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Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia.

Ginn Woods, a 161 acre tract of woodlands located in northern Delaware County, contains one of the largest remaining sections of old growth forest in East Central Indiana. Located approximately 15 miles north of Muncie, it has been regularly used by Ball State students and faculty for education and research for over 60 years. Despite this frequent use, little formal botanical exploration has been published. This study presents a comprehensive inventory of the vascular flora found in the woods and documents the composition and sizeclass distribution of the canopy tree species. The 370 species represent 237 genera and 94 families based on family classification by Gleason and Cronquist (1991). A total of 123 species were recorded for the first time in Delaware County. Of the 370 species listed, 56 or 15.1 % are non-native or naturalized species, thus indicating that the native species are dominant. The overstory canopy species are typical of a beech-maple woods with Acer saccharum and Fagus grandifolia as overallco-dominant species. However the importance of Fagus grandifolia varies in the sections known as North, South and Nixon Woods. With the fragmentation of regional ecosystems into isolated forest systems by urbanization and agricultural development, the maintenance and preservation of original communities becomes more difficult. Ginn Woods is one of the few remaining remanents of old growth forests in East Central Indiana and serves as an important reserve of the native flora of this area. The inventory and overstory tree species analysis provided by this study establishes important baseline data to which future studies can be compared.Ball State UniversityMuncie, IN 47306 / Department of Biology

Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia.

Thesis (Ph.D.)--Murdoch University, 2004. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 360-392.

Thesis (M.R.M.)--Simon Fraser University, 1995. / "This is an authorized facsimile, made from the microfilm master copy of the original dissertation or master thesis published by UMI." Includes bibliographical references (p. 83-91).

Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia. / Arts, Faculty of / Geography, Department of / Graduate

Clear-cut logging is the most widely practised forestry method in Sweden. This often conflicts with nature conservation and leads to issues where economic interests are pitted against ecological values. Bryophytes are a group of organisms commonly used as indicators of change in the environment, and several species of this group are also used as tools for assessing conservation values in the habitats they occur in. These are termed indicator or signal species, as they demand certain prerequisites regarding for example climate or substrate that are characteristic for the specific habitat type. In this thesis, the effects of clear-cut logging on five Red-Listed bryophyte species specialised in old-growth forests were tested, to see if they can survive such an intervention. This was done in ArcGIS, by overlaying layers containing 13 years of species observations from Artportalen.se and spatio-temporally matched clear-cut areas from the Swedish Forest Agency. There were 229 logged areas containing a total of 401 observations of the selected bryophyte species, of which 25 were found post-logging. Additionally, 64 % of the post-logged findings were located within a 10 m buffer strip along the edge of the logged areas. The results provide strong evidence that clear-cut logging does impact these species negatively. At the same time the data suggest that developing adequate mitigation measures, for example retention patches along the edges, and evaluating those already in use, can help these species to some extent, by mitigating the negative impact. This is the most important implication from this study, because forestry will continue to be a necessary contribution to the ongoing transition towards a fossil free society. Therefore, the practice needs to shift towards a more biodiversity-friendly management, where alternative forestry methods that are less destructive, are promoted and used to a wider extent. Furthermore, the weight of these species as indicators of high conservation value for the habitats they grow in requires special caution when planning for logging such areas. Otherwise, there is risk of losing species to regional extinction, with specialist species like the ones in this study being of greatest concern. / Den vanligast förekommande skogsbruksmetoden i Sverige är idag trakthyggesbruket. Denna metod är inte alltid kompatibel med naturvårdsintressen och leder ofta till konflikter mellan ekonomiska och ekologiska värden. En organismgrupp som ofta används som indikatorer på förändringar i naturmiljön är mossor. Flertalet mossarter är dessutom så kallade signalarter, vilket betyder att de kan användas som ett mått på naturvärden i den biotop de förekommer i, då de har artspecifika krav på särskilda förutsättningar, som till exempel klimat och substrat. I den här studien testades därför hur slutavverkning påverkar fem Rödlistade mossarter strikt knutna till äldre kontinuitetsskogar. Syftet var att undersöka om de överhuvudtaget kan överleva ett sådant ingrepp. Detta utfördes genom att analysera rumsligt matchade geodatalager i ArcGIS, innehållande 13 års artobservationer från Artportalen.se samt utförda avverkningar från Skogsstyrelsen. Det fanns 229 avverkade områden med totalt 401 artobservationer, varav 25 var funna efter utförd avverkning. Av dessa 25 fynd var 64 % observerade inom en 10 m bred buffertzon utmed det avverkade områdets kant. Resultaten visar tydligt att slutavverkning påverkar dessa arter negativt, men pekar samtidigt på att utvecklingen av lämpliga metoder för naturvårdshänsyn (till exempel hänsynsytor längs med avverkningsområdenas kantzoner) och utvärdering av de metoder som redan används kan mildra problemet. Detta är därmed den viktigaste slutsatsen från denna studie, då skogsnäringen även fortsättningsvis kommer att vara ett viktigt bidrag till den pågående gröna omställningen och det är därför nödvändigt att främja även andra, mindre destruktiva, skogsbruksmetoder för att bibehålla och stärka ekologiska värden, som biodiversitet. Dessutom bör de här arternas värde som signalarter väga tungt vid planering av avverkning i dessa områden, då de ju visar att habitaten har höga naturvårdsvärden. Annars är det risk att vissa arter dör ut, i synnerhet sådana arter som är specialiserade på de miljöer som är mål för exploatering.

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.

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