Chronicles Of Measuring Champion Trees

Black Cottonwood

Winter storms in the Pacific Northwest can be brutal. The winter of 2007-08 was an exceptionally tough one for trees in western Oregon. Hurricane-like windstorms battered the coast bringing down two of the largest trees in the state: the famed Klootchy Creek Spruce and another giant, the Rector Ridge Spruce. While the winds in the Willamette Valley were far less intense, they were still severe.

We know as professional arborists that Black Cottonwoods are notoriously weak and unstable trees. During a harsh winter, trees can sustain internal damage that only manifests after leaves and new growth are set in the spring. Storms (even mild ones) that occur after leaf set are often responsible for major branch failures.

In urban areas, cottonwood is well known for its overwhelming size, urine-like scent and extremely brittle wood. They are notorious for shedding large branches that can destroy homes and cars. Their roots are often responsible for cracking foundations, lifting sidewalks and creating snake-like speed bumps in our roadways. Cottonwood trees have been banned from planting within many neighborhoods and city infrastructures across the US.


In contrast to urban areas, along rural riverbanks the cottonwood's invasive root systems and branch shedding habits are beneficial. Cottonwood trees lose large branches from their canopies that spear into the ground, take root and skip the process of growing from seed. This can speed up the forest's recovery after a major storm or flood. Along rivers these trees' massive root systems slow erosion, stabilize river banks and improve habitat for fish and wildlife. Cottonwoods are fast growing, opportunistic trees. When light is made available, it is often the first to fill the void. These are the characteristics of a riparian pioneer tree species, and in this category of trees the cottonwood is the largest in North America. The largest Black Cottonwood in the world is located in Willamette Mission State Park just north of Salem, Oregon.

During the late winter of 2007 we contacted representatives at the Willamette Mission State Park to check-up on the big tree's health. The representatives said that the tree had lost some large branches in the windstorm and they were concerned about whether it would still 'measure up.'  Planning for everything but the weather, we set a date and set out with our crew to re-measure this classic Oregon champion tree last measured in 1984 by its finder, Maynard Drawson.

On April 19th 2008, we packed up our gear and headed south from Portland. We were very unnerved when we arrived at the tree to see that the leaves had fully set and the weather was very windy and rainy. From a distance we noticed broken branches and tearouts from previous storms which thankfully were rather minor; a few decent sized branches were down, but nothing that threatened the tree's overall health or champion status. Doing our usual pre-climb visual inspection, we found ourselves dumbstruck by the massive, column-like trunk, which kept its taper up to the first branches. Renowned big tree guru Dr. Robert Van Pelt describes this as a "WOW" (wall of wood) tree.


We set our lines in the tree's upper canopy and surveyed the weather, knowing that a spring storm could create an array of very dangerous situations for climbers. As the weather seemed to be improving we began to climb, intent on getting a height measurement and getting down before the wind picked up again. Alas, we were not so lucky. Just as we approached the top of the tree the weather took a turn for the worse.  The wind became strong and gusty as hail mixed with rain tossed us around in the canopy. We quickly realized this spring storm was the real deal, and one at a time we carefully rappelled out of the tree.

Back on the ground we took stock of the situation. Based on the fickle nature of Oregon spring weather and the difficulty of getting our crew together with all our gear, we decided to grab some lunch and try again in a few hours. Over burgers we were constantly checking the latest radar images and aimed for what looked like a gap in the storm. Our timing was good enough that when we returned the winds were calm and double rainbows were visible from the boggy meadow in which the champion Cottonwood resides. We geared up, and crossed our fingers that the weather would hold out. Our lines already set in the tree, we quickly measured the height, removed all the lines from the tree, and then measured the trunk diameter and crown spread from the ground.  Because of the various branch failures the average crown spread measured 93 ft; the previous measurement was 110 ft.  However, while 25 years had whittled away the crown's reach somewhat, and the height had gone from 158 ft down to 155 ft, the trunk had put on 2 ft 4 inches of circumference, growing from 8.5 ft to 9.23 ft in diameter. These changes increased the tree's points total from 506 to 527.


We later found out that a recently discovered Black Cottonwood in Cowlitz County, Washington had been measured and could claim 515 points. While that was enough to beat the 1984 measurements, our more recent measurements show conclusively that far from being eclipsed, the Willamette Mission Black Cottonwood is still the largest of its species in North America.


Willamette Mission State Park Brochure (requires Acrobat)



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