lessons learned: writing a book on forest growth and yield modeling aaron weiskittel university of...

Lessons Learned: Writing a Book on Forest Growth and Yield Modeling

Aaron WeiskittelUniversity of Maine

NEMO

• Oct 1 – 2, 2012

• Penn State University

• Contact Laura Leites or John Kershaw if interested in presenting

Introduction• In 1994, Jerry

Vanclay published a book on growth modeling– Bit outdated

• A few other books on the subject– Compilations or

conference proceedings

– Focused on 1 region– Focused on 1 model

type

IntroductionMeet Jerry

Vanclay in 2006 & inquire about

book

David Hann makes mention

that he will retire soon

John Kershaw mentions that has an existing book contract

Naive young assistant GY

prof arrives at UMaine

Overview• 17 individual chapters

• Covers all aspect of modeling– Development– Application– Verification

• Inclusive of all modeling approaches– Statistical– Mechanistic– Hybrid– Gap

• Research focus, but with foresters and students in mind

• Extensive bibliography

• Improved and logical organization when compared to the first book

• Example models throughout

• Focus on statistical individual tree growth models

Chapter 1 - Introduction

Chapter 1 - Introduction

Chapter 2 - Competition

Both distance-dependent and distance-independent measures discussed

Chapter 3 – Site Productivity

Advantages and disadvantages of various measures of site productivity discussed

Chapter 4 – Whole Stand and Size Class Models

Vanclay’s Original Chapter Updated

Chapter 5 – Individual Tree

Chapter 6 – Components of individual tree models

Diameter increment, height increment, and crown recession

Chapter 7 – Allometric Equations

Height to diameter, height to crown base (crown ratio), crown profile, taper/volume, biomass

Chapter 8 - Mortality

Tree and Stand-level Mortality

Chapter 9 – Regeneration & Recruitment

Seed production, dispersal, and germination; Recruitment models

Chapter 10 – Linking Models of Different Resolutions

Parameter recovery; Disaggregation; Constrained; Combined

Chapter 11 – Forest Management

Genetics, Vegetation Management, Thinning, Fertilization, Harvesting

Chapter 12 – Mechanistic Models

Light interception, Photosynthesis, Stomatal Conductance, Respiration, Carbon Allocation

Chapter 13 – Hybrid Models

Mechanically derived covariates and modifiers

Chapter 14 – Model Construction

Data Requirements; Model form; Parameter estimation

Chapter 15 – Model Evaluation and Calibration

-Model Criticism,

-Model Error Characterization,

-Model Benchmarking

-Bayesian Calibration

Chapter 16 – Implementation and Use

• Collection of Appropriate Data

• Generation of Appropriate Data

• Temporal and Spatial Scale

• Computer Interface

• Visualization

• Output

Chapter 17 – Future Directions

• Improving Predictions

• Improving Input Data

• Improving Software

Summary• Available now via Wiley

• 415 pages with 33 tables, 56 figures, and 1244 citations

• $115 (hardback) and $82 (electronic) on Amazon (cheaper than from Wiley w/ my author’s discount)

Lessons Learned!• Most time-consuming, tedious, and challenging project I have

worked on – Also the most rewarding and enjoyable

• Convincing and keeping co-authors engaged in the project is the biggest accomplishment of my career

• Despite the desire, I don’t see myself completing something like this again due to time and energy constraints

• My big royalty check won’t allow me to retire anytime soon– ~300 copies sold

Acknowledgements

• David Hann

• John Kershaw

• Jerry Vanclay

• Dave Hyink

• Robert Curtis

• Martin Ritchie

• Jeremy Wilson

• Laura Kenefic

• Jeff Gove

• Quang Cao

• Peter Marshall

• Andrew Robinson

Questions/Comments