Forests are a key resource serving a multitude of functions such as providing income to forest owners, supplying industries with timber, protecting water resources, and maintaining biodiversity. Recently much attention has been given to the role of forests in the global carbon cycle and their management for increased carbon sequestration as a possible mitigation option against climate change. Furthermore, the use of harvested wood can contribute to the reduction of atmospheric carbon through (i) carbon sequestration in wood products, (ii) the substitution of non-wood products with wood products, and (iii) through the use of wood as a biofuel to replace fossil fuels. Forest resource managers are challenged by the task to balance these multiple while simultaneously meeting economic requirements and taking into consideration the demands of stakeholder groups. Additionally, risks and uncertainties with regard to uncontrollable external variables such as climate have to be considered in the decision making process. In this study a scientific stakeholder dialogue with forest-related stakeholder groups in the Federal State of Brandenburg was accomplished. The main results of this dialogue were the definition of major forest functions (carbon sequestration, groundwater recharge, biodiversity, and timber production) and priority setting among them by the stakeholders using the pair-wise comparison technique. The impact of different forest management strategies and climate change scenarios on the main functions of forest ecosystems were evaluated at the Kleinsee management unit in south-east Brandenburg. Forest management strategies were simulated over 100 years using the forest growth model 4C and a wood product model (WPM). A current climate scenario and two climate change scenarios based on global circulation models (GCMs) HadCM2 and ECHAM4 were applied. The climate change scenario positively influenced stand productivity, carbon sequestration, and income. The impact on the other forest functions was small. Furthermore, the overall utility of forest management strategies were compared under the priority settings of stakeholders by a multi-criteria analysis (MCA) method. Significant differences in priority setting and the choice of an adequate management strategy were found for the environmentalists on one side and the more economy-oriented forest managers of public and private owned forests on the other side. From an ecological perspective, a conservation strategy would be preferable under all climate scenarios, but the business as usual management would also fit the expectations under the current climate. In contrast, a forest manager in public-owned forests or a private forest owner would prefer a management strategy with an intermediate thinning intensity and a high share of pine stands to enhance income from timber production while maintaining the other forest functions. The analysis served as an example for the combined application of simulation tools and a MCA method for the evaluation of management strategies under multi-purpose and multi-user settings with changing climatic conditions. Another focus was set on quantifying the overall effect of forest management on carbon sequestration in the forest sector and the wood industry sector plus substitution effects. To achieve this objective, the carbon emission reduction potential of material and energy substitution (Smat and Sen) was estimated based on a literature review. On average, for each tonne of dry wood used in a wood product substituting a non-wood product, 0.71 fewer tonnes of fossil carbon are emitted into to the atmosphere. Based on Smat and Sen, the calculation of the carbon emission reduction through substitution was implemented in the WPM. Carbon sequestration and substitution effects of management strategies were simulated at three local scales using the WPM and the forest growth models 4C (management unit level) or EFISCEN (federal state of Brandenburg and Germany). An investigation was conducted on the influence of uncertainties in the initialisation of the WPM, Smat, and basic conditions of the wood product sector on carbon sequestration. Results showed that carbon sequestration in the wood industry sector plus substitution effects exceeded sequestration in the forest sector. In contrast to the carbon pools in the forest sector, which acted as sink or source, the substitution effects continually reduced carbon emission as long as forests are managed and timber is harvested. The main climate protection function was investigated for energy substitution which accounted for about half of the total carbon sequestration, followed by carbon storage in landfills. In Germany, the absolute annual carbon sequestration in the forest and wood industry sector plus substitution effects was 19.9 Mt C. Over 50 years the wood industry sector contributed 70% of the total carbon sequestration plus substitution effects. / Wälder beeinflussen in vielfältiger Weise unser Leben. Für den Waldbesitzer sind sie Einkommensquelle, die Holzindustrie versorgen sie mit dem Rohstoff, aus dem unzählige Dinge für den täglichen Bedarfs hergestellt werden, wie zum Beispiel Baumaterialien, Möbel, Gartengeräte, Spielzeug und Papier. Außerdem versorgen Wälder uns mit sauberem Grundwasser, sind Lebensraum für Pflanzen und Tiere und tragen somit zum Erhalt der Artenvielfalt bei. Nicht zuletzt beeinflussen Wälder das Klimasystem, da sie der Atmosphäre das Treibhausgas CO2 entziehen und Kohlenstoff in Biomasse und Boden speichern. Förster stehen nun vor der anspruchsvollen Aufgabe, eine Balance zwischen den vielfältigen und oft auch gegensätzlichen Waldfunktionen zu finden und die Ansprüche von Interessengruppen wahrzunehmen. Zusätzlich müssen im waldbaulichen Entscheidungsprozess Risiken und Unsicherheiten durch unberechenbare externe Faktoren, wie das Klima, beachtet werden. Ziel der Arbeit war es, den Einfluss von Klima und Waldbaustrategien auf Waldfunktionen zu untersuchen. Als Testgebiet fungierte das Revier Kleinsee im Südosten Brandenburgs, in dem Kiefern- und Eichenbestände vorherrschen. In einem wissenschaftlichen Dialog mit Angestellten der Forstbehörde, Privatwaldbesitzern, Vertretern von Naturschutzverbänden sowie Wissenschaftlern definierten die Teilnehmer die wichtigsten Waldfunktionen: Kohlenstoffspeicherung, Grundwasserneubildung, Biodiversität und Holzproduktion. Die Simulationen wurden mit Hilfe des Waldwachstumsmodells 4C und einem neu implementierten Holzproduktmodell (WPM) über einen Zeitraum von 100 Jahren durchgeführt. Dabei wurden den heutigen Klimabedingungen zwei Klimaänderungsszenarien gegenübergestellt, die auf den globalen Zirkulationsmodellen HadCM2 und ECHAM4 basieren. Es stellte sich heraus, dass unter den angenommenen Klimaänderungen das Wachstum der Bestände steigt und sich damit die Kohlenstoffspeicherung und der Ertrag aus Holzernten erhöht, wohingegen Biodiversität und Grundwasserneubildung nur sehr gering beeinflusst werden. Der Nutzen der Waldbewirtschaftungsstrategien für drei Interessensgruppen (Forstbehörde, private Waldbesitzer, Naturschutzvereine) wurde mit einer multikriteriellen Analysemethode bewertet. Dabei unterschieden sich die Rangfolge und Gewichtung der einzelnen Waldfunktionen sowie die daraus resultierende Wahl der Waldbaustrategien zwischen den Naturschützern einerseits sowie den stärker ökonomisch orientierten Landeswaldförstern und privaten Waldbesitzern anderseits. Naturschutzvereine bevorzugen das Einstellen der Waldbewirtschaftung, aber auch die aktuelle Waldbaustrategie, mit mäßiger Durchforstungsintensität und einem hohen Anteil an Eichenbeständen entspricht ihren Zielsetzungen. Dagegen lag die Präferenz der Landeswaldförster sowie privaten Waldbesitzer auf einer Walbaustrategie mit einem hohen Anteil an Kiefernbeständen, um den Ertrag unter Beachtung der anderen Waldfunktionen zu steigern. Als Fazit geht aus dieser Teilstudie hervor, dass die Bewertung von Waldbaustrategien hinsichtlich ihrer Eignung für eine multifunktionale Waldbewirtschaftung unter Beachtung von Ansprüchen verschiedener Interessengruppen und ungewissen klimatischen Bedingungen unter Verwendung von 4C und einer multikriteriellen Analysemethode sehr gut möglich ist. Besonderes Augenmerk galt dem Einfluss von Waldbaustrategien auf den Kohlenstoffkreislauf, wobei nicht nur die Kohlenstoffspeicherung im Wald, sondern auch in Holzprodukten, sowie die Verringerung von CO2-Emissionen durch energetische und stoffliche Nutzung von Holz betrachtet wurden. Die potentielle Reduktion von CO2-Emissionen durch das Ersetzen von Erzeugnissen und Energie aus nicht nachwachsenden Rohstoffen durch Holz (Smat und Sen) wurde basierend auf Daten verschiedener Studien geschätzt. Eine Sensitivitätsanalyse untersuchte Unsicherheiten bei der Initialisierung des WPMs und der Berechung von Smat. Verschiedene Szenarien führten zu einem besseren Verständnis dafür, wie sich Änderungen im Energiesektor und Holzproduktsektor auf das Potential, Kohlenstoff zu speichern bzw. CO2-Emissionen zu verringen auswirken. Die Ergebnisse zeigen, dass die Reduzierung von CO2-Emissionen im Holzproduktsektor durch die Nutzung von Holz als Werkstoff und Brennstoff höher ist als durch die Akkumulation von Kohlenstoff im Wald. Im Gegensatz zu den Kohlenstoffspeichern im Wald, die sowohl Quellen als auch Senken sein können, werden durch die Nutzung von Holz CO2-Emissionen verringert, solange im Zuge der Waldbewirtschaftung Holz für die Weiterverarbeitung zur Verfügung gestellt wird. Simulationen auf Bundesebene ergaben, dass in Deutschland die Forst- und Holzwirtschaft jährlich dazu beitragen die CO2-Emissionen um 19,9 Mt Kohlenstoff zu verringern, wobei 70% auf die Holzindustrie und den Substitutionseffekt entfallen.

Final Report / Contract on 43-8371-4-628 / For: USDA, Forest Service, Southwestern Region / Regional outbreaks of western spruce budworms (Choristoneura occidentalis Freeman) have recurred at least three times in northern New Mexico since the early 1920's when the U. S. Forest Service first began systematic forest-pest surveys and documentation (Lessard 1975, U. S. Forest Service documents). The current outbreak was first noticed in a small area on the Taos Indian Reservation in 1974, and since then the defoliated areas have increased in New Mexico and Arizona to more than 370,000 acres of Federal, Indian, State and private lands (Linnane 1984). Losses in timber values can generally be ascribed to radial growth loss, height growth loss, topkilling, reduced regeneration, and mortality (Carlson et al. 1983, Fellin et al. 1983). A damage assessment project was initiated in 1978 and was aimed at obtaining measurements of some of these losses in budworm infested stands on the Carson National Forest, New Mexico (Holland and Lessard 1979). A large data base has subsequently been developed, including yearly measurements on topkilling, mortality, defoliation, and insect population changes (Stein 1980, 1981, Stein and McDonnell 1982, Rogers 1984). A growth assessment study was undertaken in 1982 to determine the feasibility of using dendrochronological methods to identify the timing of past outbreaks and to quantify radial growth losses associated with budworm defoliation (Swetnam 1984). Results of this work showed that three major outbreaks during the twentieth century were clearly visible in the tree-ring samples obtained from currently infested trees. The radial growth of host trees was corrected for age, climate and other non-budworm environmental effects, and then growth losses were computed as a percentage of expected growth (Swetnam 1984). Additional collections were obtained in 1984 in order to expand the scope of the radial growth study. The objectives included 1) assessment of a larger number of tree -ring samples, 2) comparison of radial growth losses between the two primary host species - Douglas-fir (Pseudotsuga menziesii) and white fir (Abies concolor), 3) comparison of radial growth losses between age classes, and 4) analysis of the relationship between yearly measurements of defoliation, insect populations and radial growth. This report summarizes the findings of the above analyses. Increment core samples from the 1982 collections are included here, therefore this report supersedes the earlier report (Swetnam 1984). Information is also presented on observations derived from the dated tree-ring series on the timing of occurrence of known and inferred spruce budworm outbreaks for the past 284 years (1700- 1983). This is the longest record of spruce budworm occurrence yet developed for western North America.

No description available.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study had as objective to compare the Araucaria angustifolia (Bertol.) Kuntze growth in three different places in Rio Grande do Sul state (Serra do Sudeste, Encosta Superior do Nordeste e Planalto Médio) in diameter, height and volume in function of age for each place and for the three places grouped, to establish the specie development behavior and the possibility to use suitable equations in each place. The data allowed to do an individualized study from the functions that express the behavior from the main dendrometric variables, using in growth prediction, being chosen the model with the best adjust through statistical weighed value of escores. As an evaluation mode, the specie growth was compared to the three places together, using the regression with dummy variable and through the covariance analysis.The study with dummy variable was done with the objective to select an equation of growth based on the age, for diameter, height and volume, allowing to identify the growth differences. The covariance analysis showed that there are differences in growth for each place, showing a necessity to adjust separated growth equations for each place, to minimize the estimative errors. This analyze showed that for diameter, height and volume there is a level and inclination difference from growth curves, indicating that even the growth and the productive capacity are different in the three studied places. It is possible to prove that Araucaria angustifolia, in Serra do Sudeste, shows a growth pattern similar to the other places, indicating that in this place it is also possible to invest in industrial planting from this specie. The average volume at 60 years was of 0,6866 0,6866 m³/wb in Serra do Sudeste, 0,6656 m³/wb in Encosta Superior do Nordeste and 0,5062 m³/wb in Planalto Médio. The Pearson correlation analysis proved that volume showed positive correlation with relative air humidity (0,671), altitude (0,757), clay amount (0,79), organic matter (0,847) and boron (0,974). These Pearson correlation high values indicate the importance of these environmental factors in Araucaria angustifolia growth, as well as give the elements that a regression model should have, where environmental variables in a study of araucaria growth should be used. With these results, regression equations were modeled to annual periodic increment in volume, related to environmental factors, due to stepwise factors, obtaining a good determination coefficient adjust. The increment was used, because it expresses the real growth for a determined period of time. It was proved that annual average increment suffers the influence of environmental factors, varying joined with these. The factors that most influenced were: atmospheric pressure, maximum average temperature, absolute maximum, humidity, insolation and potassium. / Este trabalho teve como objetivo comparar o crescimento de Araucaria angustifolia (Bertol.) Kuntze em três locais diferentes do Estado do Rio Grande do Sul (Serra do Sudeste, Encosta Superior do Nordeste e Planalto Médio), em diâmetro, altura e volume em função da idade para cada local e para os três locais em conjunto, para estabelecer o comportamento de crescimento da espécie e a possibilidade de empregar equações adequadas a cada local. Os dados permitiram realizar um estudo individualizado de funções que expressam o comportamento das principais variáveis dendrométricas, utilizadas na prognose do crescimento, sendo escolhido o modelo com melhor ajuste através do Valor Ponderado dos Escores Estatísticos. Como forma de avaliação, comparou-se o crescimento da espécie para os três locais em conjunto, com a utilização de regressão com variável dummy e através da análise de covariância. O estudo com variável dummy foi realizado com o objetivo de selecionar uma equação de crescimento em função da idade, para diâmetro, altura e volume, permitindo identificar diferenças de crescimento. A análise de covariância demonstrou que há diferenças no crescimento para cada local, havendo a necessidade de ajustar equações de crescimento em separado para cada local, para minimizar os erros de estimativa. Essa análise demonstrou que para diâmetro, altura e volume existe diferença de nível e de inclinação das curvas de crescimento, indicando que tanto o crescimento quanto a capacidade produtiva são diferentes nos três locais estudados. Pode-se comprovar que Araucaria angustifolia, na Serra do Sudeste, apresenta padrão de crescimento semelhante aos demais locais, indicando que neste local também pode-se investir no plantio industrial da espécie. O volume médio aos 60 anos foi de 0,6866 m³/sc na Serra do Sudeste, 0,6656 m³/sc na Encosta Superior do Nordeste e de 0,5062 m³/sc no Planalto Médio. A análise de correlação de Pearson comprovou que o volume apresentou correlação positiva com umidade relativa do ar (0,671), altitude (0,757), teor de argila (0,79), matéria orgânica (0,847) e boro (0,974). Esses altos valores de correlação de Pearson indicam a importância desses fatores ambientais no crescimento de Araucaria angustifolia, bem como fornece os elementos que devem conter um modelo de regressão no qual deseja-se utilizar variáveis ambientais em estudo de crescimento de araucária. Com esses resultados modelou-se equações de regressão para o incremento corrente anual em volume, relacionado a fatores ambientais, pelo procedimento stepwise, obtendo-se bom ajuste do coeficiente de determinação. Utilizou-se a variável incremento pois ela expressa o real crescimento para um período de tempo analisado. Comprovou-se que o incremento corrente anual sofre influência dos fatores ambientais, variando em conjunto com esses. Os fatores que mais influenciaram foram: pressão atmosférica, temperatura média máxima, máxima absoluta, umidade, insolação e potássio.

No description available.

O objetivo deste trabalho foi analisar o efeito de quatro intensidades de redução da área basal, representadas pela exploração e desbastes sistemáticos, na composição florística, diversidade, estrutura e dinâmica do extrato arbóreo, durante um período de 22 anos. O experimento se localiza na Floresta Nacional do Tapajós, município de Belterra, Pará, a altura do km 114 da Rodovia Santarém-Cuiabá. O delineamento estatístico utilizado foi Blocos ao Acaso com 4 repetições onde foram testados os seguintes tratamentos: T0: controle, representado pela floresta não explorada; T1: Abate de árvores comerciais com DAP ≥ 45cm, sem nenhuma intervenção posterior; T2: Abate de árvores comerciais DAP ≥ 55cm + desbaste de espécies não comerciais para reduzir a área basal em 20% da original; T3: Abate de árvores comerciais DAP ≥ 55cm + desbaste de espécies não comerciais para reduzir a área basal em 40% da original; T4: Abate de árvores comerciais DAP ≥ 55cm + desbaste de espécies não comerciais para reduzir a área basal em 60% da original. Cada bloco possui uma área de 36ha, sendo 9ha por tratamento. Em cada tratamento foram instaladas ao acaso 12 parcelas permanentes (PP) de 0,25ha, onde foram medidas todas árvores com diâmetro ≥ 5,0cm. A exploração de madeira foi realizada em 1982 e os desbastes foram iniciados em 1993 e concluídos em 1994, com a finalidade de reduzir a área basal do povoamento e, com isso, propiciar a maior penetração de luz, favorecendo o desenvolvimento e estabelecimento das espécies comerciais. As medições das PP na área explorada foram realizadas 1 ano antes da exploração (1981), e após a exploração nos anos de 1983, 1987, 1989, 1995 e 2003. Para a área testemunha foram realizadas 5 medições: 1983, 1987, 1989, 1995 e 2003. Os resultados mostraram que, 21 anos depois da exploração e nove após os desbastes, todos os tratamentos, exceto o testemunha, apresentaram aumento no número de espécies, o que indica o efeito positivo das intervenções. Cinco anos após a exploração, todos os tratamentos apresentaram número de árvores superior ao encontrado antes da intervenção, inclusive considerando somente as espécies de valor comercial. Porém, a área basal e o volume apresentaram recuperação mais lenta, ocorrendo de forma mais efetiva nas primeiras classes de diâmetro (5-45cm). Nas classes acima de 45cm, que foram as mais afetadas pela extração de madeira, a área basal, 21 anos após a exploração, ainda está, em média, 30% abaixo do valor original. As intervenções também alteraram a dinâmica da floresta, elevando as taxas de mortalidade, estimulando o aumento no número de ingressos e a aceleração nas taxas crescimento das árvores remanescentes. O tratamento T3 foi considerado o mais adequado porque induziu ao maior aumento na riqueza florística e favoreceu várias espécies de valor comercial madeireiro que aumentaram sua participação na abundância e área basal no povoamento. Esse tratamento também mostrou a maior taxa de recuperação da área basal comercial (aproximadamente 90%), e as maiores taxas de incremento em AB e volume, no período após a aplicação do desbaste. / The objective of this work was to analyze the effect of four intensities of basal area reduction, represented by systematic logging and liberation thinning, on the floristic composition, diversity, structure and dynamics of arboreal extract, over a period of 22 years. The experiment is located in the Tapajós National Forest, municipality of Belterra, Pará, at km 114 of the Santarém-Cuiabá Highway. The statistical delineation employed was Random Blocks with 4 repetitions, in which the following treatments were tested: T0: control, represented by unlogged forest; T1: Felling of commercial trees with DBH ≥ 45cm, with no posterior intervention; T2: Felling of commercial trees DBH ≥ 55cm + thinning of non-commercial species to reduce the original basal area by 20%; T3: Felling of commercial trees DBH ≥ 55cm + thinning of non-commercial species to reduce the original basal area by 40%; T4: Felling of commercial trees DBH ≥ 55cm + thinning of non-commercial species to reduce the original basal area by 60%. Each block measured 36ha, with 9ha for each treatment. In each treatment 12 0,25ha permanent parcels (PP) were randomly installed, in which all trees with diameter ≥ 5,0cm were measured. Logging was carried out in 1982 and the thinning treatments were begun in 1993 and concluded in 1994, with the purpose of reducing the basal area of the population and, so provide greater light penetration, favoring the development and establishment of commercial species The measurements of PP in the harvested area were carried out 1 year before logging (1981), and after logging in the years 1983, 1987, 1989, 1995 and 2003. For the unlogged area 5 measurements were done: 1983, 1987, 1989, 1995 and 2003. The results showed that, 21 years after logging nine after the thinnings, all of the treatments, except the witness, showed an increase in the number of species, which indicates the positive effect of the interventions. Five years after logging, all the treatments showed a greater number of trees than what was found before the intervention, including a count only of species with commercial value. However, the basal area and volume showed a lower recovery, occurring most effectively in the first diameter classes (5-45cm). In the classes above 45cm, which were the ones most affected by timber harvesting, the basal area, 21 years after logging, is still on average 30% below the original value. The interventions also alter forest dynamics, increasing mortality rates, stimulating an increase in the number of ingresses and acceleration in growth of remaining trees. Treatment T3 was considered the most adequate one, because it induced a greater increase in floristic diversity and favored several species with commercially valuable timber, which increased their participation in terms of abundance and basal area in the population. This treatment also showed the highest recovery rate for the commercial basal area (approximately 90%), and the greatest increments in AB and volume, in the period after application of the thinnings.

The purpose of this study was to determine if control charts are an effective tool to identify trends in forest growth and yield model accuracy. Accurate forest growth and yield models are important for projecting future forest composition. However, environmental factors have the potential to make forest growth models created from historic data inaccurate. Control charts in this study determine if forest growth predictions fall within confidence limits established for historic growth at a number of points in time. Two data sets were used in this study: the first was a Continuous Forest Inventory (CFI) from three tracts at the University of Tennessee Cumberland Research Station and the second data set was Forest Inventory and Analysis data collected by the U.S. Forest Service. The CFI plots represented a stand level data set measured every 5 years from 1962-1977 and revisited for a re-measurement in 2009. The FIA plots were a regional data with subsets of plots measured annually from 1999-2008. The FIA data set was limited to plots of the oak/hickory forest type from Tennessee, Alabama, and Georgia. Two forest growth and yield models were used to predict growth: (1) WinYield and (2) Forest Vegetation Simulator (FVS). The two different data sets were used with both FVS and WinYield to evaluate control charts using different models ad at different spatial and temporal scales. The data sets were also subset by site index, stand age, stocking percent, aspect, and species composition to determine if control charts could identify changes in model accuracy for forests subjected to different growing conditions. The CFI and FIA data had short growth predictions and control charts indicated that there were no trends affecting accuracy. The CFI data also had a long growth prediction of 32 years and the control charts found that the predictions using WinYield and FVS were inaccurate, indicating that there may be a trend causing inaccuracy in the model.

No description available.

O objetivo deste trabalho foi analisar o efeito de quatro intensidades de redução da área basal, representadas pela exploração e desbastes sistemáticos, na composição florística, diversidade, estrutura e dinâmica do extrato arbóreo, durante um período de 22 anos. O experimento se localiza na Floresta Nacional do Tapajós, município de Belterra, Pará, a altura do km 114 da Rodovia Santarém-Cuiabá. O delineamento estatístico utilizado foi Blocos ao Acaso com 4 repetições onde foram testados os seguintes tratamentos: T0: controle, representado pela floresta não explorada; T1: Abate de árvores comerciais com DAP ≥ 45cm, sem nenhuma intervenção posterior; T2: Abate de árvores comerciais DAP ≥ 55cm + desbaste de espécies não comerciais para reduzir a área basal em 20% da original; T3: Abate de árvores comerciais DAP ≥ 55cm + desbaste de espécies não comerciais para reduzir a área basal em 40% da original; T4: Abate de árvores comerciais DAP ≥ 55cm + desbaste de espécies não comerciais para reduzir a área basal em 60% da original. Cada bloco possui uma área de 36ha, sendo 9ha por tratamento. Em cada tratamento foram instaladas ao acaso 12 parcelas permanentes (PP) de 0,25ha, onde foram medidas todas árvores com diâmetro ≥ 5,0cm. A exploração de madeira foi realizada em 1982 e os desbastes foram iniciados em 1993 e concluídos em 1994, com a finalidade de reduzir a área basal do povoamento e, com isso, propiciar a maior penetração de luz, favorecendo o desenvolvimento e estabelecimento das espécies comerciais. As medições das PP na área explorada foram realizadas 1 ano antes da exploração (1981), e após a exploração nos anos de 1983, 1987, 1989, 1995 e 2003. Para a área testemunha foram realizadas 5 medições: 1983, 1987, 1989, 1995 e 2003. Os resultados mostraram que, 21 anos depois da exploração e nove após os desbastes, todos os tratamentos, exceto o testemunha, apresentaram aumento no número de espécies, o que indica o efeito positivo das intervenções. Cinco anos após a exploração, todos os tratamentos apresentaram número de árvores superior ao encontrado antes da intervenção, inclusive considerando somente as espécies de valor comercial. Porém, a área basal e o volume apresentaram recuperação mais lenta, ocorrendo de forma mais efetiva nas primeiras classes de diâmetro (5-45cm). Nas classes acima de 45cm, que foram as mais afetadas pela extração de madeira, a área basal, 21 anos após a exploração, ainda está, em média, 30% abaixo do valor original. As intervenções também alteraram a dinâmica da floresta, elevando as taxas de mortalidade, estimulando o aumento no número de ingressos e a aceleração nas taxas crescimento das árvores remanescentes. O tratamento T3 foi considerado o mais adequado porque induziu ao maior aumento na riqueza florística e favoreceu várias espécies de valor comercial madeireiro que aumentaram sua participação na abundância e área basal no povoamento. Esse tratamento também mostrou a maior taxa de recuperação da área basal comercial (aproximadamente 90%), e as maiores taxas de incremento em AB e volume, no período após a aplicação do desbaste. / The objective of this work was to analyze the effect of four intensities of basal area reduction, represented by systematic logging and liberation thinning, on the floristic composition, diversity, structure and dynamics of arboreal extract, over a period of 22 years. The experiment is located in the Tapajós National Forest, municipality of Belterra, Pará, at km 114 of the Santarém-Cuiabá Highway. The statistical delineation employed was Random Blocks with 4 repetitions, in which the following treatments were tested: T0: control, represented by unlogged forest; T1: Felling of commercial trees with DBH ≥ 45cm, with no posterior intervention; T2: Felling of commercial trees DBH ≥ 55cm + thinning of non-commercial species to reduce the original basal area by 20%; T3: Felling of commercial trees DBH ≥ 55cm + thinning of non-commercial species to reduce the original basal area by 40%; T4: Felling of commercial trees DBH ≥ 55cm + thinning of non-commercial species to reduce the original basal area by 60%. Each block measured 36ha, with 9ha for each treatment. In each treatment 12 0,25ha permanent parcels (PP) were randomly installed, in which all trees with diameter ≥ 5,0cm were measured. Logging was carried out in 1982 and the thinning treatments were begun in 1993 and concluded in 1994, with the purpose of reducing the basal area of the population and, so provide greater light penetration, favoring the development and establishment of commercial species The measurements of PP in the harvested area were carried out 1 year before logging (1981), and after logging in the years 1983, 1987, 1989, 1995 and 2003. For the unlogged area 5 measurements were done: 1983, 1987, 1989, 1995 and 2003. The results showed that, 21 years after logging nine after the thinnings, all of the treatments, except the witness, showed an increase in the number of species, which indicates the positive effect of the interventions. Five years after logging, all the treatments showed a greater number of trees than what was found before the intervention, including a count only of species with commercial value. However, the basal area and volume showed a lower recovery, occurring most effectively in the first diameter classes (5-45cm). In the classes above 45cm, which were the ones most affected by timber harvesting, the basal area, 21 years after logging, is still on average 30% below the original value. The interventions also alter forest dynamics, increasing mortality rates, stimulating an increase in the number of ingresses and acceleration in growth of remaining trees. Treatment T3 was considered the most adequate one, because it induced a greater increase in floristic diversity and favored several species with commercially valuable timber, which increased their participation in terms of abundance and basal area in the population. This treatment also showed the highest recovery rate for the commercial basal area (approximately 90%), and the greatest increments in AB and volume, in the period after application of the thinnings.

Diese Arbeit beschäftigt sich mit der Naturverjüngung von Traubeneiche (Quercus petraea (Matt.) Liebl.) unter Kiefernschirm. Eine erfolgreiche Verjüngung von Traubeneiche ist ohne menschliche Hilfe nur schwer umzusetzen. Als Ursache wird in der Literatur die Konkurrenzsituation von Begleitvegetation um die Ressource Wasser besonders hervorgehoben. Um künftige Managementmaßnahmen von Oberstand und Begleitvegetation bezüglich der Eichenverjüngung bewerten zu können, wurde das individuen-basierte Modell oak-lay entwickelt, das die Konkurrenz um Wasser explizit auf pflanzenphysiologischer Basis berücksichtigt. Die Kombination von individuen-basierten und prozess-basierten Ansätzen wird auch als Hybrid-Modell bezeichnet. In der Verjüngungsmodellierung ist bisher keine Anwendung eines Hybrid-Modells bekannt, so dass es sich vermutlich um das erste Modell seiner Art handelt. Die Arbeit ist in drei große Arbeitsschwerpunkte aufgeteilt. Im ersten Teil wird oak-lay detailliert vorgestellt und analysiert. Dabei kommen standardisierte Verfahren wie eine globale Sensitivitätsanalyse oder eine Analyse der Rechenzeit mittels Landau-Symbole zum Einsatz. Der zweite Teil analysiert mit Hilfe von Simulationsexperimenten eine neue Methode der Mortalitätsbeschreibung in individuen-basierten Modellen auf physiologischer Basis. Die prozess-basierte Wasserhaushaltsberechnung des oak-lay ermöglicht die Festsetzung einer Mortalitätsschwelle über das Druckpotential der Individuen. Für die Analysen wurde auf Ereigniszeitanalysen zurückgegriffen. Konkret angewandt wurden der Kaplan-Meier Schätzer und das semiparametrische Cox-Modell. Der dritte und letzte Teil wendet das Modell beispielhaft in einer Reihe von Simulationsexperimenten an. Dabei werden unterschiedliche Managementmaßnahmen am Oberstand und der Begleitvegetation simuliert und auf Unterschiede im Verjüngungserfolg und der räumlichen Verteilung getestet. Das Modell oak-lay konnte erfolgreich nachweisen, dass Hybrid-Modelle im Bereich der Verjüngungsmodellierung entwickelt und angewendet werden können. Die globale Sensitivitätsanalyse des Wasserhaushaltsmodells konnte die einflussreichsten Parameter identifizieren und das Laufzeitverhalten des Modells konnte ebenso analysiert werden. Die Einhaltung bestimmter Selbstdifferenzierungsmuster wurde über alle Simulationen geprüft. Dabei wurde erfolgreich die Mortalität über den Wassergehalt der Individuen bestimmt. Die Simulationsexperimente der verschiedenen Managementmaßnahmen haben gezeigt, dass eine Anwendung als Managementtool möglich ist. Die Entwicklung eines neuen Modelltyps bei der Verjüngungsmodellierung hat allerdings auch einigen neuen Forschungsbedarf generiert. Um oak-lay weiterzuentwickeln sind weitere Arbeiten nötig.