Modeling infection and spread of Heterobasidion annosum in even-aged Fennoscandian conifer stands

Abstract

Heterobasidion annosum (Fr.) Bref. s. lato causes severe damage to forests. This study describes a model for simulating the infection and spread of Heterobasidion spp. in stands of Picea abies (L.) Karst. and Pinus sylvestris L. The model includes submodels for stand dynamics (plot simulation, growth and yield, and cross-cutting of trees) and disease dynamics: (i) spore infection, (ii) stump colonization, (iii) colonization of stump roots, (iv) vegetative transfer to tree roots, (v) spread of disease in tree roots, (vi) spread of decay in stems, and (vii) disease effect on tree growth and survival. To illustrate the model, a simulation was carried out on a Swedish Norway spruce stand where logging occurred during the high-risk season for spore infection. The model provides a means of incorporating the impact of root disease into forest planning. A change of parameters indicated that model predictions were sensitive to the spread rate and presence of initial disease centers. Further research is called for in areas related to the development of coarse root systems of various tree species and the probability and rate of transfer of disease from various sources of inoculum to healthy trees. Résumé :Heterobasidion annosum (Fr.) Bref. s. lato cause des dommages sévères en forêts. Cette étude décrit un modèle pour simuler l'infection et la propagation de Heterobasidion spp. dans les peuplements de Picea abies (L.) Karst. et de Pinus sylvestris L. Le modèle inclut des sous-modèles de la dynamique du peuplement (simulation de parcelles, croissance et rendement et coupe radiale des arbres) et de la dynamique de la maladie : (i) infection par les spores, (ii) colonisation des souches, (iii) colonisation des racines associées à la souche, (iv) transfert végétatif dans les racines des arbres sains, (v) propagation de la maladie dans les racines des arbres sains, (vi) progression de la carie dans la tige et (vii) effet de la maladie sur la survie et la croissance des arbres. Pour illustrer le modèle, nous avons fait une simulation pour un peuplement d'épicéa commun en Suède qui a été coupé pendant la saison où le risque d'infection par les spores est élevé. Le modèle permet d'incorporer l'impact de la maladie de racine dans la planification forestière. Une modification des paramètres indique que les prédictions du modèle sont sensibles au taux de propagation et à la présence, initialement, de centres d'infection. D'autres recherches sont nécessaires dans les domaines reliés au dé-veloppement du système racinaire grossier de différentes espèces d'arbres et à la probabilité et aux taux de propagation de la maladie à partir de différentes sources d'inoculum vers des arbres sains.[Traduit par la Rédaction] Pukkala et al. 84

Integrating mechanistic disturbance models and stand dynamics of Norway spruce

“…Arvidson, 1954;Greig and Low, 1975;Stenlid, 1987;Tamminen, 1985;Vollbrecht and Agestam, 1995;Vollbrecht and Jørgensen, 1995;Woodward et al, 2002). The most advanced mechanistic models include Western Root Disease model (WRDM) (Frankel, 1998) incorporated into the Forest Vegetation Simulator (FVS) (Teck et al, 1996) and Rotstand consisting of three different modules: stand dynamics, fungal dynamics and their interactions (Möykkynen et al, 1998;Pukkala et al, 2005). WRDM is the only root rot model including other disturbance agents, but it does not either describe the interactive dynamics.…”

“…Hmodel (I) was developed to study the effects of Heterobasidion root rot on the stand dynamics and to assess the effect of forest management on disease development. The overall structure followed the one applied in Rotstand (Pukkala et al, 2005) with modified submodels. The spatial layout described above is included in Hmodel and therefore it was used in all the articles.…”

Wood production, wood technology, and biotechnological impacts

“…For application on the stumps, during or immediately after felling asexual spores (oidia) are spread in high densities (ca. 200-1000 spores/cm 2 ) in mechanical or hand-held application in order to quickly germinate and invade the substrate, thereby eliminating the chance for Heterobasidion to occupy the same (Gibbs et al 2002, Thor & Stenlid 2005. Thus, the main principle of antagonism resides in competition for the wooden substrate.…”

“…2). If the infested wood from clearing stems and from fallen trees is left in the forests, this will act as source of infection for yet healthy trees (Pukkala et al 2005). Removal from the forests will positively influence the general health and the sustainability of the forests.…”

A Multicriteria Risk Analysis to Evaluate Impacts of Forest Management Alternatives on Forest Health in Europe

“…Several studies have compared the theoretical effect of different forest management regimes on stand susceptibility to specific damaging agents such as strong winds in conifer stands (e.g., Gardiner and Quine 2000, Holecy and Hanewinkel 2006, Schelhaas 2008, ice in loblolly pine (Pinus taeda (L.)) stands (Goodnow et al 2008), bark beetles in Norway spruce (Picea abies (L.) Karst.) forests ), root rot fungi (Pukkala et al 2005), and game (roe deer) in Norway spruce and European larch (Larix decidua Mill.) forests (Vospernik and Reimoser 2008) using sophisticated damage functions and simulations from tree growth models.…”