by Audrey Verreault | 6 October 2023
Published in International Journal of Forest Research 2023: cpad045.https://doi.org/10.1093/forestry/cpad045
In northern hardwood forests, tree markers select the trees to be harvested during logging operations using classification systems that assign harvest priorities based on the presence of a wide range of individual defects. According to the most recent advances in our understanding of the impact of defects on both tree vigour (the risk of mortality or decline in growth) and quality (the potential for recovering valuable sawlogs), tree markers should adopt a simpler classification system that considers fewer defects than the current operational practice, and they should prioritize the removal of trees with crown dieback. Since the probability of developing defects and dying increases substantially with tree diameter, tree markers should also favour the removal of larger trees that have maintained their quality. However, these recommendations were developed based on tree-level analyses. To provide further validation at the stand scale, we compared stand improvement and value recovery under three tree marking regimes: a new, simplified regime based on the recommendations above, and two regimes used in the province of Quebec, Canada. To do so, we conducted tree marking simulations and value recovery assessments in 14 managed stands distributed across the northern hardwood range of Quebec. Our results confirmed that the simplified tree marking regime not only facilitated stand improvement by removing a greater proportion of low-vigour trees, but also recovered significantly more value (17% on average) at the stand scale. By prioritizing the removal of trees with crown dieback, the simplified regime was superior at salvaging the current value of low-vigour trees before they die or decline in quality. Based on our results, we propose simplified and empirically-validated tree marking guidelines for northern hardwood forests.
by Claire Morin | 18 September 2023
An aerial survey was conducted from February 8 to 25, 2022, over an area of 33,203 km², covering the Detour woodland caribou population’s winter range as delineated by the Québec government. This population, whose range overlaps the provinces of Québec and Ontario, has sometimes been referred to as the La Sarre herd or the Quebec-Ontario Frontier herd in Québec. A total of 338 animals were enumerated during the survey, including 83 in Québec and 255 in Ontario. At the time of the survey, calves accounted for roughly 22.4% of the population, giving a recruitment figure of 39.9 calves/100 females. The sex ratio was 37.8 males per 100 females. Based on detection rates estimated during the survey, the total abundance of the Detour population in winter 2022 would be between 446 and 465 individuals. This survey achieved the first abundance estimate for the entire cross-border Detour population. Comparison of the present results with those from earlier work is limited, since the latter covered only certain portions of the population’s range. Nevertheless, there are several indications that the Detour population has undergone a reduction in abundance since the 1980s.
by Audrey Verreault | 11 September 2023
Published in Forest Ecology and Management 545: 121304. https://doi.org/10.1016/j.foreco.2023.121304
Sugar maple (Acer saccharum Marshall) growth in the species’ southern range has been declining since the 1980s, putting at risk a variety of ecosystem services that the species provides. Heatwaves, drought, frosts, acidic deposition, and insect defoliation, all reducing photosynthetic activity, have been suggested to be behind the phenomenon. Because the geographic scope of previous studies on maple growth is limited to the southern temperate biome, it is not currently understood whether the same negative trends and factors affecting growth rates apply to the species in more northern regions of its distribution range. Here we used annual ring-width data of 1675 trees from a network of 21 sites in Quebec and Ontario between 45˚N and 48˚N to reconstruct maple growth and to analyze its trends and climatic drivers since 1950 CE. We developed a retrospective tree growth index by employing a Generalized Additive Mixed Model (GAMM) that accounted for tree age and size, terrain altitude, slope, competition and mean site climatology. Our reconstruction suggested considerable geographical variations in maple growth trends, with declining growth being less pronounced in the central portion of the study region. The growth decline persisted at the time of sampling in 2019 and 2020. Maple growth negatively correlated with the summer vapour pressure deficit (VPD) during both the previous and current growth seasons. As the decline in sugar maple growth is observed at the northern limit of its distribution, climate change may not favor the expansion of sugar maples to the north. The observed decline along with increasing VPD will likely have a negative impact on the ecosystem services supported by this species and calls for management adaptation measures.
by Audrey Verreault | 11 September 2023
https://doi.org/10.3390/books978-3-0365-8769-1
Although the evolution of principles, procedures, and predictive abilities related to seedling quality throughout the plant production chain (i.e., from seeds to sustainable plantations) has been reviewed over the past decades in various technical and scientific publications, there is still a need to develop and integrate new and efficient practices in forest nurseries and at planting sites, in order to improve the morphophysiological quality of seedlings and saplings, and their survival and growth under different site and environmental conditions in the context of climate change. We have grouped together different scientific articles in this Special Issue of Forests, entitled “Production in Forest Nurseries and Field Performance of Seedlings”. They cover different topics relating to the seedling production chain in different countries and continents, from growing media to planting performance related to reforestation, restoration, and agroforestry programs.
by Audrey Verreault | 6 September 2023
Published in Forests 14(19): 1693. https://doi.org/10.3390/f14091693
Although the evolution of principles, procedures, and predictive abilities related to seedling quality throughout the plant production chain (i.e., from seeds to sustainable plantations) has been reviewed over the past decades in various technical and scientific publications, there is still a need to develop and integrate new and efficient practices in forest nurseries and at planting sites, in order to improve the morphophysiological quality of seedlings and saplings, and their survival and growth under different site and environmental conditions in the context of climate change. We have grouped together different scientific articles in this Special Issue of Forests, entitled “Production in Forest Nurseries and Field Performance of Seedlings”. They cover different topics relating to the seedling production chain in different countries and continents, from growing media to planting performance related to reforestation, restoration, and agroforestry programs.
