This study addressed the effects of salinity and pot size on the interaction between leguminous plant hosts and arbuscular mycorrhizal fungi in four pine rockland soils using a shade house trap-plant experiment. Little is known about the belowground diversity of pine rocklands and the interactions between aboveground and belowground biota – an increased understanding of these interactions could lead to improved land management decisions, conservation and restoration efforts. Following twelve weeks of growth, plants were measured for root and shoot dry biomass and percent colonization by arbuscular mycorrhizal fungi. Overall, arbuscular mycorrhizal fungi had positive fitness effects on the four legume species (Cajanus cajan, Chamaecrista fasciculata, Tephrosia angustissima and Abrus precatorius), improving their growth rate, shoot and root biomass; pot size influenced plant-fungal interactions; and percent colonization by arbuscular mycorrhizal fungi was influenced by soil type as well as salinity.

The mountain pine beetle is associated with a diverse array of fungi. Grosmannia clavigera is the most pathogenic of these fungi. A comparison was made between two methods that have been used to assess fungal pathogenicity. Results were similar for older trees inoculated with G. clavigera using either the alternating flap technique or cork borer method. Using the cork borer method, younger lodgepole pine trees were inoculated with five different isolates of G. clavigera. After a 48 week incubation period, isolates ATCC 18086, B5 and H55 had induced stronger pathogenic indicators compared to isolates KW 1407 and B20. After a 7 week incubation period, only isolate ATCC 18086 had induced stronger pathogenic indicators. Usually, this isolate grew faster at lower temperatures and in a low oxygen environment. Isolate KW 1407 consistently produced milder pathogenic indicators during both incubation periods. Among the non-pathogenic fungal associates of the mountain pine beetle, Ceratocystiopsis minuta may be considered the most important because it is the type species for the genus Ceratocystiopsis. The history of this genus is complicated because no physical specimen exists for C. minuta. The phylogeny of the genus Ceratocystiopsis was evaluated. Many isolates of C. minuta were assessed as potential epitypes. Several isolates of C. minuta from previous work were shown to be misidentified. C. minuta isolate CBS 116796 is recommended for future genetic work within the genus Ceratocystiopsis. For morphological work, using measurements from the literature is recommended since CBS 116796 did not produce fruiting bodies. / Forestry, Faculty of / Graduate

Competition from non-crop vegetation decreases the productivity of conifer plantations across Canada. The objectives of this research were: (1) to develop reliable indices of perennial, interspecific competition; (2) to compare the responses of black spruce and jack pine seedlings to tree and brush competition in northern Ontario; and (3) to identify the silvicultural implications of the responses. An examination of potential components of a competition index considered measures based on hemispherical photographs, fractal geometry, stand maps, and mensurational data from 360 seedling-centred plots for each of the two crop species. Reliable competition indices should be simple formulations which include horizontal and vertical dimensions and which express the amount of competition relative to the size of the seedling. The optimum index was found to be the area of competing canopy on hemispherical photographs, relative to the seedling leaf area. An alternate index, requiring no elaborate equipment, was the sum of the competing stem volumes (relative to the seedling stem volume) of the largest competitor in each quadrant surrounding the seedling. Comparisons of crop tree responses were made using functional growth analysis, replacing the conventional time axis with a competition axis. The relationship between growth and competition was adequately modelled with a power exponential composite function. Jack pine and bare root stock of both species maintained superior growth despite greater sensitivities to competition, compared to black spruce and container stock, respectively. Thus, jack pine or bare root stock of black spruce would outperform the alternatives if tending were delayed, but competition should be removed in all cases to capture the maximum growth potential. The rate of growth decline in response to competition was consistently greatest at the lowest competition levels, indicating that no beneficial effect on growth was provided by a light cover of non-crop vegetation. Allometric analyses indicated that black spruce had a greater morphological plasticity than jack pine. At high competition levels black spruce allocated more biomass to branches and foliage, at the expense of stem and roots. Jack pine demonstrated no such adjustment in allocation pattern, but followed a strategy of stress avoidance through sustained high growth rates. / Forestry, Faculty of / Graduate

The study was concerned with lodgepole pine, Pinus contorta Douglas and Engelmann spruce, Picea engelmannii Parry, particularly in the southern interior of British Columbia. Classifications of the forests of the Province as well as distribution, silvics, effects of fire upon succession, forest associations, and productivity classes of the two species were described. Sample plots were located in the Interior Douglas-fir and Engelmann Spruce - Alpine Fir Biogeoclimatic Zones. Hohenadl's form factor was used to compute volume growth by individual decades from stem analyses. On 124 plots, 137 trees were collected for stem analyses, 108 saplings were used for height - age studies, 100 point samples were made for determining basal area and stand volume and several hundred heights as well as diameters and borings at breast height, were taken. Thirty-four stand variables were subjected to multiple correlation analyses, particularly in regard to forest associations and growth of height, diameter at breast height and volume of the two species. Simple regressions were used to estimate height growth of several species on similar sites, and to compare several methods of volume calculation. Trees of the same diameter at breast height grown in different competitive positions (open, moderate to dense, and suppressed), contained different volumes. The largest volume of individual trees was found with trees grown in moderate to dense competitive position. Individual young lodgepole pines had a faster increment of height, diameter at breast height, and volume, than Engelmann spruces. This trend remained the same in yield tables based on individual tree studies and constructed for stands of good (average site index 100 ft. at 100 years), medium (average site index 70 ft. at 100 years), and poor (average site index 50 ft. at 100 years) productivity classes. The mean annual increment of volume of stands culminated earlier in lodgepole pine than in Engelmann spruce. The periods required were (in brackets are shown attained average diameters at breast height, total heights and volumes per acre). In the good productivity class in lodgepole pine 40 years (8.3 in., 58 ft., 6,700 cu.ft.) and in Engelmann spruce 75 years (10.0 in., 80 ft., 6,000 cu.ft.); in the medium productivity class in lodgepole pine 60 years (6.5 in., 50 ft., 4,600 cu.ft.) and in Engelmann spruce 130 years (9.0 in., 84 ft., 5,100 cu.ft.); in the poor productivity class in lodgepole pine 85 years (5.3 in., 45 ft., 3,100 cu.ft.) and in Engelmann spruce 150 years (6.3 in., 66 ft., 3,400 cu.ft.). Yield table volumes per acre in lodgepole pine were larger than those of Engelmann spruce, in the good productivity class, to the age of 120 years, in the medium productivity class to 150 years, and in the poor productivity class for an undetermined period. Present and suggested future trends of utilization and management of stands of the two species were reviewed. Generally, forest management in British Columbia shows a trend toward more intensive forest utilization, due to the increasing demand for wood. Smaller diameter trees and "smallwood" stands will be more and more frequently utilized. Utilization of whole trees, highly mechanized "harvesting" and transportation as well as intensified management of forest stands will compensate for increasing costs due to utilization of smaller diameters. Under intensive management, lodgepole pine deserves special consideration. It is as well-suited for artificial establishment of stands by planting as Engelmann spruce, but should cost less. Its value for the woodworking industry is similar to that of Engelmann spruce. However, on a rotation of maximal mean annual increment, its volume yield per acre unit will be higher than that of Engelmann spruce, and it should yield a higher rate of return on invested capital. / Forestry, Faculty of / Graduate

A study has been conducted with the objectives of (1) identifying weevils and their parasitoids emerging from infested lodgepole pine leaders, (2) determining emergence patterns of hosts and their parasitoids, and (3) obtaining further information on the biologies of the terminal weevils and their natural enemies in British Columbia. The major experiments and biological observations were carried out in young spaced lodgepole pine, (Pinus contorta Dougl. var. latifolia Engelm.), stands at Ellis creek, near Penticton, B.C. A total of 1046 infested leaders were collected. One-third of the terminals were dissected and the numbers of weevils and parasitoids at developmental stages were recorded. The remainder of the leaders were set up for individual rearing. Observations were also made on the feeding and ovipositional behavior of the weevils. Feeding habits of the parasitoids were also studied. Dissections showed that a few adult weevils emerge in the fall of the year of attack. The majority of adults overwinter as larvae but pupation also may occur prior to winter. In addition, dissections indicated that parasitism plays an important role in larval mortality of weevils. Weevils which emerged in the laboratory were identified as being of the following species: Pissodes terminalis Hopping, Magdalis gentilis LeC. and Cylindrocopturus sp. (COLEOPTERA: Curculionidae). M. gentilis is the first weevil species to emerge, in late May. This emergence is followed by that of P. terminalis from early June through mid-July, while Cylindrocopturus sp. emerges from early June through mid-July. P. terminalis attacks the current year's leaders, whereas adult M. gentilis and Cylindrocopturus sp. feed on foliage. All three weevil species utilize lodgepole pine terminal shoots for breeding. Larval feeding under the bark almost always results in the death of the terminal. The terminal weevils have a complex of natural enemies in British Columbia. Parasitoids belong to six families of the order Hymenoptera. The pteromalid Rhopalichus pulchripennis Crawford is the most widely distributed parasitoid species in the province. Two species of Eurytoma (Eurytomidae) ranked second in abundance. Emergence patterns of adult parasitoids are closely synchronized with that of their hosts. Parasitoids were observed feeding on pollen of flowering weeds in the field. This observation suggests that natural parasitoid populations could be enhanced by cultivating lupin, Lupinus sp., in lodgepole pine stands. It was concluded that every effort should be made to minimize weevil numbers in order to prevent formation of crooks, forks and stag-heads. Early emergence of M. gentilis suggests that leader clipping projects should be carried out by early spring. Further research is recommended to ensure correct association between parasitoids and host weevil species and to develop or establish methods for preservation of parasitoids for clipped leaders for release in the forest. / Forestry, Faculty of / Graduate

Many conceptual models have been proposed to explain the fluid-flow mechanism responsible for the origin of carbonate-hosted lead-zinc deposits such as those in the Mississippi Valley and at Pine Point. This study is devoted to the quantitative investigation of one ore-genesis mechanism: gravity-driven groundwater-flow systems. Numerical modeling techniques are used to develop a self-contained computer code for two-dimensional simulation of regional transport processes along cross sections through sedimentary basins. The finite-element method is applied to solve the steady-state, fluid-flow and heat-transport equations, and a moving-particle random-walk model is developed to predict the dispersion and advection of aqueous components. The program EQ3/EQ6 is used to compute possible reaction-path scenarios at the ore-forming site. Full integration of geochemical calculations into the transport model is currently impractical because of computer-time limitations. Results of a sensitivity analysis indicate that gravity-driven ground-water-flow systems are capable of sustaining favorable fluid-flow rates, temperatures, and metal concentrations, for ore formation near the thin edge of a basin. Dispersive processes render long-distance transport of metal and sulfide in the same fluid an unlikely process in the genesis of large ore deposits, unless metal and sulfide are being added to the fluid along the flow path. The transport of metal in sulfate-type brines is a more defensible model, in which case the presence of reducing agents control the location of ore deposition. Hydrodynamic conditions that could result.--in ore formation through mixing of two fluids are rare. The theoretical approach is a powerful tool for gaining insight into the role of fluid flow in ore genesis and in the study of specific ore districts. A preliminary model of the Pine Point deposit suggests paleoflow rates on the order of 1.0 to 5.0 m³/m² yr, paleoconcentrations of zinc on the order of 1.0 to 5.0 mg/kg • H₂O, and paleotemperatures in the range 60°C to 100°C. Under these conditions, the time required for the formation of Pine Point would be on the order of 0.5 to 5.0 million years. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Pinus patula is the single most important commercial plantation forest tree species in South Africa. It accounts for 52% approximately (700,000 ha) of total commercial plantation area in the country and is utilised for saw logs and pulp and paper production. P. patula is a tropical pine species indigenous to Mexico. Excellent ex situ conservation and range-wide provenance trials have been established for P. patula in South Africa and South America. These highly organised trials provide the opportunity to perform association genetic studies with the long term aim to identify trait linked markers for future molecular improvement of P. patula. In this study, the first gene-based assessment of allelic diversity in P. patula was performed. This pilot study focused on two cellulose biosynthetic genes as representatives of wood formation genes and assayed molecular evolution parameters such as nucleotide diversity, allelic diversity and linkage disequilibrium (LD) in a species-wide reference population of P. patula. Two novel cellulose synthase (CesA) genes were isolated and characterised in P. patula. One of these genes, PpCesA1, is putatively involved in the biosynthesis of secondary cell walls of tissues such as xylem (wood), while the other, PpCesA2 is proposed to be associated with primary cell wall formation in rapidly growing tissue types. The genomic DNA copies of PpCesA1 and PpCesA2 were 6025 bp and 6365 bp in length, respectively. The corresponding cDNA sequences encoded 1083 and 1058 amino acids, respectively, and differed considerably from each other (73% amino acid identity). Both amino acid sequences contained the key domains and motifs characteristic of functional CESA proteins isolated in other higher plants. Phylogenetic analysis revealed that PpCesA1 was most similar (99%) to its putative ortholog in Pinus taeda, PtCesA3, and PpCesA2 was highly similar to a putative ortholog in Pinus radiata, PrCesA2 (99% identity). This phylogenetic analysis supported previous findings that the divergence between the primary and secondary cell wall associated CESA proteins occurred before the divergence of angiosperms and gymnosperms approximately 300 million years ago. A fragment of a putative paralogous gene copy of PpCesA1, named PpCesA1-B was also isolated. The PpCesA1-B gene fragment was found to differ from PpCesA1 by 22 nucleotide polymorphisms and its non-allelic (paralogous) status was confirmed by segregation analysis in P. patula. In order to gain an understanding of molecular genetic variation that might affect wood formation in P. patula, we sequenced multiple allelic variants of PpCesA1, PpCesA1-B and PpCesA2, which we sampled from a species-wide reference population of P. patula. The average levels of nucleotide diversity were found to be low for all three genes (π ≈ 0.0015), which may be a property of functional members of the CesA gene family. As a result of the low nucleotide diversity, only small numbers of pair-wise informative sites were available for LD analysis and the decay in LD could only be studied in PpCesA2 where it was found to decay very rapidly (within 200 bp). Tests of neutrality suggested that the exon sequences of PpCesA1 and PpCesA2 were under significant positive (adaptive) selection. Comparison of levels of nucleotide diversity and selection in different parts of the two genes indicated that the highest levels of adaptive selection occurred in areas where amino acid substitutions could alter protein structure or function. This study provides valuable insights for designing future allele discovery efforts in P. patula with the ultimate goal of developing gene-based markers for the molecular improvement of wood formation in this tree species. / Dissertation (MSc (Genetics))--University of Pretoria, 2009. / Genetics / unrestricted

The master thesis deals with the determination of the chlorophyll content in birch foliage (Betula pendula Roth) and Scots pine using hyperspectral data. The first part of the thesis concentrates on the literature search dealing with the methods of chlorophyll content in the foliage of selected plant species. In the practical part the emphasis is on the study of spectral reflectance curves and finding their relation to the chlorophyll content from the laboratory determination. Images taken with the hyperspectral sensor HyMap and spectral reflectance curves obtained with the ground ASD FieldSpec 3 spectrometer were available. Using the derived regression model chlorophyll maps were created for Scots pine for three selected locations in the Sokolov coal basin area.

Loblolly pine (Pinus taeda) and coppiced sweetgum (Liquidambar styraciflua) seedlings were grown in competition with a native weed community using soil and seed bank collected near Appomattox, Virginia. Seedlings and weeds were exposed to CO₂ (ambient and elevated) and water (water stressed and well watered) treatments for approximately one growing season in closed top chambers. Weed growth had an effect on tree growth, but the amount of variation in tree biomass explained by weed biomass was very low. It appears that the tree seedlings benefited more from available resources than the herbaceous weeds. The influence of competition with loblolly pine and elevated CO₂ did not have an influence on total weed biomass; however, it did favor C3 weed community development regardless of water availability. This suggests that weed community composition may shift toward C₃ plants in a future elevated CO₂ atmosphere. Loblolly pine height, diameter, needle, shoot and total biomass were significantly greater in the well watered treatment than the water stressed treatment. Pine root, needle, shoot and total biomass were significantly greater in the elevated treatment than the ambient treatment. While not significant, root biomass of water stressed pine seedlings was 63% greater in the elevated CO₂ treatment than the ambient treatment. There was a significant water and CO₂ interaction for pine root:shoot ratio. Under elevated CO₂, root:shoot ratio was significantly greater in the water stressed treatment than the well watered treatment. In contrast, root:shoot ratio in the ambient treatment was nearly identical under both water treatments. These results indicate that loblolly pine will respond favorably in an elevated CO₂ atmosphere, even under dry conditions. The coppiced sweetgum seedlings responded favorably to well watered conditions with significant increases in leaf area, specific leaf area, leaf, shoot and total biomass compared to water stressed conditions. Leaf, root, shoot+stump and total biomass of sweetgum significantly increased and specific leaf area decreased under elevated CO₂ compared to ambient CO₂, but differences were smaller than previous findings. This indicates that coppicing may dampen the growth response to elevated CO₂, at least in the initial growth stage after coppicing. / Master of Science

With increasing encroachment on natural communities by anthropogenic activity, it is important to understand the functions of natural ecosystems in an effort to conserve natural areas. A first-hand study of the population dynamics of South Florida Slash Pine (P. elliottii Engelm. var. densa) following a fire event provided insight to its recovery and dispersal following a fire. A natural fire (lightning-induced) occurred in the spring of 2000 at the T. Mabry Carlton, Jr. Reserve, Sarasota County, providing an opportunity to study aspects of slash pine in relation to fire. One objective of my research was to look at dispersal/recruitment conditions and slash pine dynamics in relation to fire. I looked at the varying degrees of tree mortality due to fire at different stands of slash pines. I also looked at the stands in terms of stand composition and spatial arrangement of surviving adults. Finally, I studied how variable seedling establishment and survival was between stands. Few inferences could be drawn between fire and these individual analyses; however, all analyses revealed that at the scale of this study, pine flatwoods are patchy. I also looked at the dispersal of slash pines following a fire event. I modeled my research after Ribbens et al. (1994) and Clark et al. (1998), who took a phenomenological approach to dispersal modeling. This approach involved using distances between adults and seeds/seedlings and fecundity of adults to create dispersal models based on maximum likelihood estimates (MLE). I found that, while I could predict a model within acceptable parameters for most of the stands, more data was needed to predict models that better fit the data. This finding, along with the fact that I recovered no seed data for analysis, suggests factors are contributing to dispersal and recruitment (e.g. cone-crop) that need to be accounted for in the future.