Browsing by Author "Merkle, Scott Arthur"

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    Development of a computerized seed orchard inventory-monitoring system and analysis of seed orchard productivity variables
    Merkle, Scott Arthur (Virginia Polytechnic Institute and State University, 1982)
    A computer program package for use with the southern pine seed orchard Inventory-Monitoring System (IMS) was developed and tested using 1980 and 1981 cone crop data collected from Weyerhaeuser's loblolly pine seed orchard at Magnolia, Arkansas. The Computerized IMS, written in Fortran, is accompanied by a user's guide containing data entry instructions. The IMS package includes one predictive program and two programs designed to interpret actual harvest data and make it available for the computation of predictions for future crops. The predictive program utilizes strobilus survival data from sample trees and clonal estimates for cone analysis-derived variables to compute clonal cone and seed yield predictions. Cone yield predictions calculated by the Computerized IMS for the 1980 and 1981 crops indicated that it has the potential for producing useful production estimates. Investigations of variance within the seed orchard having an impact on IMS predictions centered on clonal, age-class (within-clone), annual, orchard location and with in-crown effects on cone analysis-derived variables, cone efficiency and flowers-per-tree. Analysis of clonal variance indicated that seed potential and germination efficiency were under strong genetic control compared to the other characters. Annual clonal stability was high enough for clonal seed potential and seed efficiency to make useful regression models possible for estimating these variables without complete cone analysis. Clonal cone efficiencies displayed low annual stability, discouraging the use of stratified clones to estimate productivity, since clones could change productivity classes from year to year. Within-crown variation was not well-defined for most variables due to clone-crown sector interaction. However, cones were concentrated in the middle one-third of the crown and empty seed percentages were found to be highest in the north crown quadrant. The study indicated that clone-by-clone monitoring of seed orchard production, while the most expensive option, will produce the most reliable and useful yield predictions.
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    Development of floral primordia and prediction of flowering in white oak (Quercus alba L.)
    Merkle, Scott Arthur (Virginia Polytechnic Institute and State University, 1978)
    A two-part study was undertaken to gain a better understanding of oak floral development and flower crop variability as they relate to acorn crop variability. The first part traced the ontogeny of staminate and pistillate primordia of white oak (Quercus alba L.). It was found that staminate inflorescences are initiated in late spring and staminate flowers are structurally mature before the onset of dormancy in October. Pistillate inflorescences are not initiated until late summer, and pistillate flowers complete almost all of their development during the three weeks prior to anthesis. The second part of the study attempted to formulate predictive models for mature staminate and pistillate flower crop frequency distributions and densities by comparing the established phenology of floral differentiation with that of bud samples collected up to one month prior to flowering. It was found that the densities of staminate inflorescences (catkins), pistillate inflorescences (stalks) and total inflorescences are sufficiently predictable to make practical the use of linear models. However, because the pistillate inflorescence is so difficult to distinguish from the developing lateral bud, a large amount of error is generated in stalk counts completed one month before flowering. Also, the rapidity with which individual pistillate flowers are initiated just prior to pollination makes anticipation of their final number very difficult. The data suggests that although the year to year production of mature flower crops by a particular white oak may be consistent, it is not necessarily innate.