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 Abstracts of the conference on Natural disturbance-based silviculture: Managing for complexity. IUFRO 1.05 Uneven-aged Silviculture Research Group. May 14-18, 2006. Rouyn-Noranda, Québec. p. 269.
Published in Canadian Journal of Forest Research 40: 1791-1802
In boreal black spruce (Picea mariana (Mill.) BSP) dominated stands, careful logging around advance regeneration contributes to protect the shrub layer while increasing light availability. Therefore, it may promote expansion of bog Labrador tea (Rhododendron groenlandicum (Oeder) Kron & Judd), which can impair black spruce growth by direct competition for nutrients and by alteration of soil biochemical conditions. Such harvesting approaches may not be suited for irregular, uneven-aged black spruce stands in the context of ecosystem-based management. Our objectives were to evaluate the effects of different intensities of partial harvest on critical resource availability and to compare the physiological and morphological responses of black spruce and Rhododendron to different intensities of partial harvest treatments. Two years after harvest, photosynthesis rate of black spruce was unchanged and was lower than that of Rhododendron, which was 63% higher after harvest. Nitrogen and water use efficiency were, respectively, 171% and 42% higher in Rhododendron than in black spruce after logging. Following harvest, black spruce physiology appeared to be regulated by the atmospheric humidity deficit, but for Rhododendron, physiology was regulated by light availability. The high plasticity of Rhododendron leaf traits could be indicative of the future advantage of this species in these stands following canopy removal associated with harvest.
Published in Canadian Journal of Forest Research 36(2006): 639-651
Large gaps (equivalent to twice the height of the trees, 1590 m2) originating from group selection cutting in mixed tolerant hardwood – eastern white pine (Pinus strobus L.) stands of Québec were used for geostatistical analysis of the seasonal mean of daily percent photosynthetic photon flux density (%PPFD), soil temperature and moisture, regeneration density of white pine, yellow birch (Betula alleghaniensis Britt.), and paper birch (Betula papyrifera Marsh.)), and growth of white pine, %PPFD, which measures the quantity of light above the shrub layer, varied according to the north-south axis, the maximum being located in the northern portion of gaps. Surficial soil (5 cm) temperature and moisture varied according to both north-south and east-west axes. The southwest sector offered favourable conditions for white pine, yellow birch, and paper birch establishment, with maximum soil moisture and minimum soil temperature encountered in this position. There was no evidence of gap partitioning at the early establishment stage, although asymmetry in the microclimate was observed. However, results indicate that spatial patterns could change in the future and a partition resulting from differential survival among species could occur. Finally, results outline a possible discordance between optimal regeneration and growth niches for white pine, since planted seedlings (>1 m) had the best growth in the central and northern section of gaps.
Published in Plant and Soil 179: 207-216
Nutrient imbalances of declining sugar maple (Acer saccharum Marsh.) stands in southeastern Québec have been associated with high exchangeable Mg levels in soils relative to soil K and Ca. A greenhouse experiment was set up to test the hypothesis that the equilibrium between soil exchangeable K, Ca, and Mg ions influences the growth and nutrient status of sugar maple seedlings. Also tested was whether endomycorrhization can alter nutrient acquisition under various soil exchangeable basic cations ratios. Treatments consisted of seven ratios of soil exchangeable K, Ca, and Mg making up a total base saturation of 58%, and a soil inoculation treatment with the endomycorrhizal fungus Glomus versiforme (control and inoculated), in a complete factorial design. Sugar maple seedlings were grown for 3 months in the treated soils. Plant shoot elongation rate, dry biomass and nutrient concentrations in foliage were influenced by the various ratios of soil cations. The predicted plant biomass and foliar K concentration were highest at a soil Ca saturation of 38%, a soil K saturation of 12%, and a soil Mg saturation of 8%. Potassium concentration in foliage was dependent on the level of Ca and Mg saturation in the soil when soil K saturation was close to 12%. Foliar Ca and Mg levels were more dependent on their corresponding levels in soil than foliar K. Colonization by G. versiforme did not influence seedling growth and macronutrient uptake. The results confirm that growth and nutrition of sugar maple are negatively affected by imbalances in exchangeable basic cations in soils.
