by Svetlana Savin | 15 March 2023
Published in Current Forestry Reports 9: 101-130. https://doi.org/10.1007/s40725-023-00181-6
Purpose of Review
Intensive forest management practices are being implemented worldwide to meet future global demand for wood and wood products while facilitating the protection of natural forest ecosystems. A potential decline in wood properties associated with rapid tree growth makes it essential to quantify the potential impact of intensive management on the process of wood formation and, in turn, on its suitability for various end-uses.
Recent Findings
Wood produced over short rotations is generally of lower quality because wood properties tend to improve with cambial age (i.e. the number of annual growth rings from the pith). The intensification of silvicultural practices can thus have measurable consequences for the forest products value chain. The use of new planting material from tree improvement programs could offset such effects, but questions arise as to the effects of a changing climate on wood produced from these plantations and the best silvicultural approaches to manage them.
Summary
Based on these recent findings, we provide reflections on the need for a modelling framework that uses the effects of cambial age, ring width and position along the stem to summarise the effects of tree growth scenarios on wood properties. We then present challenges related to our limited understanding of the effects of several drivers of wood properties, such as climate variation, genetic material, and forest disturbances, among others, and highlight the need for further data collection efforts to better anticipate the quality attributes of the future wood fibre resource. We conclude by providing examples of promising new tools and technologies that will help move wood quality research forward by allowing (1) fast, efficient characterisation of wood properties, and (2) up-scaling predictions at the landscape level to inform forest management decisions.
by Claire Morin | 15 March 2023
La rainette faux-grillon de l’Ouest (RFGO), Pseudacris triseriata, a obtenu le statut d’espèce vulnérable en 2001 selon la Loi sur les espèces menacées ou vulnérables du Québec (L.R.L.Q., E-12.01, r. 2). Le suivi des populations Since 2015, studies in the Montérégie region have focused on different characteristics of the western chorus frog’s habitat to determine the parameters to be used to facilitate its restoration and development. The purpose of this document is to make current knowledge and techniques available for the development of western chorus frog habitats. The optimal landscape occupied by the western chorus frog consists of 30% wetlands, mostly open areas, and up to 25% wooded areas. The hydrology of the temporary wetland habitats used by the western chorus frog for breeding has intrinsic variability correlated with the nature of the watershed and the amount of precipitation. A breeding habitat for larval development must reach a hydroperiod of 60 to 100 days and have direct sun exposure from 10:00 a.m. to 2:00 p.m. The choice of location and an assessment of hydrological characteristics are therefore essential. Knowledge of the receiving environment, its geomorphological characteristics and water quality is essential for successful developments.
by Audrey Verreault | 10 March 2023
Published in Forest Ecology and Management 535: 120897. https://doi.org/10.1016/j.foreco.2023.120897
Cumulative effects of nitrogen (N) deposition are a matter of concern in temperate forests of northeastern North America. Increased N deposition may stimulate forest growth and carbon sequestration while also causing N saturation, which may lead to soil cation depletion, particularly in base-poor systems. We applied ammonium nitrate for 13 years in a sugar maple (Acer saccharum; SM) stand at the rates of 3 (Low N, LN) and 10 times (High N, HN) the ambient N deposition rate. N concentrations in soil layers were similar among treatments, except for a nitrate increase in the top B horizon in the HN treatment. Exchangeable Ca2+, Mg2+, and K+ were significantly lower than for the Control, at least in one of the top organic soil layers in the HN treatment. The temporal dynamics of foliar chemistry revealed that N:P ratio increased and both Ca and Mn decreased in the early years following treatment initiation, but that they did not change much thereafter. Foliar Ca values in the HN treatment are the lowest reported in the literature. This probably explains why the proportion of crown dieback steadily increased over time, reaching values as high as 80% in the HN treatment in 2017.
by Audrey Verreault | 2 March 2023
Published in Canadian Journal of Forest Research 53: 134-150. https://doi.org/10.1139/cjfr-2022-0111
Individual tree recruitment is an important element needed to understand stand dynamics, as it influences both stand composition and productivity. Forest growth simulators usually include recruitment models. The quality of recruitment predictions can have long-term impacts on estimations of forest growth, ecosystem health and the commercial utility of managed forests. The main objective of this study was to develop a recruitment model for commercial-size trees (i.e., trees with a diameter at breast height > 9 cm) of 10 species groups using different dendrometric and environmental variables. The resulting model will be included in a growth simulator used to support forest management planning. We hypothesized that accounting for sapling density as a covariate would improve the recruitment model’s predictive performance. Using empirical data from periodically measured permanent sample plots (1982–2019) located throughout the managed mixed hardwood forests of Quebec, we constructed models with and without sapling-related covariates and compared them on the basis of cross-validation model performance statistics. Our results show that including sapling density significantly improved model performance. From this, we conclude that adding sapling density as a covariate can significantly improve a recruitment model’s predictive power for eastern mixed hardwood forests.
by Claire Morin | 27 February 2023
An aerial survey of moose in hunting Zone 17 showed a 35% decline since 2009. The number of moose was estimated at 1036 (±16%; α = 0.1), or a density of 0.52 moose/10 km2. Reduction in habitat quality over the past decade would not limit the growth in moose numbers. The low ratio of 27 males/100 females is unprecedented. The highly selective hunt conducted since 1996 has become unsustainable. However, the increase in the proportion of females increases the resilience potential of this population. Nevertheless, the low ratio of 30 calves/100 females indicates a recruitment problem in Zone 17. The increase in adult mortality is more likely to be caused by overharvesting by hunting than by wolf predation. Inadequate monitoring of the Indigenous harvesting would underestimate its effect on the moose population. Speculation on the causes of mortality limits interpretation of the proportions attributable to hunting and predation. The Zone 17 ecosystem would still be favourable to growing moose numbers in a context of sustainable hunting management.
