Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

Invasive species exact important ecologic, economic, and cultural tolls in forests. This research focused on the intersections of invasive ecology, forest management, and a forest commodity. Invasive ecology was explored through an assessment of two potential biological control agents of hemlock woolly adelgid. The two species of silver fly (Leucopis spp.) from the Pacific Northwest were first examined for temporal resource partitioning patterns. The niches of these species were then examined spatially by developing a species distribution model. Leucopis spp. exhibited sinusoidal patterns of daily emergence when examined over a 29-day period, with peak daily abundances that were inversely related. Spatially, however, landscape-scale and climatic indicators were not significant in predicting the presence of Leucopis spp. in the Pacific Northwest. This adds important information about niche dynamics of Leucopis spp. in the Pacific Northwest, which may have logistical and operational implications for their use in the USDA Forest Service’s Hemlock Woolly Adelgid Initiative. Additionally, the potential opportunities and risks of using wood that has been impacted by invasive species and pests was explored through a literature analysis focused on three species posing a threat to northeastern US forests: emerald ash borer, hemlock woolly adelgid, and southern pine beetle. Based on this review, I concluded that although opportunities for the use of this wood are sometimes recognized, the phytosanitary risks in feedstock pre-treatment are not being directly addressed in US-related literature. These studies provide important evidence for adaptive solutions to forest pests that consider both forest health and forest economics.

Annual rings of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, which sustained 1 year of defoliation by the western false hemlock looper, Nepytia freemanii Munroe (Lepidoptera: Geometridae), showed a period of decrease in breast height ring width starting in the year that followed the damage. The magnitude of the decrease was related to the degree of defoliation: there was no ring width decrease on trees that were 0-10% defoliated; the decrease became progressively more noticeable in trees which sustained increasingly higher defoliation; and it was maximum in trees which sustained 91-100% defoliation. This period of reduction lasted 1 to 5 years and was followed by a period of above-normal growth which was related to defoliation in a similar manner: it was absent in trees 0-10% defoliated and maximum in the 91-100% tree defoliation class. Increase in defoliation caused a significant increase in index standard deviation, autocorrelation and mean sensitivity.

Lic.-avh. (sammanfattning) Alnarp : Sveriges lantbruksuniversitet, 2005. / Härtill 3 uppsatser.

No description available.

Au cours des dernières décennies, la détérioration de la santé des forêts a entraîné des épidémies fréquentes des ravageurs et pathogènes. Ces phénomènes menacent la capacité des forêts à fournir des biens et services écosystémiques à la société. Il est donc nécessaire de maintenir la santé des arbres et de réduire les effets des parasites et des agents pathogènes. Cette thèse considère trois problèmes de gestion du point de vue économique : l'invasion actuelle, l'invasion attendue d'un agent pathogène, et les attaques d'un parasite endémique. À partir de ces trois problèmes de gestion, la thèse vise à évaluer les impacts des ravageurs et des pathogènes forestiers et à informer sur la manière dont les ressources peuvent être réparties de façon optimale pour assurer la fourniture de biens et de services par la forêt à long terme.Les invasions biotiques ont un impact sur les prix des produits du bois du fait des chocs d'approvisionnement qui, à leur tour, influencent les choix de gestion forestière. Ceci permet d'introduire des effets de réaction entre les dynamiques écologiques et de marché. Le premier article vise à évaluer ces impacts en combinant un modèle d’équilibre partiel avec des modèles de diffusion spatiale et de mortalité, calibrés pour représenter le dépérissement du Frêne en France (causé par le pathogène Hymenoscyphus fraxineus). Les résultats montrent que les impacts dépendent généralement de la distribution des ressources, de la propagation du pathogène et de la structure du marché. On observe que les choix d’adaptation des gestionnaires forestiers (c'est-à-dire les choix de régénération et de récolte) sont une composante non négligeable de la perte de volume totale.Le deuxième article est axé sur la surveillance et le contrôle d’une invasion attendue. La surveillance et la détection précoce des espèces envahissantes sont importantes pour atténuer les dommages et réduire les coûts de contrôle. Dans le cas où plusieurs propriétaires sont concernés, l’effort de surveillance des propriétaires plus proches du point d'introduction n’est pas optimal, car il ne prend pas en compte les effets négatifs de l'invasion dans les propriétés voisines. Grâce à un jeu différentiel, combiné à un modèle épidémiologique, nous avons calculé la solution non coopérative et coopérative. Nous avons conçu un paiement monétaire pour soutenir la coopération en fonction d'une décomposition intertemporelle du système de négociation de Nash. Les résultats nous montrent que ce paiement garantit que l’accord entre les deux propriétaires est crédible et incitatif. Le modèle est calibré pour l’éventuelle invasion du nématode du pin (Bursaphelenchus xylophilus) dans le Massif Landais.L'objectif principal du troisième article est d'adapter la gestion forestière aux perturbations biotiques et abiotiques. On combine le modèle classique de Faustmann avec un modèle dynamique de population de ravageurs et un modèle de tempête pour calculer l'âge de coupe optimale et le bénéfice actualisé en séquence infinie (BASI) pour différents scénarios de perturbations. Le modèle est appliqué aux dégâts de la chenille processionnaire du pin (Thaumetopoea pityocampa) dans les Landes. Nos résultats ont montré que les tempêtes ont tendance à réduire l'âge optimal de la récolte, alors que le parasite tend à l'augmenter. Les éclaircies augmentent la rentabilité et constituent une stratégie de couverture efficace contre les deux risques. Dans le troisième article, nous avons introduit une règle de décision cut-or-keep pour modéliser le problème du propriétaire forestier après une tempête. Ces implications en termes de gestion sont étudiées plus en détail dans le quatrième article. Notre règle de décision conduit à des gains plus élevés (dans environ 75% des cas) qu’en suivant la règle, généralement utilisée en économie, qui consiste à couper et à replanter les arbres survivants indépendamment du niveau de dégâts. / In recent decades, the deterioration of forest health resulted in frequent pests’ outbreaks and the diffuse pathogens’ presence. These phenomena threaten forests’ ability to supply ecosystem goods and services to the society. It is therefore necessary to maintain tree health and reduce pest’s and pathogen’s impacts. This thesis approaches three management problems from an economic perspective such as the current invasion and the incumbent invasion of a forest pathogen as well as the outbreaks of a native pest. Starting from these three pest and pathogen management problems, the thesis aims at assessing the impacts of forest pests and pathogens and, secondly, informing how resources can be optimally allocated for assuring the long-term provision of good and services.Pest and pathogens invasions have an impact on the prices of wood products via supply shocks, which, in turn, influence forest management choices, thus introducing feedback effects between market and ecological dynamics at a large scale. The first paper aims at evaluating these impacts by combining a recursive partial equilibrium model with spatial-explicit pathogen-spread and pathogen-induced mortality models calibrated to represent the ash dieback in France (caused by the pathogen Hymenoscyphus fraxineus). Results showed that impacts are not homogeneous across regions and generally depend on the resource distribution, pathogen spread and market structure. We observed that the behavioural adaptation of forest managers (i.e., regeneration and harvesting choices) is a non-negligible component of the total standing volume loss.The second paper focusses on monitoring and control of an incumbent invasion. Monitoring and early detection of invasive species is important to mitigate the damages and reduce the control costs. However, when multiple decision-makers are involved, the monitoring effort of frontier landowners (landowners closer to the introduction point) is suboptimal because it does not consider the negative impacts of the invasion spreading to neighbouring properties. Through a two-player differential game combined with an epidemiological compartmental model, we computed the non-cooperative and the cooperative solution. We designed a monetary payment to sustain cooperation based on an intertemporal decomposition of the Nash bargaining scheme. We showed that this payment assured time-consistent outcomes, meaning that the ex-ante agreement between the two landowners was credible and self-enforcing. The model was calibrated for the possible invasion of the pine wilt nematode (Bursaphelenchus xylophilus) in south-western France.In the last two papers, the analysis is downscaled from the landscape level to the stand level and concentrates on a native defoliator pest. The main objective of the third paper is to adapt forest management to biotic and abiotic disturbances. The classic Faustmann model was combined with a pest population model and a windstorm model to compute the optimal rotation age and the land expectation value (LEV) for different disturbances scenarios. The model was calibrated for maritime pine (Pinus pinaster) plantations in south-western France and Pine Processionary Moth (PPM, Thaumetopoea pityocampa) cyclical outbreaks. Our results showed that storms tend to reduce the optimal harvest age, whereas PPM tends to increase it. Overall, the impact of PPM on the rotation length prevails and, here, risks increase rather than decrease the optimal rotation length. Thinnings increased profitability and constitute an effective hedging strategy against both risks. In the third paper, we introduced a cut-or-keep decision rule to model the forest owner problem after a storm event. Its economic and management implications are further investigated in the fourth paper. Unlike previous economic studies which assumed clearing and replanting regardless of the level of damages, the cut-or-keep condition led to higher payoffs in roughly 75% of the cases.

Made available in DSpace on 2015-03-26T13:58:41Z (GMT). No. of bitstreams: 1 texto completo.pdf: 912261 bytes, checksum: dff375c92caec2fa9d74d1caef54e18c (MD5) Previous issue date: 2014-01-28 / Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) is native to China and is the latest example of great economic, environmental and social impact of a forest pest introduced into a new environment. The forest pests are transported by material propagation and solid wood packaging material (SWPM) used in accommodating cargo in the international trade. It is estimated that pests are responsible for equal to 30% of global agricultural production losses. Currently, Brazil is the world's third largest exporter of agricultural products, and agribusiness has been the lever of the Brazilian economy. The vegetable products were the main contributors to growth of $ 5.54 billion in exports. If introduced the asian longhorned beetle represents a great risk to agribusiness and the national forest estate. This study pretend to provide guidance and guidelines to the official authorities of the country to draw up a contingency plan in taking measures and action strategies and procedures to be adopted in case of suspicion and confirmation of the outbreak of the asian longhorned beetle, A. glabripennis in order to minimize the damage caused by the pest. It is proposed phytosanitary actions involving the prevention of the introduction of the asian longhorned beetle, phytosanitary actions in a suspected outbreak, and phytosanitary actions in case of introduction of asian longhorned beetle in Brazil. / Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) é um besouro nativo da China é o exemplo mais recente de grande impacto econômico, ambiental e social causado por uma praga florestal introduzida em um novo ambiente, principalmente, na China e Estados Unidos. As pragas florestais além de serem veiculadas em materiais de propagação são transportadas em toras e madeiras serradas, principalmente, em embalagem e suportes de madeira usados na acomodação de cargas no comércio internacional. Estima-se que as pragas são responsáveis por perdas equivalentes a 30% da produção agrícola mundial. Atualmente, o Brasil é terceiro país exportador agrícola mundial, e o agronegócio tem sido a alavanca da economia brasileira. Os produtos de origem vegetal foram os que mais contribuíram para o crescimento de US$ 5,54 bilhões nas exportações. Caso introduzido o besouro asiático representa grandes riscos ao agronegócio brasileiro e ao patrimônio florestal nacional. O objetivo desse estudo é fornecer orientações e diretrizes às autoridades oficiais do país para elaboração de um plano de contingência na tomada de medidas e estratégias de ação e procedimentos a serem adotados em caso de suspeita e confirmação do foco do besouro asiático, A. glabripennis como forma de minimizar os prejuízos causados pela praga. Propõem- se ações fitossanitárias que sejam mais diretas e que envolvam a prevenção da introdução do besouro asiático, ações fitossanitárias em caso de suspeita de foco, e ações fitossanitárias no caso de introdução do besouro asiático no Brasil.

This thesis discusses the responsibility of and risk for infestations of spruce bark beetle. The spruce bark beetle, Ips typographus, is a natural part of the Swedish forest ecosystem but causes severe financial damage in forestry. Since 2018, the spruce bark beetle infestations have been substantial in Sweden. The first task of the thesis is to evaluate the balance between the forest production interests and the environmental interests, based on the legal regulation of spruce bark beetle control. Production and environment are the equal aims of the Swedish Forestry Act. The regulation of spruce bark beetle control differs depending on whether the forest is in a conservation area or not. For example, owners of forests outside conservation areas are obliged to take care of damaged, fresh wood of spruce and pine, while such an obligation in general does not exist in conservation areas. In this evaluation, I conclude that the balance between the two interests in the spruce bark beetle regulation is good as a whole.  The second question of the thesis is the legal allocation of risk for spruce bark beetle infestations. In this investigation, it is examined whether established law presents a possibility to claim damages for spruce bark beetle infestations that may derive from an adjacent forest. The conclusion drawn is that the regulation of compensation for certain kinds of environmental damage in the Swedish Environmental Code probably would not be applicable as a legal basis for such a claim. By contrast, neighbour law and the Swedish Torts Act could be used as the basis of an action for damages. However, to prove causality regarding the origins of a specific infestation might bring problems, which altogether means that an action for damages faces considerable difficulties. Therefore lastly, some alternative ways of allocating the risk for spruce bark beetle infestations are presented. / I denna uppsats diskuteras ansvar och risk för granbarkborreangrepp. Granbarkborren, Ips typographus, är en naturlig del av skogens ekosystem men orsakar stora ekonomiska skador i skogsbruket. Sedan 2018 har granbarkborreangreppen i Sverige varit omfattande.  Uppsatsens första uppgift är att utifrån regleringen av granbarkborrebekämpning i skogen utvärdera avvägningen mellan produktions- och miljöintresset, som är skogsvårdslagens jämställda mål. Den rättsliga regleringen av bekämpning av granbarkborrar skiljer sig åt beroende på om skogen är skyddad eller oskyddad. Bland annat är ägare av oskyddad skog ålagda att ta hand om skadat, färskt barrvirke, medan en sådan skyldighet ofta saknas i skyddade områden. I utvärderingen kommer jag fram till att avvägningen mellan de två intressena över lag är god i granbarkborreregleringen.  Den andra frågan i uppsatsen är fördelningen av risk för granbarkborreangrepp. För att undersöka det utreds om det enligt gällande rätt är möjligt att få skadestånd för granbarkborreangrepp som kan härstamma från närliggande skyddad eller oskyddad skog. Slutsatsen är att 32 kap. miljöbalken förmodligen inte skulle vara tillämplig, medan däremot grannelagsrätten och skadeståndslagen kan läggas till grund för en sådan talan. Att bevisa orsakssambanden kan dock innebära problem, vilket sammantaget gör att en skadeståndstalan för granbarkborreangrepp från närliggande skog möter ansenliga hinder. Sist presenteras därför några alternativa sätt att fördela risken för barkborreangrepp.