Natural regeneration is used to restock trembling aspen (Populus tremuloides Michx.) cutblocks and factors controlling regeneration are areas of interest and concern to the forest industry. Harvest operations in Manitoba require that coarse woody debris, or slash, be left and distributed in cutblocks. The objective of this study was to investigate the effects of slash loading on soil temperatures and aspen regeneration, and implications for harvest operations in the Duck Mountain area. Early sucker growth, initiation, and soil temperatures were surveyed in six winter and six summer cutblocks under different levels of slash loadings. A growth chamber study, using field temperature data as a guideline, examined the effects of diurnal temperature variation on sucker initiation and production. In winter and summer cutblocks, mean depths to sucker initiation from the parent root were 4.6 + 2.4 cm and 3.4 + 2.1 cm, respectively, and initiation of suckers occurred mainly from parental roots located in the LFH layer. Daily mean soil temperatures during the growing season were significantly lower under higher levels of slash (difference of 3.6 oC during May). Higher amounts of slash also significantly shortened the length of the growing season (89 fewer days above 0 oC in one season) and decreased the number of suckers produced (150 000 ha1 decreased to 14 000 ha-1), sucker volume (decreased by 256 cm3m-2) and leaf area index (decreased by 0.9). There was no difference in sucker production between any diurnal temperature treatments in the growth chamber study. Shallow depth to sucker initiation has important implications for harvest operations using heavy machinery especially those occurring during the summer season. Moderate levels of slash in summer cutblocks, and heavy levels of slash in winter cutblocks limit sucker growth. Although slash decreases diurnal temperature amplitudes, this may not be the reason for the decrease in sucker production associated with increased levels of slash. Both soil temperature and early sucker growth are strongly affected by slash loading; by monitoring harvest operations and the distribution of slash within cutblocks, the negative effect of heavy machine traffic and heavy piles of slash can be reduced and ensure successful forest regeneration.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-03302005-100509 |
| Date | 11 April 2005 |
| Creators | Lieffers-Pritchard, Sarah Marie |
| Contributors | Van Rees, Ken C. J., Thorpe, Jeff, Knight, J. Diane, Johnston, Mark |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-03302005-100509/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto 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 University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, 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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