Amaro A., Reed D., Soares P. (editors) Modelling Forest Systems

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30Amaro Forests - Chap 26 1/8/03 11:54 am Page 316

316 P. van Gardingen

This approach generated demand in each country for additional studies and to use

the resulting knowledge to contribute to the process of negotiation on forest man-

agement and policy issues. The feedback at these sessions indicated that new

approaches were required to present results to meet the needs of different stake-

holder groups.

Iterative approach

Each pilot study needed to involve an iterative approach to link growth and yield

tools to management and policy

. This was driven by a number of issues, including

data availability, experience of the users and the reﬁnement of the research question

as the study progressed. It is recognized that such an approach should be the norm.

The ISLA study in Guyana provides a good example, where the simple initial study

was used to demonstrate the value of yield scheduling for the association’s manage-

ment plan and is now being used to justify future investment in the collection of sta-

tic inventory. It is expected that the yield-scheduling exercise will be repeated when

the new inventory data are available and the group has further reﬁned the purpose

of the study.

Training

The provision of training to users of the tools and resulting knowledge was given a

consistently high priority in all of the pilot studies. Users in the partner countries

expr

essed a need for training in a range of topics to support the application of the

tools. In addition to training in running the tools, they assessed needs for training

in:

● basic forest management;

● statistics and data processing;

● effective presentation of results to support management and policy decisions;

and

● interpretation of results from scientiﬁc and ﬁnancial analysis and the concepts

of risk and uncertainty (to be pr

ovided to forest managers and policy makers).

The training needs assessment associated with the pilot studies emphasized

that the impact of tools supporting for

est management will only be increased when

the application of these tools is integrated with a general improvement in the skill-

base used for forest management and policy development.

Conclusions

The results from the pilot study showed that existing management tools could be

used to support management decisions and policy making for tropical forests in

developing countries. The changing nature of these activities means that the suc-

cessful implementation of these tools requires integration within a wider process of

dialogue between stakeholders. Some of the most important conclusions of the stud-

ies are summarized here.

● Existing growth and yield models for timber production are adequate for man-

agement and policy applications.

30Amaro Forests - Chap 26 1/8/03 11:54 am Page 317

317 Regulating the Yield of Goods and Services

● The management options simulated by these models need to be expanded and

improved.

● The available tools need to be expanded to cover other goods and services pro-

vided by for

ests.

● Users require guidelines on how to apply tools to support management and

policy and the pr

esentation of results.

● More than one type of tool may be required to meet the range of potential

applications. The choice of a tool will depend on the application and availabil-

ity of data. Users need assistance in choosing the best tool for their own cir

cum-

stances.

● Data availability may limit some application tools, but much can be done now

with existing data sour

ces.

● There needs to be better integration of yield regulation tools with other stan-

dar

d forest management tools, including GIS and ﬁnancial analysis.

● Financial and economic tools need to be expanded to provide new instruments

supporting the sustainable and equitable management of for

est resources.

● Involve end-users in a process of iterative action ‘research’.

● Results should be made available to a wide range of stakeholders in a form that

they can understand and use.

● Training is essential to increase the effectiveness of tools supporting multiple

objective for

est management.

The yield regulation pilot studies described in this chapter have identiﬁed a number

of issues that limit the application of gr

owth and yield tools to support forest man-

agement in developing countries. The results illustrate that stakeholders need to be

encouraged to overcome these through a variety of approaches to link growth and

yield tools within a framework for forest and land-use management and policy. It

can be argued that some form of forest inventory is an essential prerequisite for any

type of forest management. The studies have demonstrated that such data can be

utilized through the application of appropriate yield prediction tools to provide pro-

jections of future productivity. The remaining challenge is how to integrate these

tools into the decision-making and policy process for forests in developing countries

such that they deliver against accepted management and development objectives.

Acknowledgements

This chapter draws upon the work of many colleagues in institutions working in

partnership to develop the approaches described. Their assistance and support is

gratefully acknowledged. This document is an output from a project funded by the

UK Department for International Development (DFID) for the beneﬁt of developing

countries. The views expressed are not necessarily those of DFID R6915 Forestry

Research Programme.

References

Alder, D., Wright, H.L. and Baker, N. (2002) MYRLIN: Methods of Yield Regulation with Limited

Information. Oxford Forestry Institute, University of Oxford. Available at www.myrlin.org

Ashton, M.S., Mendelsohn, R., Singhakumara, B.M.P., Gunatilleke, C.V.S., Gunatilleke,

I.A.U.N. and Evans, A. (2001) A ﬁnancial analysis of rain forest silviculture in southwest-

ern Sri Lanka. Forest Ecology and Management 154, 431–441.

30Amaro Forests - Chap 26 1/8/03 11:54 am Page 318

318 P. van Gardingen

Fadilah, D. (1997) Minimum Area Model: a Financial Approach to Determine Minimum Area of

For

est Management Unit. Report and User Guide. Berau Forest Management Project, Jakarta,

36 pp.

Huth, A. and Ditzer, T. (2001) Long-term impacts of logging in a tropical rain forest: a simula-

tion study. Forest Ecology and Management 142, 33–51.

Khan, M.T. and Singh, J. (2001) Methods of Yield Regulation in Moist Tropical Forest with Minimal

Data (MYRLIN), The University of Oxford, and Silviculture and Yield Modelling for Tropical

Forests (SYMFOR), University of Edinburgh, 10–28 September. Guyana Forestry

Commission, Georgetown, Guyana, 16 pp.

McLeish, M.J. and Susanty, F.H. (2000) Yield Regulation Options for Labanan: a Financial and

Economic Analysis of Yield Regulation Options for Logged-over Forest at PT Inhutani I, Labanan

Concession. Berau Forest Management Project, Tanjung Redeb, 45 pp.

McLeish, M.J. and van Gardingen, P.R. (2001) Linking SYMFOR with Financial Models for Forest

Concessions: SYMFOR Technical Note. University of Edinburgh, 21 pp.

Phillips, P.D., Brash, T.E., Yasman, I., Subagyo, S. and van Gardingen, P.R. (2002a) An individ-

ual-based spatially explicit tree growth model for forests in East Kalimantan (Indonesian

Borneo). Ecological Modelling 159, 1–26.

Phillips, P.D., van der Hout, P., Arets, E.J.M.M., Zagt, R. and van Gardingen, P.R. (2002b) An

Ecological Model for the Management of Natural Forests Derived from the Tropenbos Permanent

Sample Plots at Pibiri, Guyana. University of Edinburgh, 21 pp.

Porte, A. and Bartelink, H.H. (2002) Modelling mixed forest growth: a review of models for for-

est management. Ecological Modelling 150, 141–188.

Proctor, W. (2001) Valuing Australia’s Ecosystem Services Using a Delibrative Multi-criteria

Approach. European Society for Ecological Economics. Frontiers 1 conference,

Fundamental issues of environmental economics, 15 pp.

Proctor, W. (2002) Assessing Ecosystem Services in Australia: 7th Biennial Conference of the

International Society for Ecological Economics, Sousse, Tunisia, 6–9 March, 16 pp.

Purnama, B., Rulsi, Y., McLeish, M.J. and van Gardingen, P.R. (2001) Policy Brief: Yield

Regulation for Logged-over Forest. Ministry of Forestry, Jakarta, 2 pp.

Ridwan and Redhahari (2001) Methods of Yield Regulation in Moist Tropical Forest with Limited

Information (MYRLIN), University of Oxford, and Silviculture and Yield Management for

Tropical Forests (SYMFOR), University of Edinburgh, 10–28 September 2001. Universitas

Mulawarman, Samarinda, Indonesia, 21 pp.

Sist, P., Nolan, T., Bertault, J.G. and Dykstra, D.P. (1998) Harvesting intensity versus sustain-

ability in Indonesia. Forest Ecology and Management 108, 251–260.

van Gardingen, P.R. (2002) Yield regulation and multiple objective forest management. ETFRN

News, 51–53.

van Gardingen, P.R., Clearwater, M.J., Niﬁnluri, T., Effendi, R., Rusmantoro, W., Noor, M.,

Mason, P.A., Ingleby, K. and Munro, R. (1998) Impacts of logging on the regeneration of

lowland dipterocarp forest in Indonesia. Commonwealth Forestry Review 77, 71–82.

van Gardingen, P.R., McLeish, M.J., Phillips, P.D., Fadilah, D., Tyrie, G. and Yasman, I. (2003)

Timber yield, ﬁnancial and ecological analysis for the sustainable management of logged-

over Dipterocarp forests in Indonesian Borneo. Forest Ecology and Management (in press).

Vanclay, J.K. (1995) Growth-models for tropical forests: a synthesis of models and methods.

Forest Science 41, 7–42.

Wright, H.L. and Alder, D. (2000) Proceedings of a Workshop on Humid and Semi-humid Tropical

Forest Yield Regulation with Minimal Data. OFI occasional papers, No. 52, Oxford Forestry

Institute, Oxford, 95 pp.

31Amaro Forests - Chap 27 1/8/03 11:54 am Page 319

27 CAPSIS: Computer-aided Projection

for Strategies in Silviculture:

Advantages of a Shared Forest-

modelling Platform

François de Coligny,

Philippe Ancelin,

Guillaume

Cornu,

Benoît Courbaud,

Philippe Dreyfus,

François

Goreaud,

Sylvie Gourlet-Fleury,

Céline Meredieu

and Laurent Saint-André

Abstract

Forest scientists build models to study, understand and represent stand growth and dynamics.

Ad hoc computer tools are often developed to implement these models, to test and to explore

the consequences of the underlying hypotheses. Some teams have also developed more inte-

grated tools, often based on a parameterizable growth model.

The aim of this chapter is to present CAPSIS, a more generic forest simulator integrating

various models, and to discuss the advantages for modellers and foresters of using such a

shared forest-modelling platform for research, management and education.

CAPSIS is free portable software, with a kernel providing the overall structure for simula-

tions and generic data descriptions for stands, trees, soil, etc. These descriptions can be com-

pleted in modules – one for each model – which implement a proper data structure and

speciﬁc evolution functions. A plug-in architecture allows the user to add tools for manage-

ment, data exportation and representation, or connections with other software. At the present

time, CAPSIS hosts six modules and two speciﬁc libraries.

This shared forest-modelling platform has already shown many advantages: allowing

modellers to re-use submodels and share speciﬁc tools; and providing to foresters and students

a single easy-to-use software platform to compare different management strategies.

UMR AMAP, France

Correspondence to: coligny@cirad.fr

Cirad Forêt, France

Cemagref, EPM, France

INRA, UR Forestières Méditerranéennes, France

Cemagref, LISC, France

INRA, Equipe Croissance et Production, France

31Amaro Forests - Chap 27 1/8/03 11:54 am Page 320

320 F. de Coligny et al.

Introduction

In order to manage forest stands, foresters need speciﬁc tools to predict stand

growth and wood quality. Many models have been developed that simulate the

dynamics of a forest stand at various scales (e.g. Pretzsch et al., 2002).

Modellers often have to implement these models in computer programs, to ease

their calibration, their evaluation on concr

ete cases and their dissemination. Most

models are implemented in ad hoc software (e.g.

CEP, FAGACÉES, FORMIND, SELVA, SEXI,

SIMCOP) which let their authors have complete control over them and choose freely

their data structures, their algorithms and their user interface. However, these iso-

lated developments produce speciﬁc programs which are sometimes not easy to use

by others and may cause difﬁculties in communicating with each other because

their architectures are too different. To beneﬁt from re-usable tools in various situa-

tions, some teams have chosen to build more generic simulators implementing a

parameterizable model (e.g.

BWIN, CO2FIX, FVS, JABOWA, MOSES, PROGNAUS, SILVA, SORTIE,

TASS). Generally, a common data structure and a set of functionalities are proposed

(growth, competition, environment, management, analysis). The simulator can then

be used for several species or forest types. However, only a few software packages

(e.g.

LMS, MUSE, SYMFOR) propose a more generic approach allowing us to use, com-

pare or compose different growth models with a single interface.

The aim of this chapter is to present such a generic forest simulator –

CAPSIS –

and to discuss the advantages for modellers and foresters of using a shared forest-

modelling platform for research, management and education.

The CAPSIS Forest-modelling Platform

CAPSIS is a generic forest simulator, developed since 1994 (Dreyfus and Bonnet,

1997). The objective of the project is to build a perennial, open and shared modelling

platform: (i) to contribute to the development and evaluation of models; (ii) to share

tools and methods; (iii) to compare results of different models; (iv) to transfer mod-

els to forest managers; and (v) to serve as teaching material. The

CAPSIS4 release is

generic enough to integrate very different kinds of models: stand models, distance-

independent or spatially explicit tree models, wood quality models, seed dispersal

models, etc. It provides forest management tools to establish and compare different

silvicultural scenarios.

CAPSIS is free software (membres.lycos.fr/coligny).

General architecture

The architecture of

CAPSIS clearly identiﬁes a kernel and some modules. The kernel offers

common services (detecting and loading models, running simulations, offering

import/export facilities, etc.) and generic data structures (for stand, trees, soil, etc.)

facilitating the integration of new models. Growth models – in a broad sense – are

integrated as independent modules. These modules contain their own data structures,

extending some templates chosen from the kernel. They also contain the algorithms

used to model stand evolution along time. Management can be automated in the

modules or processed externally, in platform extensions (plug-ins), such as: thinning,

pruning, storms, etc. Each simulation owns a root step which is associated with an ini-

tial stand. A simulation consists of computing successive states of this stand, by dele-

gating evolution phases to the module, and by processing interventions with extensions.

31Amaro Forests - Chap 27 1/8/03 11:54 am Page 321

321 CAPSIS: a Shared Forest-modelling Platform

CAPSIS extensions also include viewers and data extractors that provide represen-

tations of the stand at a certain time or along time (maps, curves, histograms,

tables), and allow the user to observe the simulation results (Fig. 27.1).

CAPSIS also

provides libraries of data structures and processes which can be used by every mod-

eller. Finally, simulations are driven through a pilot corresponding to a usage con-

text. The bilingual (French, English) interactive pilot proposes a graphical user

interface with menus and dialogues, which can easily be adapted to other lan-

guages. The script pilot can be used to run long or repetitive simulations with no

user actions required.

Very different models are already developed with

CAPSIS4

MOUNTAIN is a distance-dependent model of uneven-aged monospeciﬁc conifer for-

est. A detailed light interception submodel calculates the energy intercepted by each

tree and on the soil, which is then used to determine tree growth, probability of

death and regeneration.

MOUNTAIN has been used until now to simulate long-term

dynamic patterns in monospecies forests, to compare silvicultural strategies

(Courbaud et al., 2001) and to train students and forest managers in tree marking.

SELVA is a distance-dependent tree model, designed for the natural tropical rain-

forests of French Guyana (Gourlet-Fleury and Houllier, 2000). The three fundamen-

tal processes of forest dynamics are described: growth, mortality (split into standing

dead and two types of windthrow) and recruitment. For particular species, the

whole regeneration cycle from seed dispersal to ingrowth is modelled.

The

PNN module is a distance-independent tree growth model for pure even-

aged stands of black pine (Pinus nigra nigricans) in France and Hungary. Thinning

Fig. 27.1. A glance at CAPSIS4: Project manager, stand viewers with tree inspector, data extractors.

31Amaro Forests - Chap 27 1/8/03 11:54 am Page 322

322 F. de Coligny et al.

design considers target stocking (N, G, V, relative spacing, CCF after thinning) and

ratio of tree average diameter (quadratic mean) after thinning:before thinning.

PP3 is a distance-independent tree growth model with a whole-stand growth

regulation for pure even-aged stands of maritime pine (Pinus pinaster) in Landes of

Gascogne (south-west France). The branching model and stem proﬁle relationship

are to be implemented soon.

EUCALYPT is a distance-independent tree model developed for eucalyptus clonal

plantations in Congo (Saint-André et al., 2002). Three speciﬁc features are developed

in this module: (i) the management of coppice (several stems per stump); (ii) the

integration of a great number of models (sometimes one model per clone); and (iii)

the link between

CAPSIS and a geographic information system (GIS) (arcInfo/

arcView).

VENTOUX is a semi-spatialized model dealing with the evolution of aged artiﬁ-

cial pine stands towards mixed stands in the French Mediterranean hinterland

mountains. Seedling occurrence of invasive native species is driven by the distance

to potential seed sources (beech and silver ﬁr stands). For a multi-level spatializa-

tion, the forest is divided into homogeneous units (site, overstorey species, age),

then in grids of small cells (10 m × 10 m) containing non-spatialized trees and

seedlings.

Two libraries already offer generic tools for forest modellers

The

SPATIAL library contains speciﬁc tools concerning the spatial structure of forest

stands. The

RIPLEY data extractor describes the spatial pattern of a stand, using

Ripley’s K-function (Ripley, 1977). Moreover, we have implemented speciﬁc classes

to simulate virtual stands of various structures, using Poisson, Gibbs or Neyman–

Scott processes. These tools are available for all individual tree models (distance-

dependent or independent tree models).

The

BIOMECHANICS library proposes classes to describe the internal structure of

trunks (stem proﬁle, succession of growth units) and simulate their biomechanical

behaviour under external stress (Ancelin, 2001). Associated with the

WINDSTORM

extension, which is compatible with both distance-dependent and independent tree

models, it simulates the effect of wind in forest stands.

WINDSTORM should soon

become an intervention mechanism to study the impact of silviculture on damage

caused by wind as well as their consequences on the stand dynamics.

Discussion: Advantages of a Shared Forest-modelling Platform

After 6 years of activity, the success of the CAPSIS project conﬁrms the advantages of

such shared forest-modelling platforms. Firstly, a shared modelling platform is a

good opportunity to build a forest modellers’ community. The

CAPSIS project brings

together the main French institutions concerned with forest modelling, and encour-

ages a real partnership between more than 70 actors, both modellers and foresters,

who contribute to its speciﬁcations and coordination. It is also currently opening to

colleagues from other countries.

Secondly, such a shared platform can really allow the participants to share tools

and models. W

ithin the

CAPSIS project, the organization of regular training sessions

facilitates the interactions between computer scientists, in charge of the kernel and

common technical aspects, and modellers, in charge of the integration of their model

or library. As

CAPSIS is free software (general public licence), it is thus very easy to re-

31Amaro Forests - Chap 27 1/8/03 11:54 am Page 323

323 CAPSIS: a Shared Forest-modelling Platform

use submodels from other modules or from the kernel within the CAPSIS community.

For instance, many models have been easily integrated into new modules by simply

modifying the evolution law of an already existing model of the same type.

Libraries also provide an efﬁcient opportunity to re-use modelling tools. For

instance, the spatial tools currently used in the

MOUNTAIN module to simulate virtual

stands of various structures will soon be used in the

SELVA module too. This is also

obviously true with interfaces and graphics, which are developed by computer sci-

entist only once and re-used for each module.

Thirdly, a shared modelling platform is a very practical tool to compare models

and silvicultural scenarios, because the dif

ferent models are integrated in a single

platform, because data (such as the initial state) are compatible, and because there is

a unique scenario manager. Therefore is it easy to compare the results of a simula-

tion of two models using the same initial state, or to compare three different scenar-

ios on the same model. These facilities are of great use for model evaluation by

researchers, but also for decision making by foresters and for teaching.

Finally, we think these advantages really justify a change in our programming

habits, and r

ecommend broadening the use of such shared forest-modelling plat-

forms.

References

Ancelin, P. (2001) Modélisation du comportement biomécanique de l’arbre dans son environ-

nement forestier: application au pin maritime. PhD thesis, University of Bordeaux I,

France.

Courbaud, B., Goreaud, F., Dreyfus, P. and Bonnet, F.R. (2001) Evaluating thinning strategies

using a Tree Distance Dependent Growth Model: some examples based on the CAPSIS

software ‘Uneven-Aged Spruce Forests’ module. Forest Ecology and Management 145,

15–28.

Dreyfus, P. and Bonnet, F.R. (1997) CAPSIS (Computer-Aided Projection of Strategies In

Silviculture): an interactive simulation and comparison tool for tree and stand growth, sil-

vicultural treatments and timber assortment. In: Nepveu, G. (ed.) Proceedings of IUFRO

WP S5.01-04 Workshop ‘Connection between Silviculture and Wood Quality Through Modelling

Approaches and Simulation Software’, 26–31 August 1996, Berg-en-Dal, South-Africa. ERQB-

INRA Nancy, France, pp. 194–202.

Gourlet-Fleury, S. and Houllier, F. (2000) Modelling diameter increment in a lowland evergreen

rain forest in French Guiana. Forest Ecology and Management 131, 269–289.

Pretzsch, H., Biber, P., Dursky, J., von Gadow, K., Hasenauer, H., Kändler, G., Kenk, G., Kublin,

E., Nagel, J., Pukkala, T., Skovsgaard, J.P., Sodtke, R. and Sterba, H. (2002)

Recommendations for standardized documentation and further development of forest

growth simulators. Forstwissenschaftliches Centralblatt 121, 138–151.

Ripley, B.D. (1977) Modelling spatial patterns. Journal of the Royal Statistical Society B39,

172–212.

Saint-André, L., Laclau, J.-P., Deleporte, P., Ranger, J., Gouma, R., Saya, A. and Joffre, R. (2002)

A generic model for the dynamics of nutrient concentration within the stem wood over

the whole stand rotation. Annals of Botany 90, 1–12.

31Amaro Forests - Chap 27 1/8/03 11:54 am Page 324

32Amaro Forests - Chap 28 1/8/03 11:54 am Page 325

28 Expected Volume and Value of

Structural-dimension Lumber

From 25-, 30-, 35-, 40- and

50-year-old Loblolly Pine

Plantation Timber

Honorio F. Carino

and Evangelos J. Biblis

Abstract

The expected volume and value of structural-dimension lumber derived from plantation-

grown timber of 25-, 30-, 35-, 40- and 50-year-old loblolly pine (Pinus taeda L.) were estimated

and used to determine stumpage values through regression analysis. Also, incremental analy-

sis in conjunction with discounted-cash-ﬂow techniques were used to determine the economic

desirability of deferring the harvesting of a loblolly pine plantation stand of a given age for

purposes of producing structural-dimension lumber. The results of the study provide com-

pelling evidence that the volume and quality of sawlogs from loblolly pine plantations do

indeed generally increase with stand age. It was found that for the 25-, 30-, 35-, 40- and 50-

year-old loblolly pine stands investigated, the expected total volume yield of stress-graded

dimension lumber could be as much as 94.4, 122.4, 151.0, 179.0 and 235.0 m

/ha, respectively.

The expected annual increase in volume yield could be about 5.61 m

ha. The increased quality

of older loblolly pine plantation timber was clearly reﬂected by the percentages (based on vol-

ume yield) of stress-graded dimension lumber graded No. 1 and better, which were 16.0, 36.2,

46.7, 49.3 and 83.0%, respectively, for 25-, 30-, 35-, 40- and 50-year-old stands. This was also

reﬂected by the expected unit value yield which was $106, $123, $140, $157 and $192/m

respectively. On average, the expected annual increase in unit value yield could be about

$3.42/m

. Not surprisingly, the stumpage value of loblolly pine plantations based solely on the

value of structural-dimension lumber produced also increases with stand age. For 25-, 30-, 35-,

40- and 50-year-old stands like those investigated, the expected total value yield of stress-

graded dimension lumber could be as much as $10,006, $15,055, $21,140, $28,103 and

$45,120/ha, respectively. On average, the expected annual increase in value yield could be

about $1399/ha. Also, it was determined that it would be economically desirable to defer the

harvesting of a 25-year-old plantation stand of loblolly pine like the one investigated by 5, 10,

15 or 25 years if the minimum acceptable rate of return on investment (MARR) is less than 8.5,

7.7, 7.1 or 6.2%, respectively.

School of Forestry and Wildlife Sciences, Auburn University, USA

Correspondence to: carinhf@auburn.edu