Growing forests are extremely valuable for the climate, for our shift towards a non-fossil-based society as well as to our economy. In order to create a healthy and lucrative forest that can cope with increasing future demands and challenges, certain forestry actions are required in which pre-commercial thinning is the most important one. Studies show that pre-commercial thinning today suffers from an acute shortage of available workforce with necessary qualifications. This project investigates the possibilities of creating a forest machine that can perform pre-commercial thinning autonomously. This project resulted in a concept called CURO. CURO is a fully autonomous robot that carries out pre-commercial thinning in young forest stands. It is designed to be agile and compact to be able to move around easily in the forest. For an autonomous forest machine to be able to perform successfully in a difficult terrain, lots of data is needed. Information about the forest is gathered over time when different forestry actions are carried out in the area. This information is shared with CURO. It combines all the collected information with data perceived from its own sensors to make the best suitable decision for each individual forest stand.

The subject of this master´s thesis is evaluation availability databases sources used in forensic engineering of forest management. Theoretical part describes basic terms about forests, forest management and available databases sources. Practical part deals with describing of this databases and make methods, how can we get useful information.

In einem für das Erzgebirge (Sachsen, Südostdeutschland) typischen Wirtschaftswald aus ca. 60-jähriger Fichte (Picea abies [L.] KARST.), in den Sand-Birken (Betula pendula Roth) eingemischt sind, sollte die Wirkung der Baumartenmischung auf den Oberbodenzustand erfasst und bewertet werden. Die Befunde stammen aus einem Bestand, der sowohl hinsichtlich der Altersstruktur, des Bodentyps als auch der Stoffeinträge und der Kalkung für das Erzgebirge repräsentativ ist. Analysiert wurden photosynthetisch aktive Strahlung, Bodenvegetation, Streumenge und -verteilung, Dynamik der Streuzersetzung, Humuskörpermorphologie sowie chemische und mikrobiologische Oberbodeneigenschaften. Dabei fand ein einzelbaumweiser Ansatz in Kopplung mit Transekten Anwendung. Es wurden eindeutige Effekte durch einzelbaumweise eingemischte Birken nachgewiesen. Mit Hilfe des Einzelbaumansatzes und davon ausgehenden Transekten wurden reine Fichtenbereiche und Mischungsbereiche untersucht. Zusätzlich wurden für die Auswertung drei Straten gebildet. Die Zuordnung dafür war die folgende: Probepunkte unter der Birkenkrone ergaben das Birken-Stratum, Probepunkte unter der Fichte das Fichten-Stratum und Probepunkte im Übergangsbereich zwischen Birke und Fichte das Fichten-Birken-Stratum. Im Bereich der Birkenkronen waren überwiegend höhere Strahlungswerte festzustellen als unter den Fichtenkronen. Gezeigt wurde aber auch, dass die höheren Strahlungswerte, die unter den Birkenkronen auftraten, auch in lichteren bzw. lückigeren Partien des reinen Fichtenbestandes zu finden waren. Die Sippenanzahl der Bodenvegetation erhöhte sich sowohl unter reiner Fichte als auch in Mischung von Fichte und Birke vor allem mit zunehmender Annäherung zum Kronenrand. Insgesamt waren aber bei der Mischung von Fichte und Birke ähnlich hohe Sippenanzahlen wie im reinen Fichtenbereich zu finden. Allerdings gab es Sippen, die nur auf einer der beiden Flächen auftraten. Es waren höhere Deckungsgrade bei der Mischung von Fichte und Birke im Vergleich zur reinen Fichte sichtbar. Die Befunde der Streusammler ließen erkennen, dass in einer Entfernung von > 16 m vom Birkenstamm kaum noch Birkenstreu auftrat. Nennenswerte Trockenflussdichten wurden nur in einem Radius von 10 m festgestellt. In diesem Bereich ist ein Effekt der Birkenstreu auf die Oberbodeneigenschaften zu erwarten. Die Gesamttrockenmasse einer relativ vitalen Birke mit rund 38 cm Brusthöhendurchmesser betrug im Untersu-chungsjahr rund 8 kg. Die Modellierung unter Hinzunahme weniger vitaler Birken reduzierte die Gesamttrockenmasse auf 6,3 kg. Der Massenverlust der Birkenblätter in den Litter-Bags war in allen drei Straten bei der Mischung der Birkenblätter mit Fichtennadeln im Verhältnis 5:1 am größten. Bei den Fichtennadeln zeigten sich die höchsten Trockenmassenverluste in den reinen Nadel-Litter-Bags. Die Litter-Bags unter der Birkenkrone wiesen für alle Varianten die beste Zersetzung der Birkenblätter und der Fichtennadeln auf. Die C/N-Verhältnisse der Streu ließen keine eindeutigen positiven Effekte der Birkenkrone erkennen. Sie waren aber bei den Birkenblättern in allen Varianten, in allen Straten und zu allen Terminen deutlich enger als die der Fichtennadeln. Desweiteren war der Abfall der C/N-Kurven bei den Birkenblättern steiler als bei den Fichtennadeln. Die Mächtigkeit des Of-Horizontes wies sowohl in der Mischsituation als auch in der reinen Fichtenfläche deutlichere räumliche Muster auf als im Oh-Horizont. Im Of waren dadurch deutliche, vom Einzelbaum abhängige, Muster zu erkennen. Die höchsten Mächtigkeiten traten in Stammnähe auf. Die größten Gesamtmächtigkeiten existierten unter reiner Fichte. Beim Vergleich der Mächtigkeiten in den Straten war in der Of-Lage vor allem das Birken-Stratum signifikant verschieden vom Fichten-Stratum. Für die Oh-Mächtigkeit und somit auch die Gesamtmächtigkeit zeigte zusätzlich das Fichten-Birken-Stratum signifikante Unterschiede im Vergleich zum Birken-Stratum. Als Humusform trat der rohhumusartige Moder auf. Dabei überwog im Fichtenstratum der feinhumusreiche rohhumusartige Moder, im Fichten-Birken-Stratum und im Birken-Stratum dagegen der feinhumusarme rohhumusartige Moder. Signifikante Unterschiede zwischen Straten konnten in der Of-Lage für den pH-Wert, Cges-Vorrat, Ccarbonat-Gehalt, Nges-Gehalt, Nges-Vorrat, und den metabolischen Quotienten erfasst werden. In der Oh-Lage waren es die nachstehenden Oberbo-deneigenschaften: Corg/N-Verhältnis, Cges-Gehalt, Nmik-Gehalt, Cmik/Nmik-Verhältnis, Basalatmungsaktivität, sowie der metabolische Quotient, die sich zwischen den Straten signifikant unterschieden. Im A-Horizont zeigten sich signifikante Unterschiede der Straten beim Corg/N-Verhältnis, Cges-Gehalt, Ccabonat-Gehalt, Corg-Gehalt sowie dem Nges-Vorrat. Mit Hilfe der multivariaten Ordination (mit verschiedenen Elementgehalten und pH-Werten) ist die Stratenbildung erneut bestätigt worden. Dabei hatten die Elemente C, Mg, Ca und N den größten Einfluss. Die Auswertung der Daten der effektiven Kationenaustauschkapazität ließ vor allem für den A-Horizont Unterschiede zwischen den Straten erkennen. Dabei war die Akeff im Fichtenstratum am kleinsten und der prozentuale Anteil der sauren Kationen an der Akeff am größten. Die höchste Akeff besaß das Birken-Stratum. Eine Reihe der untersuchten Größen ließen eindeutige Baumarteneffekte erkennen. Alles in allem wurde der Nachweis erbracht, dass die Effekte in dem Bereich zu finden sind, der durch die Laubstreu der Birken geprägt ist. Bei den Oberbodeneigenschaften wurden keine Veränderungen an Punkten, die mehr als 10 m vom Birkenstamm entfernt waren, festgestellt. Aus den Ergebnissen war abzuleiten, dass für ähnliche Bedingungen wie im Untersuchungsbestand ein Mischungsanteil der Birke von mindestens 10 % zu empfehlen ist. Die Ergebnisse sind aber durch zukünftige Forschung noch zu verifizieren. Dafür sollten vor allem die Produktionsziele und die waldbaulichen Behandlungskonzepte für Mischbestände aus Fichte und Birke in Deutschland erneut konkretisiert werden. Um dafür eindeutige ökologische und ökonomische Kriterien festlegen zu können, wird eine Zusammenführung wichtiger Ergebnisse aus den verschiedenen forstlichen Forschungsbereichen (z. B. Standortskunde, Vegetationskunde, Waldwachstumskunde, Ökonomie, Zoologie, Waldbau) empfohlen. / In a typical managed forest of the Ore Mountains (Saxony, SE Germany), consisting of 60 years old Norway spruce (Picea abies [L.] KARST.) admixed with silver birches (Betula pendula Roth) the impact of the admixture on topsoil properties was quantified and evaluated. This study was conducted in a stand which is representative for the Ore Mountains regarding the soil type, deposition and liming. Photosynthetic active radiation, the layer of herbs and mosses, the mass and distribution of the litter fall, the dynamics of litter decom-position, and morphology of the humus layer as well as the chemical and microbiological topsoil properties were all analyzed. The study was based on a single-tree-approach where samples were collected along transects from selected sample trees of birch and spruce. Transects were established within areas of pure spruce as well as within areas of spruce and birch mixture. Three different strata were defined based on the situation of the examined points in relation to the crowns of birch and spruce: the birch stratum, the spruce stratum and the spruce-birch stratum with measurements from underneath the crowns of birches, spruces and the transition area between spruce and birch crowns, respectively. Higher photosynthetic active radiation values were detected in the area underneath the crowns of birch crowns in comparison with the area underneath the crowns of spruce. Higher values of photosynthetic active radiation were also registered within areas of light foliage and in gaps in the pure spruce stand. The number of ground vegetation species underneath pure spruce and in the mixture of spruce and birch was negatively correlated with the distance to the crown edge. But altogether the same number of ground vegetation species was found in the mixed stand and in the pure spruce stand. A few species were, however, specific for each stand type. A higher coverage of ground vegetation was found in the mixture of spruce and birch in comparison to the pure spruce. The results of the litter traps show marginal densities of birch leaves at a distance of more than 16 m from the birch stem. The majority of the dry flux density was found within a radius of 10 m around the birch stem. Within this area an effect of the birch litter on top soil properties was expected. The whole dry litter mass was measured in the study time of a relative vital birch with a diameter at breast high of ca. 38 cm and was ca. 8 kg. Modeling the amount of litter for birches with lower vitality indicated a dry litter mass of 6.3 kg. The mass lost of the birch leaves in the litter bags was in each stratum the highest at a ratio of 5 to 1 of birch leaves to spruce needles. The greatest loss of dry mass for spruce needles was registered in litter-bags with pure needles. The litter-bags under the birch crowns exhibited the best decomposition rate of birch leaves and spruce needles for all variants. The C/N-ratios of the litter showed no clear positive effects of the birch crown. But they were clearly smaller for the birch leaves in contrast to the spruce needles in all variants, in each stratum and at all dates. Furthermore the C/N-curves drop away more for the birch leaves in contrast to the spruce needles. The thickness of the Of-horizon in contrast to the Oh-horizon showed clear spatial patterns for the mixed situation and the pure spruce area. Thus in the Of-horizon a clear spatial pattern in connection to the single tree was apparent. The highest thickness was found close to the stem. The highest total thickness of the Of- and Oh-horizon was found underneath the pure spruce stand. When comparing the thickness of the humus layers between the stratums, significant differences where found for the Of-layer between the birch stratum and the spruce stratum. In addition, for the thickness of the Oh-layer as well as for the total thickness of all layers, significant differences were observed between the spruce-birch stratum and the birch stratum. The humus form was a mor-like moder. In the spruce stratum more fine-humus-rich variants of the mor-like moder was found, in the spruce-birch stratum and in the birch stratum it was more fine-humus-poor variants of the mor-like moder. Significant differences between the stratums in the Of-layer were found with respect to acidification, the pool of Ctot and Ntot, the content of Ccarbonat and Ntot and the metabolic quotient. For the Oh-layer significant differences between the stratums were found for the ratio of Corg and N, the content of Ctot and Nmic, the ratio of Cmic and Nmic, the basal respiration activity and the metabolic quotient. In the A-horizon significant differences between the stratums were found for the ration of Corg and N, the content of Ctot, Ccarbonat and Corg and the pool of Ntot. The results of multivariate ordination confirm the formation of stratums again. Thereby the contents of C, Mg, Ca and N had the greatest influence. The data analysis of the effective cation exchange capacity (ECEC) showed differences between the stratums mainly for the A horizon. In the spruce stratum the ECEC was lowest and the percentage of acid cations at the ECEC was greatest. The highest ECEC was in the birch stratum. Different results showed clear tree effects. These were only found in areas, which are influenced by birch leaves. In this study, a minimum tree admixture of 10% was required before an impact on the ground conditions of the whole stand was observed. Therefore, based on the results of this study, an admixture of birch of 10% is recommended. These results however must be verified through future research. These findings can be used to assist in meeting the goals of silvicultural management for mixed spruce and birch forests in Germany. Definition of explicit ecological and economic criteria created from a combination of results from different forest research sectors (e. g. Site ecology, Vegetation science, Forest Growth, Economy, Zoology, Silviculture) is recommended.

The University Forest Enterprise (UFE) is a special-purpose facility at the Technical University in Zvolen (TUZVO). The UFE is aimed at the practical education of students, scientific research associated with all forestry activities, demonstration objects, and management of the forest fund. lt is thus possible to demonstrate several aspects of forestry such as forest management, management of forest reproductive material, silviculture, logging operations, forestry constructions and ameliorations, landscape management, game management, fishery, and beekeeping. To follow these goals, 67 permanent research plots, 18 temporary plots, and 103 demonstration objects are currently maintained at the territory of the enterprise, all connected to the network of excursion and demonstration paths. The UFE manages the forest land fund (9,729 ha) according to the needs of the Technical University, and with respect to the purpose of the enterprise, 80% of the forest area managed by the enterprise is classified into the category of specialpurpose forests. The forest land fund is composed of state-owned forest land as well as forest properties of other owners. Forest plant communities ofthe UFE belang to five altitudinal vegetation zones (298-1035 m above sea level). Broadleaved tree species evidently predominate. Due to the special focus of management, the UFE uses as much as possible the concepts of the close-to-nature silviculture. Due to varied natural conditions, it is possible to apply several silvicultural systems. The application of shelterwood and selection systems with maximum utilisation of the natural potential of indigenous tree species is strongly preferred.

<p>Thesis submission for Caleb Kell</p>

No description available.

<p dir="ltr">For several decades, the ecological dominance of white oak (<i>Quercus alba</i>) has been declining throughout the species’ native range in eastern North America with failure to recruit new individuals into the overstory. White oak’s decline is concerning as the species is of great cultural, ecological, and economic value. Planting artificial regeneration is one approach to bolstering flagging natural white oak regeneration insufficient in vigor or quantity to supplant mature canopy white oak. Shelterwood harvests and artificial regeneration alone or in combination are frequently suggested to be an effective means of securing sufficient white oak regeneration in central hardwood understories. Because there is a much more comprehensive body of work examining northern red oak (<i>Quercus rubra</i>) than white oak artificial regeneration, managerial prescriptions for artificial regeneration of white oak are commonly generalized from northern red oak prescriptions. If the two species are silvically different, however, they should be managed differently to achieve maximum effectiveness of regenerative prescriptions.</p><p><br></p><p dir="ltr">I conducted both a silvicultural field trial and a more controlled shade and competition study to examine artificial white oak regeneration responses to light and competition gradients. In the silvicultural field trial, I tested the impacts of varied lengths of competition control, geographical seed source, and canopy cover on growth and survival of artificial white oak regeneration within an expanding shelterwood system. After three growing seasons, my results indicated that seedlings grow and survive at the greatest rates in areas of up to approximately 50% canopy closure, or conditions found in harvest gaps.</p><p dir="ltr">In a shade and competition study, I compared artificial northern red oak and white oak growth, morphology, and physiology responses to three light levels (10% or low, 30% or medium, and full sun or high) under the presence or absence of an invasive competitor (Amur honeysuckle (<i>Lonicera maackii</i>)). After two years, my results indicated that medium light levels resulted in the greatest height and diameter growth as well as the greatest nonstructural carbohydrate amounts in both root and shoot organs of both species. Interestingly, my physiology results indicated that northern red oak seedlings displayed lower light compensation points and greater quantum yields than white oak seedlings. These traits potentially indicate greater shade tolerance of northern red oak than white oak. Further, white oak foliar nitrogen in shaded treatments, quantum yield, and light compensation points were impacted more severely by competition than equivalent northern red oak measures, indicating that white oak seedlings may not be as well equipped to handle invasive competition pressures. These results indicate that these two upland oak species are fundamentally different, and these differences should be considered when writing management prescriptions.</p>

A exploração de impacto reduzido (EIR) é um método florestal conhecido por ter suas atividades fundamentadas em maior planejamento e colheitas controladas de madeira para garantir maior potencial de recuperação em florestas exploradas, sendo um critério essencial para o desenvolvimento sustentável. No entanto, a extração ilegal de madeira e outras práticas insustentáveis de manejo na Amazônia brasileira continuam aumentando em regiões tropicais e são responsáveis pela diminuição da disponibilidade de madeira, criando uma luta cada vez maior para garantir um rendimento sucessivo de espécies exploradas em ciclos de corte consecutivos. Para superar esse problema, investigamos o padrão de crescimento e o valor das espécies florestais manejadas, a fim de dar subsídio à futuras adequações na legislação aplicada ao manejo e garantir a sustentabilidade florestal. Além disso, buscamos conhecer quais fatores bióticos e abióticos podem influenciar o crescimento, mortalidade e recrutamento da floresta após a exploração, a fim de propor tratamentos silviculturais que acelerem a recuperação dessa floresta para o próximo ciclo de corte. Determinamos também as curvas de crescimento das espécies madeireiras e sua valorização econômica com o passar dos anos, bem como analisamos se a gestão adotada atualmente garante a sustentabilidade florestal no futuro. Essa pesquisa ocorreu na Amazônia Oriental, no Brasil, em uma floresta que foi explorada por EIR e EC. A tese consiste em cinco capítulos: a introdução geral, três capítulos de pesquisa e uma síntese com considerações finais dos estudos. No segundo capítulo, os resultados afirmaram que o crescimento da floresta é maior após o uso da EIR, porém fatores de condição das árvores e vizinhança também podem influenciar o crescimento da floresta e de grupos funcionais. Dessa forma, o aumento da quantidade de lianas, danos na copa e competição unilateral por área basal teve efeito negativo no crescimento florestal. Além disso, o aumento do nível de luz e competição multilateral por densidade pode aumentar as taxas de crescimento das árvores. Os fatores de condição das árvores e vizinhança afetam de maneira diferente os grupos funcionais. Descobrimos também que houve aumento significativo das taxas de crescimento após a colheita florestal, mostrando que as espécies aproveitam o ambiente com muita luz para crescer. No terceiro capítulo, os resultados afirmam que as técnicas de exploração florestal influenciam a mortalidade das árvores, sendo a exploração convencional responsável por maior probabilidade de mortalidade após a colheita florestal; as árvores com nível alto de lianas têm maior probabilidade de mortalidade; as árvores com danos na copa têm maior chance de mortalidade; as maiores árvores (DAP maior) são mais suscetíveis à mortalidade. No quarto capítulo, foi observado que o incremento em diâmetro e área basal, para a maioria das espécies, aumenta com o uso de técnicas de baixo impacto na exploração. As espécies têm diminuição do incremento em diâmetro devido a influência de El Niño. O crescimento de espécies como Dipteryx odorata (Aubl.) Willd., Manilkara bidentata (A.DC.) A.Chev., Manilkara elata (Allemão ex Miq.) Monach. e Handroanthus serratifilius (Vahl) S.Grose é muito lento e a alta intensidade de corte na exploração pode diminuir ainda mais a velocidade de crescimento e recuperação dessas espécies. As menores árvores apresentaram menor crescimento e as maiores árvores apresentaram oscilação das taxas de crescimento logo após a exploração. As espécies madeireiras mais valorizadas são as madeiras nobres de alta densidade, porém como elas não têm a sustentabilidade garantida pelas atividades de exploração, com o passar do tempo são substituídas por espécies de baixa densidade. Esse estudo apresenta a interface entre a ciência do manejo, silvicultura de espécies tropicais e sua prática. Dessa forma, auxilia no aperfeiçoamento das leis e normas que regem o manejo e no desenvolvimento de tratamentos silviculturais específicos em florestas tropicais. Nossos resultados mostram como é possível melhorar as técnicas de exploração de madeira, diminuir a competição, os danos florestais e otimizar a recuperação florestal visando alcançar, num futuro próximo, o manejo florestal sustentável. Esse estudo pode ser utilizado como subsídio à silvicultura de espécies e ações de manejo em diferentes ecossistemas florestais por profissionais do manejo, tomadores de decisão e cientistas, para que a ciência e o setor produtivo possam avançar. / Reduced impact logging (RIL) is a well known forestry method that requires extensive planning and controlled timber harvesting to ensure a greater recovery potential for exploited forests, an essential criteria for sustainable development. However, in the Brazilian Amazon, illegal logging and other unsustainable forest management practices continue to increase in tropical regions and are responsible for decreasing the availability of timber, creating an ever-increasing struggle to guarantee successive yields of timber species in consecutive cutting cycles. To overcome this problem, we investigated the growth pattern and value of managed forest timber species to support future legislation amendments applied to the management and guarantee of forest sustainability in Amazonian Brazil. We examined biotic and abiotic factors that may influence forest growth, mortality, and recruitment after exploration, which gave indication to potential silvicultural treatments that can accelerate forest recovery in succeeding cutting cycles. We also determined timber species growth curves and estimated their financial increase potential overtime as well as analyze whether the management practices currently adopted guarantees forest sustainability in the future. This research took place in Eastern Amazonia, Brazil in a forest that had been harvested using RIL and CL (Conventional logging) techniques. This thesis consists of five chapters: the general introduction, three research chapters and a concluding chapter synthsizing the major findings from the study. In the second chapter, results confirm forest growth to be higher after implementing RIL, but factors related to tree and neighborhood condition can influence forest growth and functional groups. Thus, an increased amount of vines, crown damage and unilateral competition by basal area had a negative effect on forest growth. In addition, increasing light levels and multilateral competition may increase rates of tree growth. Furthermore, factors of tree condition and neighborhood seemed to affect the functional groups differently. We also found there was a significant increase in growth rates after harvesting, indicating that species take advantage of the greater availability of light within their environment. In the third chapter, the results affirm that the techniques of forest logging influence the mortality of the trees, being the conventional exploitation responsible for a greater probability of mortality after the forest harvest; trees with high lianas have greater likelihood of mortality; trees with crown damage have higher chance of mortality; the largest trees (DBH larger) are more susceptible to mortality. In the fourth chapter, it was observed that most species diameter and basal areas increased with the use of low impact logging techniques. Decreased in species diameter was mainly attributed to the influence of El Niño events. The growth of species such as Dipteryx odorata (Aubl.) Willd., Manilkara bidentata (A.DC.) A.Chev., Manilkara elata (Allemão ex Miq.) Monach. and Handroanthus serratifilius (Vahl) S.Grose are generally very slow growing and high intensity logging may the rate of growth and recovery of these species even more. The smallest trees recorded presented lower rates of growth compared to larger trees which presented an growth rates that oscillated soon after exploitation. The most valued timber species are those of high density, but as they do not have the sustainability guaranteed by exploration activities, over time they are replaced by low density species. This study presents an interface between the science of forest management, forestry of tropical species and its practice. Therefore, it helps to improve the laws and regulations governing the management and development of specific silvicultural treatments in tropical forests. Our findings show how it is possible to improve logging techniques, reduce competition and forest damage and optimize forest recovery in order to achieve sustainable forest management in the near future. This study can be used as a subsidy to the forestry of species and management actions in different forest ecosystems by management professionals, decision makers and scientists, so that science and the productive sector can move forward.

Le thème de l'évolution historique de la productivité forestière est abordé pour les deux grands feuillus sociaux du territoire, hêtre commun (Fagus sylvatica L.) et chêne sessile (Quercus petraea Liebl.), conduits en futaie régulière et pure, en forêt domaniale, avec un objectif de description et quantification du phénomène à l'échelle du peuplement. L'analyse privilégie la croissance en hauteur dominante, indicateur classique de la productivité forestière. Elle repose sur la comparaison d'accroissements reconstitués de façon rétrospective (analyses de tiges) de deux générations de peuplements, associés en couples pour assurer un contrôle efficace des conditions de fertilité. L'évolution de la vitesse de croissance est estimée par une modélisation statistique des accroissements, qui prend en compte l'effet du stade de développement des peuplements et les différences de fertilité entre couples. Le diagnostic a été régionalisé, conduisant à échantillonner les hêtraies dans 2 secteurs (Normandie/Picardie et Lorraine/Alsace) et les chênaies dans 4 secteurs (Normandie, val de Loire, plaine d'Allier, Lorraine/Alsace). Une analyse complémentaire de la croissance radiale dominante (lectures de cernes) et de la densité du bois (microdensitométrie aux rayons X) à 1,30 m a été réalisée dans les hêtraies du Nord-Est. Les conditions trophiques et climatiques des peuplements ont été caractérisées. <br />L'augmentation de la vitesse de croissance en hauteur dominante a un caractère général sur le territoire, structuré selon un gradient longitudinal. Pour chaque essence, elle est plus marquée dans le Nord-Est, tandis qu'elle reste faible ou récente dans le Nord-Ouest. L'essentiel de l'évolution a été acquis dans la seconde moitié du siècle. La progression est ponctuée de crises d'origine climatique, communes ou spécifiques, dont la plus marquée est celle de la décennie 1940. Défavorable au hêtre, la décennie 1990 a été bénéfique au chêne, et explique que l'évolution constatée pour cette essence culmine en fin de siècle à un niveau bien supérieur à celui du hêtre. L'augmentation séculaire est comprise pour les extrêmes entre +20% et +100%, et atteint dans le Nord-Est un niveau commun aux deux essences de +50-60% en excluant la période récente. Dans ce secteur, les évolutions de croissance radiale et en hauteur du hêtre sont similaires. La densité du bois est restée stable. En conséquence, la productivité en biomasse a pu suivre l'évolution estimée sur la hauteur dominante. L'analyse des relations croissance - facteur du milieu permet d'aborder la causalité des changements de productivité, et suggère un déterminisme multifactoriel. Le climat aurait eu jusqu'alors des conséquences essentiellement conjoncturelles. Des effets saisonniers opposés sur la croissance sont de plus possibles. Le caractère récent des évolutions constatées, leur organisation spatiale, conjugués à une sensibilité des essences aux conditions trophiques, font ressortir le rôle clé possible des dépôts atmosphériques azotés dans la réponse aux changements de l'environnement.

Ph.d.-afhandling. Den Kongelige Veterinær- og Landbohøjskole, 2006. / Haves også i trykt udg. Thesis (Ph.D.). 22 ill., 14 tables; approx. 90 ref. Summaries (Da, En).