I investigated the impacts of a catastrophic ice storm on the old-growth, hardwood forests of Mont St. Hilaire, Quebec. The mass of litter resulting from the ice storm of January 1998 was estimated using equations relating the basal diameter of fallen branches with branch mass for each of the ten major species. The ice storm of January 1998 produced 19.9 metric tonnes or 33.6 m3 of woody-litter per hectare. These losses of woody biomass are approximately 20 times greater than what is expected in a normal year and correspond to between 7--10% of the total above-ground biomass of the prestorm forest. This level of litter production positions the ice storm of 1998 as the most severe ice storm on record and amongst the most powerful forms of climatic disturbance experienced in forested ecosystems. / I also investigated differences in the magnitude and nature of the biomass losses sustained by each study species. While the magnitude of biomass lost by the study species was not related to either wood strength or stiffness, the nature of the biomass lost was. All species primarily lost branches less than 5 cm in diameter, but it was the relatively few branches greater than this diameter that accounted for the majority of downed biomass. Smaller branches were lost in relation to differences in species-specific mechanical properties, while larger branches appear to be lost in response to weakening by decay and other age-dependent factors. The ecological and evolutionary implications of these results emphasise the need for an analysis of the interplay between mechanical properties and canopy architecture in determining overall susceptibility to ice damage.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.29899 |
| Date | January 1999 |
| Creators | Hooper, Michael Craig. |
| Contributors | Lechowicz, Martin J. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001686396, proquestno: MQ55067, Theses scanned by UMI/ProQuest. |
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