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Investigation into the productivity of fire-origin lodgepole pine and lodgepole pine-black spruce stands

University of British Columbia

The purpose of this study was to develop a better understanding of the growth differences between unmanaged, fire-origin, even-aged lodgepole pine {Pinus contorts var. latifolia Dougl. ex Loud) and lodgepole pine-black spruce (P/'cea mariana (Mill.) B.S.P.) stands. Both species commonly grow together on "d" (Labrador tea-mesic) ecosites of the Upper Foothills subregion of Alberta. During the summer of 2000, 27 study stands were selected to assess growth, structure and productivity of pine and pine and pine-spruce stands. These stands were stratified into (i) two stand types: pine and pine-spruce; and (ii) four age classes: (1) 50 - 60, (2) 60 - 80, (3) 90 - 100, and (4) 100 - 120 years at breast height. Vegetation, soil, and stand data were collected and analyzed to determine: (a) site quality, (b) site index, (c) stand structure (diameter, height, and crown height frequency distributions), (d) height and basal area growth, and (e) stand volume. The vegetation and soil analyses confirmed the initial field assessment of fresh, nitrogen-poor sites. The variation in pine site index across age classes varied between 12.3 m and 13.9 m and was not significantly different. Similarly, there was no difference in the mean pine site indices between pine stands (13.5 m) and pine-spruce stands (12.6 m). It was concluded that the sampled plots were ecologically equivalent and were suitable for the productivity comparison of pine vs. pine-spruce stands. Growth of pine in height and diameter was not impeded when it grew with spruce. There was no significant difference between the mean dimensions of pine trees (dbh, height, and height to live crown) in pine vs. pine-spruce stands. The relatively small differences in stand characteristics in both species between age class 2 and 3 stands were attributed to density-dependent mortality and the progressive ingress of spruce into the canopy. Pine-spruce stands were consistently two-storied across age classes with pine in the upper canopy stratum.

Thesis/Dissertation

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2009-08-05

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http://hdl.handle.net/2429/11768

Forestry

University of British Columbia

UBCV

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