article id 564,
                            category
                        Research article
                    
        
                                    
                                    
                            Abstract |
                        
                                    View details
                             |
                            
Full text in PDF |
                        
Author Info
            
                            Early establishment of white spruce (Picea glauca) in mixedwood boreal  forest stands following fire was examined at several times-since-fire  (1-, 2-, 4-, 6-, 14-years). Abiotic and biotic conditions in the stands  were assessed at two scales, tree plot (5 m x 5 m) and microsite (1 m x 1  m), along with presence, density and height of white spruce seedlings.  Germination and survival of seed sown 1- and 4-years post fire were  quantified. Survival and growth of nursery-grown seedlings, and  mycorrhizal colonization, survival and growth of sterile seedlings,  planted 1-year post-fire were assessed. At the tree plot scale, presence  of white spruce seedlings 1-year post-fire could be reliably predicted  by organic layer depth and distance to and strength of seed source. In  contrast, none of the biotic or abiotic factors measured was strongly  correlated with occurrence or density of white spruce seedlings 6- and  14- years post-fire. At the microsite scale, seedling recruitment  immediately post-fire was limited to a distinct subset of available  microsites (greater % cover of downed wood and moss, lower % cover of  litter and herbaceous vegetation). Likewise, seedling occurrence in  older burns was associated with distinct microsite conditions; although  this was more likely an effect of white spruce presence, rather than the  cause. Less than 3% of seed sown 1 yr post-fire survived to become 1yr  old germinants, survival was 41% over the next three years. Availability  of suitable regeneration microsites declines rapidly with  time-since-fire; less than 0.3% of seed sown 4 yrs post-fire survived  one year. High rates of mycorrhizal colonization were found on white  spruce seedlings planted 1-year post-fire, including early and late  stage fungal species. Microsite characteristics were only weakly  correlated with mycorrhizal fungal communities. We propose that  immediate post-fire recruitment of white spruce is a key process in  mixedwood boreal succession.
                        
                
                                            - 
                            Purdy,
                            Dept. of Renewable Resources, University of Alberta, Edmonton, AB, Canada T6G 2E3
                                                        E-mail:
                                                            bgp@nn.ca
                                                                                
 
                                            - 
                            Macdonald,
                            Dept. of Renewable Resources, University of Alberta, Edmonton, AB, Canada T6G 2E3
                                                        E-mail:
                                                            ellen.macdonald@ualberta.ca
                                                                                        
                                                     
                                            - 
                            Dale,
                            Dale, Dept. of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9
                                                        E-mail:
                                                            mrtd@nn.ca