Seeding survival has been a continuing problem since the start of the commercial pine plantation in 1950s. The first-year survival of bare-root loblolly pine seedlings at intensively prepared sites in Louisiana has reached a survival plateau of 75 to 85 % with an average of almost 80 %. The major hypothesis of this research was that the survival plateau is a function of the interaction between the frequency distribution of seedling quality and the frequency distribution of microsite quality. This study examined bare-root seedlings and microsite variation, and analyzed the possible options to increase the first-year seedling survival.
The study was approached with simulation and field studies. In simulation study, twenty hypothetical seedling and microsite quality distributions were paired in a manner that simulated 400 plantings. In field study, caliper, stem height, shoot-root ratio, leaf area, and xylem pressure potential were measured for a bale of nursery seedlings and the quality distribution was computed from the seedling volume. Similarly, the microsite variables soil penetration, bed height, moisture content, total mineral nitrogen, and texture were measured and the quality distribution of 8 Weyerhaeuser planting sites was generated from the height increment of associated seedlings. The distributions were combined to predict the first year survival from the assumptions about proportional survival for each pairing.
The simulation results provided initial support to the hypothesis that consistent survival results from random pairing of initial seedling and site quality distributions. The average caliper was 4.22 mm for the seedling sample obtained from a local nursery. The sample contained at least 31 % inferior quality seedlings and, the planting sites contained 21 % adverse microsites. Analysis showed that the significant proportion of inferior seedlings and adverse microsites would result in lower average survival based on assumed survival matrix. The elimination of seedlings below 5 mm caliper of the nursery stock increased the survival to 90 % at the cost of 40.9 ¢ per seedling, an increase of 37 ¢ per seedling.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-08062010-100101 |
| Date | 10 August 2010 |
| Creators | Khanal, Puskar Nath |
| Contributors | Wang, Jing, Cao, Quang V, Dean, Thomas J |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-08062010-100101/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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