Search results for "Taiga"
showing 10 items of 103 documents
Wood-inhabiting fungi with tight associations with other species have declined as a response to forest management
2017
Research on mutualistic and antagonistic networks, such as plant-pollinator and host-parasite networks, has shown that species interactions can influence and be influenced by the responses of species to environmental perturbations. Here we examine whether results obtained for directly observable networks generalize to more complex networks in which species interactions cannot be observed directly. As a case study, we consider data on the occurrences of 98 wood-inhabiting fungal species in managed and natural forests. We specifically ask if and how much the positions of wood-inhabiting fungal species within the interaction networks influence their responses to forest management. For this, we…
New insight to the role of microbes in the methane exchange in trees: evidence from metagenomic sequencing
2021
Methane (CH4) exchange in tree stems and canopies and the processes involved are among the least understood components of the global CH4 cycle. Recent studies have focused on quantifying tree stems as sources of CH4 and understanding abiotic CH4 emissions in plant canopies, with the role of microbial in situ CH4 formation receiving less attention. Moreover, despite initial reports revealing CH4 consumption, studies have not adequately evaluated the potential of microbial CH4 oxidation within trees. In this paper, we discuss the current level of understanding on these processes. Further, we demonstrate the potential of novel metagenomic tools in revealing the involvement of microbes in the C…
Micro-site conditions affect Fennoscandian forest growth
2021
Abstract The long tradition of dendroclimatological studies in Fennoscandia is fostered by the exceptional longevity and temperature sensitivity of tree growth, as well as the existence of well-preserved subfossil wood in shallow lakes and extent peat bogs. Although some of the world’s longest ring width and density-based climate reconstructions have been developed in northern Fennoscandia, it is still unclear if differences in micro-site ecology matter, and if so, whether they have been considered sufficiently in previous studies. We developed a Fennoscandia-wide network of 44 Scots pine ring width chronologies from 22 locations between 59°–70 °N and 16°–31 °E, to assess the effects of moi…
Landscape structure influences browsing on a keystone tree species in conservation areas
2020
Aspen is a keystone species in boreal forests. The future of aspen in many conservation areas is threatened by ungulate browsing. Our aim was to study the effect of browsing on aspen regeneration and population structure in conservation areas in Central Finland, and the effect of surrounding landscape structure on browsing. Aspen density varied greatly among and within conservation areas. In about half of the conservation areas, middle-sized aspens were scarce or missing, which indicates heavy browsing in the recent past. In addition, the number of dead, large aspens in advanced decay stages were rare. Browsing pressure varied greatly among the areas, but on average, a bit more than half of…
No growth stimulation of Canada’s boreal forest under half-century of combined warming and CO 2 fertilization
2016
Considerable evidence exists that current global temperatures are higher than at any time during the past millennium. However, the long-term impacts of rising temperatures and associated shifts in the hydrological cycle on the productivity of ecosystems remain poorly understood for mid to high northern latitudes. Here, we quantify species-specific spatiotemporal variability in terrestrial aboveground biomass stem growth across Canada’s boreal forests from 1950 to the present. We use 873 newly developed tree-ring chronologies from Canada’s National Forest Inventory, representing an unprecedented degree of sampling standardization for a large-scale dendrochronological study. We find significa…
Spatial Variation of Leaf Optical Properties in a Boreal Forest Is Influenced by Species and Light Environment
2017
Leaf Optical Properties (LOPs) convey information relating to temporally dynamic photosynthetic activity and biochemistry. LOPs are also sensitive to variability in anatomically related traits such as Specific Leaf Area (SLA), via the interplay of intra-leaf light scattering and absorption processes. Therefore, variability in such traits, which may demonstrate little plasticity over time, potentially disrupts remote sensing estimates of photosynthesis or biochemistry across space. To help to disentangle the various factors that contribute to the variability of LOPs, we defined baseline variation as variation in LOPs that occurs across space, but not time. Next we hypothesized that there wer…
Responses of boreal carabid beetle assemblages (Coleoptera, Carabidae) to clear-cutting and top-soil preparation
2006
Today, forestry is the most important disturbance force in Fennoscandian boreal forests, having remarkably altered fauna and flora in this biome. However, since the late 1900s, forest-management practices have been modified to better consider biodiversity while harvesting timber. For example, green-tree retention, gap felling, and lighter top-soil preparation methods (harrowing) have been introduced, but little is known about the ecological effects of these changes. We sampled carabid beetles in seven clear-cut stands that were subsequently harrowed. We studied the effects of (1) clear-cut size by comparing carabid catches of small gaps (ca. 0.16 ha) with those of larger clear-cuts (ca. 2 h…
Impacts of forestry on boreal forests : An ecosystem services perspective
2017
Forests are widely recognized as major providers of ecosystem services, including timber, other forest products, recreation, regulation of water, soil and air quality, and climate change mitigation. Extensive tracts of boreal forests are actively managed for timber production, but actions aimed at increasing timber yields also affect other forest functions and services. Here, we present an overview of the environmental impacts of forest management from the perspective of ecosystem services. We show how prevailing forestry practices may have substantial but diverse effects on the various ecosystem services provided by boreal forests. Several aspects of these processes remain poorly known and…
How to reconcile wood production and biodiversity conservation? The Pan-European boreal forest history gradient as an "experiment".
2018
There are currently competing demands on Europe's forests and the finite resources and services that they can offer. Forestry intensification that aims at mitigating climate change and biodiversity conservation is one example. Whether or not these two objectives compete can be evaluated by comparative studies of forest landscapes with different histories. We test the hypothesis that indicators of wood production and biodiversity conservation are inversely related in a gradient of long to short forestry intensification histories. Forest management data containing stand age, volume and tree species were used to model the opportunity for wood production and biodiversity conservation in five no…
Optimal conservation resource allocation under variable economic and ecological time discounting rates in boreal forest
2016
Resource allocation to multiple alternative conservation actions is a complex task. A common trade-off occurs between protection of smaller, expensive, high-quality areas versus larger, cheaper, partially degraded areas. We investigate optimal allocation into three actions in boreal forest: current standard forest management rules, setting aside of mature stands, or setting aside of clear-cuts. We first estimated how habitat availability for focal indicator species and economic returns from timber harvesting develop through time as a function of forest type and action chosen. We then developed an optimal resource allocation by accounting for budget size and habitat availability of indicator…