The purpose of the study was to investigate how the above-ground tree biomass components
(stem, branches, and foliage) and the ratios between these biomass components change with age,
site quality, initial spacing, and total stand volume. The species studied was coastal Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco). To examine stands of various stand characteristics,
virtual stands were generated from the Tree and Stand Simulator (TASS), a provincial growth
and yield model. The stands ranged in site index (height at 50 years breast-height age) from 20
to 40 m at 5 m site index intervals, initial plant spacing of 1.0 to 5.0 m at 0.5 m spacing intervals,
and from 10 to 200 years at 10-year intervals, for a total combination of 900 stands. Published
tree biomass equations from the Pacific Northwest were applied to these generated stands to
produce a stand-level biomass estimate for each stand. Stand-level biomass regressions were
also developed from the modelled stands. Over the modelled 200-year horizon, stand-level stem
and branch biomass is expected to increase, whereas foliage biomass is predicted to increase then
plateau or peak then decline. At a given age, predicted biomass was higher for denser stands and
richer sites. However, for a given total stand volume and initial spacing, predicted biomass was
slightly higher for poor sites. At a given volume, more dense stands also had lower predicted
stem and branch biomass, and higher predicted foliage biomass. In terms of the proportion ratios
among components of biomass, the proportion of foliage and branch biomass in total
aboveground tree biomass over time was predicted to decrease then plateau, whereas the
proportion of stem biomass was predicted to increase then plateau. For a given stand volume,
denser stands had proportionally less predicted above-ground tree biomass in stem biomass and
proportionally more in foliage and branch biomass. From the stand-level biomass regression
analysis, it was found that in addition to total stand volume, other stand variables, especially
basal area, improved the predictive abilities of the stand-level biomass equations.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/13042 |
| Date | 11 1900 |
| Creators | Wong, Ann Yone |
| 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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