<p> The effects of cultural intensity (operational and intensive) and planting densities (741, 1483, 2224, and 2965 ha^-1) on modulus of elasticity (MOE), modulus of rupture (MOR) and specific gravity (SG) of small clear samples obtained from 15 and 16 year-old loblolly pine (<i> Pinus taeda</i>) from the Lower Coastal Plain and Piedmont region of the southeastern United State were examined. Planting density and distance from pith showed a significant (<i>p</i> &lt; 0.0001) and strong main effect on stiffness (MOE) and strength (MOR) for the samples. Regardless of planting density, MOE, MOR and SG of samples increased significantly from pith toward bark. A significant culture &times; density interaction (<i> p</i> &lt; 0.0001) was observed for the samples obtained from the Lower Coastal Plain. </p><p> The project also determined the feasibility of measuring microfibril angle (MFA) on solid wood loblolly pine samples using scanning electron microscopy and transmission electron microscopy with the angle analyzed using image analysis. Measurements of MFA revealed minor differences (5⁰) between juvenile wood and mature wood.</p>

<p> Fire is an important tool in the sustainable management of ecosystems at global and local scales. In addition to increasing biodiversity, fire has been shown to decrease exotic species invasion, promote growth of commercially and ecologically important trees, and reduce risk of wildfire. Missouri has a long history of anthropogenic and naturally induced fire aiding the establishment of oak and pine-dominated woodlands and savannas. Fire has been reintroduced through forest management in the region after a period of fire suppression to help retain oak-dominance in forests throughout Missouri. Research on the effects of fire is ample for many wildlife species and plants but virtually excludes insects including ants, especially in Missouri and most of the United States. Ants are considered ecosystem engineers for their contribution to soil turnover, aeration and chemical and structural modification and are important seed dispersers. The effects of prescribed burning on ant assemblage diversity, abundance, composition and function were examined in oak-hickory and oak-pine forests in the Missouri Ozark Highlands. Where fire was present annually for over sixty years, ant abundance, Generalized Myrmicinae, soil and litter nesters and small ants increased. Fire every four years for over sixty years resulted in higher Shannon diversity, Cryptic Species, litter nesters and small and medium ants. In addition, this treatment shared ants with both the control and annually burned plots. Control plots were dominated by Subordinate Camponotini, Cold Climate Specialists, wood nesters and medium sized ants. Ants were also assessed after just two fires over the course of ten years. Five and six years after fire ant assemblages were more affected by topographic position than by prescribed burning. Ant assemblages of burned and unburned sites were homogenous when compared using a Morisita Similiarity index. When comparing these treatments to those that have been burned for over sixty years using the Similarity index, both were more similar to the control. In summary, long term fire implementation results in more lasting changes in ant communities because habitat alteration is maintained over time. Habitat heterogeneity produces a more diverse assemblage of ants at the landscape scale and hence higher functional diversity. Finally, categorization of ant communities may simplify ant sampling so that the natural history of each species need not be known in order to assess ecological effects of ant assemblages associated with burn treatments.</p>

<p> This study implemented LiDAR (Light Detection and Ranging) remote sensing technology and applied ITD (Individual Tree Detection) methods as an approach to estimate some essential tree variables, such as DBH (Diameter at Breast Height), height, volume, and biomass for Ford Forest Research Center in Upper Peninsula, Michigan. There were 34 deciduous (1 bigtooth aspen, 9 red oaks, 20 sugar maples, 2 white birches, and 2 yellow birches) and 17 coniferous (2 eastern hemlocks, 11 red pines, and 4 white pines) subject tree species. There were two different available LiDAR datasets from the same area that were collected in 2011 and 2017. Height measurements were done at 96% and 97% accuracy for hardwood and softwood tree species, respectively. </p><p> Several other tree variables derived from LiDAR point cloud were used to estimate DBH by using regression analysis for both 2017 and 2011 datasets. Estimation equations were tested on the other dataset. The best-fitted formula was 2017&rsquo;s, with 0.55 adjusted R&sup2; and less than 0.0001 p-values on 2017 LiDAR data while 0.42 adjusted R&sup2; and less than 0.0001 p-values on 2011&rsquo;s dataset. Some additional analysis that includes calculating PRMSE (Predicted Root Mean Square Error), BIAS (Mean Error), and MAD (Mean Absolute Difference) have been applied. The equation that was generated by using data from 2017 has &ndash;0.57 BIAS for Hardwood and 1.13 BIAS for softwood. That result indicates that the equation has &ndash;0.57 centimeters (cm) estimation error for hardwood and 1.13 cm for softwood on DBH estimations. </p><p>

In recent years, interest in uneven-aged forestry has been increasing in Britain, particularly for sensitive areas such as recreation and amenity forests. Literature on the economics of uneven-aged forestry is scarce and few operational, uneven-aged forests are available for study. Therefore, in order to quantify the operating costs associated with uneven-aged forestry, a modelling approach was chosen. The resulting model is written in FORTRAN and uses a series of square two-dimensional arrays to represent a block of forest. The block may then be managed by clearfelling and replanting at a specified age, or by a system of group management with a choice of four group sizes. The resulting model was then used to investigate the effect of the following management strategies on operating times: 1. Varying the scale of working (i.e. the group size and forest size) in the uneven-aged forest. 2. Using shortwood or pole-length harvesting systems and a range of machine types within each harvesting system. 3. Varying the length of time taken to transform the structure of the forest from even-aged to uneven-aged. 4. Varying the age of the trees when the transformation from even-aged to uneven-aged structure begins. The results obtained from running the model show that the time taken to carry out an operation is influenced both by the absolute size of the group within the forest block and by the number of groups of that size within the forest block. This fragmentation effect explains why it is difficult to determine the absolute costs of working for a specific group size, because it is the combination of group size, number of groups and forest block size, which determines costs. Most of the results below are based on a range of group sizes from 1.000 ha. to 0.0625 ha., with a block size of 16 ha. Forwarders were penalized when the group size was decreased to 0.0625 ha. (-12% increase over clearfelling), because very small groups do not contain full forwarding loads and a large proportion of total forwarding time is spent manoeuvring into and out of groups. However, the operating times for the three group sizes 1.00 ha., 0.25 ha. and O. 1 1 ha. were very similar indicating that the group size can be quite small before any extra forwarding costs are incurred. On poor sites, the cost differential between the largest and smallest groups is greater. In contrast to forwarding, skidders are most penalized with the decision to adopt an uneven-aged system, and once that decision has been made, there is not a clear increase in costs with decreasing group size. During the transformation period, felling and thinning times in the uneven-aged system are significantly higher than those for the even-aged system, because trees are being harvested prematurely to create the early groups, but this difference is reduced once the forest is transformed. Felling and thinning times increase gradually as the group size decreases, because more care is needed for the felling operation and more time is needed for snedding coarse edge trees. Replanting times for the uneven-aged forest are approximately 8% - 14% higher than replanting times for clearfelling. The results from the model were then analysed using the EXCEL spreadsheet programme to examine, among other things, the cost implications of varying group size, and the relative profitability of uneven-aged and even-aged management. First,optimum ages to begin transformation were found, which varied with the Yield Class and discount rate chosen. Then, the effect of the length of the transformation period was examined and a long transformation period (80-years) was found to be preferable to a short transformation period (40-years). The analysis showed that at high discount rates even-aged and uneven-aged management had similar Net Present Values, but at lower discount rates the even-aged system was preferred. The greatest financial penalty was incurred with adoption of an uneven-aged system, and reducing the group size had relatively little impact on Net Present Values. Other costs and benefits, such as scenic beauty and recreation potential, could not be included in the model, because research relating these values to forest management variables has not been carried out. Therefore, these mostly non-financial factors were discussed for even-aged and uneven-aged forestry, based on a review of the literature.

Les espaces forestiers occupent à l’Époque contemporaine, vers 1830 – 1960 un sixième de la partie septentrionale et centrale du Vexin français, petite région du bassin parisien située au nord-ouest de Paris (France). Les espaces forestiers participent à la trame des paysages sous forme de massifs, de bois, de bosquets diversement localisés dans l’espace vexinois. Ils gagnent 1700 ha en cent trente ans, 3 % du territoire. Cette progression inégalement répartie aboutit à une retouche ponctuelle des paysages. Elle résulte d’une succession de boisements et de déboisements mêlés dans le temps et dans l’espace. Les nouveaux espaces forestiers, issus de l’emboisement des délaissés de culture et de plantations, qui constituent 40 % de bois sur la période, contribuent au renouvellement des formations boisées. Ces espaces forestiers sont quasi totalement privés, répartis entre des milliers de propriétaires, partagés de façon inégalitaire. Quelques dizaines en détiennent 60 % de la surface, quelques centaines de moyens et petits en possèdent un quart, des milliers de très petits propriétaires en disposent de moins de 15 %. Des nombreux transferts de propriétés, majoritairement réalisés par transactions produisent des recompositions des propriétés forestières qui ne remettent pas en cause l’architecture d’ensemble des structures foncières. Les propriétaires forestiers sont en majorité des ruraux. Mais, l’exode rural qui touche le Vexin, les transformations de l’agriculture, l’essor de villes bordières et de leurs activités, et surtout la croissance économique et démographique de Paris et de sa banlieue entrainent une réduction du nombre des propriétaires ruraux et de la surface de leurs bois. Les propriétaires citadins, surtout «parisiens» se renforcent en nombre et en surface boisée qui dépasse celle des ruraux au milieu du XXe siècle. Initialement marquée par la proximité, la résidence des propriétaires de bois se dissémine, davantage en Vexin, dans les vallées périphériques, dans toute la région parisienne et le territoire national. Les actifs liés au travail de la terre et à la vie des campagnes régressent en nombre et en surface boisée. Les acteurs de l’économie moderne centrée sur les villes, ainsi que quelques gros agriculteurs renforcent leurs possessions forestières. Les propriétaires forestiers en Vexin sont des propriétaires fonciers dont une partie des fonds est composée de bois. La part des bois est proportionnelle à la dimension des propriétés globales. Elle se renforce pour toutes les catégories foncières. Les valeurs fiscales des bois, nombreuses, révèlent leur diversité. La progression en surface des bois affectés de valeurs hautes est un indice de l’amélioration de la qualité des peuplements, celle des valeurs faibles est un indicateur de l’apparition de nouveaux espaces forestiers. La production sylvicole demeure le principal usage des espaces boisés. Initialement, la production de bois était dévolue principalement à la satisfaction des besoins en bois de feu pour la population locale et en bois d’œuvre pour les activités artisanales. La part de production destinée aux villes voisines et à Paris s’est intensifiée. La diminution de l’utilisation du bois de chauffage et la demande accrue en bois d’œuvre avec la croissance de la région parisienne a favorisé le renforcement des taillis sous futaie et celui des plantations.Les usages sociaux de forêts comme la chasse se renouvellent tandis que d’autres liés au monde urbain apparaissent tels les centres de santé associés aux bois ou les circuits de randonnées qui les parcourent. / In 1830-1960, forested areas occupied in the modern era, a sixth of the northern and central part of the French Vexin, a small region of the Paris basin located north-west of Paris (France). The forest areas participate in the fabric (structure) of landscapes in the form of massifs, woods, groves, diversely located in the Vexin region. They earn 1700 ha in one hundred and thirty years, or 3% of the territory. This unevenly distributed progression leads to a specific retouching of the landscapes. It results from a succession of afforestation and deforestation mixed in time and space. The new forest areas, resulting from the afforestation of abandoned areas of crops and plantations, which constitute 40% of wood over the period, contribute to the renewal of woodlands. These forest areas are almost completely private, divided between thousands of owners, unequally shared. A few dozen hold 60% of the surface, a few hundred medium and small own a quarter, thousands of very small owners have less than 15%. Numerous property transfers, mostly made through transactions, result in the reconstruction of forest properties that do not affect the overall architecture of the land structures. The forest owners are mostly rural people. But the rural exodus that touches the Vexin, the transformations of agriculture, the development of bordering towns and their activities, and especially the economic and demographic growth of Paris and its suburbs lead to a reduction in the number of rural owners and the surface of their woods. Urban owners, notably the "Parisians", are growing in number and wooded area. They exceed that of rural people in the middle of the twentieth century. Initially marked by their proximity, the woods owners residences spread further in Vexin, the peripheral valleys, throughout the Paris region and the national territory. The assets related to the work of the land and the life of the countryside are declining in number and on wooded surface. The actors of the modern economy centered on the cities, as well as some large scale farmers reinforce their possessions of forest.The forest owners of Vexin are landowners for whom part of their property consists of woods. The share of woods is proportional to the size of their global properties. It is trending up for all the land categories. The numerous woods tax values reveal their diversity. The surface progression of high-value woods is an indication of the improvement of (planted) wood species in the woods, the low tax values are an indicator of the emergence of new forest areas. Forestry production remains the main use of the wooded areas. Initially, wood production was mainly intended to meet firewood needs for the local population and softwood lumber for craft activities. The share of production destined for neighboring towns and Paris has intensified. The decrease in the use of firewood and the increased demand for softwood lumber linked to the growth of the Paris region has encouraged the strengthening of coppice groves and plantations. The social uses of the forest, such as hunting, are renewed while others linked to the urban world appear, i.e.: health centers associated with woods, hiking circuits that run through them…

Source: Dissertation Abstracts International, Volume: 29-07, Section: B, page: 2252. / Thesis (Educat.D.)--The Florida State University, 1968.

No description available.

1v. (various paging) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.1979)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1979

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (M.S.)--Oregon State University, 1965. / Typescript. Includes bibliographical references (leaves 34-35). Also available on the World Wide Web.