by Audrey Verreault | 28 April 2021
Published in Energies 13(18): 4609. https://doi.org/doi:10.3390/en13184609
Natural disturbances are common in Canadian boreal managed forests. For example, during and after insect epidemics, foresters must deal with significant amounts of degraded or dead wood that cannot be processed into sawn timber or pulp. Bioenergy could be an alternative pathway for this wood. A case study in Quebec (Canada) was used to evaluate the profitability of pellet production for bioenergy using degraded trees from insect epidemics. A bioenergy scenario was simulated in which degraded trees were harvested for bioenergy alongside sound wood for timber and pulp. This scenario was compared to a reference scenario in which degraded trees were left on cutovers. Using wood pellets as a case study, the results showed that at current market prices, harvesting degraded trees for pellet production is not as profitable as leaving them in the forest. Nevertheless, the overall forest operations for procuring wood for timber and pulp were still profitable, even with very high degradation levels. Procuring degraded trees reduced the overall fixed costs per harvested m3 and allowed average savings of C$2.83/harvested m3. The silvicultural savings associated with lower site preparation needs following procurement of degraded trees ranged from C$0/ha to C$500/ha, resulting in average savings of C$2.31/harvested m3. Depending on the stand conditions, the distribution of fixed costs and silvicultural savings of biomass procurement could be either low or significant.
by Audrey Verreault | 28 April 2021
Published in Ecography 43(7): 967-978. https://doi.org/10.1111/ecog.04995
Disturbance regimes are changing in forests across the world in response to global climate change. Despite the profound impacts of disturbances on ecosystem services and biodiversity, assessments of disturbances at the global scale remain scarce. Here, we analyzed natural disturbances in boreal and temperate forest ecosystems for the period 2001–2014, aiming to 1) quantify their within- and between-biome variation and 2) compare the climate sensitivity of disturbances across biomes. We studied 103 unmanaged forest landscapes with a total land area of 28.2 × 106 ha, distributed across five continents. A consistent and comprehensive quantification of disturbances was derived by combining satellite-based disturbance maps with local expert knowledge of disturbance agents. We used Gaussian finite mixture models to identify clusters of landscapes with similar disturbance activity as indicated by the percent forest area disturbed as well as the size, edge density and perimeter–area-ratio of disturbed patches. The climate sensitivity of disturbances was analyzed using Bayesian generalized linear mixed effect models and a globally consistent climate dataset. Within-biome variation in natural disturbances was high in both boreal and temperate biomes, and disturbance patterns did not vary systematically with latitude or biome. The emergent clusters of disturbance activity in the boreal zone were similar to those in the temperate zone, but boreal landscapes were more likely to experience high disturbance activity than their temperate counterparts. Across both biomes high disturbance activity was particularly associated with wildfire, and was consistently linked to years with warmer and drier than average conditions. Natural disturbances are a key driver of variability in boreal and temperate forest ecosystems, with high similarity in the disturbance patterns between both biomes. The universally high climate sensitivity of disturbances across boreal and temperate ecosystems indicates that future climate change could substantially increase disturbance activity.
by Audrey Verreault | 28 April 2021
Published in Forest Ecology and Management 472: 118237. https://doi.org/10.1016/j.foreco.2020.118237
Understanding the importance of dead wood-associated biodiversity and related ecological functions has become increasingly important in forest ecosystem management. Yet, studies on dead wood diversity frequently focus on conspicuous organisms such as birds or saproxylic beetles, and are rarely deployed across significant climatic gradients. Here, we investigated the potential role of deadwood as a habitat for springtails, an understudied group of invertebrates generally associated with soils, and tested how these communities were influenced by climate. Black spruce logs were placed in 13 natural forest sites which were distributed among 3 latitudinal zones (southern, central and northern Quebec, Canada). We compared the springtail communities that colonized the logs through different metrics: abundance, richness and species composition. Our results indicated that dead wood was used as a habitat by 74 springtail species. A clear latitudinal diversity gradient was observed, with southern communities being on average two times richer and over 13 times more abundant than the northern ones per log. Moreover, distinct community compositions were observed in the three zones. Overall, our results suggest that (1) dead wood retention could be beneficial for small invertebrates such as springtails and (2) such biodiversity conservation measures would be more efficient if done systematically along large geographic gradients encompassing different biomes, particularly in the context of climate change.
by Audrey Verreault | 15 April 2021
This user guide introduces the different features of the Forêt ouverte interactive map, including how to use the map themes, add layers to customize a map, use the measure and draw tools, import a personal layer, export a customized map and download data.
by Marie-Claude Boileau | 15 April 2021
This user guide facilitates the identification of surficial deposits and borrow pits using LiDAR data and aerial photographs. The high accuracy of LiDAR data is particularly useful for observing geomorphological details that are difficult to see using other data sources (e.g., aerial photographs only). The shaded relief digital terrain model produced from LiDAR data removes the masking effect of vegetation, exposing the underlying terrain and thus allowing an easier and more precise identification of surficial deposits. Using this guide to identify more easily and more precisely surficial deposits can undoubtedly facilitate preliminary analyses and field work, as well as the search for material favourable to civil engineering work and the construction of roads.
