Thesis (Ph. D.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references (leaves 133-143). Also available on the World Wide Web.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 148-156). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 148-156). Also available on the Internet.

Intercropping is defined as a management approach where two or more crops are planted on the same forested site simultaneously. The advantages of applying this concept on young pine plantations in the south can increase site utilization, reduce weed competition, provide annual or semi-annual revenues early in the timber rotation, ameliorate the soil, and diversify production. Research was initiated to determine the feasibility of using various plants as intercrops on pine plantations in Virginia and North Carolina. Regional crops were categorized into four groups based on management intensity, end use, and crop value. These crop groups included: 1. Field Crops: Corn, Sorghum, Cotton, Small Grains, 2. High Value Crops: Tobacco, Peanuts, Snap Beans, Tomatoes, Cucurbits, 3. Forage Crops: Grasses and Legumes, 4. Biomass Crops: sycamore, Sweet Gum, European Black Alder, Cottonwood. The ecological and management characteristics of these crops were examined to determine their compatibility with pine plantation management. In every case, three significant constraints were noted; intercropping on plantations reduced the number of trees carried to maturity by 50 to 60 percent; intercrop production was highly sensitive to row spacings and required seedling row widths of 4 to 8 m; and great emphasis was placed on site preparation, with per hectare costs increasing by approximately 250 percent. Investment analysis of several hypothetical intercrop scenarios suggested that forest intercropping can be financially rewarding under a variety of crop combinations. Intensively managed intercrops provided substantially greater returns than a conventional plantation investment. A field crop-pine combination was the most attractive intercrop scenario for large scale plantation intercropping, due to consistently high profit margins, low total investment costs, and fewer marketing constraints. Vegetable-pine combinations were typically high cost alternatives which generated equally attractive net revenues. However, the high costs and intensive management requirements restricted the introduction of vegetable crops to small plantation acreages where adequate attention would be available. Forage and biomass intercrops were relatively inferior investments relative to the more intensive vegetable and field crop combinations. Wide intercrop spacings dramatically increased average DBH of simulated pine stands configured for intercrop management, resulting in greater sawlog and veneer size log production and lower yields of pulpwood sized timber. Although the difference in net revenue from the pine component marginally favored the intercropped plantation, the difference in product mix suggests that companies or individuals interested in diverse timber products may wish to consider plantation intercropping as one means of diversifying plantation timber yields. Further study is suggested to quantify the biological effects of forest intercropping on component crops, with emphasis on intensively managed crops. Practical application is restricted to fertile, highly productive plantation sites capable of supporting both agricultural and forest crops. / Ph. D.

Eucalypts are a major forest resource globally and the area of eucalypt plantations for pulp and paper production is expanding rapidly in Australia. Consequently, there is an increasing need to breed eucalypts with improved wood properties. Since many high value wood traits are under strong genetic control, identification of DNA markers linked to these traits will have application in breeding programs. In recent years there has been a shift in marker strategy away from QTL mapping in pedigrees to association studies in unrelated populations. In the latter approach, single nucleotide polymorphisms (SNPs) in candidate genes are screened to identify SNPs that significantly associate with wood traits. Significant SNPs could be used for marker-assisted selection (MAS) in breeding programs. The objectives of this study were to identify candidate genes that may influence pulp yield in eucalypts and to identify SNP variants in those genes that associate with superior wood and pulp traits. / Approximately 300 trees from a full-sib Eucalyptus nitens progeny derived from a wide intra specific cross were used for gene discovery. DNA microarrays containing ~5800 young xylem of cDNAs Eucalyptus grandis were screened with probes synthesised from RNA isolated from trees with either high or low pulp yield. Forty-six transcripts were differentially regulated, of which 27 were more abundant in high pulp trees and 19 were more abundant in low pulp trees. All differentially expressed cDNAs were partially sequenced and searched against existing gene databases. Six genes were selected as putative pulp yield candidate genes based on their significant similarity to genes with known function and were named EgrCesA3 (cellulose synthase), EgrNAM1 (NAM family protein), EgrXET (xyloglucan endotransglycosylase), EgrGalk (galactokinase), EgrHB1 (class III homeodomain leucine zipper protein) and EgrZnf1 (C3HC4 type zinc finger protein). / Real-Time PCR was carried out on selected genes to confirm the accuracy of the microarray results. Full length cDNAs were obtained for EgrCesA3, EgrHB1 and EgrZnf1 and the candidate genes were partially characterised. An additional candidate gene, the novel gene EgrPAAPA, was selected based on previous research due to its high expression in the cambium and its expression in eucalypt branches. EgrPAAPA was cloned by screening an E. grandis cDNA library and fully sequenced. The full length EgrPAAPA encodes a short 172 amino acid protein rich in alanine, glutamic acid and proline residues. The EgrPAAPA protein appears to be a hydroxyproline-rich glycoprotein (HRGP) and the repetitive ‘PAAPA’ motif suggests that it might play a structural role in cell wall development. Southern blot analysis revealed that E. grandis has a single copy of the EgrPAAPA gene and northern blot analysis revealed that EgrPAAPA is most strongly expressed in xylem tissues. / Allelic variation in EnCesA3, EnNAM1, EnPAAPA and EnHB1 was examined by sequencing each gene in 16 to 24 unrelated E. nitens individuals. SNPs were identified by sequence analysis and patterns of nucleotide diversity, linkage disequilibrium and the selection of suitable polymorphisms were estimated. A moderate level of nucleotide diversity (θw = 0.0056 and π = 0.0039) was observed and linkage disequilibrium was generally low, extending only a few hundred base pairs in each gene. Negative selection has been operating in EnHB1. Selected TagSNPs from EnNAM1, EnHB1 and EnPAAPA were genotyped across 300 unrelated E. nitens trees which had been phenotyped for six wood quality traits including pulp yield, cellulose, lignin, Klason lignin, microfibril angle (MFA) and density. Five highly significant genetic associations (p<0.01) were detected between several SNPs in EnHB1 and all wood quality traits except density. A significant association was also found between EnPAAPA and MFA (p<0.05). No significant associations were found with any of the EnNAM1 SNPs. The strong genetic associations between SNPs in EnHB1 and a range of wood traits is consistent with this gene’s known role as a transcription factor controlling vascular development. Validation of these associations in different populations will be necessary in order to confirm these results. Alternatively, QTL mapping can be performed in order to confirm whether QTL for wood property traits can be detected at the EnHB1 and EnPAAPA loci.

Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 182-201.

The minimum number of tree heights that are necessary, with a probability of 0.95, to obtain a merchantable plot volume estimate of loblolly pine within ± 3, 5, and 10% of the volume observed if all plot trees had been measured for height were determined for all combinations of volume estimation techniques and sample designs examined in this study. The volume estimation techniques examined in this study were: 1) a volume equation using measured tree diameters and either measured heights or height estimates obtained from a plot height-diameter relationship, 2) a volume equation using strata average diameter and average height, and\ 3) a strata volume/basal area ratio estimator. The examined sampling designs were: 1) a simple random sample, 2) a stratified random sample, 3) a stratified systematic sample, and 4) a purposive sample. Both combined and separate stratified estimators were used for volume estimation techniques 2 and 3 when a stratified sample design was used. Of all the possible combinations of volume estimation techniques and sample designs, two combinations, volume estimation technique 1 and a stratified random sample, and volume estimation technique 1 and a purposive sample, are the only combinations that have sample sizes of no more than 30 trees for all three accuracy levels and require the smallest or nearly the smallest number of sample tree heights at these accuracy levels. / Master of Science

The superior growth of Grand fir (Abies grandis) compared to Douglas-fir (Pseudostuga menziesii) on suitable coastal sites has previously been recognized on the basis of qualitative observations with little empirical evidence. For example, D.E. McMullan (1977, pers. comm.) reported 18% higher volume for a grand fir tree of the same height and age as a 108-year old Douglas-fir plus tree (No. 622) This study was undertaken by Bernardy (1988) to examine possible differences in the growth of grand fir and Douglas-fir growing in a mixed 40-year-old plantation of unknown origin. Trends in height, diameter and annual volume increment between the two species over time were examined. Expected growth performance (i.e. volume and form) of each species was inferred from trends identified at time of sampling.

Reforestation is being considered as a mitigation option to help combat the climate change predicted to result from atmospheric carbon dioxide pollution. Forestry-based carbon storage projects are being introduced in many tropical countries, and assessment of species-specific carbon storage potentials is made difficult by a lack of species-level information. This study focuses on teak (Tectona grandis), to measure many of the characteristics affecting the carbon storage potential both of the trees themselves and of the plantations they are in. Root-to-shoot ratio, above- and belowground biomass, as well as tissue carbon content were measured in 20-year-old teak trees in Panamanian plantations. A regression relating diameter at breast height (DBH) to total tree carbon storage for trees of various sizes was developed. To scale up to the plantation level, this regression was used to estimate the carbon storage of the trees of four plantations. Litter, undergrowth, and soil were studied to estimate carbon storage in these compartments. These estimates were collated to form a global estimate of carbon storage in Panamanian harvest age teak plantations. Various methods of calculation of carbon storage in short-rotation plantations are discussed. This work will allow greater precision in the assessment of carbon storage in individual plantations.

Thesis (M. For. Sc.)--University of Canterbury, 2006. / Title from PDF title page (viewed on Feb. 9, 2008). Includes bibliographical references (leaves 170-175). Also issued in print.