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.

This thesis is focused on evaluation of the compatibility of entomopathogenic fungus Isaria fumosorosea with different species of entomopathogenic fungi and mycoparasitic fungi at different temperatures. The strains of species Beauveria bassiana, Metarhizium anisopliae, Lecanicillium muscarium, Coniothyrium minitans and Clonostachys rosea f. catenulata were selected for experiments base on compatibility. The results showed that combination of I. fumosorosea with species L. muscarium is compatible. The species do not limit to each other in the environment at all temperatures (15, 23 and 25 °C). On the other side, fungus I. fumosorosea in combination with other species have affected their growth and spore production. The efficacy of entomopathogenic fungi against larvae Tenebrio molitor was evaluated. The most effective species against larvae were species I. fumosorosea, B. bassiana and M. anisopliae. On the contrary, the smallest effective was observed after infection larvae by L. muscarium. Mycoparasitic fungus C. rosea f. catenulata was not able to directly infect larvae of T. molitor. This species did not infect healthy larvae. However it is able to infect weakened individuals or is growing as saprotrophs on the cadavers.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-08-31T11:25:30Z No. of bitstreams: 2 Dissertação - Camila Fernanda Dias - 2017.pdf: 2762484 bytes, checksum: ba0a7f01bf4043f7d50515ada115a0f8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-09-15T13:39:00Z (GMT) No. of bitstreams: 2 Dissertação - Camila Fernanda Dias - 2017.pdf: 2762484 bytes, checksum: ba0a7f01bf4043f7d50515ada115a0f8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-09-15T13:39:00Z (GMT). No. of bitstreams: 2 Dissertação - Camila Fernanda Dias - 2017.pdf: 2762484 bytes, checksum: ba0a7f01bf4043f7d50515ada115a0f8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-23 / Artificial dyes are commonly used in the food industry, both for their low cost and for ease of procurement. The consumer market, however, requires healthier products and a viable alternative would be the use of natural pigments. In addition to plants, flowers, fruits and animals, micro-organisms can be the source of this type of pigment, such as fungi, bacteria and microalgae. Therefore, the present study had as objective to produce pigments from the solid fermentation and submerged by filamentous fungus Monascus ruber CCT 3802 using maltose syrup as substrate. The effect of substrate concentration on maltose syrup and the influence of pH on pigment production was studied by evaluating the radial growth rate, pigment production and pigment properties by thermal stability. The main results demonstrate that the highest radial growth velocity was obtained from the plate containing 5 g L-1 maltose syrup 0.1053 mm h-1 , which corresponds to an increase of 71.70% when compared to the medium extract of Malt agar (MEA). In the submerged fermentation the concentration of 10 g L-1 of maltose obtained the highest absorbance (14.54 AU), lower biomass (4.65 g L-1 ) and greater dark red intensity. For pH determination, the highest radial growth rate was obtained when the fungus was cultivated at pH 6.5 and the production of yellow pigment was obtained at low pH (2.0 and 2.5) while the production of orange pigments was in the pH range (3.0 and 3.5) and the red pigment yield obtained when the fungus was grown at pH above 4.0. Thus, it can be concluded that maltose syrup and pH exerted a significant influence on both the radial growth rate and the production of pigments in submerged fermentation, showing that lower substrate concentrations favor higher amounts of red pigment and that associated with the culture in PH 6.5 favored the formation of red pigments. / Corantes artificiais são comumente utilizados na indústria de alimentos, tanto pelo seu baixo custo quanto pela facilidade de obtenção. O mercado consumidor, entretanto, requer produtos mais saudáveis e uma alternativa seria a utilização de pigmentos naturais. Além de plantas, flores, frutos e animais, micro-organismos podem ser fonte deste tipo de pigmento, como fungos, bactérias e microalgas. Portanto, o presente estudo teve como objetivo produzir pigmentos a partir da fermentação sólida e submersa pelo fungo filamentoso Monascus ruber CCT 3802 utilizando xarope de maltose como substrato. Foi estudado o efeito da concentração do substrato xarope de maltose e a influência do pH na produção de pigmentos, avaliando a velocidade de crescimento radial, a produção de pigmentos e as propriedades dos pigmentos mediante a estabilidade térmica. Os principais resultados demonstram que a maior velocidade de crescimento radial foi obtida da placa contendo 5 g L-1 de xarope de maltose 0,1053 mm h-1 , que corresponde ao um aumento de 71,70% quando comparado com o meio extrato de malte ágar (MEA). Na fermentação submersa a concentração de 10 g L-1 de maltose obteve a maior absorbância (14,54 UA), menor biomassa (4,65 g L-1 ) e maior intensidade da cor vermelho escuro. Já para determinação da influência do pH a velocidade de crescimento radial mais elevada foi obtida quando o fungo foi cultivado em pH 6,5. A obtenção dos pigmentos, amarelo, laranja e vermelho, deu-se nos intervalos de pH 2,0-2,5, 3,0-3,5 e acima de 4,0 respectivamente. Assim, pode-se concluir que a concentração de xarope de maltose e o pH exerceram influência significativa tanto na velocidade de crescimento radial quanto na produção de pigmentos em fermentação submersa, mostrando que menores concentrações de substrato favorecem maiores quantidades de pigmento vermelho e que associados ao cultivo em pH 6,5 favoreceram a formação de pigmentos vermelhos.

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

Cette thèse a pour objectif de déterminer le devenir des populations marginales d’arbres boréo-montagnards dans le contexte des changements climatiques. La réponse dendroclimatique et la structure génétique des espèces sont analysées conjointement sur des gradients incluant les zones de distributions continues et marginales. Les deux modèles biologiques choisis sont le thuya occidental en limite nordique (forêt boréale canadienne) et le pin cembro en limite occidentale (Alpes). Les hypothèses suivantes ont été testées : le réchauffement climatique au cours du XXe siècle a entrainé une augmentation de croissance ; la variabilité de croissance est reliée à la structure génétique aux niveaux intra- et inter-populationnels. Une baisse de croissance du thuya a été observée après 1980 en zone marginale, qui serait liée à une limitation par la sécheresse. Pour les deux espèces, les relations climat-croissance étaient essentiellement modulées par le volume des précipitations, mais également par des variables édaphiques et par la taille des arbres. L’existence d’un lien significatif entre la structure génétique et certaines variables climatiques laisse néanmoins espérer un potentiel d'adaptation génétique, dont l’ampleur dépendra de la diversité génétique disponible pour la sélection naturelle. Par ailleurs, le synchronisme de croissance entre les arbres était à la fois influencé par la diversité génétique intra-populationnelle et par le volume des précipitations. En conclusion, il apparaît très difficile de distinguer les effets du climat et de la génétique sur la croissance des arbres étudiés. / This thesis aims to assess the fate of marginal populations, in the context of climate change, for boreo-mountain tree species. The dendroclimatic response and the genetic structure of the species are jointly analyzed on gradients including both the continuous and the marginal distribution zones. Two biological models have been chosen for this research, white cedar at its northern limit (boreal forest) and stone pine at its western limit (temperate mountain forest). The following hypotheses were tested: global warming during the twentieth century has led to increased growth; growth variability is related to the genetic structure at the intra- and inter-population levels. A decline in cedar growth was observed after 1980 in marginal zone, which could be linked to drought constraints on growth. For both species, climate-growth relationships were essentially modulated by the amount of precipitation, but also by soil and tree-size variables. The existence of a significant link between genetic structure and some climatic variables still leaves some hope for a genetic adaptation potential, which magnitude will depend on the genetic diversity available for natural selection. The growth synchronicity between the trees was both influenced by the intra-population genetic diversity and the amount of precipitation. In conclusion, it is very difficult to disentangle the effects of climate and genetics on the growth of the studied trees.

La fertilisation et les amendements sont des pratiques courantes en agronomie dont l’intérêt a été prospecté dans le domaine forestier. Des dispositifs expérimentaux de fertilisation ont été mis en place et étudiés par le passé. Le but de ces dispositifs était de déterminer si l’apport d’éléments nutritifs dans des milieux forestiers initialement pauvres ou acides pouvait augmenter la croissance voire restaurer l’état des cimes des arbres en situation de dépérissement. Par ailleurs, des études physiologiques ont montré l’implication de l’eau dans l’absorption des éléments nutritifs du sol et leur transport par la sève brute mais aussi via des effets combinés dans divers processus tels que la croissance cellulaire ou la régulation stomatique. Récemment, des épisodes de sécheresse extrême, responsables de vagues de dépérissement sur de nombreuses essences forestières, ont suscité l’inquiétude des gestionnaires. De plus, les modèles climatiques prédisent une augmentation de fréquence et d’intensité de l’aléa sécheresse dans un futur proche et la gestion forestière doit être adaptée pour y faire face. Dans ce contexte et grâce aux connaissances déjà acquises sur les interactions entre nutrition minérale et hydrique, nous cherchons à savoir si l’apport d’éléments nutritionnels pourrait atténuer les effets négatifs des déficits hydriques en agissant à la fois sur les capacités à supporter les sécheresses et à retrouver des niveaux de croissance optimale après l’aléa, c’est-à-dire améliorer la résilience des arbres. A l’inverse, la vulnérabilité des arbres aux déficits hydriques se trouverait-elle augmentée ? Pour répondre à cette problématique, nous avons exploité des dispositifs expérimentaux de fertilisation situés dans trois forêts en France sur deux essences forestières, le chêne sessile et le sapin de Douglas. Sur chacun de ces sites, des arbres sélectionnés ont été carottés à cœur afin de tracer les variations annuelles de croissance radiale à partir de mesures des largeurs de cernes. Ces courbes de croissance ont servi de base au calcul des indices de résistance, récupération et résilience de la croissance à des déficits hydriques du sol, calculés quant à eux à l'aide du modèle de bilan hydrique BILJOU©. Sur le site de Bercé, l’efficience d’utilisation de l’eau a de plus été appréhendée à partir du δ13C contenu dans le bois final des cernes. La croissance radiale des chênes de Bercé et de Tronçais a significativement été augmentée par la fertilisation et les variations interannuelles de croissance ont été modélisées par le climat et le déficit hydrique du sol. La croissance du sapin de Douglas quant à elle n’a que très peu été augmentée par l’apport en nutriments en forêt des Potées. Par ailleurs, cette analyse montre que la stimulation de croissance par la fertilisation est transitoire : moins de 10 ans après l’apport d’éléments nutritifs à Bercé et 20 ans à Tronçais, plus aucun effet sur la croissance ne subsiste. Malgré cet effet positif transitoire sur les croissances radiales du chêne, aucune différence entre les traitements sur les capacités des arbres à résister et récupérer après des épisodes de sécheresse. Les résistance et récupération de la croissance sont dépendantes de l’intensité et de la durée du déficit hydrique, donc de la sévérité de l’aléa et non de l’apport de nutriments. Ces résultats corroborent les analyses du δ13C dans les cernes des chênes qui, là encore, ne sont significativement corrélées qu’avec le climat et sont indépendantes du traitement. L’absence de modification de la résilience entre les traitements, quel que soit le site et l’essence étudiés, est discutée. Plus largement, ces travaux interrogent le concept de résilience et son utilisation en dendroécologie / Fertilization and liming are usual practices in agronomy but uncommon in forestry. Experimental liming or fertilization in forest were tested in the 1970’s. The initial aim of these experimentations was to determine if the addition of nutrients on poor or acidic forest soil could increase tree growth or even restore crown condition in case of decline. Physiological studies have established the implication of water availability in soil nutrients uptake and their transport in the sap and also via combined effects in various processes such as cell growth or stomatal control. Recently, extreme drought events responsible of many forest species diebacks have aroused the concern of forest managers. In addition, climate models predict an increase in the frequency and intensity of drought hazards in the future and forest management must be adapted to face them. In this context, and thanks to the current knowledge on the interactions between mineral and water alimentation, we investigate whether nutrient supply could mitigate the negative effects of water deficits by increasing the capacity 1/ to withstand droughts and 2/ to recover optimum growth after the drought induced crisis, i.e. to improve the resilience of trees. Conversely, would the vulnerability of trees to water deficits be increased? To answer this question, we investigated fertilization experiments located in three forests in France and applied on two species, sessile oak and Douglas fir. On each of these sites, selected trees were cored to the pith to determine the annual variations of radial growth from measurements of the tree-rings widths. These growth variations were used as a basis to the calculation of resistance, recovery and resilience indices to drought events, which were quantified using a soil water deficit index computed by the water balance model BILJOU©. On the site of Bercé, the water-use efficiency was estimated from the δ13C of the latewood. Retrospective analyses shown that the radial growth of oak trees in Bercé and Tronçais was significantly increased after the fertilization. Radial growth was then modelled from climate and soil water deficit. Douglas fir radial growth was slightly impacted by the nutrient supply in the Potées site. This analysis highlights the time-limited effect of this nutrient supply on the growth stimulation: no effect subsists more than 10 years after nutrient supply in Bercé and more than 20 years in Tronçais. Despite this transient effect on oak growth, no differences between treatments on the capacity of trees to resist and to recover after drought events was observed. The main factors influencing resistance and recovery of growth were the soil water deficit intensity and duration. These results corroborate δ13C analyzes in oak rings, which, again, were only significantly correlated with climate and were independent of treatment. The lack of modification of the resilience between the treatments, whatever the site and the species studied, is discussed. More broadly, the concept of resilience and its use in dendroecology are questioned

The Earth's climate system has recently experienced substantial warming which likely impacts temperature-limited communities close to their distribution margins. The alpine treeline ecotone represents upper distributional limit of montane/subalpine forests. This biogeographic boundary relies mainly on decreasing temperature with increasing elevation. Surprisingly the response of treeline ecotone to ongoing warming has varied a lot and the reasons of this variability are poorly understood. The aim of this dissertation thesis is the assessment of growth trends and tree ring response of Norway spruce (Picea abies[L.] Karst.) to climatic oscillations at treelines and montane forests of East-Central Europe. This dissertation deals with both inter-regional and intra-regional (aspect, elevation) variability of tree growth. The presented results are based on an extensive data set of growth curves for almost 1400 trees. All study sites revealed close relationship between tree ring widths and growing season temperatures as well as the temperatures of October preceding to ring formation season. The main site-dependent differences in growth trends and temperature responses were attributed to elevation, the effect of aspect was relatively less significant. At treelines between the Krkonoše Mts. and Nízké Tatry...

Several researchers have concluded that there is little or no relationship between specific gravity and ring width or growth rate in yellow-poplar (Liriodendron tulipifera L.). Because most mechanical properties of wood are also closely related to specific gravity, it would thus be of interest to learn how minimum suppression and maximum release years' evidence that can be extracted from radial growth patterns based on a modified radial growth averaging (RGA) technique's influence the compression parallel to grain strength and specific gravity of wood. This study is designed to evaluate the effects of growth suppression and release on ultimate crushing stress and specific gravity for small-sized yellow-poplar specimens. Additionally, the relationship between specific gravity and ultimate crushing stress is investigated. Twenty-three yellow-poplar cores were examined for their growth ring widths. Minimum suppression and maximum release years were identified based on the modified RGA criteria method. From each increment core, three 1 Ã 1 Ã 4 mm specimens from both minimum suppression and maximum release years were tested for their ultimate crushing stresses using a micro-mechanical test system. The specific gravity of each specimen was also recorded. These data were analyzed using a paired samples t test and a simple linear regression. The results indicate that the mean ultimate crushing stress and specific gravity of maximum release years were significantly higher than that of minimum suppression years. Furthermore, the ultimate crushing stress was linearly related to the specific gravity of the specimens. / Master of Science

In Mitteleuropa werden zukünftig häufigere Trocken- und Hitzeperioden mit wirtschaftlichen Einbußen in der Waldwirtschaft erwartet. Die Douglasie (Pseudotsuga menziesii (Mirb.) Franco) wird als Alternative für die wirtschaftlich bedeutsame, jedoch trockenheitsempfindliche Fichte diskutiert (Picea abies (L.) H.Karst.). Zwei Unterarten, die Küsten- (FDC) und die Inlandsdouglasie (FDI), sind im ausgedehnten natürlichen Verbreitungsgebiet in Nordamerika beheimatet, welches ein großes Potenzial für die Auswahl produktiver und trockenresistenter Herkünfte bietet. Unser Ziel war, die Trockenreaktion verschiedener Douglasienherkünfte unter Verknüpfung morphologischer und physiologischer Parameter und die der Trockenheitsresistenz bzw. -empfindlichkeit zugrundeliegenden Mechanismen zu erforschen. Ein Herkunftsversuch in Südwestdeutschland ermöglichte die Untersuchung 50-jähriger Douglasien verschiedener Herkünfte entlang eines Höhengradienten. Unter kontrollierten Bedingungen simulierten wir die Effekte einer Hitzewelle auf Jungbäume zweier Provenienzen. Wir analysierten die Kohlenstoff- und Sauerstoff-Stabilisotopenzusammensetzung, den Gaswechsel der Blätter, Veränderungen im Stoffwechsel und das Baumwachstum. Unsere Ergebnisse zeigen bei FDC aus humiden Regionen hohe Wachstumseinbußen unter Trockenheit und moderat bis stark verringerte stomatäre Leitfähigkeit, unterstützt durch Photoprotektion. FDC aus Regionen mit starker Sommertrockenheit reagierten kaum mit Stomataschluss und Wachstumseinbußen auf Trockenheit, jedoch mit starker Osmoregulation und Monoterpen-Emissionen, welche zur Trockenresistenz beitragen könnten. FDI aus einer ariden Region zeigten hohe An, geringes Wachstum und stark antioxidative und photoprotektive Mechanismen. Die Herkünfte unterscheiden sich stark in ihrer Trockenreaktion und ihren Schutzmechanismen. Der Anbau trockenresistenter Herkünfte wird an Standorten von Vorteil sein, für die eine Häufung von ariden Sommerperioden vorhergesagt wird. / In Central Europe, more frequent periods of dry and hot weather are expected in the future with economic losses in the forestry sector. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is discussed as a timber species alternative to the economically important but drought-sensitive spruce (Picea abies (L.) H. Karst.). Two subspecies, the coastal (FDC) and the interior Douglas-fir (FDI), are native to an extensive natural range in North America, offering a great potential for the selection of productive and drought tolerant provenances. Our goal was to investigate the drought response of different Douglas-fir provenances on the morphological and physiological level, as well as the mechanisms underlying drought resistance or susceptibility. A provenance trial in southwestern Germany established in 1958 allowed the study of 50-year-old Douglas-fir trees of diverse provenances along a height gradient. Under controlled conditions, we simulated the effects of a heat wave on young trees of two provenances. We analyzed carbon and oxygen stable isotopic composition, leaf gas exchange, changes in metabolism and tree growth. FDC from humid regions responded to drought with strong growth decline and a medium to strong stomatal closure, supported by enhanced instantaneous photoprotection. FDC from regions with very dry summer conditions showed a small growth decline and anisohydric regulation of stomatal conductance under drought, supported by high levels of osmotic adjustment. High monoterpene emissions might contribute to the drought resistance. FDI from an arid region showed high assimilation rates, low growth potential and a high antioxidant, photoprotective, drought and heat protective potential. The provenances differ greatly in their dry reaction and their protective mechanisms. The cultivation of drought resistant crops will be beneficial at sites predicted to accumulate arid summer periods.