by equipewp | 15 July 2021
Published in For. Sci. https://doi.org/10.1093/forsci/fxab012
Acer saccharum and Acer rubrum, two main maple species in North America, will be affected by ongoing global warming. Several studies predict a southern limit contraction but limited northward expansion of maple distribution for the future. We aimed to understand the main drivers of current maple distribution to quantify potential changes to maple habitat in this context. We identified the local conditions of maple stands and assessed the potential changes under warming scenarios. We selected two regions in Quebec, Canada, at the northern distribution of the species and applied probability distribution function and principal component analysis to identify the factors explaining the occurrence of maple compared with other forest species, croplands, and grasslands. Maple habitat was estimated under warming scenarios up to 2°C. We observed a lower density of maple stands in the north (7.76 %), compared to the south (33.01 %). Warming increased maple stands by 3.54 and 1.45 % in the northernmost and southernmost regions, respectively, with the highest increases being estimated at the initial warming (+1.0°C). We conclude that maple of northern regions can benefit from local warming if precipitation does not become limiting. These changes could increase the potential for the regional maple industry and forest management.
Study Implications : Future warming may enhance the opportunities to exploit maple and its products at the northern boundary of this species, under a sufficient precipitation regime. Plantations could be considered in habitats favorable for maple, which would allow the value of the resource at the northern edge of the temperate mixedwood forest to be increased. Our spatially explicit outcomes will encourage forest managers and small landowners to plan new maple plantations. The local maple industry and forest management in northern regions could benefit from such an increase in maple habitat and enhanced production of hardwood species.
by Claire Morin | 15 July 2021
In 2017, the analysis of species monitored by Quebec Conservation data centre (CDC) by the Ministère des Forêts, de la Faune et des Parcs (MFFP) highlighted the need to harmonize the available information on threats to biodiversity. Although internationally recognized classifications were already available, their degree of precision did not facilitate the identification of precise conservation issues.
Therefore, a more precise classification was developed by the MFFP, in collaboration with several partners from Quebec, Canada and beyond, allowing to articulate the former 42 general threats to biodiversity into 162 detailed categories. The described threats are organized according to their hierarchical ranks, starting from generic wording (level 1), which is progressively defined into precise descriptions (level 3). When necessary, the classification entries are accompanied by a description, specifications allowing the description of inclusions and exclusions and may also be accompanied with examples.
This important collaboration in between the MFFP and its partners allowed for a joined effort to refine international classifications into a practical tool for conservationists.
by equipewp | 14 July 2021
Published in Can. J. For. Res. 51(6): 842-847. https://doi.org/10.1139/cjfr-2020-0365
Assisted migration, the human-mediated movement of species and populations, is one adaptive strategy to climate change. Plant phenology affects the survival and distribution of species under local conditions, and its potential modifications need to be explored in the context of assisted migration. We conducted identical experiments in January and April (experiment I and II) and monitored the timing of bud break in sugar maple (Acer saccharum Marshall) under cooling and longer photoperiod to simulate a northward migration. The bud break in experiment II started 55 days earlier than experiment I. In experiment I, a longer photoperiod was more effective than warming in advancing bud break. Compared with experiment II, cooling and long photoperiod had stronger effect in experiment I. Our results demonstrated the significant effect of chilling and confirmed that photoperiod outweighs temperature in initiating bud break when the chilling requirement is unfulfilled. These findings suggest that the future mild winters in the southern range of sugar maple may reduce chilling accumulation and result in the delayed bud break. Sugar maples migrating northward could benefit from longer day lengths, which could partly counteract the delayed effects of colder springs in northern regions, thus ensuring a sufficient growth period.
by equipewp | 14 July 2021
Published in Forest Ecosystems 8(1): 27. https://doi.org/10.1186/s40663-021-00305-z
Background: Tree-related microhabitats (hereafter, “TreMs”) are key components of forest biodiversity but they are still poorly known in North American hardwood forests. The spatial patterns of living trees bearing TreMs (hereafter, “TreM-trees”) also remain to be determined. As logging practices can lead to a loss of TreM-trees and of their associated biodiversity, it is essential to identify the factors explaining TreM occurrence to better integrate them into forest management. We therefore inventoried TreMs in 4 0.5-ha survey strips in northern hardwood forests in Quebec, Canada, while recording the spatial location of each tree. Two strips were located in unmanaged oldgrowth forests, and 2 were in forests managed under selection cutting. All 4 stands were dominated by sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrn.). Beech bark disease, an exotic pathology, was observed in all the strips.
Results: Large diameter at breast height and low tree vigor were the main characteristics explaining the presence of TreMs at the tree scale. TreM-trees presented slight spatial aggregation patterns. These aggregates, however, were not well-defined and were generally constituted by a large number of trees bearing few different types of TreMs. Two TreM classes (broken branch or top and woodpecker lodge) also presented a spatial aggregation. Logging practices had no significant effect on TreM occurrence. Beech bark disease increased the frequency of senescent beeches. The impact of this pathology on TreMs was however mitigated by the small size of infected trees and probably by the short time elapsed since its appearance.
Conclusion: The factors explaining the presence and abundance of TreMs on trees has so far been little studied in North American hardwood forests. Our results highlight that TreM-tree characteristics in the surveyed forests are consistent with those of previous studies conducted in other forest types and regions (e.g., Europe or Northwestern America). To our knowledge, this study is also the first to identify a spatial aggregation of TreM-trees and of specific TreM classes. It will be nevertheless necessary to determine whether the small impact of logging activities we observed results from current or past management practices.
