Sunday, June 15, 2014

Darby Creek

Arriving at Darby Creek

Hitching post and beautiful flowers (is it a currant bush?)
I went out to Idaho to help some long time friends of the family (and friends of mine) with some tree trimming.

The Brown's place on Darby Creek is a very special place.  When I approached, all that I could see was a non-descript shed and a hitching post.  Shire Brown greeted me as his parents are currently in Switzerland.  Shire strikes me as an earnest, sensitive, articulate young man, somewhere in his mid twenties.  It had probably been 15 years or longer since I had seen him last.
The obvious 8 lane highway into Darby Creek

The Darby Creek overpass with tourist overlook pullout
Creeks run and foot bridges run across them.  Cedar shingles and old plants and old buck fences and old rare poppies abound.  Red lichen encases all of the old stuff as a testament to its age.  I love it here.  I saw the mother of the hops plants that we have back in Pinedale.  Over 20 years ago my father dug a clipping and it now surrounds our house as well.  This is the same hop plant we hope will encase the new pergola.  There was a nice stand of river birch next to the guest house with white peeling beautiful bark.  I had reminded myself to take a picture of the stand but somehow I forgot.

Darby Creek
To get to the main house, guest house, woodshed and other outbuildings requires stepping through a green curtain of trees and other plants through a shadowed path.  From the outside, the place is completely hidden by the plants.  The path to the house looks like a rarely used game trail.  I hiked in the 100 feet or so and widened it a bit with my considerable size.  Shire treated me to a cup of strong delicious black coffee and we re-introduced ourselves and caught each other up on our lives and families as much as possible in half an hour.  Then we got to work.

The Job

Lichen covered moose antlers, buck fence, wild rose (not yet bloomed)
Gordon Brown (Shire's father) and I have been discussing this job through email correspondence for a long time, perhaps a year.  The enormous P. angustifolia (narrow leaf cottonwood) had a number of large limbs, many of them dead, looming over the guest house and woodshed from high above.  Gordon has been concerned that their eventual fall will result in significant damages to the property.  He had sent me some pictures but they really didn't do the situation justice.  The trees and limbs were larger and more precarious in person.

Shire expertly dismantles large limbs with a chainsaw
Shire had no experience with tree work, but is an accomplished climber and mountaineer so he was able to assist me with very little training.  After a safety briefing, I ascended several of the trees and began removing all of the threatening dead limbs and many of the biggest and most threatening live ones.  Shire hooked and unhooked the necessary equipment from my climbing line as I was aloft and trimming.  We both wore helmets and I wore a harness with a redundant tie-in system in full OSHA compliance.

As I dropped limbs, Shire further dismantled them and organized them.  Eventually I worked my way to the top of the forest canopy, dense as individual canopies overlapped.  By that time the wind had come up quite a bit and there was up to 6 feet of play in the tree due to the wind.

On swaying trees


A giant twisted cottonwood sways in the wind differently than any other species.  This is because the truck is not straight like a ship's mast, but typically grows with a tilt in one direction for 5 or 10 feet and then a tilt in a different direction for the next several feet.  This irregular tilting growth continues to the top of the tree.  Each section of the growth tapers to the next section.  The result of the irregular jointed shape of the trunk results in the top describing a highly irregular motion as each varying section of the tree moves in a different direction in response to the wind and inertial forces of their adjoining sections.  What it means for a human at the top of one of these in high wind is that it moves all over the place with no apparent rhyme or reason.  Having been in a number of these cottonwoods, I can anticipate some of these movements and I also allow myself to gently sway with the tree comfortably rather than freezing, or fighting, or falling off.  The swaying of a cottonwood reminds me of a spirograph or the crazy office toys that move in erratic directions.

Why Cottonwood sways erratically (photo cred to Ivy from Flikr)

Large straight trunked conifers sway in the wind like a ship's mast in high seas.  As a wave comes underneath the ship, the mast tips away from the approaching wave, stands straight up as the peak of the wave passes under the ship, and then points away from the departing wave.  At the trough of the wave again the mast stands straight up.  Large conifers are pushed by the wind and then snap back, over compensating into the wind.  I have been in a 100 foot tall spruce with 15 feet or so of sway in strong winds, but the tip describes a line segment in the same direction as the wind.  Even when the wind seems steady, the conifers sway a lot as they move with and against the wind.  Old sailors in a crows nest at the top of a ships mast experienced the same movement.

Oaks, ash, and willow in high winds are pushed in the direction of the wind by their canopies and are held there in place as long as the wind is steady.  Then as the wind drops off, they move back into a straight up position.  I find these trees the least interesting in swaying in high winds.

High winds while climbing would terrify me and cause me to cancel tree trimming 10 or 15 years ago.  Now I feel gently rocked, awed and appreciative of these giant life forms.

I don't know how tall palm trees sway in the wind as I have never climbed one.

Back to the job

The author eyeing the most difficult limb removal of the day (cred to Shire w/ my phone)

There was one 25% dead limb that particularly threatened the guest house.  This limb was about 40 feet long and a foot and half in diameter where it joined the tree.  It was particularly difficult to remove as there was no growth above it to tie myself into or rig drops from.  I gracelessly shimmied out on this limb and cut giant heavy pieces from it.  I tied these pieces and ran the rope through a carabineer attached to a sling attached further up to a branch and then run through a friction device attached to an anchor attached to the base of the trunk and then run out to Shire who did an admirable job belaying them down.  He belayed somewhere between 6 and a dozen pieces of 100 pounds or more slowly and safely to the ground.  Uncontrolled their fall could easily demolish a structure.  There is a lot more stored potential energy in a tall tree than most people realize.  I once felled a 100 pound limb from 60 feet up in a lombardi poplar into a concrete car pad and punctured right through it.

Eventually we finished clearing the branches and I left all of the debris for Shire to clean up and organize.  I packed out all of the gear over the bridges and flowing creeks back out to the truck and headed home.

Shire and I cut the canopy from above the guest house and wood shed.  At the start of the day, little sky was visible, but by the end there was a giant circle of sky.  I told Shire that in a year or 2 the canopy of the existing trees will envelop the space, growing to capture any light for photosynthesis.  In several years they will start to grow in girth and in a decade or 2 tree trimming will be necessary again.  Cottonwoods drop enormous limbs as a part of their growth process and evolutionary heritage.  They are great examples of CODiT (Compartmentalization Of Disease in Trees).  When a limb is weak or dying, cottonwoods restrict resources to it and it dies and drops off the tree.  Here in rural Wyoming along creek beds one can see huge vibrant cottonwoods with many giant dead limbs below.  This makes large cottonwoods an especially problematic tree around homes.  Properly managed, they can be dealt with and I hope I helped at Darby Creek.

No comments:

Post a Comment