I explored the importance of decaying wood to survival and growth of trees in south coastal
British Columbia, and the effect of decaying wood on the intensity of podzolization on mesic
sites.
A field pot study was carried out in both high light and low light conditions using woody and
non-woody forest floor materials. After two growing seasons, Pseudotsuga menziesii, Tsuga
heterophylla, and Abies amabilis seedlings growing in clearcuts had greater survival and growth
in the non-woody substrate; however, in the understory, the effect was much less. The
proliferation of western hemlock roots was used as an indicator of the value of decaying wood to
trees. In both greenhouse trials (using seed sown on a series of planting pots with each half filled
with either a woody substrate or a non-woody substrate), and in field sampling of woody and
non-woody substrates in mature stands, the non-woody substrate had a larger density of fine and
very fine roots compared to the woody substrates or mineral soil.
Ten litres of concentrated solutions of non-woody humus substrate and woody substrates
were leached through soil columns. Both the non-woody and woody solutions had similar mean
pH but significantly different chemical properties. The non-woody solution leachate had greater
net average output of dissolved organic C, Fe, and Mn. The mineral soil treated with the nonwoody
solution had significantly greater concentrations of total N and pyrophosphate-extractable
Fe. In the field, forest floor and soil samples were compared between pedons having large
accumulation of decaying wood and pedons with non-woody humus forms. Despite large and
significant differences in chemical properties between the two substrates, there were generally no
significant differences between the chemical properties of the soils directly under these
substrates. In most cases, the results of (3-analyses showed that the means were not
pedologically different. Additionally, 18 pairs of zero tension plate lysimeters were installed
under the two substrates. The lysimeter solutions showed no significant differences.
I concluded that coarse woody debris appears not to have either a positive effect of increased
productivity of trees or a negative effect of increased intensity of podzolization.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/11350 |
| Date | 11 1900 |
| Creators | Kayahara, Gordon John |
| 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 | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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