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NOTE TO USERS This reproduction is the best copy available. Population Dynamics of Interior Douglas-fir (Pseudotsuga menziesii var. ghuca) in Canada's Four Mountah Parks by Rod A. Lastra A thesis presented to the University of Manitoba in partial fuifiilment of the requirements for the degree Master of Science in the Faculty of Graduate Studies Department of Botany University of Manitoba Winnipeg, Manitoba, Canada R3T 2N2 O Rod Lastra 2001 National Library Bibliiuenationale du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 385, rue W~n~ OttawaON KlAOW OltawaON KlAW Canada Canada The author has granteci a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant a la National Librayy of Canada to Bibliothèque nationale du Canada de reproduce, loan, distriiute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic fomats. la forme de rnicrofiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts &om it Ni la thèse ni des extraits substantiels may be pruited or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. THE UNIVERSITY OF MANITOBA FACULTY OF GRADUATE STüDIES ***** COPYRIGEï PERMISSION POPULATION DYNAMICS OF INTERIOR DOUGLAS-FIR (PSEUDOTSUGAiMEN2EW VAR. GLAUCA) tN CANADA'S FOUR MOUNTAIN PARKS ROD A. LASTRA A Thesis/Practicum submitteâ to the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment of the requirement of the degree of MASTER OF SCIENCE ROD A. LASTRA O 2001 Permission has been granted to the Libxary of the University of Manitoba to lend or seIl copies of this thesis/practicum, to the National Library of Canada to microfilm this thesis and to lead or sel1 copies of the film, and to University Microfilms Inc. to publish an abstrrrct of this thesis/practicum. This reproduction or copy of this thesis bas ken made available by authority of the copyright owner solely for the purpose of private study and iiescrirch, and may on@ be reproduced and copied as permitted by copyright iaws or with express written authorization fmm the copyright owner. Pseudotsuga menziesii var. glauca Interior Douglas-fir (Pseudotsuga menziesii var. glauca) is endemic to western north America, reaching its eastern distributionai Mt in the Alberta Rockies- Douglas-fr is a long- Lved species (>Smyears) that is characterized by its relatively large stature and thick, furrowed outer bark, Interior Douglas-fir forests are considered one of the few montane comrnunities in the Rocky Mountains that are able to attain 'old-growth status'. Within this region, scattered stands occur on south-facing montane slopes, but relict individuals trees may also occur in cooter-wetter forests of the montane and lower subalpine ecoregions. This study was prompted by growing concerns that past and current land-use practices within the Four Mountain Parks (Banff, Jasper, Kootenay and Yoho National Park) may be detrimental to the long-tenn ecological integrity of 'old-growth' Douglas-Fi stands. Two hundred and twenty plots were enumerated within Banff, Jasper, Yoho and Kootenay National Park to assess the status of these forests. Stands were characterized by estimating percent cover of al1 vascular and nonvascular plants, In addition, tree size and age data were obtained, and environmental information collected, fkom each plot- Species abundances were used to classïfy the data into three stand-types (I, II and III) and seven sub-types: Ia = very xenc (n = 34); Ib = xeric (n = 61); Ha = subxeric (n = 32); Ilb = submesic (n =30); iIc = mesic (n =18); ma = subhygric (n =31) and ïIIb = hygric (n =14), In addition, statistical analyses were performed to determine relationships between plots, species, and environmental variables. Stands were found to be distributed along a light- moisture gradient. Soi1 texture, soil nutcients, slope/aspect, and incident solar radiation, and fire history are strong determinants of stand structure and floristic composition. The growth response of Douglas-fir saplings was examined across each stand-type. Growth of advance regeneration was limited by low soil moisture and high daily temperatures within dry open-canopied forests (stand-type 9- Low-light levels and insufflent seedbed conditions in hygnc stands (stand-type IiI) decrease the mean growth rate of seedlings, Spatially heterogeneous canopy conditions created areas of differential growth within mesic stands (stand-type 11)- Radial growth was favoured under canopy gaps (IIb & IIc) and underneath canopy cover in the dner sub-variant @a). Cornpetitive interaction restricted the growth of Douglas-fir to more marginal growing conditions. A regeneration of Douglas-fir was shown to be dependent on both available understory light, soil moisture, and seed source proximity. Probable successional vectors were created for each stand-type using static size class ordination, under the assumption that species composition/abundance in the subcanopy and regeneration layers are indicative of the future canopy composition. In the absense of fire, DougIas-frr forms self-perpetuating stands in xeric open-canopied forests and is replaced by white spruce in more hygric growing conditions. Management of Lnterior Douglas-fir forests in the Four Mountain Parks should be contingent on an understanding of the 'natural States and processes' that have shaped these communities for the last 8,000 yem as well as the inherent variability which exist in these forests. Given the changes in climatic condition over the last 1,000 years it seems erroneous to restore these forests to some arbitrary point in time. Instead, management considerations should attempt to recognize the dynamics and resilience of natural forests communities. Consideration should be given to the effects of natural fuel pest or pathogen attacks, herbivory/granivory and episodic stoçhastic events on stand development. The synergistic interaction of these factors has historically given nse to complex spatial and temporal vegetation patterns currently evident in forest structure and composition. Natural disturbance such as these increase Iandscape heterogeneity, promoting species diversity at the stand level, and increasing genetic diversity at the population level. Funding for the project was provided by a contract through Heritage Canada, Parks Service, the Foothills Mode1 Forests, Alberta and a grant by Natural Science and Engineering Research Council of Canada (Dr. Nom Kenkel). 1 would Like to extend my gratitude to the foliowhg people at the Banff, Jasper, Kootenay and Yoho National Parks service for their genuine interest and continued' support of this project: Dave Gilbnde, Ian Pengeiiy, Rob Waker, Alan Westhaver and Darryl Zell- 1 would personally like to thank Ian for initiating this study, contributing valuable comments along the way as well as logistic support, I would also like to thank Peter Achuff and Cliff White for their feedback and helpful advice. Special thanks goes out to Heather Dempsey, Don Gome and Cathy Hourigan. 1 would like to thank my field assistants, Dan Baluta and Steve Kembel for their dedication and work ethic under trying conditions without whorn this would not have been possible. In addition 1 would also like to acknowledge Richard Caners, Jane Lastra, Shaunna Morgan Enc Saczuk, and Joachim Vos for volunteering theu time and effort in the field and David Walker for his technicdfield assistance as weU as comments. In addition, 1 would also like to thank the support staff and faculty of the Department of Botany especially to Dr, Jeanifer Shay for her suggestions and helpful references and to Dr. Isobel Waters for motivating me to go into Botany to begin with. Gratitude is extended to my committee (Dr- Rick Baydack, and Dr. Bruce Ford) for their helpful cornrnents, and suggestions- A special thanks to my advisor Dr. Nom Kenkel for his assistance, encouragement, and insights throughout my time as a grad student. Special mention goes to my fiiend Eric Saczuk - thanks for encouraging me to visit your "debris-flow sites" in Banff National Park, August 1996 (especially for footing the bill!), that trip sparked my interest to work in the Canadian Roçkies. To Richard Caners, my "extended coffee break" pal, - thanks for the great conversations on music, philosophy and ecology. Last but not least, this thesis would not have ken possible without the moral support, generosity, and encouragement of my mom and dad -- and to my best friend and wife Jane, for her unwavering support, patience, and understanding. 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