Naturespeak A naturalist's view of the world

May 28, 2008

I Came, I Seed, I Conquered

Filed under: Uncategorized — wykes @ 8:14 pm

  They issued from the tree cavity one by one and encircled the trunk in a general downward direction. Six brand new Red Squirrels tentatively made their way toward the ground 10 feet below to gather maple seeds. Moving in nervous spurts – as if driven by puffs of inner air – they constantly stopped to employ their keen senses toward predator detection. Arriving at the base, they extended their tiny bodies out only as far as absolutely necessary in order to snatch a winged seed from the ground with their mouths. Most kept their hind feet firmly in contact with the bark while venturing leech-like with their forequarters toward the intended prize.

  Seed in mouth, they retracted and scurried back to a horizontal location on a branch or root platform to perform a precise culinary dissection (see above). The seeds were dispatched with a few peeling bites to expose the green inner core and the dry wings were released to the breeze.

  These young squirrels were well on their way to independence but highly nervous about life in general. The shadow of a passing robin eventually sent them into a panic. All the adventurers swiftly retreated to the safety of the den hole where they remained for the rest of the afternoon.

  This litter of Reds had the good fortune to be born into a banner maple seed year. They will have the luxury of overstuffing on the nutritious meal stuff well before the supply runs out. Their efforts will have little or no impact on the maple crop. It is very likely that several seeds will go on to sprout and several squirrels will grow into obnoxious adults this year.

  Last year, the story would have been very different.  Many of last years squirrlets would have grown up without tasting a single maple seed because the entire seed crop failed. I tried to follow the course of the Red and Silver Maples from flower to seed last spring but found that an early cold spell nipped the production in the bud. These two species put out their seeds early in the season– a risky behavior during a cold spring. Other maples wait until fall to produce their precious packets of life. I literally found only a few dozen spring seeds that matured and spiraled to the ground.  Such was the case throughout the region. 

  Trees, like the Red and Silver maples, tend to be very resilient and follow bad years with incredibly productive ones like this one. To those of us who are homeowners that have to clean out our gutters and sweep off our driveways, this may not seem to be especially welcome news. But, I suggest you take a squirrel’s eye view of the situation and welcome the opportunity.

  Maple seeds are technically called “samaras” – another one of those Latin words which means “elm seed.”  This, of course, makes no sense but since elm seeds are winged, the term has come to refer to all seeds that have wings (and you don’t argue with dead Latin people). They, the seeds that is, are made to autogyrate their way to the ground via their stiff mono wings.

  The samaras start off as mismatched but conjoined pairs (see here) but upon maturing split up into independent travelers. The purpose of the wing is to slow down the seed descent enough so that the wind can transport it away from the parent tree. Landing directly under the tree will place you into a fatal shadow land where growth is impossible. It takes about a foot and a half of drop before the seeds re-orient themselves seed first and begin to spin (a fact I discovered after taking this ill fated art shot!). At this point in the fall, the wing is engaged (naturally designed at a perfect 3:1 ratio of length to width) at a 15 degree tilt and rotation begins. The fall is reduced to approximately 3 feet per second and the wind is given a chance to carry the seed away from the parent tree. 

  Most of the seeds don’t make it very far.  On the ground around the Red Squirrel maple, I counted an average density of 40 seeds per square foot!  Most -if not all -of the seeds will end up as sun-deprived seedlings, squirrel meal, or victims of a rotating steel blade.  I witnessed a few that fortuitously dropped during a stiff breeze, and these were carried up and out of sight. Maybe one or two of these will find soil and sanctuary.

  My little Red Squirrels could care less about such things, but they too will need to spread away from the home tree in order to survive. Their parents will drive them off just as the wind pushes samaras to distant locations. In the real world, an apple needs to fall far from the tree in order to have any chance at life.

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