Understanding the Factors Influencing Stem
Form with Modelling Tools
Robert Schneider
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
2 Data Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
3 Quantifying Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
3.1 Ring Width Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
3.2 Stem Taper . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 300
3.3 Comparing Allometric Exponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
4 Theoretical Conception of Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
4.1 Hydraulic Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
4.2 Biomechanical Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304
5 Empirical Evidences of Changes in Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
5.1 Literature Review . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 305
5.2 Untangling the Effect of Wind and Climate on Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . 306
6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Abstract The shape of tree trunks has been studied in Forest Sciences for a long
time, since the volume and biomass of the tree is directly related to its shape. This
paper reviews the tools used to study the stem form, theories that explain the
observed variations and some empirical observations of changes in stem form with
climatic variables. A case study using balsam fir (Abies balsamea) data is used to
highlight some modelling aspects. The ways to quantify stem form have evolved
over time, and now it is mainly studied by either modelling the vertical growth
distribution along the stem or with stem taper models. The results of the former will
have implications in the fields of dendrochronology and wood properties and the
latter is more important for estimating volume in national forest inventories or for
Communicated by Hans Pretzsch
R. Schneider (*)
Chaire de recherche sur la forêt habitée, Département de Biologie, Université du Québec à
Rimouski, Rimouski, QC, Canada
e-mail: Robert_Schneider@uqar.ca
© Springer International Publishing AG, part of Springer Nature 2018
Progress in Botany (2019) 80: 295–316, DOI 10.1007/124_2018_21,
Published online: 24 June 2018
295
Form with Modelling Tools
Robert Schneider
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
2 Data Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
3 Quantifying Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
3.1 Ring Width Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
3.2 Stem Taper . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 300
3.3 Comparing Allometric Exponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
4 Theoretical Conception of Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
4.1 Hydraulic Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
4.2 Biomechanical Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304
5 Empirical Evidences of Changes in Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
5.1 Literature Review . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 305
5.2 Untangling the Effect of Wind and Climate on Stem Form . . . . . . . . . . . . . . . . . . . . . . . . . . 306
6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
Abstract The shape of tree trunks has been studied in Forest Sciences for a long
time, since the volume and biomass of the tree is directly related to its shape. This
paper reviews the tools used to study the stem form, theories that explain the
observed variations and some empirical observations of changes in stem form with
climatic variables. A case study using balsam fir (Abies balsamea) data is used to
highlight some modelling aspects. The ways to quantify stem form have evolved
over time, and now it is mainly studied by either modelling the vertical growth
distribution along the stem or with stem taper models. The results of the former will
have implications in the fields of dendrochronology and wood properties and the
latter is more important for estimating volume in national forest inventories or for
Communicated by Hans Pretzsch
R. Schneider (*)
Chaire de recherche sur la forêt habitée, Département de Biologie, Université du Québec à
Rimouski, Rimouski, QC, Canada
e-mail: Robert_Schneider@uqar.ca
© Springer International Publishing AG, part of Springer Nature 2018
Progress in Botany (2019) 80: 295–316, DOI 10.1007/124_2018_21,
Published online: 24 June 2018
295