Estimating the stock recovery rate using matrix models

Picard Nicolas, Yalibanda Yves, Namkosserena Salomon, Baya Fidèle. 2008. Estimating the stock recovery rate using matrix models. Forest Ecology and Management, 255 (10) : 3597-3605.

Résumé : The stock recovery rate, that is the ratio of the exploitable wood stock at the end of a felling cycle over the exploitable wood stock at the beginning of this cycle, is a key parameter used in the management plans of the natural forests in central Africa. Estimating this rate requires a model of forest dynamics. Forest managers usually use a formula that is based on a simple model that assumes constant vital rates. A generalization of this formula is based on matrix models of population dynamics. The stock recovery rate at the end of the k th felling cycle can be simply computed using matrix models. The asymptotic stock recovery rate (that is the limit as k tends to infinity) is the asymptotic growth rate (that is the dominant eigenvalue) of a transition matrix that includes harvest. The estimate of the stock recovery rate can be completed by its confidence interval using bootstrap methods. When applied to sapelli (Entandrophragma cylindricum, Meliaceae), a major timber species in central Africa, it turns out that a few thousands observations are required to estimate the stock recovery rate with an accuracy of at least 10%. The number of observations available on an experimental site in the Central African Republic does not permit to do better than an accuracy of about 45% at level 95%. This does not permit to conclude whether the asymptotic stock recovery rate is greater or less than one. As a conclusion, in management plans in central Africa, stock recovery rates should be given together with an indication of the variability of their estimate (standard error or confidence limits).

Mots-clés Agrovoc : forêt tropicale, abattage d'arbres, régénération, modèle mathématique, modèle de simulation, Entandrophragma, peuplement forestier, dynamique des populations, développement durable, technique de prévision

Mots-clés géographiques Agrovoc : Afrique centrale

Mots-clés complémentaires : Entandrophragma cylindricum

Classification Agris : U10 - Informatique, mathématiques et statistiques
F40 - Écologie végétale
K10 - Production forestière

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Picard Nicolas, CIRAD-ES-UPR Dynamique forestière (GAB)
• Yalibanda Yves, Ministère des eaux et forêts, chasses, pêches et tourisme (République centrafricaine) (CAF)
• Namkosserena Salomon, Institut centrafricain de la recherche agronomique (CAF)
• Baya Fidèle, Ministère des eaux et forêts, chasses, pêches et tourisme (République centrafricaine) (CAF)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/544146/)

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