Restoration Of Boreal Forests Research Articles

Trait-environment interactions of saproxylic beetles as a guide to biodiversity conservation strategies

Conservation of biodiversity requires in-depth knowledge of trait-environment interactions to understand the influence the environment has on species assemblages. Saproxylic beetles exhibit a wide range of traits and functions in the forest ecosystems. Understanding their responses to surrounding environment thus improves our capacity to identify habitats that should be restored or protected. We investigated potential interactions between ecological traits in saproxylic beetles (feeding guilds and habitat preferences) and environmental variables (deadwood, type and age of surrounding forest). We sampled beetles from 78 plots containing newly created high stumps of Scots pine and Silver birch in boreal forest landscapes in Sweden for three consecutive years. Using a model based approach, our aim was to explore potential interactions between ecological traits and the surrounding environment at close and distant scale (20 m and 500 m radius). We found that broadleaf-preferring beetle species are positively associated with the local broadleaf-originated deadwood and broadleaf-rich forests in the surrounding landscapes. Conifer-preferring species are positively associated with the local amount of coniferous deadwood and young and old forests in the surrounding landscape. Fungivorous and predatory beetles are positively associated with old forests in the surrounding landscapes. Our results indicate that both local amounts of deadwood and types of forests in the landscape are important in shaping saproxylic beetle communities. We particularly highlight the need to increase deadwood amounts of various qualities in the landscape, exempt older forests from production and to increase broadleaf-rich habitats in order to meet different beetle species’ habitat requirements. Trait responses among saproxylic beetles provide insights into the significance of broadleaf forest and dead wood as essential attributes in boreal forest restoration, which helps conservation planning and management in forest landscapes.

Assessing the relative contribution of increased forest cover to decreasing river runoff in two boreal forested watersheds of Northeastern China

Boreal forests biomes are of great importance for regulating the hydrological cycling of global ecosystem. However, how boreal forest restoration affect the river runoff were poorly understood. In this study, two boreal forest watersheds, the upper Huma River and Ganhe River located in the Da Hinggan Mountains of Northeastern China were selected to quantify the effects of increased forest cover on runoff from 1980 to 2012 using the Budyko hypothesis associated with elasticity coefficients of runoff. The results indicated that the annual runoff existed a decreased trend associated with the rapidly increase in forest cover after the implementation of the Natural Forest Protection Project in two study watersheds. The quantitative results of the method of the Budyko hypothesis associated with elasticity coefficients of runoff showed that climate variability was the dominate driver (the relative contributions were 56.11% and 71.92% in the upper Huma River and Ganhe River watersheds, respectively) for decreasing annual runoff, while forest cover changes also played an important role for decreasing annual runoff in boreal forested watersheds in Northeastern China, which accounted for 41.20% and 23.80% of the total change of river runoff, respectively. The results of this work highlight the importance of considering the effects of increased forest biomes on streamflow and also inform our understanding of the interaction between boreal forest change and surface water resource in the study region and similar boreal forest regions across the globe.

Back to Roots: The Role of Ectomycorrhizal Fungi in Boreal and Temperate Forest Restoration

Temperate and boreal forests are increasingly suffering from anthropic degradation. Ectomycorrhizal fungi (EMF) are symbionts with most temperate and boreal forest trees, providing their hosts with soil nutrients and water in exchange for plant carbon. This group of fungi is involved in woody plants’ survival and growth and helps plants tolerate harsh environmental conditions. Here, we describe the current understanding of how EMF can benefit temperate and boreal forest restoration projects. We review current evidence on promising restoration plans that actively use EMF in sites contaminated with heavy metals, affected by soil erosion, and degraded due to clearcut logging and wildfire. We discuss the potential role of this group of fungi for restoring sites invaded by non-native plant species. Additionally, we explore limitations, knowledge gaps, and possible undesired outcomes of the use of EMF in forest restoration, and we suggest how to further incorporate this fungal group into forest management. We conclude that considering EMF – host interactions could improve the chances of success of future restoration programs in boreal and temperate forests.

Restoring volume, diversity and continuity of deadwood in boreal forests

Restoration of boreal forests by emulating natural disturbances is used to bring back typical components of natural forests that are reduced by silvicultural management. The volume, diversity and continuity of deadwood are the most important factors determining the diversity of deadwood-dependent species. In a large-scale experiment consisting of 43 experimental stands and 15 controls we assessed how alternative restoration methods enhancing deadwood availability (felling and felling + burning with two levels of felling: 20 and 40 % of initial volume of living trees, and a storm treatment) would affect short- and long-term deadwood volume and diversity using 7-year deadwood measurements and simulation modelling. In short-term, restoration by felling + burning increased both the volume and diversity of deadwood, whereas felling only increased merely the volume of deadwood. The simulations of tree growth, mortality and wood decomposition indicated that in comparison to controls, felled and storm-treated stands have greater deadwood volumes up to 40 years and felled + burned stands more than 60 years after restoration. Our results suggest that felling with 20 % of initial tree volume does not harm the future deadwood continuity, whereas intensive burning may imperil the deadwood continuity in a stand level. In conclusion, restoration clearly speeds up the development of the deadwood volumes needed to host large portions of biodiversity, and burning is the most effective restoration method in short- and long term. In practice, several restoration methods could be used concurrently in the landscape to obtain the best results.

Prioritizing boreal forest restoration sites based on disturbance regime

Selection of high priority sites for ecological restoration becomes essential with globally decreasing forest cover following natural and anthropogenic disturbances. A disturbance gradient resulting from native insect (Choristoneura fumiferana) outbreaks and non-native moose (Alces alces) browsing was studied in balsam fir forest stands in Newfoundland (Canada) to inform land managers where active vs. passive restoration would be most appropriate. The disturbance gradient ranged from small gaps (area <5ha) to medium and large gaps created by insects, in addition to a control (i.e., “no gap”) closed canopy mature balsam fir forest. In all areas seedlings and saplings (<2m) were browsed by moose causing failed forest regeneration. Differences in the vegetation community, environmental conditions and species functional groups were quantified across the disturbance regime using non-metric multidimensional analysis and nested analysis of variance. In this study, the closed canopy stand retained the optimal conditions for balsam fir forest regeneration and does not need active restoration to regenerate if moose densities are low. Insect-disturbed areas <5ha retained conditions that would allow them to regenerate naturally under conditions of low herbivory (i.e., they would not need active restoration); they were dominated by late succession forbs, retained low densities of balsam fir adults and optimal abiotic conditions for seedlings, with an increase in sunlight and decline in the quality of feathermoss seedbed. In contrast, a complete shift was observed in open areas >5ha, which were dominated by grasses, early succession forbs and had abiotic conditions closer to early succession boreal forest, indicating an ecological threshold had been crossed, confirming the need for active restoration. To allow regeneration regardless of gap size, reduction of moose numbers must be continued. Threshold identification in the boreal forest should be based on disturbance regime and used to inform critical areas for future forest restoration strategies. Based on our study, insect outbreak areas >5ha should be prioritized for active restoration, as the crossing of a biotic threshold indicates that such sites cannot naturally return to pre-disturbance balsam fir forests.

Influence of tree species and salvaged soils on the recovery of ectomycorrhizal fungi in upland boreal forest restoration after surface mining

Surface mining in the Canadian boreal forest involves the removal of vegetation and soils, resulting in the local loss of biodiversity and ecosystem functioning. Ectomycorrhizal (EM) fungi are critical to ecosystem processes; however, their recovery following reclamation is not well understood. This study investigated the importance of reclamation cover soils (forest floor material, peat, and subsoil) and tree seedling species (Populus tremuloides Michx., Pinus banksiana Lamb., and Picea glauca (Moench) Voss) in structuring the community composition of EM fungi. We used 1-year-old seedlings to assay cover soils in the field for 3 months, and grew seedlings in each of the cover soils in a growth chamber assay for 5 months. Nonmetric multidimensional scaling indicated host identity structured the community composition of EM fungi in the field, while both host identity and cover soil influenced the composition of EM fungi in the growth chamber. However, pre-colonization of seedlings by nursery fungi complicates interpretation of field results. The rate of EM fungus colonization of seedlings collected across both assays was relatively low, approximately 23%. Our results indicate cover soils used in reclamation of surface-mined landscapes retain propagules of EM fungi, and using a wide variety of tree species in upland boreal forest restoration may increase the diversity of EM fungi recovered.

Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs

Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce ( (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest on the chain-saw felled logs and most of the common polypore species were most frequent on this substrate. However, among the natural logs, number of species increased more steeply with increasing number of logs, suggesting greater variation in community composition on this substrate. The old-growth forest indicator occurred frequently on natural logs, occupied a few girdled logs but was absent from chain-saw felled logs. Our results show that from the polypore perspective created logs do not fully mimic natural logs, suggesting that creating substrates for species may pose a challenge for restoration.Picea abiesPhellinus ferrugineofuscus