Orientador: Sílvio José Bicudo / Banca: Teresa Losada Valle / Banca: José Carlos Feltran / Banca: Marina Aparecida de Moraes Dallaqua / Banca: Ricardo Augusto Dias Kanthack / Resumo: A poda da parte aérea da mandioca é prática comum nos cultivos comerciais destinados à industrialização. Vem sendo praticada principalmente por possibilitar o controle das plantas infestantes com herbicidas no segundo ciclo vegetativo. Seus efeitos no desenvolvimento das plantas e na produtividade de raízes de mandioca ainda não são claros e resultados controversos são encontrados na literatura. Com o objetivo de estudar os efeitos da poda foram realizados seis experimentos, em dois ambientes: Botucatu, experimentos 1, 3 e 5 e em São Manuel, experimentos 2, 4 e 6. Os experimentos 1 e 2 tiveram como causas de variação cinco variedades de mandioca cultivadas com e sem poda. Os experimentos 3 e 4 avaliaram nove épocas de poda frente a uma testemunha conduzida sem poda. Os experimentos 5 e 6 tiveram como causas de variação quatro densidades de plantio avaliadas com e sem poda. Concluiu-se que: a poda altera a produtividade de matéria seca de raízes de maneira distinta considerando a variedade e o ambiente; a poda anterior ao período de repouso fisiológico ou após o início do segundo ciclo vegetativo reduz a produtividade de matéria seca de raízes; em altas densidades de plantio, a poda reduz de maneira significativa a produtividade de matéria seca de raízes. Desse modo, a poda da parte aérea da mandioca não deve ser recomendada de maneira genérica, devendo considerar entre outros, os fatores avaliados no presente estudo / Abstract: Cassava pruning is common in commercial crops destined for industrialization, a practice mainly aimed at enabling weed control with herbicides in the second growth cycle. Its effects on plant development and cassava yields remain unclear and controversial results are reported in the literature. With the objective of studying the effects of pruning, six experiments were conducted in two environments: in Botucatu, experiments 1, 3 and 5, and in São Manuel, experiments 2, 4 and 6. In experiments 1 and 2, the established variables were five varieties of cassava cultivated with and without pruning. Experiments 3 and 4 evaluated nine pruning dates compared with control cultivated without pruning. The established variables in experiments 5 and 6 were four planting densities, evaluated with and without pruning. It can be concluded that: cassava pruning causes distinct alterations in the productivity of dry root matter, depending on the variety and culture environment; pruning before or after the period of physiological rest or after the onset of the second growth cycle reduces the productivity of dry root matter; and pruning in high planting densities significantly reduces the productivity of dry root matter. Thus, cassava pruning cannot be recommended as a general practice, as currently occurs, and the factors evaluated in this study should be taken into consideration / Doutor

Made available in DSpace on 2016-12-06T17:42:05Z (GMT). No. of bitstreams: 1 PGPV14DA011.pdf: 1428690 bytes, checksum: 449aef7542bd13e0b624b66ceb10523f (MD5) Previous issue date: 2014-10-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The proper choice of plant arrangement is important to maximize maize grain yield. This work was carried out aiming to evaluate the best strategies to manipulate plant arrangement in order to reach grain yields higher than 18,000 kg ha-1. Four field experiments were set during the 2010/2011 and 2011/2012 growing seasons. In the first experiment, the effect of increasing plant density was assessed. The plant populations of 3, 5, 7, 9 and 11 pl m-2 were tested at two row spacing (40 and 80 cm). In the second trial, the effect of reducing row spacing was studied. Five row spacings were tested: 40, 60, 80, 100 cm and twin rows. Each row spacing was tested at two plant densities (7 and 9 pl m-2). In the third trial, plant uneven emergence at the sowing row was evaluated. Five levels of unevenness in plant emergence were studied: 0, 2.5, 5, 7.5 and 10 days. In the level 0, all seeds were sowed in the same day. In the other treatments, half seeds were sowed in day 0 and the other half 2,5, 5, 7.5 and 10 days after. It the forth trial spatial uneven plant distribution in the sowing row was simulated. Five levels of spatial unevenness were addressed: 0, 25, 50, 75 and 100 of the variation coefficient (C.V.). In the level 0, all seeds were placed at the same distance from each other in the sowing row. Uneven temporal and spatial distribution was studied at 18 19 two row spacings: 40 and 80 cm. In the first experiment, grain increased linearly with the increment in plant population from 3 to 11 pl m-2 when maize was grown with the row spacing of 40 cm. In the second trial, grain yield was greater with 9 pl m-2 than with 7 pl m-2 and row spacing did not affect the crop productivity. In the third experiment, the increase in temporal variability of plant emergence decreased grain yield when maize was grown with rows 80 cm apart. In the fourth trial, grain yield was reduced by the increment in spatial variability among plants at the sowing row when the crop was grown with the row spacing of 40 cm. The use of supra-optimum plant densities ( 9 to 11 pl m-2), associated to narrow row spacing (40 cm), are efficient strategies to manipulate plant arrangement in order to lift maize grain yield above 18,000 kg ha-1, as long as the plants are evenly distributed in space and time at the sowing rows / A escolha adequada do arranjo de plantas é importante para potencializar o rendimento de grãos do milho. Este trabalho foi conduzido com o intuito de identificar as melhores estratégias de manipulação do arranjo de plantas para alcançar tetos produtivos superiores a 18.000 kg ha-1. Foram conduzidos quatro experimentos nas safras 2010/2011 e 2011/2012. No primeiro avaliou-se o efeito do incremento na densidade de plantas sobre o desempenho agronômico do milho. Foram testadas as densidades de 3, 5, 7, 9 e 11 pl m-2, nos espaçamentos entre-linhas de 40 e 80 cm. No segundo avaliou-se o impacto da redução do espaçamento entre-linhas no potencial produtivo do milho. Foram avaliados os espaçamentos entre-linhas de 100, 80, 60 e 40 cm e o de linhas gêmeas, nas densidades de 70.000 e 90.000 pl ha-1. No terceiro quantificou-se o efeito da irregularidade temporal na emergência das plantas na linha de semeadura sobre o rendimento de grãos. Foram testados cinco níveis de desuniformidade temporal, equivalentes a 0, 2,5, 5,0, 7,5 e 10 dias. No nível 0 todas as sementes foram semeadas no mesmo dia. Nos demais níveis, metade das sementes foi semeada no dia 0 e a outra metade 2,5, 5,0, 7,5 e 10 dias após. No quarto experimento analisou-se o efeito da desuniformidade espacial na linha sobre o rendimento de grãos do milho. Foram testados cinco níveis de desuniformidade espacial, equivalentes a 0, 25, 50, 75 e 100 % do coeficiente de variação, onde o nível 0 equivale as plantas uniformemente distribuídas nos sulcos. Cada nível de desuniformidade temporal e espacial foi avaliado nos espaçamentos entre-linhas de 40 e 80 cm. No primeiro ensaio, o rendimento de grãos aumentou linearmente com o incremento na densidade de plantas no espaçamento de 0,4m entre-linhas. No segundo ensaio, os rendimentos foram maiores na densidade de 9 pl m-2 do que na de 7 pl m-2 e não houve diferenças significativas no rendimento de grãos entre os cinco espaçamentos entre-linhas. No terceiro trabalho, o aumento da variabilidade temporal das plantas na linha diminuiu o rendimento de grãos do milho quando o mesmo foi cultivado com espaçamentos entre-linhas de 80 cm. No quarto ensaio, o rendimento de grãos reduziu com o aumento do C.V na distribuição espacial de plantas quando o milho foi cultivado no espaçamento entre-linhas de 40 cm. A utilização de densidades supra-ótimas (9 a 11 pl m-2) e de espaçamento entre-linhas reduzido (40-50 cm) são estratégias efetivas de manipulação do arranjo de plantas para alcançar produtividades superiores a 18.000 kg ha-1 em lavouras com distribuição espacial e temporal uniforme das plantas na linha de semeadura

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-03-31T20:17:42Z No. of bitstreams: 2 Dissertação - Mariana Vaz Bisneta - 2015.pdf: 6629201 bytes, checksum: b7081f288e6426640f564925ba69b856 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-04T14:26:36Z (GMT) No. of bitstreams: 2 Dissertação - Mariana Vaz Bisneta - 2015.pdf: 6629201 bytes, checksum: b7081f288e6426640f564925ba69b856 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Made available in DSpace on 2016-04-04T14:26:36Z (GMT). No. of bitstreams: 2 Dissertação - Mariana Vaz Bisneta - 2015.pdf: 6629201 bytes, checksum: b7081f288e6426640f564925ba69b856 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) Previous issue date: 2015-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In Brazil determinate stem termination soybean plants with long juvenile period are traditionally grown. In the last five years, indeterminate and semideterminate soybean plants, especially early maturity varieties in early sowing dates, were adopted in different latitudes, aiming to cultivate a second crop. When grown on different densities, soybean plants have compensation mechanisms on stem height, number of branches and pods per plant. The objectives of this study were: i) evaluate the effect of sowing date and plant density on soybean morphoagronomic traits of soybean cultivars with different stem termination; ii) correlate grain yield with morphoagronomic traits in each type of growth and sowing date, and yield components with each other in each type of growth and density; iii) perform discrimination among types of growth in soybean cultivars, identifying sowing conditions that cause changes in the response of morphological traits with ambiguity in the phenotypic expression of growth types. Three experiments were: early October (10.02.13), mid November (11.18.13) and early January (08.01.14) in the experimental area of Embrapa Arroz e Feijão in Santo Antonio de Goiás, Brazil (16°29’S, 49°17’W), at 2013/2014 season. Trials were performed in a randomized complete block design with three replications. Treatments included two factors, stem termination and plant population density. Four cultivars were used for each stem termination; determined, semideterminate and indeterminate. The plant densities corresponded to 50%, 100% and 150% of commercial recommendation to each variety. The traits assessed were number of days to flowering, number of days to maturity, plant height at flowering, height of first pod, plant height at maturity, growth percentage after flowering, number of nodes on main stem, number of branches on main stem, number of pods per node, number of pods per plant, number of grains per pod, number of grains per plant, one hundred grain weight and yield. For most assessed traits, soybean plants of each type of growth respond differently to changes on sowing date and plant density. Only in November sowing, the determinate type of growth showed lower yield comparing to the others types. The increase in plant density causes higher plants on flowering and maturity, less number of nodes and branches in the main stem, and lower average on yield components. Regardless of the type of growth, in the first sowing date yield showed greater correlation, positive, with number of seeds per pod; however, in other sowing dates this correlation occurred with one hundred grain weight. Plant density has more influence on the associations among yield components in the determinate and indeterminate growth types, than in the semideterminate type. The greatest variation in morphoagronomic traits was observed between determinate stem termination and the other types of growth. Most change on classification of type of growth (ambiguity) occurs in late sowing and high plant density. The percentages of growth after flowering and main stem node and branches numbers are the most important traits on type of growth discrimination. / No Brasil tradicionalmente são cultivadas plantas de soja com tipo de crescimento determinado e portadoras de período juvenil longo. Nos últimos cinco anos, plantas de soja com tipo de crescimento indeterminado e semideterminado, sobretudo de ciclo precoce, nas várias faixas de latitude, passaram a ser adotadas no início da época de semeadura, visando o cultivo da segunda safra (safrinha). Quando cultivada em diferentes densidades populacionais, as plantas de soja apresentam mecanismos de compensação, por exemplo, na altura, no número de ramificações e de vagens por planta. Assim, os objetivos deste trabalho foram: i) avaliar o efeito da época e densidade de semeadura em caracteres morfoagronômicos de plantas de soja com diferentes tipos de crescimento; ii) correlacionar a produtividade de grãos com caracteres morfoagronômicos, em cada tipo de crescimento e época de semeadura, assim como os componentes de produção entre si, em cada tipo de crescimento e densidade de plantas, buscando-se identificar mudanças nas associações, decorrentes do efeito da densidade de plantas; iii) discriminar os tipos de crescimento em cultivares de soja, identificando condições de semeadura que provoquem mudanças na resposta de caracteres morfoagronômicos, implicando em ambiguidade na expressão fenotípica dos tipos de crescimento. Foram instalados três experimentos em diferentes épocas de semeadura: início de outubro (02/10/13), meados de novembro (18/11/13) e início de janeiro (08/01/14), em área experimental da Embrapa Arroz e Feijão, em Santo Antônio de Goiás (16°29’S, 49°17’W), na safra 2013/2014. Os ensaios foram realizados em delineamento de blocos completos casualizados, com três repetições. Os tratamentos incluíram dois fatores, tipos de crescimento e densidades de semeadura. Foram utilizadas quatro cultivares para cada tipo de crescimento; determinado, semideterminado e indeterminado. As densidades de plantas corresponderam a 50%, 100% e 150% da população recomendada comercialmente para cada cultivar. Foram avaliados 14 caracteres; número de dias para florescimento, número de dias para maturação, altura da planta na floração, altura de inserção da primeira vagem, altura de planta na maturação, porcentagem de crescimento após a floração, número de nós na haste principal, número de ramificações na haste principal, número de vagens por nó, número de vagens por planta, número de grãos por vagem, número de grãos por planta, massa de cem grãos e produtividade. Para a maioria dos caracteres estudados, as plantas de cada tipo de crescimento responderam diferentemente às variações de época e densidade de semeadura. Apenas na semeadura de novembro o tipo de crescimento determinado resultou em menor produtividade que os outros tipos. O aumento da densidade de plantas provocou maior altura de plantas, tanto na floração como na maturação; assim como menor número de nós e de ramificações na haste principal e menor média dos componentes de produção. Independentemente do tipo de crescimento, na primeira época de semeadura a produtividade mostrou-se correlacionada positivamente e em maior magnitude com o número de grãos por vagem; já nas outras épocas, a correlação foi maior com a massa de cem grãos. A densidade influencia mais a associação entre os componentes de produção nos tipos de crescimento determinado e indeterminado do que no tipo semideterminado. A maior variação nos caracteres morfoagrônomicos ocorreu entre o tipo determinado e os outros tipos. A plasticidade de tipos de crescimento (ambiguidade) ocorre, principalmente, na semeadura tardia e sob alta densidade de plantas. A porcentagem de crescimento após a floração, número de ramificações e de nós na haste principal são as variáveis mais importantes na discriminação dos tipos de crescimento.

Abstract Peppermint (Mentha x piperita L.) oil is one of the most popular and widely used essential oils, mostly because of its main components menthol and menthone. Peppermint oil is used for flavouring pharmaceuticals and oral preparations. Corn mint is the richest source of natural menthol. Carvone-scented mint plants, such as spearmint (M. spicata), are rich in carvone and are widely used as spices, and they are cultivated in several countries. Studies were made into the yield and essential oil content of several mint species and the original. The general aim of the work was to examine the optimal conditions for cultivating mint in Northern Finland. The specific aims of the study were (first) to investigate the differences in the oil content for several mint species and (secondly) to compare the effect of various factors such as plant spacing (10, 20 and 30 × 50 cm), liming (0, 4, 8, 12 and 16 tons ha-1), propagation methods (micropropagated and conventionally propagated plants) and harvest date (once at the end of August in comparison with first cut at the beginning of August and second cut in mid September) on the cultivation success, quality and quantity of the plants. The constituents of the essential oil were analysed from leaf samples using GC-MS. Among the peppermints of different origins studied, peppermint of USA and Egypt origin ('Black Mitcham') contain the highest menthol and optimum oil yield. Corn mint and Sachalin mints both had high menthol content. Due to several reasons, such as no significant differences between the different densities and oil composition, markedly higher amount of weeds at 30 × 50 cm than at 10 × 50 and 20 × 50 cm spacing and the high seedling costs and the danger of fungi and disease at a 10 × 50 cm spacing, a plant optimum of 20 × 50 cm spacing is recommended for Northern Ostrobothnia. If the pH value is lower than 6, or levels of Mg and Ca are low, liming at a rate of 4–8 t ha-1 for sandy soils in Finland is recommended in order to achieve higher fresh and oil yields. In the first year, there were no differences in the dry leaf yield of micropropagated and conventionally propagated plants, but the menthol content was significantly higher in conventionally than in micropropagated plants. In the second year, only the dry leaf yield of micropropagated plants was higher than that of their conventionally propagated counterparts. Cutting peppermint only once during full bloom (the end of August) gives the maximum oil yield of good quality. In conclusion, it is possible to achieve as high as or even higher oil quality and dry yield in North Ostrobothnia than it is in central Europe or south Asia. However, this requires observing certain cultivation factors such as having the right type of mint, soil pH, planting density, harvesting time and propagation method In addition, mints must be cultivated in the same place for only two and a maximum for three years.

In general, yield reduction in most dryland maize growing areas of South Africa occur because seasonal rainfall distribution is erratic with annual variation that cannot be predicted accurately. Cultivar selection, planting date and plant density are other factors that consistently affect maize yield. Long growing season maize cultivars are higher yielding, particularly under conditions of good moisture and nutrient supply. However, as both moisture and nutrient availability becomes more limiting, yield tends to decline. Short growing season maize cultivars could yield more than long season counterparts because they can maximize the growing season and potentially reach the critical flowering stage before traditional midsummer droughts occur. The short growing season maize cultivars, which have only recently been developed, have traits, which can address the problem of reduced yield, which is ascribed to midsummer drought. There has been no previous effort to evaluate the effects of planting dates and plant densities on yield and yield components of these short and ultra-short growth period maize cultivars. This prompted research in the 2004/05 growing season. One field experiment was conducted at each of two selected areas (Bethlehem&Potchefstroom) in the “Maize Triangle” of South Africa. The aim was to evaluate the response of short and ultra-short growth period maize cultivars to planting dates and plant densities at two localities with distinct environmental conditions. The effects of planting date, plant density and cultivar on yield and yield components were investigated. Both yield and yield components were affected by planting date, plant density and cultivar at both localities. At both localities early and optimum planting dates as well as low and optimum plant densities promoted increases in yield components, which contributed to increased grain yield. As for the cultivars, PAN6017 proved to be the most consistent since it out-performed other cultivars in terms of both vegetative growth, yield components and grain yield at both localities. At both localities, plant height, leaf area index and dry matter yield were affected by both planting date and plant density, with optimum planting date and optimum plant density contributing to highest yield components and yield. PAN 6017 was superior to the other cultivars at all planting dates and plant densities at both localities. In order to make findings from a study such as this applicable to the “Maize Triangle”, more research on short and ultra-short growth period maize cultivars should be conducted over a wider range of locations and seasons. / Dissertation (M Inst Agrar (Agronomy))--University of Pretoria, 2007. / Plant Production and Soil Science / M Inst Agrar / unrestricted

Hintergrund und Zielstellung Im Zuge des Waldumbaus wird die Rotbuche (Fagus sylvatica L.) über Voranbau in Fichtenreinbestände eingebracht. Deren Bewirtschaftung zielt meist auf die Erzeugung von Wertholz ab. In diesem Zusammenhang dient der Fichtenschirm als Instrument der Steuerung der Ressourcenversorgung und damit der Qualifizierung der Buchen („edle Halbschattform“). Die in der Vergangenheit zumeist niederdurchforstungsartige Behandlung bedingt jedoch, dass viele Fichtenbestände hinsichtlich ihrer Stabilität keine geeigneten Ausgangsbedingungen für eine langfristige Schirmstellung bieten. Die Schadbilder infolge immer häufiger auftretender Windwurfereignisse verdeutlichen dies eindrucksvoll und belegen unmissverständlich, dass diesbezüglich Handlungsbedarf besteht. Die vorliegende Untersuchung ging daher den Folgen eines unplanmäßigen, sturmbedingten Schirmverlusts für Wachstum und Qualität vorangebauter Rotbuchen nach. In diesem Zusammenhang wurden auch der Einfluss von Pflanzendichte und Entwicklungsstadium des Voranbaus geprüft. Material und Methoden In den beiden Modellregionen „Thüringer Wald und Hügelland“ sowie „Sächsisches Erzgebirge und Vorland“ wurden Qualitätserhebungen (vgl. BÖRNER ET AL. 2003) auf insgesamt 29 Buchenvoranbauflächen durchgeführt. Auf 17 dieser Flächen wurde der Fichtenschirm im Januar 2007 durch den Orkan KYRILL meist vollständig geworfen. Seitdem entwickelten sich die Rotbuchen ohne Schirmschutz. Alle weiteren Voranbauten stehen nach wie vor unter Fichtenschirm und dienen als Referenz für Wachstum und Qualität. Jedem Voranbau wurde das auf den Freistellungszeitpunkt bezogene Entwicklungsstadium (vor oder nach Dickungsschluss) zugewiesen. Zur repräsentativen und objektiven Festlegung der Aufnahmeeinheiten in den Flächen wurde ein rasterbasiertes Probekreisverfahren gewählt. Das quadratische Gitternetz mit einer Weite von 20 m wurde mittels GPS im Gelände eingemessen. Die Rasterschnittpunkte bildeten zugleich die Zentren der 19,95 m² großen Probekreise (Plotradius: 2,52 m). Die Datenaufnahme erfolgte auf insgesamt 204 repräsentativen Plots. In jedem Probekreis wurde die Pflanzenzahl erhoben und auf Hektarwerte hochgerechnet. Für die Referenzflächen erfolgte hier weiterhin eine Ansprache des Überschirmungsgrads. Einbezogen wurden nur Plots mit locker-lichtem Fichtenschirm. Die Datenerhebung wurde an den maximal sechs höchsten Buchen eines jeden Probekreises vorgenommen und konzentrierte sich damit auf die (vor-)herrschenden und somit vitalsten Bestandesglieder. Daraus resultierte ein Stichprobenumfang von 895 Einzelbäumen. Die Datenaufnahme fand nach Abschluss der Vegetationsperiode 2012 statt, sodass seit der Freistellung sechs Jahre vergangen waren. Mathematisch-statistische Auswertung Aufgrund der räumlich geschachtelten Versuchsanlage kamen bevorzugt gemischte Modelle zur Anwendung. In Abhängigkeit vom Skalenniveau der Response-Variable und dem vorliegenden Verteilungstyp wurden lineare gemischte Modelle (LMM) oder aber generalisierte lineare gemischte Modelle (GLMM) eingesetzt. Multinomialdaten mit einer festen Rangordnung der Response-Kategorien wurden mit einem erweiterten logistischen Regressionsmodell, der Proportional Odds Logistic Regression (POLR), analysiert. Zur Umsetzung aller beschriebenen Methoden wurde die Statistiksoftware R (Version 3.0.1) genutzt. Ergebnisse • Wachstum und Zuwachsreaktion: Sechs Jahre nach dem Sturmereignis besteht kein signifikanter Höhenunterschied zwischen den Buchen auf Sturmflächen und unter Schirm. Allerdings stiegen die Haupttrieblängen ab dem zweiten Jahr der Freistellung an, sodass der Wachstumsgang der freigestellten Individuen signifikant von dem der überschirmten Bäume abweicht. Hohe Stammzahldichten im Voranbau fördern das Höhenwachstum. Das Durchmesserwachstum profitiert im Vergleich dazu deutlich stärker von der Freistellung, wie die signifikant größeren Wurzelhalsdurchmesser der freigestellten Buchen belegen. Entsprechend intensiv fiel auch die Reaktion des Radialzuwachses aus, die ohne Verzögerung bereits im Jahr der Freistellung einsetzte. Der stärkste Grünast zeigt einen im Vergleich zum Stamm synchronen Wachstumsgang, wenn auch auf niedrigerem Niveau. Unabhängig von der Überschirmung dämpfen hohe Bestandesdichten das Durchmesserwachstum. Gemessen am H/D-Verhältnis weisen die Buchen unter Schirm sowie bei hoher Pflanzendichte einen schlankeren Wuchs auf. Zwischen den beiden Entwicklungsstadien, das heißt vor oder nach Dickungsschluss, bestand kein Unterschied. • Astigkeit und Astreinigung: Sechs Jahre nach dem Schirmverlust sind an den freigestellten Buchen signifikant größere Astdurchmesser bei zugleich steileren Astwinkeln zu erkennen. Mit zunehmender Pflanzenzahl im Voranbau werden die Buchen feinastiger, während der Astwinkel unbeeinflusst bleibt. ASIX und Grünastdichte sinken nur auf der Freifläche merklich, erreichen dadurch aber ab Pflanzenzahlen von 8.500 St./ha bzw. 6.000 St/ha niedrigere Werte als Buchen unter Schirm. Zwischen den beiden Entwicklungsstadien sind hinsichtlich der Wirkung des Schirmverlusts keine Unterschiede zu verzeichnen. Totastanzahl und grünastfreie Schaftlänge hingegen werden durch die Freistellung nicht beeinflusst. Auf der Freifläche wurden jedoch stärkere Totäste gefunden. Mit zunehmender Pflanzenzahl im Voranbau steigen Anzahl und Durchmesser der Totäste sowie die grünastfreie Schaftlänge signifikant. Am deutlichsten tritt dieses Phänomen bei Voranbauten nach Dickungsschluss zutage. • Schaft- und Kronenmorphologie sowie Häufigkeit von Z-Baum-Anwärtern: Sechs Jahre nach dem Schirmverlust sind an freigestellten Buchen signifikant häufiger Steiläste und vor allem Zwiesel erkennbar. Im Stadium vor Dickungsschluss treten auf Freiflächen doppelt bis dreifach so häufig Tiefzwiesel auf wie unter Fichtenschirm. Mit zunehmender Pflanzenzahl im Voranbau sinkt die Zwieselanzahl moderat, der Anteil tief gezwieselter Buchen sogar rapide. Dadurch kommen im Stadium nach Dickungsschluss ab 9.000 Buchen pro Hektar unabhängig von der Überschirmung kaum noch Tiefzwiesel vor. Die gutachterliche Qualitätsansprache bestätigt, dass durchschnittlich etwa 60–70 % aller Buchen auf den KYRILL-Flächen den Zwieseltypen zuzurechnen sind, während unter Fichtenschirm mit ca. 90 % die (sehr) guten Formen dominieren. Mit zunehmender Bestandesdichte steigt der Anteil der besseren Qualitäten tendenziell, jedoch nicht signifikant. Die gutachterliche Qualitätsansprache zeigt eine sehr hohe Übereinstimmung mit der anhand von ASIX, Astwinkel und Zwieselzahl einer Buche modellierten Qualitätsklasse. Unter Fichtenschirm ist die Dichte der Z-Baum-Anwärter grundsätzlich sechsmal so hoch wie in freigestellten Voranbauten. Diese steigt aber unabhängig vom Schirm mit der Pflanzendichte des Voranbaus signifikant an. Schlussfolgerung und Handlungsempfehlungen Der Fichtenschirm hat eine herausragende Bedeutung für die Qualitätsdifferenzierung von Buchenvoranbauten. Eine locker-lichte Überschirmung stellt den geeigneten Kompromiss zwischen vitalem Wachstum und Qualitätsentwicklung der Buchen dar. Ungeachtet aller weiteren Faktoren bewirkt ein plötzlicher, unplanmäßiger Schirmverlust gravierende Qualitäts-einbußen der an den Halbschatten adaptierten Buchen. Sehr gute Qualitäten, das heißt wipfelschäftige Buchen mit gering dimensionierten, horizontal ausgerichteten Ästen und zügiger Astreinigung, sind nur durch die Kombination aus langfristig stabiler Überschirmung und Pflanzendichten im Voranbau ab 6.000–8.000 St./ha zu erreichen. Eine Kompensation des Freistellungseffekts ist durch hohe Pflanzenzahlen im Voranbau nur in sehr begrenztem Umfang möglich. Ein hoher Seitendruck kann den fehlenden Schirmdruck demnach nicht ersetzen. Selbst bei höchster Bestandesdichte waren die Formen auf den Freiflächen weitaus schlechter als unter Schirm. Dies gilt unabhängig vom Entwicklungsstadium der Voranbauten. Der Bestandesschluss bewahrt also offenbar nicht vor freistellungsbedingten Qualitätsverlusten. Allerdings gewährleisten Pflanzendichten ab 8.000–9.000 St./ha, dass die Tiefzwieselbildung in geschlossenen Buchendickungen auch bei einer abrupten Freistellung weitgehend unterbleibt und eine hinreichende Anzahl von Z-Baum-Anwärtern zur Verfügung steht. Ist es erst einmal zu einem Schirmverlust über einem Buchenvoranbau gekommen, bestehen kaum Möglichkeiten, aktiv zugunsten der Buchenqualität tätig zu werden. Die einzige Chance besteht im gezielten Erhalt bestehender Z-Baum-Anwärter und deren konsequenter Pflege. Für zukünftige Waldumbaumaßnahmen wird deshalb ein standort- und risikodifferenziertes Vorgehen beim Buchenvoranbau empfohlen. Dieses sollte sich an erster Stelle an der Stabilitätssituation des Fichtenschirms orientieren. Ausschließlich bei gegebener Stabilität ist das Produktionsziel Buchenwertholz als realistisch einzustufen, sodass kostenintensive Voranbauten mit den oben genannten Pflanzendichten angelegt werden sollten (Funktionsumbau). Bei einer offensichtlich (sehr) hohen Prädisposition der Fichtenschirme gegenüber Sturm und Borkenkäferbefall ist stattdessen ein extensiver Voranbau mit reduzierter Pflanzenzahl vorzuziehen. Dieser zielt im Sinn eines Nachhaltsumbaus primär auf eine Stabilisierung der Waldökosysteme ab und trägt zur Erhöhung der Flexibilität der zukünftigen Waldbewirtschaftung bei (WAGNER 2007, 2008). / Backround and Objectives In the course of forest conversion European beech (Fagus sylvatica L.) is introduced in spruce monocultures by advanced planting. Management of beech stands aims mostly on production the of high quality timber. In this context, the shelterwood of spruce officiates as an instrument for controlling resource availability and thus to qualify advanced planted beech. But because of low-thinning treatment in past, most spruce stands do not provide suitable conditions for long-term shelterwood with regard to their missing stability. The situation of forest damage due to periodic windthrow events illustrate this impressively and show need for action. Therefore, the present study analyzed the consequences of an unplanned, storm-related loss of canopy for growth and quality of advanced planted beech. In this context, the influence of stand density and developmental stage of advanced regeneration will be examined as well. Material and Methods In two model regions "Thuringian Forest” (middle of Germany) and "Saxon Oremountains” (East of Germany) quality investigations (cf. BÖRNER ET AL. 2003) were carried out on a total of 29 advanced planted beech stands. In 17 of these stands the spruce canopy was mostly completely thrown by hurricane KYRILL in January of 2007. Thus, the beech trees have grown without shelter since then. The other advanced regeneration stands are still under spruce canopy and serve as a reference for growth and quality. A developmental stage (before or after thicket-stage) was designated to each advanced planting site in reference to the time of overhead canopy release. For representative and objective definition of experimental plots a grid-based plotdesign was used. The square grid with distance of 20 m was calibrated by GPS in the field. The grid inter-sections built the centers of 19.95 m² circular sample areas (plot radius 2.52 m). Data was collected on a total of 204 representative plots. On each plot, the number of beech plants was collected and extrapolated to hectare values. In addition, the canopy closure was also estimated for reference plots within the sample plots. For data collection only plots with moderate canopy closure were included (maximum area of canopy gaps: one crown projection). Data collection was carried out at maximum of six highest trees per plot. Thus it is concentrated on (pre-) dominant and therefore most vital individuals. This resulted in a sample size of 895 trees. The data collection was started after growing season in 2012, six years after canopy release. Mathematical and statistical analysis Due to spatially nested plot design Mixed Models have been applied preferably. Depending on scale level of the response variable and given distribution type, Linear Mixed Models (LMM) or Generalized Linear Mixed Models (GLMM) were used. Multinomial data with fixed order of response categories was analyzed with an extended logistic regression model, the Proportional Odds Logistic Regression (POLR). These calculations were implemented by statistical software R (version 3.0.1). Results • Growth and reaction of annual increment: Six years after the storm event there is no significant difference in height between beech trees on storm areas and such under shelterwood. However the annual increment of terminal shoot rose from the second year after release, so the trend of increment deviates significantly from beech trees under shelterwood. High stand density in advanced planting promotes height growth. Diameter growth benefits significantly more from release compared to height growth. So released beech trees showed significantly larger root collar diameters. Reaction of radial increment, which began immediately after release, was appropriately intensive. The thickest living branch shows synchronous trend of increment, but on a lower level. Regardless of canopy cover high stand densities delimitate diameter growth. The H/D-ratio demonstrated that beech trees under shelterwood and in high density stands showed more slender forms. There was no difference between the two developmental stages. • Branchiness and natural pruning: Six years after the loss of spruce canopy significantly greater branch diameters in combination with steeper branch angles were found on released beech trees. With increasing stand density in advanced planting the beeches showed finer branches while branch angles remain unaffected. ASIX and the density of living branches decreases appreciably for released trees only, so reached lower values than trees under shelterwood by stand densities off 8.500 pcs/ha and 6.000 pcs/ha, respectively. There was no difference of release effect between the developmental stages. Number of dead branches and bole-length without living branches however, were not affected by loss of canopy. However more dead branches were found on beeches in the opening. With increasing stand density in advanced planting, the number and diameter of dead branches and bole-length without living branches increased significantly. This was most distinct for beech stands that reached thicket-stage before release. • Stem- and crown shape, number of crop tree candidates: Six years after canopy-loss, released beeches showed significantly more steep branches and especially forks. Released stands before thicket-stage showed two to three times as likely deep-forks in relation to stands under spruce canopy. With increasing stand density in advanced planting the number of forks per trees decreased moderately, the proportion of deep-forks even rapidly. In consequence, regardless of the canopy cover, deep-forks only occurred marginally in beech stands after thicket-stage with at least 9.000 pcs./ha. The expert quality estimation confirms that on average about 60–70 % of beeches on KYRILL sites belong to a “fork type”, while under spruce shelterwood (very) good shapes dominate with about 90 %. With increasing stand density, the proportion of good shapes tends to increase, however not significantly. The estimated quality class showed a very high correlation with the modeled one, based on ASIX, branch angle and fork number per beech. The density of crop tree candidates under spruce canopy is basically six times as high as in released stands. However, regardless of shelterwood it increases significantly with stand density. Conclusion and silvicultural implication: Spruce canopy is of outstanding importance for quality and differentiation of advance planted beech. A moderate shelterwood is the appropriate compromise between vital growth and good quality development. Regardless of any other factors, a sudden and unplanned loss of canopy effects a loss of quality of shade adapted beech trees. Very good qualities, that means straight to top trees with fine, horizontally oriented branches and timely self-pruning, can only be achieved by combining of long-term shelterwood and stand densities in advanced planting of at least 6.000–8.000 pcs./ha. Compensation of the release effect through high stand density in advanced planting is only possible to a very limited extent. High intraspecific competition cannot replace the lack of shelterwood. Beech shapes were far worse than under shelterwood, even at the highest stand density. This applies regardless of the developmental stage of a beech stand. So closing of advanced planted beech stand (thicket-stage) does not prevent release related quality losses. However, plant densities from 8.000–9.000 pcs./ha ensure that deep fork formation in closed beech thickets is largely suppressed and a sufficient number of crop tree candidates is available, even after abrupt release. Once an abrupt loss of canopy above advanced planted beech has occurred, there are hardly any opportunities to actively engage in favor of beech quality. The only chance is maintenance of existing crop tree candidates and their consistent care. Therefore, for future forest conversion with beech, a site- and risk-differentiated approach is recommended for advanced planting. This should be based firstly on the stability of shelterwood. Only with high stand stability, the target of high-grade beech-timber is realistic, so costly beech plantings with high stand density mentioned above should be applied. For spruce stand with an obvious (very) high risk towards bark beetles and / or storms, an extensive advanced planting with reduced stand density is preferable. In terms of “Sustainability-conversion” this aims primarily on stabilizing forest ecosystems and increasing flexibility for future forest management (WAGNER 2007, 2008).

A series of field, rainshelter, growth cabinet and modelling studies were conducted to investigate hot pepper response to different irrigation regimes and row spacings; to generate crop-specific model parameters; and to calibrate and validate the Soil Water Balance (SWB) model. Soil, climate and management data of five hot pepper growing regions of Ethiopia were identified to develop irrigation calendars and estimate water requirements of hot pepper under different growing conditions. High irrigation regimes increased fresh and dry fruit yield, fruit number, harvest index and top dry matter production. Yield loss could be prevented by irrigating at 20-25% depletion of plant available water, confirming the sensitivity of the crop to mild soil water stress. High plant density markedly increased fresh and dry fruit yield, water-use efficiency and dry matter production. Average fruit mass, succulence and specific leaf area were neither affected by row spacing nor by irrigation regimes. There were marked differences among the cultivars in fruit yields despite comparable top dry mass production. Average dry fruit mass, fruit number per plant and succulence were significantly affected by cultivar differences. The absence of interaction effects among cultivar and irrigation regimes, cultivars and row spacing, and irrigation regimes and row spacing for most parameters suggest that appropriate irrigation regimes and row spacing that maximize productivity of hot pepper can be devised across cultivars. To facilitate irrigation scheduling, a simple canopy cover based procedure was used to determine FAO-type crop factors and growth periods for different growth stages of five hot pepper cultivars. Growth analysis was done to calculate crop-specific model parameters for the SWB model and the model was successfully calibrated and validated for five hot pepper cultivars under different irrigation regimes or row spacings. FAO basal crop coefficients (Kcb) and crop-specific model parameters for new hot pepper cultivars can now be estimated from the database, using canopy characteristics, day degrees to maturity and dry matter production. Growth cabinet studies were used to determine cardinal temperatures, namely the base, optimum and cut-off temperatures for various developmental stages. Hot pepper cultivars were observed to require different cardinal temperatures for various developmental stages. Data on thermal time requirement for flowering and maturity between plants in growth cabinet and open field experiments matched closely. Simulated water requirements for hot pepper cultivar Mareko Fana production ranged between 517 mm at Melkassa and 775 mm at Alemaya. The simulated irrigation interval ranged between 9 days at Alemaya and 6 days at Bako, and the average irrigation amount per irrigation ranged between 27.9 mm at Bako and 35.0 mm at Zeway. / Thesis (PhD)--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted

Die vorliegende Arbeit beschäftigt sich mit der Frage, wie der Buchen-Voranbau als Regelverfahren des Waldumbaus von Fichtenreinbeständen angelegt und bewirtschaftet werden soll, damit keine Qualitätseinbußen entstehen und das Wachstum unter Schirm nicht zu stark geschmälert wird. Dahinter stehen im Kern drei Fragen. Die erste zielt darauf ab herauszufinden, welche Auflichtung in Fichtenaltbeständen notwendig und zweckmäßig ist. Dabei lässt sich der Bogen über zu dichte Oberstände und die Gefahr des Kümmerns sowie dauerhaft plagiotropen Wuchses sowie eine zu niedrige Schirmdichte spannen, die wiederum das Risiko von Frostschäden verstärken kann und negative Auswirkungen für die Qualität bedeutet. Zweitens ist von Interesse, ab welchem Alter der Voranbau-Buchen (Standzeit seit der Pflanzung) sich mögliche Qualitätsunterschiede überhaupt bemerkbar machen. Drittens wird gefragt, ob sich die teure Anlage von Voranbauten mit hohen Stückzahlen lohnt, wenn qualitativ gute Dickungen und angehende Stangenhölzer erzielt werden sollen. Die zu untersuchende Alternative lautet dabei, ob die Pflanzenzahlen abgesenkt werden können und der Verlust an qualitätsförderndem Seitendruck durch einen dichteren Altbestandesschirm aufgefangen werden kann. Die abgeleiteten Arbeitshypothesen unterstellen der Fichtenüberschirmung und der Pflanzenzahl im Voranbau einen gerichteten Effekt auf Wachstum, Stabilität, Astreinheit, Astreinigung, Stammform und Achsenmorphologie der Buchen-Vorausverjüngung. Es wird außerdem angenommen, dass sich Unterschiede in Überschirmungsdichte und Pflanzenzahl erst ab einem bestimmten Alter bemerkbar machen. Die zwölf Untersuchungsflächen liegen im nordrhein-westfälischen Sauerland und im sächsischen Elbsandsteingebirge in einer Höhenlage zwischen 250 und 550m ü NN auf terrestrischen Standorten mittlerer bis ziemlich armer Trophie. Die Altbestände sind zwischen 66 und 102 Jahre alt und weisen fünf Jahre vor der Datenaufnahme konstante Schirmdichten auf. Die Buchenvoranbauten sind mindestens horstweise angelegt und seit ihrer Pflanzung ohne Pflege- oder Ästungsmaßnahmen. Das Alter variiert zwischen acht und 20 Jahren, die 1,68 bis 11,70m hoch sind. Eine Verbissbelastung kann ausgeschlossen werden. Die Stückzahl je Hektar variiert zwischen 4.444 und 10.417 Stck./ha. Die Flächen lassen sich einer zweistufigen Versuchsanlage zuordnen. In der ersten Stufe variieren Alter, Überschirmungsdichte und Dichte im Voranbau. Je nach den Verhältnissen auf der Fläche werden in homogenen Voranbauten rechteckige Kernflächen etabliert und in Subflächen unterteilt. Bei weiten Pflanzverbänden oder ungleichmäßiger Bestockung dient ein Probekreisraster dazu, die Probebuchen auszuwählen. Die Anzahl an Probebuchen wird im Nachhinein um solche bereinigt, die Schäden haben, nicht vital sind, unteren soziologischen Klassen angehören oder von anderen Baumarten in der Verjüngung berührt werden (n=2.991). Für alle diese Buchen werden im ersten Teil der Arbeit das Alter, der mittlere Standraum und die direkt über dem Wipfeltrieb befindliche Überschirmungsdichte mit der Qualitätseinstufung (sehr gut, gut, zwieselig, unzureichend) in Verbindung gebracht. Dieses Merkmal betrachtet die Gesamtmorphologie als Kombination aus vier Kronen- und drei Stammformklassen. Als statistische Methode wird ein kumulatives, gemischtes Schwellenwertmodell verwendet. Es ermöglicht, eventuelle unerwünschte räumliche Korrelationen aus dem Regressionsmodell zu eliminieren. Dazu werden die Daten auf Ebene der Plots bzw. Subflächen aggregiert. Der Stichprobenumfang reduziert sich dadurch auf n=619. Das Ergebnis zeigt, dass ein weiterer Standraum zu einer höheren Wahrscheinlichkeit schlechterer Qualitätstypen führt und andererseits eine intensivere Überschirmung diesen Trend umkehrt. So sind bei gleicher Wahrscheinlichkeit für sehr gute und gute Buchen entweder 7.140 Stck./ha bei moderatem Schirm oder 2.860 Stck./ha bei intensivem Schirm nötig. In der Validierung des Modells zeigen sich jedoch gravierende Unterschiede anhand der Daten aus den beiden Bundesländern. Im zweiten Teil der Untersuchung wird von den vorausgewählten Probebuchen eine Unterstichprobe von n=186 gezogen um daran Höhe, Wurzelhalsdurchmesser, hd-Wert, den maximalen Grünastdurchmesser je Schaftabschnitt (Schaftabschnitt 1: 0,0-1,5m, Schaftabschnitt 2: 1,5-3,0m, Schaftabschnitt 3: 3,0-4,5m), den relativen maximalen Grünastdurchmesser (ASIX von STRUCK & DOHRENBUSCH 2000), den kleinsten Grünastansatzwinkel, den Astwinkelindex von HAGEMANN (2005), das Vorhandensein von steilen Ästen, den Schaftanteil ohne Grünäste, den neu eingeführten Ästigkeitsindex, den Durchmesser des stärksten Totastes, den relativen Durchmesser des stärksten Totastes (ASIX), das Auftreten von Tiefzwieseln, die Ansatzhöhe des untersten Zwiesels, die Stammneigung und die Krummschaftigkeit zu messen, einzuschätzen bzw. aus Hilfsmessgrößen zu berechnen. Die Konkurrenzsituation dieser Einzelbuchen wird in Bezug auf den Oberstand und den Voranbau erfasst. Beim Oberstand sind es die Grundfläche je Hektar und der HEGYI-Index, die auf eingemessenen Stammverteilungsplänen der Kernflächen bzw. Plotrasterflächen beruhen, die um einen Rahmenbereich von 15m Breite ergänzt werden. Innerhalb der Verjüngung sind es der mittlere Standraum, der HEGYI-Index mit zwei verschiedenen Suchmodi (Suchradius 1/3 der Höhe und Suchkegel mit 60° Öffnungsweite am Baumfußpunkt) und der neu eingeführte Ast-Index nach CLUZEAU et al. (1994), der nahe am Baum stehende Buchen mit ihrem am weitesten auf den Zentralbaum zuragenden Ast und dessen Parametern einbezieht. Die berechneten Regressionsmodelle sind alle gemischt und fangen über einen gestuften Zufallseffekt mögliche unerwünschte räumliche Korrelationen auf. Die verwendeten Modelltypen sind die lineare und die binäre logistische Regression. Bei der Auswertung werden die unabhängigen Variablen in acht festen Varianten miteinander kombiniert. Neben der Homoskedastizität der Residuen beim linearen Modell sind die Modelle u.a. auf eine mögliche erhöhte Multikollinearität hin überprüft. Aus den maximal acht Regressionsmodellen pro Qualitätsmerkmal ist dasjenige das Endmodell, welches den niedrigsten Strafterm (AIC-Kriterium) verbunden mit einer akzeptablen Multikollinearität aufweist. Im Ergebnis ist der HEGYI-Index sowohl für den Oberstand als auch für die Verjüngung überdurchschnittlich häufig in den Endmodellen vertreten. In der Diskussion steht die Frage nach der Genauigkeit der Oberstands-Indices, die durch den zu kleinen Rahmenbereich von 15m und daher möglicherweise fehlenden, aber wirksamen Konkurrenten beeinträchtigt wird. Die Ergebnisse für die Einzelmerkmale zeigen, dass ein enger Standraum unverzichtbar ist, wenn qualitativ hochwertige Buchen herangezogen werden sollen. Kein Merkmal verhält sich in Bezug darauf indifferent. Zusätzlich bedarf es eines dichten Schirms, wenn die absoluten Grünastdurchmesser in allen drei Schaftabschnitten gering, der relative Grünastdurchmesser im Schaftabschnitt 3,0 bis 4,5m niedrig, der Grünastansatzwinkel in Bezug auf die Vertikale weit, der astfreie Schaftanteil hoch und die relative Dimension des stärksten Totastes groß sein sollen. Demgegenüber stellt eine niedrige Überschirmungsintensität bei engem Standraum in der Verjüngung sicher, dass sich die Höhe nicht zu stark reduziert, der relative Grünastdurchmesser minimal wird, der Durchmesser bereits abgestorbener Äste steigt, Tiefzwiesel weniger wahrscheinlich sind und der unterste Zwiesel hoch ansetzt. Steile Äste sind nur dann weniger wahrscheinlich, wenn der Standraum eng ist. Der Überschirmung gegenüber verhält sich dieses Merkmal dagegen indifferent. Ein weiter Standraum bewirkt in Kombination mit einem intensiven Schirm, dass die Schäfte junger Buchen weniger stark gekrümmt sind oder schief stehen. Die jungen Stämme sind bei weitem Standraum häufiger zweischnürig, was unabhängig von der Überschirmungsdichte ist. Bezüglich der Wurzelhalsdurchmesser und der hd-Werte wirkt sich ein weiter Standraum positiv aus, wenn gleichzeitig ein Schirm geringer Dichte über dem Voranbau stockt. Insofern werden die Arbeitshypothesen nicht vollumfänglich bestätigt, weil auch indifferente Reaktionsmuster der jungen Buchen vorkommen. Der Alterseffekt bzw. die Auswirkungen der unterschiedlichen Buchenhöhen sind in Bezug auf die Höhe, den Wurzelhalsdurchmesser, den stärksten Grünastdurchmesser im mittleren Schaftabschnitt, den grünastfreien Stammanteil, die Astreinigung in den unteren beiden Abschnitten, den absoluten und relativen Durchmesser des stärksten Totastes, der Stammneigung und die Krümmungsstärke besonders ausgeprägt. In der Diskussion wird die Reaktion der jungen Buchen auf unterschiedliche Auswirkungen der Konkurrenz in Raum und Zeit aufgegriffen. Die Bäumchen reagieren sowohl auf physiologischer, histologischer, anatomischer und morphologischer Ebene, was sich im Laufe der Entwicklung in der Bedeutung für den gesamten Organismus verschiebt. Diese vielfältigen Reaktionen können dafür verantwortlich gemacht werden, dass Unterschiede bei den ausgewerteten Qualitätsmerkmalen hervortreten. Zusätzlich wird die Frage diskutiert, welchen Einfluss genetische Komponenten oder der Standort auf die Qualität haben können. Für die Praxis wird empfohlen, die Pflanzenzahlen nicht unter 7.700 Stck./ha abzusenken. Für die Überschirmung ist eine Grundfläche von 25-40m²/ha empfehlenswert, wobei der Altbestand erst nach 20 Jahren vollständig geräumt werden soll. Zu dichte Fichtenoberstände sind u. a. aus Gründen der Wuchshemmung für den Voranbau, der damit einhergehenden Produktionszeitverlängerung und dem gesteigerten Risiko von Bruch und Wurf des Oberstandes nicht anzuraten. Für eine Absenkung der Pflanzenzahlen ist aus Sicht der Qualität im Voranbau lediglich ein Rahmen von 5.000 bis 7.700 Stck./ha denkbar. Diese Absenkung geht zu Lasten der Astreinigung und Feinästigkeit und sie erfordert außerdem, den Oberstand bei Grundflächen über 40m²/ha zu halten und in einem Zeitraum von mehr als 20 Jahren langsam abzuräumen. Das Bestreben bei den Pflanzen- und Pflanzungskosten einzusparen, wird insgesamt als risikobehaftet eingestuft. / The following study deals with the problem how to install and to manage advance-planting as a standard method for forest conversion in order to obtain a good quality combined with an adequate growth of young beech trees. There are three main questions that have to be answered. First, it is necessary to point out the intensity of a spruce shelter which is needed for the mentioned aims. On the one hand nor it is favourable for the vitality nor it is for the morphology of the underplanted beeches if spruce shelters are too dense. On the other hand a too sparse shelter increases the risk of frost damage and other negative effects on beech quality. Second, it has to be revealed at which time since plantig differences in quality due to various competition conditions become visible. Third, one needs to know if the use of a high amount of plants is worthwile in order to obtain the desired quality traits of thickets and young poles. Maybe it could be a meaningful alternative to plant less beeches under a more dense spruce shelter. It is hypothesized that there exists a directional effect of spruce shelter intensity as well as underplanting density on growth, stability, branchiness, stem form and morphology of advance-planted beeches. Furthermore it is supposed that young beeches show a visible reaction not immediatly after planting. Within the scope of the study, twelve sample areas were established in North-Rhine-Westphalia in the Sauerland region as well as in Saxony in the Sandstone Mountain region. The stands stock at terrestrial sites which are elevated between 250 and 550 m above sea level. The spruce shelters vary in age from 66 to 102 years and have had a constant density five years before data collection started. The underplantings have at minimum clump size and vary in age since planting from eight to 20 years with heights from 1,68 to 11,70m. They are not damaged through browsing and no thinning or pruning have taken place. The density within the underplantings lies between 4.444 and 10.417 pieces per hectare. At the study site, a two-staged sampling design is used. The first stage varies age of the young trees, shelter density and density within the underplanted area. If the beeches are homogeneously planted, rectangular plots were established, subdivided into smaller units. If the planting resulted in wide-spread or a scattered, inhomogeneous spatial distribution of young beech trees, circular sample plots were established fixed in a regular grid pattern. The relevant sample trees are vital beeches of a high sociological order without damage and without a visible competition caused by young naturally established individuals of other tree species (n=2.991). The first part of the study analyzes the effect of age, mean standing area per beech and shelter density on morphological quality (very good, good, forked, not sufficient). This trait focuses on the habitus of a young beech where crown form (four classes) and stem form (three classes) are combined. As statistical method for the analysis a mixed proportional-odds regression model is used. By this means undesirable spatial autocorrelation residual structures can be eliminated which can potentially be found. In order to reach this, sample data had to be aggregated on subplot respectively on circular sample plot level (n=619). The result shows on the one hand the negative effect of widely spaced beeches. This leads to a higher probability of worse quality classes. On the other hand, a more dense shelter can reverse the mentioned effect of a sparse density in underplanted areas. Either 7.140 beeches per hectare at a moderate shelter density or 2.860 pieces per hectare at a dense shelter will lead to the same probability level of very good and good beeches. The validation of the regression model shows great differences between the data from NRW and SAX. In the second part of the study at a subsample of 186 beeches following quality treats are measured respectively calulated afterwards: height, girth at a height of 20cm above ground, hd-ratio, diameter of the thickest living branch per stem sector (stem sector 1: 0,0-1,5m, stem sector 2: 1,5-3,0m, stem sector 3: 3,0-4,5m height above ground), relative branch diameter of the thickest living branch (ASIX after STRUCK & DOHRENBUSCH 2000), minimal branching angle out of all measured living branches, branch-diameter-angle-index of HAGEMANN (2005) for the thickest alive branch, steep branches, relative length of the branch-free bole, a new branchiness-index, absolute and relative diameter of the thickest dead branch, occurence of low forks, height of the first fork, stem leaning and crookedness. The competitional situation is assessed related to shelter as well as to regeneration. Several competition indices are used. For the spruce shelter, basal area per hectare and the index after HEGYI are calculated, based on stand maps which are established at the sample plots and additionally at a surrounding area as a margin with width of 15m. Within the regeneration, the mean standing area, two variants of the index after HEGYI based on two selection modi (radius 1/3rd of the height and searching cone with an angle of 60°) and a newly introduced branch competition index after CLUZEAU et al. (1994) are the tools to quantify the intensity of competition. The new branch competition index uses competitors nearby and in particularly their branch which is directly oriented to the sample tree and has simultaneously the greatest horizontal elongation. The regression models are mixed ones and use a spatially hierachical random effect in order to eliminate undesirable spatial correlation structures of residuals. As model types, linear and binary logistic regression types are used. The analysis combines independent variables to eight fixed variants. All linear models are investigated if their residuals are homogeneously distributed, furthermore all models are checked for an acceptable extent of collinearity amongst others. The further analysed and interpreted model ist the result of a selection process focused on an acceptable extent of collinearity and a low AIC-value. The competition index after HEGYI is the one which has the best performance among all used indices, for shelter density as well as in relation to regeneration density. Methodically, accuary of the shelter-competition-indices is discussed. The unaccuracy evolved from the fixed margin width of 15m and the fact that relevant competitors outside of this zone are missing. The results clearly show the importance of a narrow spacing in the underplanting in order to reach the goal. There is no quality trait which does not show a reaction to a varying spacing. Additionally, a dense shelter is needed if diameters of the thickest alive branches in all stem sections and the relative branch diameter at a stem height from 3,0 to 4,5m shall be small, if the branching angle shall be wide in respect to the stem axis, if the branch-free bole shall be long and if the relative branch diameter of the thickest dead branch shall be of great dimension. In contrast, a low shelter density combined with narrowly planted beeches supports other quality traits: height is not reduced so much, relative branch diameter of the thickest living branch decreases, dead branch diameter reaches a high level, low forks do not occur frequently and forking appears in the uppermost parts of the stem. Steep branches do less prevail only, if there is a narrow spacing independent of shelter density. If spacing is wide, highly crooked stems or vertical intensively leaned ones are rare. Independently of shelter density, stem form ist less crooked. Wide spacings and simultaneously a low shelter density lead to tight stem diameters of underplanted beeches and therefore to a good stability. That is why the postulated hypotheses can not completely be accepted – there are indifferent growth reactions related to quality traits, too. Age effect and impact of varying beech heights, respectively, can mainly be detected in relation to height, stem diameter, diameter of the thickest living branch in the second stem section, branch-free bole length, pruning dynamics in the lowermost stem sections, absolute and relative branch diameter of the thickest dead branch, stem leaning intensity and to intensity of crookedness. The general discussion argues the reaction of the young beech trees to different effects of competition dependent of space and time. The young beeches show a clear physiological, histological, anatomical and morphological response which is attended by a shift of importance during life time. The sum of response is the reason for differences in quality traits detected in the study. Additionally the discussion focuses on genetic aspects and site conditions which also may have an impact. Practical recommendations lead to an amount of 7.700 pieces per hectare as a minimum to let management match the quality goals. Spruce shelter density should vary between 25 to 40m² per hectare, optimally lasting ca. 20 years before complete removing. If the spruce shelter becomes too dense, this is not any more appropriate for an acceptable regeneration growth intensity which leads to a prolonged production time for the beech understorey. Also the risk of dying old overstorey stocking is increased. If regeneration density has to be decreased for operative reasons, 5.000 to 7.700 pieces per hectare are recommended. Nevertheless pruning dynamics will deteriorate and branchiness will also increase. Furthermore an approach like this requires a dense spruce shelter beyond 40m² per hectare whith a longer lasting period, longer than 20 years, until complete removing. If someone wants to economize on planting costs one should keep in mind the mentioned risks and efforts on the whole. At the end the study takes into account how forest conversion is generally discussed with respect to the needs of wood-working industry which are in contrast to the widely used silvicultural method.

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The adjustment plant arrangement is one of the fundamental management techniques for canola show positive reaction in the ability to absorb light energy, nutrients and water, which reflects on maximizing the production of photosynthate directed to the plant and grains. The aim of this study was to assess the interference of arrangement plant on direct and indirect components of yield in canola, and includes determining the effects produced in oil content. The study was conducted at the Instituto Regional de Desenvolvimento Rural do Departamento de Estudos Agrários da Universidade Regional do Noroeste do Estado do Rio Grande do Sul (IRDeR/DEAg/UNIJUÍ) in Augusto Pestana, RS, involving the execution of three experiments for different spacing of 0.20, 0.40 and 0.60m. The experimental design consisted of a factorial arrangement in randomized blocks with four replicates of 2 x 2 x 4, for the crop year (2008 and 2009), genotype (Hyola 432 and 61) and plant density (20, 40, 60 and 80 plants m-2) in each set line spacing. Components were determined direct and indirect grain yield, oil content, morphological and adaptive, as well as the thermal and solar radiation during the grain filling. The year of cultivation was more effective in changing the grain yield and other traits in canola direct production and oil content, followed by the genetic potential to grow and smaller share of the planting density. The cv. Hyola 432 shows greater effectiveness in maximizing grain yield over Hyola 61 regardless of year, row spacing and planting density. Moreover, in the shortest space of culture, the character of direct and indirect yield high values of heritability and character number of tertiary branches shows stability when subjected to strong variations in the plants arrangement. The thermal shows no correlation with grain yield and oil content. On the other hand, variables related to the crop cycle are associated with the thermal and solar radiation accumulated in the grain filling stage of canola. / O ajuste do arranjo de plantas representa um dos termos de manejo fundamental para a canola mostrar reação positiva na capacidade de absorção de energia luminosa, nutrientes e água, o que reflete em maximizar a produção de fotoassimilados direcionados a planta e aos grãos. O objetivo deste trabalho foi verificar a interferência do arranjo de plantas sobre os componentes diretos e indiretos do rendimento de grãos em canola, incluindo também, a determinação dos efeitos proporcionados no conteúdo de óleo. Nesse sentido, foi desenvolvido um experimento nos anos agrícolas de 2008 e 2009 no Instituto Regional de Desenvolvimento Rural, pertencente ao Departamento de Estudos Agrários da Universidade Regional do Noroeste do Rio Grande do Sul (IRDeR/DEAg/UNIJUÍ), localizada no município de Augusto Pestana, RS. Para o estudo dos diferentes arranjos de população, foram utilizados três espaçamentos entrelinhas (0,20, 0,40 e 0,60 m), quatro densidades de plantas por metro quadrado (20, 40, 60 e 80 plantas m-2) e utilizando dois híbridos de canola (Hyola 432 e Hyola 61). O delineamento experimental foi o de blocos completamente casualizados com quatro repetições, num esquema fatorial 2 x 3 x 4, para ano, genótipo e densidade de cultivo em três distintos espaçamentos entre linhas, respectivamente. Foram determinados os componentes direto e indiretos do rendimento de grãos, o conteúdo de óleo, caracteres morfológicos e adaptativos, bem como a soma térmica e a insolação durante o período de enchimento de grãos. O ano de cultivo foi mais efetivo em alterar o rendimento de grãos e demais caracteres diretos de produção em canola, bem como o teor de óleo, seguido do potencial genético de cultivar e de menor participação da densidade de cultivo. A cultivar Hyola 432 mostra maior efetividade em maximizar a produção de grãos em relação a Hyola 61, independente do ano, espaçamento entre linhas e densidade de cultivo. Além disso, no menor espaçamento de cultivo, os caracteres diretos e indiretos do rendimento de grãos apresentam elevados valores de herdabilidade e o caráter número de ramos terciários evidencia forte estabilidade quando submetido a variações no arranjo de plantas. A soma térmica não apresenta correlação com o rendimento de grãos e teor de óleo. Por outro lado, variáveis relacionadas ao ciclo da cultura apresentam associação com a soma térmica e com a insolação acumulada na fase de enchimento de grãos de canola.