The demographic structure of European aspen (Populus tremula) populations in managed and old-growth boreal forests in eastern Finland

2007 ◽  
Vol 37 (6) ◽  
pp. 1070-1081 ◽  
Author(s):  
Tarja Latva-Karjanmaa ◽  
Reijo Penttilä ◽  
Juha Siitonen
Keyword(s):  
Protected Areas ◽  
Boreal Forests ◽  
Large Scale ◽  
Populus Tremula ◽  
Managed Forests ◽  
Mature Trees ◽  
Old Growth ◽  
European Aspen ◽  
Eastern Finland

European aspen ( Populus tremula L.) is a keystone species for biodiversity in boreal forests. However, large aspen have largely been removed from managed forests, whereas regeneration and the long-term persistence of mature trees in protected areas are matters of concern. We recorded the numbers of mature (≥20 cm diameter) aspen in old-growth and managed forests in eastern Finland, based on a large-scale inventory (11 400 ha, 36 000 living and dead trees). In addition, saplings and small aspen trees were surveyed on thirty-six 1 ha sample plots. The average volumes of mature living and dead aspen were 4.0 and 1.3 m3/ha in continuous old-growth forests and 0.2 and 0.6 m3/ha in managed forests, respectively. These results indicate that large aspen trees in managed forests are a legacy of the past, when forest landscapes were less intensively managed. We conclude that the long-term persistence of aspen in protected areas can only be secured by means of restoration measures that create gaps large enough for regeneration to occur. More emphasis should be given to sparing aspen during thinning and to retaining mature aspen during regeneration cutting in managed forests.

(A review) Atlas of especially protected natural areas of Saint Petersburg / Ed. in chief V. N. Khramtsov, T. V. Kovaleva, N. Yu. Natsvaladze. St. Petersburg, 2013. 176 p.

2014 ◽  
pp. 124-129
Author(s):  
Z. V. Karamysheva
Keyword(s):  
Protected Areas ◽  
Large Scale ◽  
Natural Areas ◽  
Natural Protected Areas ◽  
Saint Petersburg ◽  
Natural Processes ◽  
Original Illustrations ◽  
Vegetation Maps ◽  
Protected Natural Areas

The review contains detailed description of the «Atlas of especially protected natural areas of Saint Petersburg» published in 2013. This publication presents the results of long-term studies of 12 natural protected areas made by a large research team in the years from 2002 to 2013 (see References). The Atlas contains a large number of the historical maps, new satellite images, the original illustrations, detailed texts on the nature of protected areas, summary tables of rare species of vascular plants, fungi and vertebrates recorded in these areas. Special attention is paid to the principles of thematic large-scale mapping. The landscape maps, the vegetation maps as well as the maps of natural processes in landscapes are included. Reviewed Atlas deserves the highest praise.

Ecological restoration for biodiversity conservation triggers response of bark beetle pests and their natural predators

2020 ◽  
Author(s):  
Anne-Maarit Hekkala ◽  
Simon Kärvemo ◽  
Martijn Versluijs ◽  
Jan Weslien ◽  
Christer Björkman ◽  
...  
Keyword(s):  
Ecological Restoration ◽  
Bark Beetle ◽  
Boreal Forests ◽  
Bark Beetles ◽  
Large Scale ◽  
Prescribed Burning ◽  
Gap Cutting ◽  
Population Sizes ◽  
And Function

Abstract The restoration of forest structure and function is increasingly being used in boreal forests in order to halt the loss of biodiversity. Often ecological restoration is aimed at increasing the volume of dead and dying trees to enhance the biodiversity of deadwood-dependent organisms, but it may also increase population sizes of pest bark beetle species, even several years following restoration. Herein, we used a large-scale restoration experiment in Northern Sweden to assess the 5 years post-restoration effects of restorative gap cutting and prescribed burning on the populations of a set of economically harmful pest bark beetles (Ips typographus, Polygraphus poligraphus, Tomicus piniperda and Pityogenes chalcographus) and the most important predators of bark beetles, Thanasimus spp. In addition, we assessed the effects of forest stand characteristics at stand and landscape scale on the abundance of I. typographus. Five years post-restoration, gap-cut stands supported the highest abundances of P. poligraphus and contained the highest count of spruce trees newly attacked by bark beetles. By contrast, prescribed burning generally sustained the lowest abundances of pest bark beetles, especially I. typographus and P. poligraphus, and the highest abundance of their natural predators Thanasimus spp. The population abundance of I. typographus was also positively affected by the area of clear cuts within a 500 m radius from the stand. In conclusion, prescribed burning appears to be a safer method for ecological restoration than gap cutting in the long-term. According to our results, a risk of a local bark beetle outbreak still remains 5 years following the initiation of ecological restoration treatments on spruce-dominated mature gap-cut stands.

Effects of experimental harvesting on spider (Araneae) assemblages in boreal deciduous forests

2008 ◽  
Vol 140 (4) ◽  
pp. 437-452 ◽  
Author(s):  
Christopher M. Buddle ◽  
David P. Shorthouse
Keyword(s):  
Indicator Species ◽  
Boreal Forests ◽  
Large Scale ◽  
Wolf Spider ◽  
Natural Disturbance ◽  
Old Growth ◽  
Partial Cutting ◽  
Clear Cutting ◽  
Old Growth Forests ◽  
Geographic Separation

AbstractTwo large-scale forestry experiments, in Quebec (Sylviculture et aménagement forestiers écosystémique (SAFE)) and Alberta (Ecosystem Management by Emulating Natural Disturbance (EMEND)), were established in the late 1990s to test the effects of alternative silvicultural strategies (e.g., partial cutting) on biodiversity in northern boreal forests. We collected spiders in pitfall traps 2 years after the application of partial-cutting treatments in deciduous stands at EMEND and 6 years after similar treatments in deciduous stands at SAFE. Although we are aware of the challenges imposed by disparate locations and whole-scale experimental methods, our objective was to compare the effects of partial cutting on spider assemblages (diversity and community composition), and in doing so, to formulate a few general statements. Overall, 98 species (6107 individuals) were collected from Alberta and 86 species (3414 individuals) from Quebec. Of these, 44 species were common to both regions. Ordination and indicator-species analyses revealed a distinct effect of geographic separation: the spider assemblages in deciduous stands within the boreal plains ecoregion of Alberta and the boreal shield in Quebec were distinct. However, the effects of partial cutting on spider assemblages within each project were similar: removal of 25%–33% of trees shifted a characteristic old-growth fauna toward one more typical of clearcuts. Indicator-species analysis also revealed the dominance of wolf spider (Lycosidae) species in clearcuts within both experiments and we present evidence that clear-cutting homogenizes spider assemblages. Old-growth forests contain spider faunas that are easily disrupted by moderate partial cutting. In the face of intense harvesting practices, managing for the maintenance of biodiversity and conservation of spider faunas in northern forests will require retention of old-growth forests.

scholarly journals Fungus gnats (Diptera: Bolitophilidae, Diadocidiidae, Keroplatidae and Mycetophilidae) new to Finland

2006 ◽  
Vol 17 (2) ◽  
Author(s):  
Alexei Polevoi ◽  
Jevgeni Jakovlev ◽  
Alexander Zaitzev
Keyword(s):  
Male Genitalia ◽  
Large Scale ◽  
General Distribution ◽  
Original Material ◽  
Old Growth ◽  
Fungus Gnats ◽  
Old Growth Forests ◽  
First Time ◽  
Eastern Finland

Thirty-seven species of fungus gnats new to Finland are reported. Eleven of these are reported in Fennoscandia for the first time: Diadocidia fissa Zaitzev, Macrocera estonica Landrock, M. nigricoxa Winnertz, M. pusilla Meigen, Boletina pallidula Edwards, Mycetophila morata Zaitzev, M. ostentanea Zaitzev, Trichonta nigritula Edwards, T. subterminalis Zaitzev & Menzel, Neoempheria winnertzi Edwards and Neuratelia sintenisi Lackschewitz. The records are based on original material collected in large-scale trapping projects in Southern and Eastern Finland mainly in old-growth forests during 1997–1998. Detailed information on Finnish findings, and data on the general distribution of the species are given. Several species are known with only one (typematerial) or a few previous records ranging from Norway to Sakhalin. For two poorly-known species, Neuratelia sintenisi Lackschewitz and Rymosia pinnata Ostroverkhova, new figures of male genitalia are presented.

Aspen detection in boreal forests: Capturing a key component of biodiversity using airborne hyperspectral, lidar, and UAV data

2020 ◽  
Author(s):  
Timo Kumpula ◽  
Arto Viinikka ◽  
Janne Mäyrä ◽  
Anton Kuzmin ◽  
Pekka Hurskainen ◽  
...  
Keyword(s):  
Tree Species ◽  
Boreal Forests ◽  
Large Scale ◽  
Forest Canopy ◽  
Tree Level ◽  
Gradient Boosting ◽  
Support Vector ◽  
Species Classification ◽  
Learning Methods ◽  
European Aspen

<p>Importance of biodiversity is increasingly highlighted as an essential part of sustainable forest management. As direct monitoring of biodiversity is not possible, proxy variables have been used to indicate site’s species richness and quality. In boreal forests, European aspen (Populus tremula L.) is one of the most significant proxies for biodiversity. Aspen is a keystone species, hosting a range of endangered species, hence having a high importance in maintaining forest biodiversity. Still, reliable and fine-scale spatial data on aspen occurrence remains scarce and incomprehensive. Although remote sensing-based species classification has been used for decades for the needs of forestry, commercially less significant species (e.g., aspen) have typically been excluded from the studies. This creates a need for developing general methods for tree species classification covering also ecologically significant species.</p><p> </p><p>Our study area, located in Evo, Southern Finland, covers approximately 83km<sup>2</sup>, and contains both managed and protected southern boreal forests. The main tree species in the area are Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst), and birch (Betula pendula and pubescens L.), with relatively sparse and scattered occurrence of aspen. Along with a thorough field data, airborne hyperspectral and LiDAR data have been acquired from the study area. We also collected ultra high resolution unmanned aerial vehicle (UAV) data with RGB and multispectral sensors.</p><p> </p><p>Our aim is to gather fundamental data on hyperspectral and multispectral species classification, that can be utilized to produce detailed aspen data at large scale. For this, we first analyze species detection at tree-level. We test and compare different machine learning methods (Support Vector Machines, Random Forest, Gradient Boosting Machine) and deep learning methods (3D convolutional neural networks), with specific emphasis on accurate and feasible aspen detection. The results will show, how accurately aspen can be detected from the forest canopy, and which bandwidths have the largest importance for aspen. This information can be utilized for aspen detection from satellite images at large scale.</p>

Twenty-five years of vegetation change along a putative successional chronosequence on the Tanana River, AlaskaThis article is one of a selection of papers from The Dynamics of Change in Alaska’s Boreal Forests: Resilience and Vulnerability in Response to Climate Warming.

2010 ◽  
Vol 40 (7) ◽  
pp. 1273-1287 ◽  
Author(s):  
Teresa N. Hollingsworth ◽  
Andrea H. Lloyd ◽  
Dana R. Nossov ◽  
Roger W. Ruess ◽  
Brian A. Charlton ◽  
...  
Keyword(s):  
Plant Community ◽  
Boreal Forests ◽  
Vegetation Change ◽  
Turning Points ◽  
Community Change ◽  
Ecosystem Structure ◽  
Mature Trees ◽  
Successional Stage ◽  
Long Term Ecological Research

Along the Tanana River floodplain, several turning points have been suggested to characterize the changes in ecosystem structure and function that accompany plant community changes through primary succession. In the past, much of this research focused on a presumed chronosequence that uses space for time substitutions. Within this chronosequence, permanent vegetation plots repeatedly measured over time provide an excellent test of the turning points model. We analyzed both canopy and understory vegetation data collected since 1987 in the Bonanza Creek Experimental Forest at the Bonanza Creek Long Term Ecological Research site to address the following questions: (i) Do long-term changes in the densities of seedling, sapling, and mature trees and shrubs of the dominant woody taxa at each successional stage support the turning points model? (ii) How does the entire plant community change with time at each hypothesized turning point? (iii) Do we see evidence of directional and synchronous shifts in species composition across successional stages? We conclude that some aspects of vegetation change during the last 25 years were consistent with the turning points model; however, many changes were not consistent, indicating the potential roles of biological, environmental, landscape, and climate controls in vegetation patterns.

Nitrogen cycling in undisturbed and manipulated boreal forest

1982 ◽  
Vol 296 (1082) ◽  
pp. 419-425 ◽  
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Forest Canopy ◽  
Mineral Soil ◽  
Terrestrial Ecosystems ◽  
Ecosystem Functions ◽  
Managed Forests ◽  
Available N ◽  
Humus Layer

Like most forests and several other natural terrestrial ecosystems, the boreal forest accumulates N in biomass and soil organic matter, even although measured rates of biological N 2 fixation are normally low. The accumulation of N is disrupted if the forest canopy is removed by natural causes (fire, wind-felling or insect outbreaks) or by cutting. During the period after such a ‘catastrophe’ (in fact a common event in boreal forests, considered in a long-term perspective), the accumulation is discontinued or even changed into a loss of N from the site. Some losses are caused directly by fire or, in managed forests, by removal of biomass. These losses are usually small, except with whole-tree utilization. Nitrogen losses associated with nitrification processes (both leaching and denitrification) may be more serious on a cleared area, where uptake by vegetation is inconsiderable for some period. Nitrate formation may then take place both in the humus layer (the mor) and in the mineral soil, although the pH may be well below 4.5 in the mor layer. Scarcity of available N in the soil is a common cause of slow growth. Effects of fertilization on ecosystem functions are discussed.

Sign in / Sign up

Export Citation Format

Share Document