Many paradoxes exist about postglacial tree migration and they dont solve for many European trees. One example is wetland trees subgenus Alnus, which spread across Europe during the last glacial very quickly according to fossil records. The aim of this thesis is detection their migration potential, with the help of empirical evaluation of interpolated pollen data (interpolation method IDW) and a simulation model based on environmental characteristics of the species. The results of interpolated maps are similar to the rate previously estimated speed and the results of simulation model achieve these speeds only by A. incana but with specific extreme environmental conditions. The mason of this may be adapting its seeds to anemochorii because the simulation model confirmed their good potential to spread by the wind. Results of model for A. glutinosa don´t confirm the ability to rapidly spread by the wind and the observed rate must have another explanation. Maybe rivers can explain the empirical spread rate. This suggests visualization of migration lines and river networks. The model has also been disclosure of environmental properties that are related to migration potential. Within the parameterization of the model is demonstrated, that R0 of A. glutinosa is significantly better than A. incana. But main parameters of anemochory model are terminal velocity and generation time, which is shorter by the A. incana, and therefore is probably able to spread faster than A. glutinosa.

Increasing the taxonomic resolution of fossil pollen identification is important for accurate paleoecological reconstructions. Here, an attempt is made to identify the critical morphological features that will permit differentiation of Alnus pollen in fossil records. Palynologists working in the Pacific Northwest often distinguish alder pollen into two morphotypes. However, no definitive method outlining the validity of species level identifications has been devised to date. To test and validate species-level identifications, the pollen morphology of the three main alder species (Alnus viridis subsp. sinuata, Alnus incana subsp. tenuifolia and Alnus rubra) that occur in westernNorth America is examined with the goal of identifying morphological characteristics with which to distinguish the pollen of these species in fossil records. Modern pollen samples were collected from 27-35 individual plants from across the range of each of the three alder species. Pollen grains (n=30) from each individual plant were examined using light microscopy at 1000´ magnification under oil immersion. For each individual pollen grain, six quantitative traits (pollen grain diameter, exine thickness, arci width, and annulus height, width and area), and three qualitative traits (pore protrusion, grain shape and arci strength) were measured. In total, 21,390 alder pollen were examined from 93 separate collections. In addition, the number of pores was determined for 200 pollen grains from each individual plant. Statistically significant differences between species were found for all quantitative traits when traits were compared via nested ANOVA. However, there is high variability in pollen morphology within each species and pollen morphology is best described as occurring along a morphological continuum. A single morphological trait is insufficient for precise identification of alder pollen to species. CART analysis, when used to derive a multi-trait classification model, is shown to be a useful tool in separating the pollen of A. rubra and A. viridis subsp. sinuata into two separate ‘morphotypes,’ analogous to species identification. The confounding intermediate morphology of A. incana subsp. tenuifolia precludes the possibility of distinguishing the pollen of all three species. CART modelling isolates A. rubra and A. viridis subsp. sinuata pollen based on annulus width, arci strength, diameter and exine thickness, traits that support the differences used by palynologists for separating alder pollen into ‘morphotypes.’ Sensitivity analysis shows clearly that the common practice of using small sample sizes (e.g. n=7 and n=15) for identifying critical morphological traits for pollen identification produces misleading and erroneous results. Regional differences in pollen morphology were also assessed by splitting the dataset into regions. Classification accuracy is diminished from over 70% to less than 20% when a CART model derived from pollen grains from one region is used to classify grains from a different region. This research underscores the importance of using large sample sizes from across species’ ranges when attempting to determine the diagnostic morphological features for accurate pollen identification. / Graduate

Les patrons de distribution chez les micro-organismes reposeraient sur leurs capacités à disperser dans le temps et dans l'espace, en lien avec des facteurs abiotiques comme les propriétés du sol, le climat, et des interactions biotiques, notamment avec l'hôte dans le cas des symbiontes, mais aussi sur les traits d'histoire de vie propres aux micro-organismes, telle que la capacité à sporuler. Frankia sp. est une actinobactérie sporulante et fixatrice d'azote à la biogéographie complexe, car vivant à la fois de façon saprophytique dans le sol, en symbiose racinaire (nodosité) avec les plantes actinorhiziennes dont les aulnes (Alnus, Betulaceae). Deux types de souches de Frankia génétiquement différentes ont été décrites dont la distinction phénotypique majeure réside dans la capacité à maintenir (Sp+) ou non (Sp-) leur sporulation in planta. Cette sporulation endophytique est à notre connaissance unique dans un contexte symbiotique et son implication dans la biogéographie de Frankia, reste peu connue. Ces travaux de thèse intègrent à la fois des approches descriptives et expérimentales, sur le terrain et au laboratoire, afin d'accroître la compréhension du rôle écologique de la sporulation in planta de Frankia. Dans un premier temps, nous avons étendu la description de la phylobiogéographie des souches de Frankia Sp+ afin de tester la validité du patron de distribution centré sur les milieux froids des zones de haute altitude et de haute latitude de l'hémisphère nord. Un intérêt tout particulier a été porté sur les aires géographiques où une plus forte diversité de Frankia était attendue, dans la zone d'origine de l'aulne et ses refuges glaciaires. Dans un second temps, nous avons étudié l'influence du partenaire végétal dans la distribution observée des Frankia Sp+ et l'implication du trait Sp+ dans la capacité d'association à l'hôte. Des croisements expérimentaux ont été réalisés au laboratoire afin de découpler les effets de l'espèce-hôte et du climat, et tester les implications du trait Sp+ en termes d'infectivité, compétitivité et spectre d'hôte. Enfin, nous avons étudié les conséquences écosystémiques de l'expansion subalpine du complexe symbiotique Alnus/Frankia, au niveau de la diversité microbienne et du fonctionnement du cycle de l'azote, en fonction du phénotype de sporulation des souches associées. Des analyses pédologiques, en association avec des mesures de nitrification, dénitrification et fixation d'azote, ainsi que des analyses de diversité microbienne (globale et fonctionnelle), ont été réalisées dans différentes aulnaies Sp+, Sp- ou mixte, à différents stades de colonisation de l'aulne. Les résultats obtenus démontrent une prédominance des souches Sp+ associées aux espèces d'aulne des milieux froids sur les 3 continents de la zone Holarctique, avec une diversité nouvelle dans l'aire d'origine et les zones refuges de l'aulne. Les croisements effectués révèlent une infectivité et compétitivité plus forte des Sp+ par rapport aux Sp-. De plus, contrairement aux Sp- à spectre d'hôte très large, les Sp+ présentent un spectre limité entraînant des incompatibilités d'association suggérant une dépendance forte à une espèce-hôte donnée. Les modifications des communautés microbiennes du sol en réponse à l'expansion du complexe symbiotique Alnus/Frankia ont été démontrées, en lien avec la stimulation du cycle de l'azote dans les milieux sub-/alpins. Les premiers résultats sur l'efficience comparée de la fixation d'azote in natura des souches Sp- par rapport aux Sp+ suggèrent que 100% de l'azote de l'aulne est obtenu par le biais de la fixation. Aucun patron n'est mis en évidence entre souches Sp+ et Sp-, suggérant un effet plus complexe de la saisonnalité, de l'âge de l'arbre et de celui de la nodosité. Les résultats obtenus nous permettent de mieux appréhender les facteurs guidant la biogéographie de Frankia et de discuter de l'évolution de ces patrons de distribution en réponse au réchauffement climatique / Microbial biogeography would be based on the ability of microorganisms to disperse across time and space, as a function of abiotic factors such as soil properties, climate, and of biotic interactions, in particular with the host in the case of symbionts, but also on life history traits such as the ability to sporulate. Frankia sp. is a spore-forming and nitrogen-fixing actinobacterium that has a complex biogeography given its abilities for both saprophytic life and root symbiotic interaction with actinorhizal plants such as alders (Alnus, Betulaceae). Two distinct groups of Frankia lineages have been described according to a major phenotypic divergence, based on the presence (Sp+) or the absence (Sp-) of spores in planta.. To the best of our knowledge, this endophytic sporulation is an original trait in a symbiotic context and very little is known about its incidence in Frankia biogeography. This work integrates descriptive and experimental approaches on both field and laboratory areas, in order to improve the understanding of the ecological role of Frankia in planta sporulation. First, we have extended the description of the phylobiogeography of Sp+ Frankia strains to validate the previously proposed distribution pattern focused on cold environements at high altitude or high latitude. A phylogeny has been computed using a large number of nodular strains coming from the 3 continents of the Northern Hemisphere and 10 different Alnus species. Special attention was paid to geographic areas where a higher diversity was expected, in Asia, and in its glacial refuges. Second, we studied the influence of the host-plant on the distribution of Fankia Sp+ and the incidence of Sp+ in the symbiotic interaction. Experimental crosses have been performed to disentangle host and climate effects and to test the incidence of the Sp+ trait in terms of infectivity, competitiveness and host-range. Finally, we studied the ecological consequences of the Alnus/Frankia symbiotic complex, on the microbial diversity and on the nitrogen cycle functionning, with respect to the sporulation of Frankia and to the Alnus expansion on sub-/alpine grasslands. Soils analyses were performed in association with measures of nitrification and denitrification, as well as global and functional microbial diversity analyses, in Sp+, Sp- or mixed alder stands and at different colonization stages. In each part of this work, alder ectomycorhizae were analyzed to compare the distribution pattern between the two symbionts and to highlight potential interactions with the Sp+ trait of Frankia. Our results show the dominance of Sp+ strains in nodules of alder species from cold environments over the 3 continents of the Holarctic zone, with original diversity patterns in alder area of origin and in glacial refuges. Even if these strains are genetically homogenous, host-specific clusters were observed in the phylogeny. Crosses revealed that Sp+ strains were more infective and competitive than Sp- strains. Moreover, unlike Sp- strains that harbor a wide host-range, Sp+ strains have a narrower specificity leading to association’s incompatibilities and suggesting strong host dependence. For the first time, modifications of microbial communities were revealed in response to the Alnus-Frankia symbiotic complex colonization and were linked to a stimulation of the nitrogen cycle in the sub-/alpine grasslands. The first comparative results of nitrogen fixation between Sp+ and Sp- strains in natura suggest a maximal efficiency of fixation, representing almost 100% of the alder nitrogen. However, unlike previous reports in literature, no pattern was observed between Sp+ and Sp- strains, suggesting a complex effect of seasonality, alder age as well as that of nodules. Altogether, the previous results contribute to a better understanding of the Frankia biogeography drivers and allow us to discuss the expected evolution of distribution pattern in response to the global warming

Previous field research show, that late successional species correspond with soil development, especially with organomineral A horizon developing. Aim of my thesis was to compare plant growth on different types of soil from spoil heaps. They were taken from three chronosequencies of different age - nonrecultivated and soils recultivated with planting of alder (Alnus) and spruce (Picea). In my research were used 7 types of plants - Arrhenatherum elatius, Centaureae jacea, Festuca rubra, Lychnis flos-cuculi, Lotus corniculatus, Plantago major, Trifolium medium. Spontaneous sites support more species than reclaimed ones this difference increase with plot age without distinct difference between early and late succession species. Key words Succession, recultivation, germination alder (Alnus), spruce (Picea), Arrhenatherum, Centaureae, Festuca, Lychnis, Lotus, Plantago, Trifolium.

Information on alder (Alnus jorullensis silvics and dendrology, propagation, and management were synthesized into four alternatives for fuelwood management in Saraguro, Loja, Ecuador. Stem volume was estimated from diameter and height measurements taken in 16 stands of known age in Ecuador using an empirical equation developed in Costa Rica. An empirical equation describing the relationship between stem volume and tree age for alder in Ecuador was then developed. Measurements of 5 fuelwood units from Saraguro were used to determine the market price for a cubic meter of fuelwood. Four mangement regimes using a 20 year rotation were then examined at four discount rates. Using a 15% real rate of interest, thinning at 10 years yielded a present net value of 891,059 sucres and a benefit-cost ratio of 1.31. The analysis was more sensitive to changes in fuelwood price than to changes in wage rate.

Extraction of mineral resources causes landscape degradation and the aim of reclamation efforts is to restore ecosystems. Our research was carried out on spoil heaps after brown coal mining near Sokolov (Czech Republic). We compared twenty years old spontaneously developed sites and reclaimed sites afforested by alders Alnus glutinosa and A. incana. Biomass and nutrient budget were evaluated for herbs and woody plants, separately for species Salix caprea, Populus tremula and Alnus glutionosa. Alder showed significantly higher concentrations of nitrogen and carbon compared to other tree species. The total amount of biomass, carbon and nitrogen was higher on reclaimed sites whereas phosphorus was more represented on spontaneously developed sites. Most of nitrogen was accumulated in the below-ground tree biomass and the largest amount of phosphorus was in the above-ground tree biomass. Woody plants of non-reclaimed sites produced more litter whilst litter of alder stands showed a higher concentration of nitrogen. Higher values of biomass, carbon and nitrogen of reclaimed sites were probably achieved through alder ability to fix atmospheric nitrogen.

This literature review is a synthesis of recent publications and developments regarding the growing acceptance and potential of Alnus rubra (Bong) commonly called red alder. The project summarized some of the concerns and benefits of including red alder in coastal forest mixedwood management strategies. Some of the concerns include overtopping of conifers and competition for light. Some benefits include increases to site productivity, biodiversity, forest health and diversification of the coastal forest industry. It also examined past and current industry and government policies towards alder in mixedwood management and recent changes in some of these policies including the just released “Hardwood Management in the Coast Forest Region” policy paper. There is now recognition of the importance of alder management and there is a framework in place for patch mixedwood management in coastal BC. But before intimate mixedwood strategies are accepted and used operationally, further research and trials are required. There needs to be a better understanding of both the competetitive and beneficial effects of red alder in mixture with conifers for complex forests to in order to assist forest managers in making sustainable management decisions.

This research looks at some issues confronting community forestry in Nepal. Analytic Hierarchy Process (AHP) was used to analyze the issues confronting community forestry in mid hills region of Nepal. Results indicate that experts as well as local community users think positive aspects of community forestry to be more important than its negative aspects. In addition, through the comparison of three forest types, Alnus nepalensis found to be the most important forest type for conservation and Schima-Castanopsis to be the most important forest type for local benefits. Similarly, results also indicate that increase in carbon prices lengthen an optimal rotation age. Also, Land Expectation Value (LEV) increases substantially with the increase in carbon prices.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 5 uppsatser.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on Nov. 26, 2008). Includes bibliographical references (p. 24-33).