Warning! Note: Prof. García retired from UNBC in December 2014, and this site is no longer updated. More info here.

Forest Growth and Yield

The FRBC / West Fraser Endowed Chair in Forest Growth and Yield was established at the University of Northern British Columbia with funding from Forest Renewal BC (FRBC), and from West Fraser Timber Co. Ltd. Operation began in April 2000. The overall goal was:
"to enhance British Columbia's forest growth-and-yield knowledge-base to accurately predict and sustain timber production in an ecologically, economically, and socially acceptable fashion. Although the program will be provincial in scope, the emphasis will be on northern species and stand types." More...

Long time horizons in forestry cause experience, experimentation, and trial-and-error to be much less useful than in other disciplines such as agriculture or medicine. Therefore, for centuries forest planning has relied on predictive quantitative models that pull together shorter-term observations and synthesize available knowledge. Foresters were also among the first in applying the new statistical theories appeared in the first half of the 20th Century.

In British Columbia, recent interest in this area has been relatively low, due in part to a pioneering development of successful models in the 1960's and 70's, and to the industry focus on timber extraction from virgin forests rather than on tree growing. Increasing emphasis on carbon sequestration and bio-fuels, and the coming on stream of second-growth forests planted over the last few decades, are likely to change that. Carbon management requires knowledge of forest development over the whole life history, not just final logging yields. A wider range of stand density manipulation and other treatments needs to be analyzed, and management may be intensified concentrating in a smaller area of the land base. More flexible predictive tools are required to cope with these and other challenges arising from a changing environment.

Much of our work has dealt with the development of forest growth models based on modern dynamical systems theory. The basic principles, taken for granted in a specialized form in physics and engineering since the time of Isaac Newton, were clarified and generalized in the 1960's. Now applied in many fields, the theory facilitates dealing with systems that evolve in time. Recent research has produced models that integrate physio-ecological knowledge about trees and their interactions, improving data-use efficiency and allowing for environmental change.

Quick links

On this page: Addresses. Teaching. Research. Publications. Presentations.
Other: SIPLAB. Aspen model, Spruce modelSite index. EasySDE. Growth-curve Explorer. Loblolly pine model, TADAM. Mixedwoods. G&Y course. Personal pages. 2005 G&Y Meeting. Process Models Wiki. IUFRO 4.01.05. Stats course.


Oscar García
+1 (250) 960-5004

(Currently operating from Cochoa,Viña del Mar, Chile)

Graduate Research Assistant, PhD Student
Min Jun Lee, MSc
+1 (250) 960-5741

University of Northern British Columbia
3333 University Way
Prince George, B.C.

Ecosystem Science and Management Program


FSTY 405 - Forest Growth and Yield.  Link to the course website .
NRES 710 - Modelling and Simulation (Fall 2011).
NRES 798 - Statistical Methods for Ecologists (Winter 2013). Link.


Here is a background/discussion paper on growth modelling in BC.
(To access this and other materials here you may need to Get Acrobat Reader).

Research update, February 2007.


Stand level models based on TASS. More...

Boreal Mixedwoods

Analysis of the development of mixed aspen - white spruce stands in the Fort Nelson Forest District.  Project under contract with the BC Ministry of Forests.  Completed, see publication by Kabzems & García (2004) below.  More...

Modelling growth of aspen and of aspen-spruce mixtures is underway.

Site index models for spruce and lodgepole pine

New site index/height growth models for interior spruce and for lodgepole pine in the SBS biogeoclimatic zone. The spruce model was part of an MSc thesis by Zhengjun Hu, see Hu & Garía (2010) in the Publications list below.  The pine model was an MSc thesis by Adrian Batho (Batho, 2011).  A combination of stem analysis and PSP data was used, together with advanced dynamic modelling and statistical techniques.   More information and software...

Spruce growth modelSpruce data

A whole-stand growth model for interior spruce in the SBS Zone has been completed, based partly on  Zheng Hu's MSc thesis.   A spreadsheet implementation and details are available.


Software for site index modelling in even-aged stands.  Get it here.

Growth-curve Explorer

A Java applet demonstrating a general family of growth equations and probability distributions.  See here.

Individual-tree modelling in complex stands

Min Jun Lee's PhD research focuses on the development of forest dynamic models for mixed-species stands. The objective is to record and describe tree interactions within complex stands, in order to improve individual-based modelling techniques. Detailed tree stem-mapped data has been collected for a number of stands in central British Columbia. Component species included interior spruce (a hybrid complex of white and Engelmann spruce), trembling aspen, cottonwood, paper birch, and willows. The results from this study are expected to contribute to better understand the processes of forest dynamics, as well as to produce suitable models of individual tree growth for silvicultural and ecological decision-making.

Integrating empirical and process-based growth models

Jack Lonsdale's MSc research combined a dynamic re-implementation of the existing British yield tables for Sitka spruce, elements of the 3-PGS process-based model, and remote sensing for stand closure.  The new model would be expected to predict more accurately the development of young stands.  It would also provide for more flexible modelling of initial spacing and thinning treatments, and of the effect of environmental factors. Work is currently on hold. Conference presentation.

Growth model for loblolly pine in the southeastern USA

A dynamical growth model for loblolly pine plantations was developed in collaboration with Harold Burkhart and Ralph Amateis from Virginia Tech. It followed the structure of the Scube spruce model, validating the methods with a much more extensive dataset. More...

Trembling aspen growth model

A stand growth model for aspen in Western Canada. See here.


García, O.  Siplab, a spatial individual-based plant modelling systemComputational Ecology and Software 4(4): 215-222. 2014. Abstract / Text.

García, O.  Can plasticity make spatial structure irrelevant in individual-tree models?Forest Ecosystems 2014, 1:16. Abstract / Text.

García, O.  A generic approach to spatial individual-based modelling and simulation of plant communitiesMathematical and Computational Forestry and Nat.-Res. Sci. 6(1), 36-47. 2014. Abstract / Text (MCFNS).

Tewari, V.P., Álvarez-González, J.G., and García, O.  Developing a dynamic growth model for teak plantations in IndiaForest Ecosystems 1:9. 2014. Abstract / Text.

Batho, A., and García, O.  A site index model for lodgepole pine in British ColumbiaForest Science 60(5), 982-987. 2014. doi: 10.5849/forsci.13-509Preprint.

García, O.  Forest Stands as Dynamical Systems: An Introduction.  Modern Applied Science 7(5), 32-38. 2013. doi: 10.5539/mas.v7n5p32.

García, O.  Building a dynamic growth model for trembling aspen in Western Canada without age data. Canadian Journal of Forest Research 43(3),  256-265. 2013. doi: 10.1139/cjfr-2012-0366.   Preprint.


García, O.  Self thinning limits in two and three dimensions.  Mathematical and Computational Forestry and Nat.-Res. Sci. 4(2), 66-72. 2012. Abstract / Text (MCFNS).

García, O.   LINK News: Growth and yield of interior spruce: filling in the blanks.  BC Journal of Ecosystems and Management 12(3), xvi–xvii. 2011.  Text (BCJEM).

García, O., Burkhart, H. E., and Amateis, R. L.   A biologically-consistent stand growth model for loblolly pine in the Piedmont physiographic region, USA.  Forest Ecology and Management 262(11), 2035–2041. 2011. doi: 10.1016/j.foreco.2011.08.047Preprint.

Batho, A.  A site index model for lodgepole pine in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia.  University of Northern British Columbia.  M.Sc. Thesis.  April 2011.

García, O.  Dynamical implications of the variability representation in site-index modelling..  European Journal of Forest Research 130(4), 671-675. 2011. doi:10.1007/s10342-010-0458-0

García, O.  A parsimonious dynamic stand model for interior spruce in British Columbia.  Forest Science 57(4), 265-280. 2011. Abstract / text. Preprint.

García, O.   Models and limits to predictability. Natural Resources and Environmental Studies Institute Occasional Paper No. 6, University of Northern British Columbia, Prince George, B.C., Canada. 2010.   Download (NRESI)

Hu, Z. and García, O.   A height-growth and site-index model for interior spruce in the Sub-Boreal Spruce biogeoclimatic zone of British ColumbiaCanadian Journal of Forest Research 40(6), 1175–1183. 2010.   doi:10.1139/X10-075

García, O.  A simple and effective forest stand mortality model.  Mathematical and Computational Forestry and Nat.-Res. Sci. 1(1), 1-9. 2009.   Text (MCFNS).

García, O.  Visualization of a general family of growth functions and probability distributions — The Growth-curve Explorer. Environmental Modelling and Software 23(12), 1474-1475. 2008.  Abstract/Text.

García, O. Dimensionalidad en los modelos de crecimiento [Dimensionality in growth models]. Cuadernos de la Sociedad Española de Ciencias Forestales 23, 19-25. 2007. Copy (Spanish). English version above, "Models and limits to predictability", 2010.

Batho, A. and García, O.   De Perthuis and the origins of site index: A historical note . Forest Biometry, Modelling and Information Sciences 1, 1-10. 2006.    Text (FBMIS)

García, O.  Scale and spatial structure effects on tree size distributions: Implications for growth and yield modelling. Canadian Journal of Forest Research 36(11), 2983-2993. 2006.   Abstract/Text at CJFR website.   Local copy.

Salas, C., and García, O.  Modelling height development of mature Nothofagus obliqua . Forest Ecology and Management 229, 1-6. 2006.   Abstract/text on line.  Preprint.

García, O.  Unifying sigmoid univariate growth equations.   Forest Biometry, Modelling and Information Sciences 1, 63-68. 2005.   Text (FBMIS)

García, O. Distributions and spatial structure.  In: Reynolds, Keith M. (ed)  "Sustainable forestry in theory and practice:  Recent advances in inventory and monitoring, statistics and modeling, information and knowledge management, and policy science".  USDA Forest Service,  Pacific Northwest Research Station, Gen. Tech. Rep. PNW-GTR-688.  CD-ROM and on line. Text.

García, O.  TADAM: A dynamic whole-stand approximation for the TASS growth model. The Forestry Chronicle 81(4), 575-581. 2005.  Errata: 81(6), 815, 2005.  Abstract/textErrata.

García, O.  Thinking about Time.  In: Naito, Kenji (ed.)  The Role of Forests for Coming Generations -- Philosophy and Technology for Forest Resource Management, p.47-54.  Japan Society of Forest Planning Press.   Utsunomiya, Japan, 2005.  Preprint.

García, O.  Site index: Concepts and methods.  In: Cieszewski, C. J., and Strub, M.  (eds.).  Second International Conference on Forest Measurements and Quantitative Methods and Management & The 2004 Southern Mensurationists Meeting, p.275-283.  Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA.  2006.  Text.

García, O.  Comparing and combining stem analysis and permanent sample plot data in site index models.  Forest Science 51(4), 277-283. 2005. Abstract/text.

García, O. and Batho, A.  Top height estimation in lodgepole pine sample plotsWestern Journal of Applied Forestry 20(1), 64-68. 2005. Abstract/textComputer(3) code.


Kabzems, R.D. and García, O.  Structure and dynamics of trembling aspen-white spruce mixed stands near Fort Nelson, B.CCanadian Journal of Forest Research 34(2), 384-395. 2004.  Abstract/text.

García, O.  Dimensionality reduction in growth models:  An example.   Forest Biometry, Modelling and Information Sciences 1, 1-15. 2003.   Text at FBMIS

García, O. and Ruiz, F.  A growth model for eucalypt in Galicia, SpainForest Ecology and Management 173(1-3), 49-62. 2003.  Abstract/textErrata.

Some conference presentations

When the wrong model is best: Confounding and confusion in individual-tree models, Monterey, California, 22-24 June 2014.  PDF (1.7 Mb).

Ecosystem Design for Multiple Services with an emphasis on Eurasian Boreal Forests, St. Petersburg, Russia, 9-11 November 2011.  PDF (450 Kb).

Colloque INRA "Modélisation pour les Resources Naturalles", Montpellier, France, 18-20 June 2008.  PDF (1.8 Mb).

2008 World Conference on Natural7 Resource Modelling, Warsaw, Poland, 15-18 June 2008. PDF (1.6 Mb).

Western Mensurationists Conference, Hilo, HI, July 2005.  Transcript (PDF, 675 Kb).  Original slides.

The Role of Forests for Coming Generations: Philosophy and Technology for Forest Resource Management, Utsunomiya, Japan, October 2004. PDF (834 Kb).

2nd International Conference on Forest Measurements and Quantitative Methods and Management, Hot Springs, AR, June 2004. PDF (661 Kb).

2003 Western Mensurationists Conference, Victoria, BC, July 1-3.  PDF (399 Kb).

Western Mensurationists ' Conference, Leavenworth, WA, June 2002.  PDF (335 Kb).

WESBOGY Association Meeting, Peace River, Alberta, September 2001.   PDF (572 Kb).

Southern Mensurationists Conference, Jekyll Island, GA, November 2000.   PDF ( 468 Kb).

Meeting on "Growth and Yield in Central and Northeastern BC", held at UNBC, 29 June 2005

Link to web site.