Cynthia Patry and Ilona Lehtokoski sample vegetation near La Tuque, Quebec.
Data will be used to compare the understory vegetation of forests under management in Finland, Quebec and New Brunswick with that of natural forests. To do this Cynthia, a PhD student with Christian Messier, will use the functional traits approach. Photo by Mélanie Arsenault. Picture by :©Mélanie Arsenault.
Simulation result using SORTIE software, by Marilou Beaudet
The concept of neighbourhood is often used in modelling ecological phenomena. Using this concept, a phenomenon observed at a point in space can be described by the surrounding conditions. In being spatially explicit (all elements are localized in space), the SORTIE model maximizes information on the spatial distribution of trees to simulate the fundamental processes that govern forest dynamics (dispersal and establishment of seeds, survival and growth, light competition). The model also simulates spatially explicit disturbances, notably forest harvesting. Thus, in this example, we simulate the effect of the spatial arrangement of skid trails in a selection cut. The location of skid trails (in green) has a significant impact on the spatial distribution of regeneration. For example, species such as yellow birch regenerate preferentially on certain soil substrates (e.g. mineral soil). Picture by :©Marilou Beaudet.
Hardwood stand subjected to selection cutting, by Alain Paquette
Selection cutting is the most widely used silvicultural treatment in tolerant hardwood forests in southern Quebec. Several researchers are interested in the influence of this type of cut on the structure and composition of these forests. To assess the effects that other silvicultral treatments would have, Marilou Beaudet , Virginie-Arielle Angers and Christian Messier use the SORTIE model. They hope to identify strategies to retain certain structural attributes typical of old-growth hardwood forests. Picture by :©Alain Paquette.
Modified photo of a yellow birch stand used to measure structural complexity, par Isabelle Witté
Digital images are composed of pixels that can be used to calculate indicators such as the Mean Information Gain (MIG), which allow us to differentiate populations whose history of disturbances, natural or man-made, are different. This image, the result of a photo taken in a yellow birch stand partially cut from the Haute-Mauricie, allowed Isabelle Witté, a PhD student under the supervision of Christian Messier and Daniel Kneeshaw, to measure the complexity of the vertical structure and distribution of vegetation at different heights. Picture by: ©Isabelle Witté.
Vegetation mapping in the region of the Adirondacks, by Charles D. Canham
Geographic Information Systems (GIS) and spatial analysis are essential tools in the study of the complexity and biogeochemical cycles of forests. In this example, we considered the effect of the spatial arrangement of forest stands on the concentration of organic carbon in lakes of the Adirondacks (Canham et al. 2004). We found that older stands dominated by conifers have an impact of greater importance on the lakes. This example illustrates the complexity of nutrient cycles that occur in meta-ecosystems (Gravel et al. 2010). Meta-ecosystems are ecosystems that are connected by flows of matter, nutrients and organisms. The dynamic is very complex because of the many exchanges that occur in space and between the different components of the ecosystems (Massol et al. 2011). Picture by: ©Charles D. Canham.
Delaunay triangulation in a yellow birch plantation, by Isabelle Witté
Graphical representation of a stand of yellow birch in the Haute-Mauricie region (Quebec), as part of a study by Isabelle Witté, a PhD student under the supervision of Christian Messier and Daniel Kneeshaw. This is the result of a Delaunay triangulation, where the trees are shown (points), the distance to their nearest neighbours (solid lines) and the space they occupy (dotted line). In the study of complexity, this tool in particular is used to understand the interaction network between individuals, and for calculating indicators of spatial and structural heterogeneity of stands. Picture by :©Isabelle Witté.
Representation of different gaps of a mixed stand, by Isabelle Witté
PhD student under the supervision of Christian Messier and Daniel Kneeshaw, Isabelle Witté mapped the canopy gaps present in forest stands that have undergone various types of natural and anthropogenic disturbances in the Haute-Mauricie region (Quebec). This work allowed her to measure the proportion of opening in the canopy, the characteristics of gaps (shape, size) and their spatial distribution (dispersed, aggregated, etc…). This information allowed her to quantify the heterogeneity of the canopy structure in response to various disturbances (logging, windthrow, grazing by deer). Picture by: ©Isabelle Witté.
Hemispherical photograph of a red maple and balsam fir stand, by Alain Paquette
While it has long been accepted that monocultures provide better yields of timber than mixed stands, Alain Paquette, postdoctoral fellow at UQAM and Christian Messier found the opposite. The physiology and functional traits of each species being different, they use resources differently and optimize them accordingly. This study was listed in the top 10 discoveries of the year of the Quebec Science Magazine. The researchers are continuing their investigation with an experiment located at MacDonald College (McGill), Sainte-Anne-De-Bellevue (Quebec). This site is part of the IDENT network, which includes experimental sites in several countries in North America and Europe.
FCM 2012 Summer School Participants
Held from May 28th to June 1st at the Laurentian Biology Station, this summer school brought together a group of 56 people! Introduction to complex systems, recent advances in ecology and forest ecology were on the schedule, as well as more advanced lectures on spatial analysis and landscape modelling. To see the whole photo gallery as well as the schedule, visit the Summer school section. Picture by: ©Éric Valiquette.