The forest product industry is keenly interested in extending the normal planting season, as well as in the comparative field performance of standard nursery bare-root seedlings and containerized rooted cuttings. The effect of seasonal planting dates on survival, above and belowground biomass allocation, water relations, gas exchange attributes and foliar carbon isotope composition (δ13C) of two stock types of slash pine (Pinus elliottii Engelm.) were examined. Slash pine bare-root seedlings (BRS) and containerized rooted cuttings (CRC) were hand planted in September, November, January, March and April in three consecutive planting seasons (2000-2001, 2001-2002 and 2002-2003) on three sites with silt loam topsoils in southwestern Louisiana. First-year mean survival of CRC across all planting dates and sites was consistently high at 96 to 98%, whereas BRS survival was significantly (P < 0.0001) lower at 59 to 81% and highly variable among study sites and dates through three planting seasons. Generally, there was a negative relationship between soil moisture at the time of planting and first-year survival of BRS planted September through March in 2001-2002 and 2002-2003 planting seasons, whereas the opposite was observed only for BRS planted in April 2002 and 2003. Survival of CRC was affected very little by the variation in soil moisture. Containerized rooted cuttings had higher early above and belowground biomass, and height and diameter than did BRS. However, three years after planting the size differences between stock types disappeared or became negligible. Early size differences among trees planted September through March also decreased after three years, although September trees were tallest. Growth of the April-planted trees was poor compared to trees planted in other months. Late-planted April trees had higher δ13C values, and higher water-use efficiency in the first growing season compared to earlier planted trees. Differences in δ13C values among the planting dates disappeared in the second growing season. Net photosynthesis rates did not differ considerably between stock types or among planting dates in the second and third growing seasons. This study indicates that it is possible to extend the planting season to as early as September and as late as March by using CRC.

The forest product industry is keenly interested in extending the normal planting season, as well as in the comparative field performance of standard nursery bare-root seedlings and containerized rooted cuttings. The effect of seasonal planting dates on survival, above and belowground biomass allocation, water relations, gas exchange attributes and foliar carbon isotope composition (&#948;13C) of two stock types of slash pine (Pinus elliottii Engelm.) were examined. Slash pine bare-root seedlings (BRS) and containerized rooted cuttings (CRC) were hand planted in September, November, January, March and April in three consecutive planting seasons (2000-2001, 2001-2002 and 2002-2003) on three sites with silt loam topsoils in southwestern Louisiana. First-year mean survival of CRC across all planting dates and sites was consistently high at 96 to 98%, whereas BRS survival was significantly (P < 0.0001) lower at 59 to 81% and highly variable among study sites and dates through three planting seasons. Generally, there was a negative relationship between soil moisture at the time of planting and first-year survival of BRS planted September through March in 2001-2002 and 2002-2003 planting seasons, whereas the opposite was observed only for BRS planted in April 2002 and 2003. Survival of CRC was affected very little by the variation in soil moisture. Containerized rooted cuttings had higher early above and belowground biomass, and height and diameter than did BRS. However, three years after planting the size differences between stock types disappeared or became negligible. Early size differences among trees planted September through March also decreased after three years, although September trees were tallest. Growth of the April-planted trees was poor compared to trees planted in other months. Late-planted April trees had higher &#948;13C values, and higher water-use efficiency in the first growing season compared to earlier planted trees. Differences in &#948;13C values among the planting dates disappeared in the second growing season. Net photosynthesis rates did not differ considerably between stock types or among planting dates in the second and third growing seasons. This study indicates that it is possible to extend the planting season to as early as September and as late as March by using CRC.

This thesis studies two related topics in liner shipping. The first topic is the contract pricing problem for container carriers. The second part studies the interaction of the longer term contracts and the spot markets/exchanges for the same goods/services. Most containerized freight is transported under the provisions of medium term contracts between ocean carriers and shippers. One of the biggest challenges for an ocean carrier is to find optimal ways to structure the prices in those contracts. In particular, an ocean carrier would like to set the prices such that the best match between supply and demand can be obtained to maximize its profit. We propose three optimization models as decision tools that carriers can use to plan the contract price structures, as well as the anticipated freight flows and empty container flows for the period covered by the contracts. Based on the models, we propose algorithms and build decision tools that generate the following output: optimal prices to be charged for the movement of freight, the anticipated freight flows and empty flows, containers to be leased, rented and purchased, and the additional voyage capacities to be procured. The first two models are deterministic and represent the problem at different levels of detail. In addition, a three-stage stochastic model is proposed to handle uncertainties in demand rates, costs, bookings and transit times on feeder arcs. Recent developments in information technology and communication make spot transactions more economical and more convenient. Nevertheless, the incidental spot transactions still count for only a very small portion of freight transported both by the large carriers who are the leaders in implementing e-commerce and in the industry as a whole. The second part of the thesis studies models to provide insight into the effect of spot market participation rates on various economic quantities. This may have implications for freight transportation industries, such as the sea cargo industry, in which longer term contracts are still prevalent. We focus our study on the following situation. Option contracts are signed before the demand is observed. As is common in liner shipping, sellers (carriers) also sell goods/services on the spot. Buyers (shippers) may or may not buy in the spot market as a matter of policy. We investigate the effects of spot market participation on the contract market and on the surpluses of all market players. It is found that the contract market shrinks as more and more buyers participate in the spot market. However, the effects on the surpluses of different market players are much more complicated and depend on the following factors: market structure, demand variation along time, demand variation among buyers and capacity level.

El terminal portuario del Callao es el más importante del Perú, ya que es considerado como la principal conexión del país con el mundo por concentrar diversas operaciones de carga. El servicio de despacho anticipado es una modalidad de despacho aduanero que permite numerar la declaración de la importación antes de que ésta llegue al puerto. Para realizar el despacho anticipado, se deben cumplir con algunos requisitos como, por ejemplo, tener la Declaración Única de Aduanas (DUA) numerada y cancelada, con lo cual se podrá realizar el levante de su mercancía cuando ésta llegue al terminal portuario, en un plazo de 48 horas computados a partir del día siguiente del término de descarga, además de reducir costos. Sin embargo, no todos acceden a este beneficio. Por tal motivo, el objetivo de esta investigación fue identificar cuáles fueron los factores operativos que afectaron al despacho anticipado. Para ello se utilizó un enfoque de investigación cualitativa. Del mismo modo, se realizaron entrevistas, que constaron de 12 preguntas, a 20 trabajadores de las agencias aduaneras, la cual arrojó como resultado que los factores operativos que dificultaron al despacho anticipado de carga contenerizada fueron los trámites burocráticos, así como también la carencia de una infraestructura vial adecuada y la presencia de un parque automotor antiguo de transporte terrestre. En general, estos factores impactaron en sobrecostos y demoras excesivas en el despacho anticipado no pudiendo obtener los beneficios aduaneros. Luego del análisis se brindaron recomendaciones necesarias para poder optimizar la cadena logística. / The Callao port terminal is the most important in Peru, since it is considered the main connection between Peru and the world for concentrating various operations. The advance clearance service is a customs clearance modality that allows the import declaration to be numbered before it arrives at the port; To carry out the early dispatch, some requirements must be met, such as having the Unique Customs Declaration numbered and canceled, with which your merchandise can be released when it arrives at the port terminal, within a period of 48 hours computed at starting the day after the discharge term, in addition to reducing costs; however, not everyone has access to this benefit. For this reason, the objective of this investigation was to identify which were the operational factors that affected the anticipated dispatch. For this, a qualitative research approach was used. In the same way, interviews, consisting of 12 questions, were conducted with 20 workers of the customs agencies, which showed as a result that the operational factors that made it difficult to dispatch containerized cargo in advance were bureaucratic procedures, as well as the lack of a Adequate road infrastructure and the presence of an old land transport vehicle fleet, in general these factors impacted on cost overruns and excessive delays in early clearance, not being able to obtain customs benefits. After the analysis, the necessary recommendations were provided to optimize the logistics chain. / Tesis