Observing “Fall” Harvest

Apples on the barnyard tree Lisa A. Wisniewski

Apples on the barnyard tree
Lisa A. Wisniewski

Plunk, plink, thunk.  Plunk, thunk, plink.  Plink, plunk, THUNK!

Autumn’s symphony began in my area, complete with falling buckeyes, black walnuts, and apples from the trees surrounding my house.  At any given hour, one or all of the trees allows its bounty to fall from limb to ground, making noise upon impact.  The heavier apples and black walnuts make a deeper, lower sound as they hit the grass or the gravel in the driveway.  The lighter buckeyes fall more gracefully, hit the ground with a higher pitch, and split into pieces to reveal shiny dark brown inner treasure.

Buckeyes broken open Lisa A. Wisniewski

Buckeyes broken open
Lisa A. Wisniewski

The plunking, plinking, and thunking the past few weeks kept me busy.  A cold front with rain and wind knocked much of the fruit and nuts to the ground.  I raked the fallen “harvest” into piles, shoveled the piles into the wheelbarrow, and dumped the contents into ruts along the edge of the fields.  Black walnuts and buckeyes make very good fill for ruts, though sometimes I end up with a small forest in early spring with saplings sprouting from the cracked shells.

Annual Music Festival

This annual music and cleanup festival started many years ago when my grandmother owned the property.  Back then, we also had pear and chestnut trees in the yard, adding their own sounds to the mix.  Before mowing the grass, Gram would lead us grandkids around the yard with bamboo rakes, a short handled flat shovel, and a squeaking wheelbarrow.  We’d take turns raking, shoveling, and wheeling.  Afterwards, Gram would mow the grass while we played or did other chores for her.

The chestnuts were first to fall each year, usually in late September, and the prickly outer shells made them our least favorite pickup duty.  Even with gloves, we’d end up getting pinched and hear Gram say a few swear words.  The chestnuts also had a pungent, sour smell that could be overbearing if the weather was warm.

Pears typically fell next, attracting ants, bees, yellow jackets, and wasps with the sweet juice emitted from bruises and cracks.  The Bartlett pear trees lined the driveway and the road, so cleanup was a bit more time consuming.  There was also a Seckel pear tree in the middle of the front lawn.  We had to hand pick pears from the gravel in the driveway and the road pavement and be very careful of traffic.  Pears in the grass could be raked, though caution was required with all the insect activity.  Some pears without blemishes, bruises, or insect infestation were salvaged for eating, making jam, and baking pies.

Buckeyes everywhere! Lisa A. Wisniewski

Buckeyes everywhere!
Lisa A. Wisniewski

Buckeye pickup overlapped pear cleanup, but was usually less eventful.  Though the buckeye shells had spikes, they typically fell off upon hitting the ground.  Many of the buckeye tree leaves also fell at the same time, so sometimes we’d use a tarp instead of a wheelbarrow and drag the tarp way over to the middle of the north field.

Yellow apples in my yard Lisa A. Wisniewski

Yellow apples in my yard
Lisa A. Wisniewski

Apples usually started falling along with pears and buckeyes, adding to our cleanup efforts and time spent helping Gram.  Apple cleanup meant apple pie and apple cake, so we never complained about this chore.  Rakes could be used when the apples were small and first started falling, but once the apples grew larger, we had to hand pick them from the ground.  Like the pears, apples attracted insects, so we had a few adventures with bites, stings, and chases.

Black walnuts on the tree Lisa A. Wisniewski

Black walnuts on the tree
Lisa A. Wisniewski

Black walnuts came last and with abundance.  The two gigantic trees in the back yard had the ability to unleash several wheelbarrows of walnuts in a 24 hour period.  Once they started falling, so did the leaves and dead twigs from the branches.  Cleanup could be a chore at times with all the mess, not to mention the black stains left on hands not wearing gloves.  Gram always kept an abundance of white cotton gloves in a barrel, specifically for cleanup and for us grandkids.  By the end of cleanup season, our gloves were stained deep brown or black and reeked strongly of walnut juice.

Physics of Falling

One aspect of the fall harvest that has always fascinated me is the force exerted by falling fruit and nuts.  Questions that flooded my mind during my child and teenage years included:

  • What causes the falling?
  • What force can falling objects exert?
  • Why do the apples and walnuts bounce when hitting the ground?

As I grew older, I learned the answers, most of which entailed physics and Newton’s Laws of Motion.

Newton’s Laws can be summarized as follows:

  • An object in motion tends to stay in motion and an object at rest tends to stay at rest unless a force acts upon it.
  • Force is equal to the change in momentum over change in time and for objects of a constant mass, the force exerted is equal to the mass times acceleration, or F = ma.
  • For every action, there is an equal and opposite reaction.
Apples waiting to fall Lisa A. Wisniewski

Apples waiting to fall
Lisa A. Wisniewski

Apples, buckeyes, and walnuts stay attached to the tree branches via their stems.  Rain, wind, or other forces acting upon them increases the potential for falling.  Falling occurs when the stem can no longer support the weight of the fruit or nut.  The stems can become brittle from sunlight, wind, or rot.

Another factor is rain or moisture.  Raindrops add weight to the fruit and nuts, which exert a stronger downward force upon the stem.  When the force is too much for the stem to withstand, the stem releases the fruit and nuts, allowing them to fall to the ground.

Falling from high up in this tree results in a thud Lisa A. Wisniewski

Falling from high up in this tree creates a rather large force
Lisa A. Wisniewski

As the fruit and nuts fall, they accelerate due to gravity.  The force exerted is equal to the mass of the fruit or nut times the acceleration of gravity, 9.8 m/s2 or 32.17405 ft/s2.

Upon impact with the ground, the force of the fruit or nut is reciprocated by the ground, causing the fruit and nuts to bounce and sometimes roll.

Carrying on the Tradition and Staying Healthy

Towering black walnut tree Lisa A. Wisniewski

Towering black walnut tree
Lisa A. Wisniewski

Though a good number of the trees from my childhood have succumbed to age, storm damage, or blight, the few remaining trees are quite large and typically provide an overabundance of fruit and nuts.  The buckeye tree by the driveway is easily 45 feet tall and the walnut tree behind the house is a good 50 feet tall and 25 feet wide.  Its deep crevices in the bark are prime locations to find shells from locusts during July and August.

The apple tree by the garage yields yellowish red fruit about three inches in diameter that are great for pies, applesauce, and baked apples.  The apple tree over in the old barn yard yields smaller red striped apples that are tarter tasting and great for snacking.  These trees are quite old and were part of an orchard on the property many years ago.

The chore of cleaning up the fallen harvest has become a tradition to me, one I treasure despite all the work it entails.  Something about the raking and smells in the air adds an ambiance to the season that I find relaxing and therapeutic.  Plus, the exercise is good for the mind, body, and soul.

Sunrise in the breeze under the black walnut tree Lisa A. Wisniewski

Sunrise in the breeze under the black walnut tree
Lisa A. Wisniewski

References and Related Links

Apples – http://pennsylvaniaapples.org/apples/facts/

Bartlett pears – http://usapears.org/bartlett/

Black walnut tree identification – https://www.extension.iastate.edu/forestry/iowa_trees/trees/black_walnut.html

Buckeye tree – http://www.britannica.com/plant/buckeye

Chestnut trees – http://www.acf.org/field_guide.php

Exercise benefits – http://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise/art-20048389

Gravity – http://www.engineeringtoolbox.com/accelaration-gravity-d_340.html

Locusts – http://animals.nationalgeographic.com/animals/bugs/locust/

Newton’s Laws of Motion – https://www.grc.nasa.gov/www/K-12/airplane/newton.html

Physics – http://www.physics.org/article-questions.asp?id=18

Raking as exercise – http://www.iowachiroclinic.com/how-to-turn-raking-leaves-into-a-healthy-workout/

Seckel pears – http://www.treesofantiquity.com/index.php?main_page=product_info&products_id=358

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