Description: Das Projekt "Multi-proxy tree-ring analysis of conifer trees disturbed by insect outbreaks" wird vom Umweltbundesamt gefördert und von University of British Columbia, Faculty of Forestry, Department of Forest Resources Management Vancouver durchgeführt. Insect outbreaks are a major disturbance influencing forest dynamics in many ecosystems and can affect forest productivity worldwide. Reconstruction of insect outbreak history is fundamental to forest management. While the action of cambium feeders on trees leads to the formation of scars, that of defoliators is observable via growth suppression in tree rings. The occurrence of past insect attacks can thus be inferred from such tree-ring signatures. However, it necessitates an accurate dating of events, with high temporal resolution, as well as their correct attribution to the right disturbance agent. Fire also leaves scars on trees that can occur on cross-sectional disks where insect scars are already present, thus making them difficult to distinguish. Furthermore, insect-elicited reductions in radial growth may not be clearly visible on samples, and the radial growth response to defoliation often bears a lag of one or more years. This project tackles these issues directly by proposing a multi-proxy approach aiming at improving tree-ring reconstructions of insect outbreaks. Tree rings will be investigated to study radial variations of tree-ring width, wood anatomy, wood density, and wood chemistry. While dendrochronologists have long relied on tree-ring width variations to track the signal induced by climate, geomorphic and ecological processes, they have scarcely exploited the potential of other proxies and rarely used them in combination. The most advanced studies that have embraced these possibilities are owed to dendroclimatologists. The core of this research therefore lies in the use of multiple wood traits to provide answers to the above mentioned dendroecological questions. Two conifer tree species from British Columbia and their respective pests are within the scope of this study: the mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins), a cambium feeder, on lodgepole pine (Pinus contorta Douglas), and the western spruce budworm (WSBW, Choristoneura occidentalis Freeman), a defoliator, on Douglas-fir (Pseudotsuga menziesii Franco). It is hypothesized that insect outbreak disturbance in the form of bark beetle or defoliation events results in abrupt significant structural differences between the wood formed prior to and after the insect attack. Based on pioneering tree-ring research on insect outbreaks, there are great prospects that the variations of wood traits be proven useful for differentiating MPB scars from fire scars and for identifying WSBW defoliation events, possibly with higher temporal resolution. The study of multiple wood traits (proxies) will help gain an understanding of the influence of insect outbreak disturbance on wood formation and tree physiological processes, a prerequisite for improving the detection and dating of events in tree-ring series. (...)
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Käfer ? Jahresring ? Douglasie ? Entlaubung ? Fichte ? Kiefer ? Insekt ? Nadelgehölz ? Bär ? Anatomie ? Niob ? Columbia ? Baum ? Borkenkäfer ? Haushund ? Kronenverlichtung ? Ökologie ? Skigebiet ? Brunnen ? Graben ? Waldressourcen ? Datierung ? Brand ? Laubblatt ? Prospektion ? Verfahrenskombination ? Tierlärm ? Bildung ? Berg ? Bohrkern ? Management ? Störfall ? Studie ? Schadorganismus ? Wertermittlung ? Forschung ? Forstwirtschaft ? Klima ? Ökosystem ? Produktivität ? Ressourcenbewirtschaftung ? Wald ? Gebirge ? Globale Aspekte ? Änderung ? Rechte ? GEGENWART ? FRAGE ? Wachstum [biologisch] ? AUSGEWAEHLT ? cambial scar ? conifer tree ? GRUNDLAGE ? HILF ? insect outbreak ? wood trait ? Art [Spezies] ? BAEUME ? Kreuzung [biologisch] ? SONSTIG ? UMGESTALTUNG ? DICHTE ? PROJEKT ? Laub ? AUSBRUCH ? MISCHUNG ? MOEGLICHKEIT ? EIN ? Mittel ? EINSATZ ? ERGEBNIS ? VERRINGERUNG ? VORHERIG ? NACHWEIS ? PERSPEKTIVE ? POTENZIAL ? PROBE ? FORMBLAETTER ? FORTSCHRITTLICH ? VERANTWORTUNG ?
Region: Kalifornien
Bounding box: 10.37779° .. 10.37779° x 54.42669° .. 54.42669°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2013-05-01 - 2015-04-30
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