Anecdotal Mensurationor

The Persistence of Mensurational Myths

by David Anderson

Olympic Resource Management

Overview

• Set the stage

• Introduce the characters

• Lights, Camera, Action

• Grand Finale

• Credits

Who is ORM

• Pope and Talbot 1850

• Pope Resources 1985

• Olympic Resource Management 1997• Fee Timber 112,000 Acres• Timberland Management• Consulting

Anecdote

Those trees in Dewatto grow funny That a soil hardpan condition present in

the Dewatto block produces trees with stagnant height growth after age forty to fifty that is not explained by site index.

Anecdote Implications

• That timber yields were less than would be expected in Dewatto

• That I was going to have to do extra work to model this hardpan effect.

Where is ORM and Dewatto

Lets See Some Trees

Cast of Characters

• Mining Timber Inventory

• Felled stem analysis

• Locate original reference for growth impact

Data Mining

• 1999 Inventory Project• New aerial photos and stand typing• Cruise all stands >= 45 years of age• Measure site trees

Total Height vs Total Age from Inventory

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Total Age

To

tal H

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ht

TotalHeightKing 70

More Anecdotes

• Me to Head Forester: I’m going to Dewatto to do a felled stem analysis

• Head Forester: Well you know the hardpan isn’t everywhere, maybe only half of Dewatto

Felled Stem Analysis

Had to be cheap, simple and accurate Measure trees on three plots

Two Plots in Hardpan Zone One Plot in non-Hardpan Zone

Plots coincidentally happened to be located in areas with active logging.

Measurements Taken

Stump Age Stump Diameter Height to Crown Base Age at Crown Base Diameter at Crown Base Interwhorl Distances from crown base to

top of stem

Felled Stem Plot Card

Pope Resources:

Total Height vs Total Age for Dewatto Felled Stem Analysis

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Total Age

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King Site 100

Anecdote History• 1956 paper by Willard Carmean about

Puget Sound Trough Soils

• DNR used this paper to adjusted yields lower for lands in the area.

• Charles Chambers years later reviewed the paper and questioned some of the conclusions.

Anecdote History

• DNR did a cooperative felled stem study with Simpson who had used earlier DNR results

• ORM’s CEO from September 2000 to December 2001 formerly was an executive with Simpson.

DNR Anecdote

DNR Felled Stem Study

Grand Finale

• Data mining showed no hardpan

• Felled stem analysis showed no hardpan

• Historical version of anecdote had been disproved

• Dewatto Hardpan is a rural legend.

Credits

Byron Hinners for assisting in felled stem analysis

Charles Chambers who told me the DNR story.

The hardpan anecdote for giving me a opportunity to measure some trees.