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Age effects on seed productivity in northern black spruce forests (Picea mariana)

dc.contributor.advisorJohnstone, Jillen_US
dc.contributor.committeeMemberWilson, Kenen_US
dc.contributor.committeeMemberJohnston, Marken_US
dc.contributor.committeeMemberMcLoughlin, Philipen_US
dc.contributor.committeeMemberLamb, Ericen_US
dc.creatorViglas, Jayme Nicoleen_US
dc.date.accessioned2011-05-12T11:55:48Zen_US
dc.date.accessioned2013-01-04T04:30:45Z
dc.date.available2012-05-30T08:00:00Zen_US
dc.date.available2013-01-04T04:30:45Z
dc.date.created2011-04en_US
dc.date.issued2011-04en_US
dc.date.submittedApril 2011en_US
dc.description.abstractClimate change is predicted to increase rates of fire activity in boreal forests. A shortened fire return interval may result in different outcomes of community structure in the northern boreal forest, since the age of a forest influences seed production and potential post-fire regeneration. With two closely timed fires, dominant boreal conifers such as black spruce (Picea mariana) may be vulnerable to regeneration failures after fire because of the long time required to reach reproductive maturity. I report on the relationship between stand age and seed productivity of black spruce in northern Yukon Territory and central Alaska. I used fire history maps to select sites of various stand ages, including stand ages that would occur in a short fire return interval (less than 80 years) versus longer fire intervals (up to 200 years). At each site, I measured stand density and basal area using the point-center-quarter method. Ten black spruce trees were randomly selected for cone surveys and age analysis. I also selected a subset of five trees for detailed analyses of cone and seed production within yearly cohorts. The results of this study illustrate the strong relationships between stand age and stand basal area with cone and seed production of northern black spruce. The resulting equations can be used to predict the seed capacity and regeneration potential of black spruce stands with known stand basal area or stand age. I estimate, along with the number of seeds required to produce a two year old black spruce seedling on high quality seedbeds, stands burned at an age less than 50 years will likely have reduced black spruce post-fire density. On low quality seedbeds, black spruce forests are more vulnerable to regeneration failures and fire cycles less than 150 years are likely to result in reduced recruitment. Under a shortened fire return interval these northern black spruce forests are likely to have reduced post-fire density.en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-05122011-115548en_US
dc.language.isoen_USen_US
dc.subjectblack spruceen_US
dc.subjectclimate changeen_US
dc.subjectfire return intervalen_US
dc.subjectstand ageen_US
dc.subjectseeden_US
dc.subjectboreal foresten_US
dc.subjectconeen_US
dc.titleAge effects on seed productivity in northern black spruce forests (Picea mariana)en_US
dc.type.genreThesisen_US
dc.type.materialtexten_US
thesis.degree.departmentBiologyen_US
thesis.degree.disciplineBiologyen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M.Sc.)en_US

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