This thesis describes the research undertaken for the degree of Doctor of Philosophy, testing the hypothesis that spectrometer data can be used to establish usable relationships for prediction of pasture quality attributes. The research data consisted of reflectance measurements of various temperate pasture types recorded at four different times (years 2000 to 2002), recorded by three hyperspectral sensors, the in situ ASD, the airborne HyMap and the satellite-borne Hyperion. Corresponding ground-based pasture samples were analysed for content of chlorophyll, water, crude protein, digestibility, lignin and cellulose at three study sites in rural Victoria, Australia. This context was used to evaluate effects of sensor differences, data processing and enhancement, analytical methods and sample variability on the predictive capacity of derived prediction models. Although hyperspectral data analysis is being applied in many areas very few studies on temperate pastures have been conducted and hardly any encompass the variability and heterogeneity of these southern Australian examples. The research into the relationship between the spectrometer data and pasture quality attribute assays was designed using knowledge gained from assessment of other hyperspectral remote sensing and near-infrared spectroscopy research, including bio-chemical and physical properties of pastures, as well as practical issues of the grazing industries and carbon cycling/modelling. Processing and enhancement of the spectral data followed methods used by other hyperspectral researchers with modifications deemed essential to produce better relationships with pasture assay data. As many different methods are in use for the analysis of hyperspectral data several alternative approaches were investigated and evaluated to determine reliability, robustness and suitability for retrieval of temperate pasture quality attributes. The analyses employed included stepwise multiple linear regression (SMLR) and partial least squares regression (PLSR). The research showed that the spectral research data had a higher potential to be used for prediction of crude protein and digestibility than for the plant fibres lignin and cellulose. Spectral transformation such as continuum removal and derivatives enhanced the results. By using a modified approach based on sample subsets identified by a matrix of subjective bio-physical and ancillary data parameters, the performance of the models were enhanced. Prediction models from PLSR developed on ASD in situ spectral data, HyMap airborne imagery and Hyperion and corresponding pasture assays showed potential for predicting the two important pasture quality attributes crude protein and digestibility in hyperspectral imagery at a few quantised levels corresponding to levels currently used in commercial feed testing. It was concluded that imaging spectrometry has potential to offer synoptic, simultaneous and spatially continuous information valuable to feed based enterprises in temperate Victoria. The thesis provide a significant contribution to the field of hyperspectral remote sensing and good guidance for future hyperspectral researchers embarking on similar tasks. As the research is based on temperate pastures in Victoria, Australia, which are dominated by northern hemisphere species, the findings should be applicable to analysis of temperate pastures elsewhere, for example in Western Australia, New Zealand, South Africa, North America, Europe and northern Asia (China).

How do gender separation and the transition to wind pollination happen in temperate trees? What does the reproductive ecology in the crowns of temperate forest trees look like? These connected questions intrigued researchers before and since Darwin but it is only in the last years that a direct study of the latter question has been enabled. A research crane was used to study the flowering ecology of Fraxinus excelsior, Acer platanoides, Acer pseudoplatanus and Tilia cordata in Leipzig’s floodplain forest. These species originate from hermaphrodite insect pollinated plant families and exhibit different grades of gender separation and different stages between insect and wind pollination. As they are typical elements of temperate deciduous forests, an ecological comparison of their flowering ecology may shed new light on the evolution of gender separation and wind pollination in this habitat. Using the crane, gender distribution, flowering phenology in relation to microclimate, pollination levels (including pollen tubes in the styles) and fruit set were studied in ca. 200 trees over 2-4 years. Main results are a new appreciation of the sexual system of Fraxinus excelsior as dioecy, of Tilia cordata as andromonoecy and a detailed description of the intricacies of the heterodichogamous sexual system of Acer pseudoplatanus. Several flowering phenological patterns are described in Fraxinus excelsior and Acer platanoides in relation to microclimate in early spring. The role of small arthropods is underlined as gall mites may play a role in gender specialisation in Fraxinus excelsior, gall midges are related to maleness in T. cordata and thrips are probably the pollinators of Acer pseudoplatanus in the stand. Thrips pollination is suggested to be a possible stepping-stone between insect pollination and wind pollination, which may drive the transition in Acer pseudoplatanus and possibly in intensively flowering dominant species in other habitats. The study presents the complexity of the reproductive systems and the strong interdependencies among their elements.

Nothofagus moorei is a long-lived, Gondwana relict cool temperate rainforest tree. Nothofagus-dominated rainforests were widespread across much of eastern Australia during the mid-Tertiary but today, N. moorei occurs only as a series of disjunct, isolated populations in south-east Queensland and northern New South Wales. Clonal regeneration via coppicing is reported to be a common feature of most N. moorei populations, while successful sexual regeneration is believed to be rare, occurring largely only in niches with high light levels and limited competition. While clonal propagation enables population persistence and individual longevity, it cannot generate novel genotypes. Isolated populations, potentially high levels of clonality, low-potential for successful sexual regeneration, long-lived individuals and predicted global warming effects make N. moorei vulnerable to local, if not total, population extinction. The current study aimed to assess the relative conservation status of extant N. moorei populations in order to develop appropriate conservation management strategies for long-term population persistence. Levels of genetic diversity and population structure were examined across the remaining natural distribution of N. moorei using nuclear amplified fragment length polymorphism (AFLP), microsatellite and chloroplast DNA markers. In total 607 individuals were sampled from 20 populations and 5 geographical regions: Lamington/Border Ranges, Ballow, Dorrigo/New England, Werrikimbe and Barrington. Genetic results were then analysed to assess conservation status of each population and geographical region. Microsatellite and AFLP data identified comparatively high levels of genetic diversity in all remnant populations sampled. The prevalence of coppicing in the northern Lamington/Border Ranges populations appears to have had little impact on relative levels of genetic diversity, heterozygosity or population structure. Population differentiation was limited, with the majority of genetic variation retained within populations, no regional structuring and high levels of admixture. Analysis of cpDNA variation showed that the three Dorrigo/New England populations were divergent from all other populations, suggesting an ancient divergence in N. moorei prior to Pleistocene glaciations. While levels of genetic diversity were essentially the same across all populations, Bayesian analysis of genetic structure did identify four populations with differing gene pool proportions which would be important to include in conservation efforts in addition to individuals from other populations. Similarly, individuals from four significantly differentiated groups identified using traditional F-statistics suggests individuals from each of these four groups should be included in future conservation plans. In order to maintain ancient chloroplast lineages, populations from the Dorrigo/New England region should also be assigned special conservation value. Populations of N. moorei appear to have retained significant levels of genetic diversity and show little population divergence in spite of marked reductions in the natural distribution since the Early Miocene. Sampling of these ancient trees however, suggests current levels of diversity in N. moorei actually reflect past diversity and differentiation, and that there have been insufficient generations since the historical contraction in distribution for genetic diversity to be adversely affected and regional differentiation to evolve. Long-term persistence of N. moorei is still threatened by future accelerated climate change and the limited preferred habitat that remains where N. moorei can expand its range. While the ability to regenerate clonally may enable long-term persistence of N. moorei, populations are still likely to continue to decline as climatic conditions will increasingly favour sub-tropical and warm temperate species across much of N. moorei's northern distribution. Southern populations of N. moorei, in contrast, could expand their ranges into eucalypt woodlands as predicted climate becomes warmer and wetter. However, this will ultimately be determined by the frequency of fires, with increased fire frequencies favouring the expansion of eucalypts and contraction and possible local population extinction of N. moorei dominated cool temperate rainforests.

The thesis concerns the community structure of saproxylic insects with a heavy focus on beetles. It presents a review on change of insect assemblages along small-to-large scale gradients and the importance of saproxylic organisms in forest ecosystems. The fine-scale vertical stratification of saproxylic beetles assemblages and their differences between forests habitats of different latitude and altitude are investigated. Further, the importance of open-grown trees for saproxylic diversity is assessed.

Current research looked into the effects of supplementing essential amino acids L-lysine and DL-methionine to lactating dairy cows, grazing annual ryegrass and receiving a low protein concentrate meal. Twenty Holstein cows were managed in a 2x2 crossover experimental design, with two treatments and two periods. Cows received the same diet in both treatments, except for the inclusion of 20g lysine and 60g methionine in one treatment. This aimed at supplying 6.92% and 2.34% of the metabolizable protein in lysine and methionine, respectively, as suggested by the Cornell Net Carbohydrate and Protein System (CNCPS). No significant differences were found in milk (36,19 vs. 35,97kg), total crude protein (1,14 vs. 1,15kg) and lactose (1,62 vs. 1,66kg) yields, casein content (2,55 vs. 2,55%), somatic cell count (309 vs. 363cél.mL-1), milk urea nitrogen (12,40 vs. 12,15mg.dL-1), and blood urea (25,01 vs. 25,09mg.dL-1) for the control and the amino acid supplemented treatments, respectively. The amino acid supplemented treatment presented a lower milk fat content (3,58 vs. 3,39%), but no differences yield (1,29 vs. 1,21kg), which led to the same 4% milk fat corrected milk yield (33,8 vs. 32,6kg). The lower milk fat content resulted in a lower total milk solids content (12,56 vs. 12,26%) in the amino acid supplemented treatment, in spite of this treatment presenting similar crude protein (3,17 vs. 3,20%) and lactose (4,48 vs. 4,61%) contents. Animals receiving the amino acid supplementation also presented lower creatinine blood (0,74 vs. 0,89mg.dL-1) suggesting a lower muscle tissue mobilization, in spite of their similar urine urea nitrogen test (264,15 vs. 351,30 mg.dL-1) and urine creatinine (42,46 vs. 38,04mg.dL-1). Rumen-protected lysine and methionine supplementation did not affect milk yield but did affect milk composition and reduced serum creatinine. / Neste trabalho, avaliou-se os efeitos da adição dos aminoácidos essenciais L-lisina e DL-metionina na dieta de vacas em lactação, mantidas em pastagens de azevém anual e suplementadas com concentrado de baixo teor proteico. Foram utilizadas 20 vacas da raça holandesa em um delineamento experimental crossover (2x2), submetidas a dois tratamentos e dois períodos. Ambos tratamentos receberam dietas iguais, com exceção da inclusão ou não de 20 e 60g dos aminoácidos lisina e metionina, respectivamente, buscando atingir os níveis de 6,92% de lisina e 2,34% de metionina na proteína metabolizável, sugeridos pelo Cornell Net Carbohydrate and Protein System (CNCPS). Não foram encontradas diferenças significativas para produção de leite (36,19 vs. 35,97kg), produção total de proteína bruta (1,14 vs. 1,15kg) e de lactose (1,62 vs. 1,66kg), teor de caseína (2,55 vs. 2,55%), contagem de células somáticas (309 vs. 363cél.mL-1), nitrogênio ureico no leite (12,40 vs. 12,15mg.dL-1) e ureia no sangue (25,01 vs. 25,09mg.dL-1) para os grupos controle e com adição de lisina e metionina, respectivamente. O grupo que recebeu a suplementação apresentou menor teor de gordura no leite (3,58 vs. 3,39%), mas igual volume de gordura produzido (1,29 vs. 1,21kg), não interferindo na produção de leite quando esta variável foi corrigida para 4% de gordura (33,8 vs. 32,6kg). O teor menor de gordura fez com que o teor de sólidos totais fosse menor no grupo que recebeu os aminoácidos (12,56 vs. 12,26%), embora este tenha apresentado teor igual de proteína (3,17 vs. 3,20%) e superior de lactose (4,48 vs. 4,61%). Os animais que receberam os aminoácidos também apresentaram teores inferiores de creatinina no sangue (0,74 vs. 0,89mg.dL-1) sugerindo uma mobilização menor de tecidos musculares, embora tenham apresentado níveis semelhantes de ureia na urina (264,15 vs. 351,30 mg.dL-1) e creatinina na urina (42,46 vs. 38,04mg.dL-1). O fornecimento dos aminoácidos lisina e metionina protegidos na degradação ruminal, não influenciou a produção total de leite, mas sim sua composição, além de reduzir os níveis de creatinina sérica.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The present study was carried out to determine the effects of supplementing fresh ryegrass forage based diets with starch, rumen degradable or undegradable protein sources on intake, digestion and nitrogen retention, rumen digestibility and the duodenal nitrogen flow. Ten Corriedale lambs (26 kg mean body weight), kept in metabolic cages were used in a 5 x 5 Latin Square experimental design. Five lambs were previously fitted with permanent ruminal and duodenal cannulae. Treatments tested were: fresh ryegrass forage cut daily and feed without supplementation (AZ); or same forage supplemented with either cassava meal (FM); calcium caseinate (CA), corn gluten meal 21% CP (FMG 21) or corn gluten meal 60% CP (FGM 60). Feeding FGM 21, FGM 60 and CA increased (P<0.05) intake of total dry matter (DM) (P<0.05), organic matter (OM) and digestible organic matter. True digestibility of OM and neutral detergent fibre (NDF) digestibility were similar between treatments, whereas CA and FM treatments increased DM and OM digestibilities. Nitrogen intake was higher (P<0.05) in lambs receiving nitrogen supplements, but microbial N synthesis and N retention was similar between treatments. Ruminal pH values and ammonia N concentration varied in a cubic (P<0.05) way wit time after feeding. Duodenal flux of amino acids was higher (P<0.05) for lambs consuming the FGM 60 supplement. All supplements increased (P<0.05) apparent and true OM ruminal digestibility. The efficiency of rumen microbial N synthesis decreased (P<0.05) in animals fed FGM 21, CA or FM supplements. In conclusion all supplements increased intake of MOD, but only supplement containing rumen undegradable protein increased the amino acids to lambs fed with ryegrass. / Este estudo foi conduzido com o objetivo de avaliar se e em que grau a oferta suplementar de amido ou proteína degradável no rúmen, assim como de proteína não degradável, afetam o consumo, os processos de digestão, a retenção de nitrogênio, a digestibilidade ruminal e o fluxo duodenal das frações nitrogenadas em ovinos alimentados com azevém (Lolium multiflorum, Lam) à vontade. Foram utilizados dez cordeiros castrados Corriedale (PV médio de 26 kg), mantidos em gaiolas de metabolismo em um delineamento experimental Quadrado Latino 5 x 5. Cinco destes animais foram implantados com sondas permanentes no rúmen e com cânulas duodenais. As dietas experimentais utilizadas foram azevém sem suplementação (AZ) ou azevém mais farinha de mandioca (FM), caseinato de cálcio (CA), farelo de glúten de milho 21% PB (FGM 21) ou farelo de glúten de milho 60% PB (FGM 60). A suplementação com FGM 21, FGM 60 e CA aumentou (P<0,05) consumo total de matéria seca (MS), matéria orgânica (MO) e MO digestível. As suplementações com CA e FM melhoraram (P<0,05) a digestibilidade aparente da MS e MO, no entanto, a digestibilidade verdadeira total da MO e a digestibilidade da fibra em detergente neutro (FDN) foram similares entre os tratamentos. O consumo de nitrogênio (N) foi superior (P<0,05) pelos cordeiros que receberam suplementação nitrogenada. A síntese de N microbiano, assim como a retenção de N foram similares entre os tratamentos. Os valores de pH ruminal e concentração de Namoniacal no fluído ruminal variaram cubicamente (P<0,05) ao longo do tempo após a alimentação. O fluxo duodenal de aminoácidos foi superior (P<0,05) nos cordeiros suplementados com FGM 60. A suplementação aumentou (P<0,05) a digestibilidade ruminal aparente e verdadeira da MO. A eficiência de síntese de nitrogênio microbiano diminuiu (P<0,05) nos cordeiros suplementados com FGM 21, CA e FM. Em conclusão, todos os suplementos aumentaram o consumo de MOD, mas somente o suplemento caracterizado por ter proteína de baixa degradabilidade aumentou a oferta de aminoácidos aos animais alimentados com azevém.

Made available in DSpace on 2014-08-20T14:22:05Z (GMT). No. of bitstreams: 1 Dissertacao - Tiago_ Madruga_ Telesca_ da_ Silveira.pdf: 862919 bytes, checksum: 61ee8816da2a09b561b1dc673a73aabc (MD5) Previous issue date: 2008-07-14 / Temperate fruit species have a great economic and social importance for the South and Southeast region of Brazil. Among the several fruit species which can be produced in these regions, some were recently introduced in the country and others had a limited expansion. Blueberry (Vaccinium ashei Read) is part of the first group whereas japanese plums (Prunus salicina L.) and blackberries (Rubus spp), are examples of the last case. Pollination and fertilization process is, perhaps, the most important in the production system, since yield is directly dependent of it. The objectives of the this work were: verifying the need of cross pollination of a few blackberry and plum genotypes; to observe the main pollinizers for blueberries and blackberries, under the climatic conditions of Rio Grande do Sul State and to observe a possible influence of the pollen on fruit quality. Seven experiments were conducted, during the year of 2007, under field conditions, using plants of the Embrapa Clima Temperado collections of plums, blackberries and blueberries. Another experiment was carried out under greenhouse conditions with potted plants of blueberry cultivars. Four blackberry selections and three selections and one cultivar of plum were tested for degree of self-fertilization, bagging production branches, before flower anthesis. Potential pollinizers were observed for both species as well as possible pollinators of the studied plum genotypes. Observations were made on blueberry pollinizers. Controlled crosses of two blueberry selections and two cultivars were done with the aim of measuring possible effects of pollen on fruit quality. Under the conditions tested, the blackberry selections 6/96, 16/96 and 6/2001 were selfertiles whereas 4/96 needed cross pollination. The most frequent insects observed on the blackberry flowers and potential pollinizers were honeybees, Apis mellifera. The cv Gulf Ruby does not produce when isolated from others and cv. Gulf Blaze is a good pollinator for it. Plum selections 1, 17 and 21 had a reasonable degree of fruit set, by self pollination. However, it is believed that it can be improved by the use of a pollinator.Laboratory tests showed that Selection 21 can pollinate Pluma 7 and cv Rosa Mineira can be a pollinator for Selection 17. The cv. America is not a good pollinator for Selection 19. Honeybees are good for pollen transportation in plum orchard. In both species, blueberry and plums, the pollen source influenced in size and soluble solids. Bumble bees (Bombus sp) are the most effective pollinizers for blueberries and the complement the honeybees activities. Trigona spinipes cause damage to blueberry flowers and also to the set. / As espécies frutíferas de clima temperado têm grande importância econômica e social na região Sul e Sudeste do Brasil. Dentre as várias espécies que podem ser aí produzidas, algumas foram recentemente introduzidas no sistema produtivo da região ou tiveram pouca expansão. Enquanto no primeiro caso encontra-se o mirtilo (Vaccinium ashei Read), no último, enquadram-se a ameixeira (Prunus salicina Lindi) e a amoreira-preta (Rubus sp.). O processo da polinização e fertilização é o mais importante elo na cadeia reprodutiva: dele depende toda a produção frutífera. Os objetivos desse trabalho foram verificar a necessidade de polinização cruzada alguns genótipos de amoreira-preta e de ameixeira-japonesa, além de determinar os principais agentes polinizadores em mirtilo e amoreira-preta nas condições do Sul do Rio Grande do Sul, bem como observar uma possível influência da polinização sobre a qualidade das frutas. Foram realizados sete experimentos com plantas dos pomares experimentais de amoreira-preta, mirtilo e ameixeira-japonesa e um em plantas de mirtilo, cultivadas em vasos em casa de vegetação, na Embrapa Clima Temperado, Pelotas-RS, durante o ano de 2007. Em quatro seleções de amoreirapreta foi feito estudos para verificar a autofertilidade ensacando flores ou não, três seleções e uma cultivar de ameixeira-japonesa foram observadas também as polinizadoras potenciais de ameixeira e insetos visitantes florais. Em mirtilo foram feitos cruzamentos controlados com 2 cultivares e 2 seleções e observado o efeito desses na qualidade das frutas. Foram ainda observados os prováveis polinizadores dessa cultura. As seleções de amoreira-preta 6/96, 16/96 e 6/2001 se comportaram como autoférteis, enquanto que a seleção 4/96 necessita de uma polinizadora; Os insetos mais freqüentemente, presentes no pomar de amoreira-preta e potenciais polinizadores dessa cultura são as abelhas, A. mellifera. A cultivar Gulf Ruby não produz quando isolada, sendo a cultivar Gulf Blaze uma boa polinizadora da mesma. As seleções 1, 17 e 21 de ameixeira-japonesa testadas a campo têm razoável grau de autofertilidade. Testes de compatibilidade em laboratório mostram que a seleção 21 é boa polinizadora para a cultivar Pluma 7 e que a cultivar Rosa Mineira é boa polinizadora para a seleção 17; A cultivar América não é polinizadora potencial da seleção 19; As abelhas Apis. mellifera são bons transportadores de pólen no pomar de ameixeira. Em ameixeira-japonesa, bem como em mirtilo, a fonte de pólen tem influência no tamanho e sólidos solúveis totais nas frutas. As mamangavas (Bombus sp.) são os insetos efetivos polinizadores para a cultura do mirtilo e complementam a polinização com as abelhas (Apis mellifera). As irapuás (Trigona spinipes), são insetos prejudiciais à cultura do mirtilo.

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Les écosystèmes forestiers constituent le principal réservoir à long terme de carbone. Toutefois, les dynamiques saisonnières de productions de cette biomasse ligneuse, en relation avec l'assimilation du carbone par l'écosystème et les déterminants environnementaux, restent peu étudiées, limitant notre compréhension du cycle du carbone et particulièrement sa sensibilité aux changements actuels du climat. Cette thèse a pour objectif de comprendre les relations entre le processus de séquestration du carbone dans le bois en formation, la physiologie de l’arbre, l’assimilation du carbone par le peuplement, et les conditions environnementales du site. L’étude porte sur trois sites instrumentés d’une tour à flux avec un peuplement constitué principalement par, respectivement l’épicéa à Tharandt en 2016, le hêtre à Hesse en 2015-2017, et le chêne à Barbeau en 2016. La formation du bois a été suivis par prélèvement hebdomadaire de microcarottes contenant, le phloème, le cambium et le xylème en formation sur des arbres dominants sélectionnés dans l’empreinte de mesure de la tour. La productivité primaire brute a été estimée par Eddy-Covariance, et les variables climatiques mesurés grâce aux dispositifs de la tour. En premier, nous avons mis au point une nouvelle approche histologique, plus rapide et plus précise que la méthode précédemment publiée sur les résineux, pour quantifier la dynamique intra-annuelle de la séquestration du carbone dans le bois en formation, basée sur des mesures répétées de la densité apparente du xylème, et applicable également aux angiospermes. Dans le 2nd chapitre, nous avons montré que l’occurrence en même temps du développement de la canopée et de la reprise de l’activité cambiale pouvait ralentir la croissance radiale du xylème, et favoriser la formation d’un xylème à porosité élevée mais rapidement fonctionnel. Dans le 3ème chapitre, nous avons démontré que le plan ligneux détermine la coordination temporelle entre la croissance en taille et en biomasse du tronc au cours de la saison de végétation, la séquestration du carbone dans le bois en formation étant toujours décalée derrière la croissance radiale du tronc due aux processus internes de la xylogenèse, avec une tendance croissance du décalage temporel pour l’épicéa et le hêtre, mais une tendance décroissante chez le chêne. Le 4ème chapitre démontre que indépendamment du peuplement, la dynamique d'assimilation du carbone présentait une courbe en cloche symétrique culminant en Juin, tandis que la dynamique saisonnière de la séquestration du carbone variait entre les 3 espèces. Le peuplement de hêtres a concentré la séquestration du carbone dans le tronc en Mai-Juillet, tandis que les peuplements d'épicéa et de chênes ont plutôt culminé en Juin-Août et ont concentré cette séquestration vers la 2ème partie de la saison de végétation. Dans le 5ème chapitre, grâce à un suivi de trois ans des flux de carbone, de la croissance des arbres, et des facteurs environnementaux dans le peuplement de hêtres matures, nous avons montré que le classement du bilan de carbone annuel n'était pas maintenu d'une année à l'autre, avec l’assimilation de carbone annuel la plus élevée en 2017, mais la production de biomasse ligneuse la plus élevée en 2016. Cela suggère que l'allocation du carbone de l'assimilation à la séquestration dans la tige ne suit pas une simple règle d’allométrie. Enfin, nous avons observé que, parallèlement à la formation d'un nouveau xylème, la teneur en amidon augmentait également durant la formation du bois. Cela suggère que le stockage de carbone et la croissance du tronc étaient étroitement liés, avec une proportion plus importante chez le chêne que chez l’épicéa et le hêtre. Ainsi, cette thèse a permis d'améliorer nos connaissances sur la dynamique de l'allocation du carbone dans l'arbre, de l'assimilation au niveau des feuilles à la séquestration à long terme dans le bois, et d'explorer leur sensibilité respective aux conditions climatiques. / Forest ecosystems are the major and most perennial terrestrial carbon pool. However, the seasonal dynamics of production of this woody biomass, in relation to the ecosystem carbon uptake remain poorly studied, limiting our understanding of the carbon cycle and particularly its sensitivity to current climate changes. This thesis aimed to better understand the underlying process of carbon sequestration within forming wood, as related to tree physiology, stand carbon assimilation and site environmental conditions. The study was conducted on three instrumented site with a flux tower, the stand is dominated respectively by spruce in Tharandt in 2016, by beech in Hesse in 2015-2017, and by oak in Barbeau in 2016. To monitor wood formation, wood samples containing phloem, cambial zone, and developing xylem were collected weekly on dominant trees within the tower footprint. Flux tower measurements were used to estimate the daily GPP of the stand, and record the climatic conditions. In the 1st chapter, we developed a novel histologic approach, to quantify the intra-annual dynamics of carbon sequestration in spruce forming wood. This approach, based on repeated measurements of xylem apparent density, is easier, faster, and more accurate than the previously available method, and is applicable also to angiosperm species. In the 2nd chapter, we showed that simultaneous occurrence of the canopy development and the resumption of cambial activity slowed down xylem radial growth, and might entail the formation of xylem with high porosity but functional at early growing season. In the 3rd chapter, we demonstrated that the tree-ring structure determined the temporal coordination between stem growth in size and in biomass along the growing season, with carbon sequestration in forming wood always lagging behind stem radial growth due to inner processes of xylogenesis. Indeed, we showed an increasing timelag ranging from ten days to nearly one month for spruce and beech, but a decreasing timelag from nearly three to one week for oak trees. In the 4th chapter, we observed that regardless of the stand, carbon assimilation followed a large and symmetric bell curve peaking in June, while seasonal dynamics of carbon sequestration differed among the three species. The beech trees concentrated carbon sequestration in stem in May-July, while the spruce and oak trees rather peaked in June-August, and completed stem growth towards the second part of the growing season. In the 5th chapter, based on a three-year monitoring of carbon fluxes, trees growth and environmental factors in the mature beech stand, we showed that ranking of annual carbon balance was not maintained from one year to another, with higher carbon assimilation during the hottest year, but higher woody biomass production in the wettest year. This suggests that allocation of carbon from assimilation to sequestration in stem is not following a simple allometric rule. In the last chapter, we observed that parallel to formation of a new xylem, starch content also increased in forming wood, suggesting that storage and stem growth were tightly connected along the growing season, with higher allocation to storage for sessile oak, compared to spruce and beech. This thesis has improved our knowledge about the dynamics of carbon allocation in the tree, from assimilation at the leaf level to long-term sequestration into the wood, and allowed to explore their respective sensitivity to climate conditions. A better quantification of the shift between stem growth in size and in biomass will require to disentangle the kinetics of cellulose and lignin deposition. However, our work contributed to a better understanding of the intra-annual dynamics of stem radial growth and carbon sequestration, which could help to improve modelling of forests net primary productivity, in the context of current global warming.