1. General Model Information

Name: Dryades

Acronym: DRYADES


Main medium: terrestrial
Main subject: forestry, population dynamics,
Organization level: Ecosystem, Population
Type of model: gap model
Main application: management
Keywords: forest gap model, coniferous forest, forest dynamics, forest management, forest succession, partial cutting, spatial simulation model

Contact:

Daniel Mailly


Ministere des Ressources Naturelles, Dir. Rech. For., 2700 rue Einstein, Sainte-Foy (Qué.), G1P 3W8 Canada

Phone: 1 (418) 643-7994 .369
Fax: 1 (418) 643-2165
email: daniel.mailly@mrn.gouv.qc.ca

Author(s):

Mailly, D., J.P. Kimmins, R.T. Busing.

Abstract:

Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Disturbance and succession in a coniferous forest of northwestern North America: simulations with DRYADES, a spatial gap model. Ecological Modelling 127: 183-205. In this paper we describe a model of forest development that has been adapted for use in a coniferous forest of northwestern North America. The simulator, DRYADES, is a spatial gap model used to examine the effects of disturbances of different types, sizes, and frequencies in mature Douglas-fir dominated forests on zonal sites of the Coastal Western Hemlock drier maritime (CWHdm) subzone of British Columbia. Simulation exercises were carried out to test the following (not mutually exclusive) hypotheses in relation to forest compositional variations observed within the study area today: (1) disturbance-mediated succession can accelerate the conversion of early successional forest communities dominated by pioneer tree species (e.g. Douglas-fir) to later successional associations; (2) when present in the canopy, long-lived, tall, pioneer species such as Douglas-fir strongly influence stand dynamics, regardless of the type of canopy disturbance; (3) silvicultural practices that em! ulate the autogenic natural disturbance regime of small canopy gaps will maintain a late- successional character at the stand level. Model simulations of forest successional dynamics suggested that: (1) repeated, small-scale disturbances such as light windstorms or small patch harvesting can accelerate the rate of tree species replacement by accelerating forest succession; (2) large-scale disturbances such as infrequent severe fires set back succession to an earlier seral stage dominated by Douglas-fir; (3) clearcutting without Douglas-fir planting accelerates forest succession towards a western hemlock/western redcedar forest; (4) on mesic sites in the CWHdm subzone, Douglas-fir will not dominate stand dynamics, unless there are infrequent, severe fire disturbances; (5) the creation of small openings through partial harvesting did not allow shade intolerant species to reestablish naturally and dominate the forest stand dynamics. It was concluded that modelled successional dyn! amics and composition of these forests are largely a function of the initial competitive interactions and the relative shade tolerance of species involved.


II. Technical Information

II.1 Executables:

Operating System(s): Windows, PowerMacintosh daniel.mailly@mrn.gouv.qc.ca

II.2 Source-code:

Programming Language(s): Windows (Delphi), Powermacintosh (Pascal) contact daniel.mailly@mrn.gouv.qc.ca

II.3 Manuals:

contact daniel.mailly@mrn.gouv.qc.ca

II.4 Data:

See: Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Ecological Modelling 127: 183-205.

III. Mathematical Information


III.1 Mathematics

See: Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Ecological Modelling 127: 183-205.


III.2 Quantities

See: Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Ecological Modelling 127: 183-205.


III.2.1 Input

See: Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Ecological Modelling 127: 183-205.

III.2.2 Output

See: Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Ecological Modelling 127: 183-205.


IV. References

Mailly, D., J.P. Kimmins et R.T. Busing. 2000. Disturbance and succession in a coniferous forest of northwestern North America: simulations with DRYADES, a spatial gap model. Ecological Modelling 127: 183-205.

Busing, R. T. 1995. Disturbance and the population dynamics of Liriodendron tulipifera: simulations with a spatial model of forest succession. J. Ecol. 83, 45-53.

Busing, R. T. 1991. A spatial model of forest dynamics. Vegetatio 92, 167-179.



V. Further information in the World-Wide-Web


VI. Additional remarks

Dryades is derived from the Space model (Busing 1991, 1995) translated from FORTRAN to PASCAL, and with several modifications to make it a true management-oriented forest gap model
Last review of this document by: Mon Apr 17 16:33:23 2000
Status of the document: Contributed by Daniel Mailly
last modified by Tobias Gabele Wed Aug 21 21:44:41 CEST 2002

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