Following the appointment of the new Cabinet, the Forest Sector now reports to the ministère des Ressources naturelles et des Forêts, while the Wildlife and Parks Sectors report to the ministère de l'Environnement, de la Lutte aux changements climatiques, de la Faune et des Parcs. Adjustments will be made to the website over time.
Published in Canadian Journal of Soil Science 93: 567-572. doi: 10.4141/CJSS2013-046
Soil warming is expected to reduce organic carbon pools. We incubated soils from a balsam fir stand previously subjected to 3 yr of in situ experimental warming (+4°C). Mineralizable carbon was significantly reduced (16-25%) in heated soils, corresponding to a 0.4-0.8% decline in the organic carbon pool.
Published in Forests 4: 613-631. https://doi.org/10.3390/f4030613
Sustainable management of boreal ecosystems involves the establishment of vigorous tree regeneration after harvest. However, two groups of understory plants influence regeneration success in eastern boreal Canada. Ericaceous shrubs are recognized to rapidly dominate susceptible boreal sites after harvest. Such dominance reduces recruitment and causes stagnant conifer growth, lasting decades on some sites. Additionally, peat accumulation due to Sphagnum growth after harvest forces the roots of regenerating conifers out of the relatively nutrient rich and warm mineral soil into the relatively nutrient poor and cool organic layer, with drastic effects on growth. Shifts from once productive black spruce forests to ericaceous heaths or paludified forests affect forest productivity and biodiversity. Under natural disturbance dynamics, fires severe enough to substantially reduce the organic layer thickness and affect ground cover species are required to establish a productive regeneration layer on such sites. We succinctly review how understory vegetation influences black spruce ecosystem dynamics in eastern boreal Canada, and present a multi-scale research model to understand, limit the loss and restore productive and diverse ecosystems in this region. Our model integrates knowledge of plant-level mechanisms in the development of silvicultural tools to sustain productivity. Fundamental knowledge is integrated at stand, landscape, regional and provincial levels to understand the distribution and dynamics of ericaceous shrubs and paludification processes and to support tactical and strategic forest management. The model can be adapted and applied to other natural resource management problems, in other biomes.
Published in Forest Ecology and Management 307: 333-340. https://doi.org/10.1016/j.foreco.2013.07.031
Using planted trees to restore the attributes of natural forest is especially challenging when disturbances are still effective. Chronic browsing by large herbivores can act as such a chronic disturbance curtailing natural regeneration and potentially altering successional trajectory of forest. In the context of herbivore overabundance encountered in many regions of the world, plantation strategies must thus address both the top-down pressure exerted by consumers on planted trees and the bottom-up control related to competition for resources. In this paper, we explore whether selection of competition-adapted balsam fir (Abies balsamea L.) seedling stock types (small, 110 cm3 container; medium; 200 cm3; or large, 350 cm3) could be used together with the management of white-tailed deer (Odocoileus virginianus) populations in order to lower the effect of local competition as well as minimizing browsing on seedlings. When the top-down pressure from herbivores is low or absent, we hypothesize that height and diameter growth as well as survival will be proportional to the initial size and biomass of seedlings. Inversely, in plantations exposed to deer, the apparency hypothesis predicts that herbivores are most likely to feed on taller, more obvious seedlings. Overall, we predict that medium stock size seedlings will outperform small and larger ones as they offer the best size compromise to withstand competition while maintaining a minimum level of apparency in the establishment phase. After 3 growing seasons, the height and diameter of medium stock size seedlings (48.6 ± 0.7 cm and 1.06 ± 0.05 cm, respectively) were similar to large ones (51.7 ± 1.1 cm, p = 0.12 and, 1.22 ± 0.05 cm, p = 0.07) that had been almost twice their biomass at the onset of plantation. The overall browsing occurrence was under 10% for all stock types exposed to browsing, yet the relative risk of being browsed increased by almost 20% for seedlings 30 cm vs. 60 cm at the end of the previous growing season. Mortality rate was unrelated to the browsing regime (p = 0.14) but overall, medium stock seedlings performed slightly better (2.9 ± 0.3%) than both small (7.0 ± 0.2%, p = 0.10) and large ones (10.5 ± 0.4%, p = 0.03). Based on the prominent effect of bottom-up control over top-down control in our experimental plantation, we conclude that choosing a size-adapted stock can optimize the cost of the restoration scheme following herbivore population reduction.
Published in New Forests 44: 827-847. https://doi.org/10.1007/s11056-013-9368-6
In arid zones, the use of compost for plant production in forest nurseries is hindered by a lack of water. The main objectives of this study were
(1) to evaluate the physical stability of composts produced from shredded branches of Acacia cyanophylla and A. cyclops subjected to a repeated drying and wetting cycles, similar to those used at the operational scale in nurseries in arid regions and to compare these composts with a standard peat-vermiculite (PV) substrate;
(2) to identify the relevant substrate physical variables that correlate with seedling growth.
Carob (Ceratonia siliqua L.) was cultivated during a production cycle of 27 weeks in a completely randomized block experiment. Substrate physical variables were measured at the beginning, middle and end of the experiment. Seedling growth variables were evaluated over the course of the production cycle, while gas exchange and water-relation variables were measured during a wetting and drying cycle at the end of the experiment. All three substrates produced vigorous seedlings with well-developed root systems that colonized the entire root plug. The growth of seedlings produced in the PV substrate was better than those grown in the compost-based substrates. No significant differences in gas exchange capacities and water relation variables were observed among the three substrates at the end of experiment with the exception of net photosynthesis, which was higher for the PV substrate at high substrate matric potential. Excessive drainage was negatively correlated with growth variables while water availability in the early growth phase and air porosity towards the end of experiment were positively correlated. Performance of the two composts could be increased by improving their initial structure and stability and by adjusting the irrigation regime.
Published in International Journal of Remote Sensing 35(5): 1769-1785
This paper describes the development of a fully automated system for collecting high-resolution spectral data over a forested footprint. The system comprises a pair of off-the-shelf spectrometers in a custom-built thermal enclosure with a fixed off-nadir downward (target)-pointing fibre and upward-pointing fibre for irradiance measurement. Both instruments sample simultaneously via custom-written and user-controlled software during all weathers and sky conditions. The system is mounted on a 25 m eddy covariance scaffolding tower, approximately 7 m from a Scots pine forest canopy. The system was installed at the University of Helsinki’s SMEAR-II Field Station in Hyytiälä in March 2010 and has been operating continuously through a joint programme between the Universities of Edinburgh and Helsinki. The system was designed to capture diurnal and seasonal variation in vegetation light-use efficiency and fluorescence through the capture and analysis of well-defined narrow spectral features, but its implementation would permit the extraction of further optical signals linked to vegetation biophysical variables, and provide a continuous data stream with which to validate satellite data products including vegetation indices such as the photochemical reflectance index (PRI) as well as spectral indicators of solar induced fluorescence.
