldy I planted in various places around the yard back in late March.  At least some were alive, since they had sprouted.  I didn't keep track, but must have planted over a hundred seeds.  Soon after, we had a little snow, and then a hard freeze.  I didn't worry too much, figuring that, such wild species could take a little weather on their own.  Then I got very busy and forgot about them.  A very dry spring followed.  I finally sought out the little patches I had planted, and found not a single shoot.  No survivors.  I had forgotten for awhile that plants succeed at least as much from their numbers as their toughness.  Yet another lesson in the hard facts of life.

This year's crop of black oak young-in's is coming along nicely.

*That modification has come at the expense of most of the ten million-odd species sharing the earth.

**Although, weirdly enough, an oak tree can put predators to work!

***In a process called "cold stratification."  Actually, I tossed them into the trunk of my car, to be exposed to something like natural temperatures, but not to predators.

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