scholarly journals Continuity forest or second-generation forest? Historic aerial photos provide evidence of early clear-cutting in northern Sweden

Silva Fennica ◽  
2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Hanna Lundmark ◽  
Lars Östlund ◽  
Torbjörn Josefsson

Modern forestry, which mainly consists of clear-cutting, is one of the most important factors influencing today’s boreal forests. In Sweden, the breaking point for modern forestry is generally considered to be around 1950. Recently, our common knowledge of the implementation of clear-cutting in Sweden has increased, and new research indicates that clear-cutting systems were already applied before the 1950s. In this case study, we used aerial photographs from the 1940s to analyze the extent of contemporaneous clear-cuts and even-aged young forests in an area in northern Sweden. Our results show that almost 40% of the study area had already been clear-cut by the end of the 1940s, but also that clear-cutting had been applied to 10% of the forest land in the early 1900s. This implies that the historical development of forestry in northern Sweden is more complex than previously thought, and that certain proportions of the forest land were already second-generation forests in the 1950s. Our results have implications for the use of concepts such as “continuity forest”, suggesting that this concept should employ a time frame of at least 100 years.

2020 ◽  
Vol 50 (8) ◽  
pp. 819-828
Author(s):  
Matti Koivula ◽  
Harri Silvennoinen ◽  
Hanna Koivula ◽  
Jukka Tikkanen ◽  
Liisa Tyrväinen

Forest management, characterized in many northern countries by the predominance of clear cutting and growing even-aged and -sized trees, has simplified the structure of boreal forests. Consequences include alterations in cultural ecosystem services such as forest attractiveness, i.e., combined aesthetic and recreational values. Continuous-cover forestry might mitigate these effects through the use of selection and gap cutting, but these methods have been little studied, particularly from the attractiveness viewpoint. We used photo surveys to assess Finnish citizens’ perceptions of attractiveness of in-stand scenery of Scots pine (Pinus sylvestris L.) forests logged using different methods. (i) The attractiveness scores, given by respondents, declined steadily from unharvested forest through continuous-cover methods to seed-tree and clear-cut methods. (ii) Respondents with a negative attitude to forest management gave lower scores than respondents with a positive attitude, but the declining slopes of attractiveness against logging intensity were similar. (iii) In unharvested and less intensively managed stands, summer photos received higher scores than corresponding winter photos. (iv) Background variables (gender, education, living environment, memberships in recreational or nature NGOs, forestry profession, and forest ownership) had negligible effects on the scores. We recommend the use of continuous-cover logging methods in settlement and recreational areas.


2020 ◽  
Author(s):  
Iris Mužić ◽  
Patrik Vestin ◽  
Anders Lindroth ◽  
Meelis Mölder ◽  
Tobias Biermann ◽  
...  

<p>Land cover conversion affects climate by imposing perturbations in the surface properties and greenhouse gas fluxes. Forest management systems often disregard that modification in surface albedo influences the exchange of energy and greenhouse gases. In this study, we examine the net climatic effect of clear-cutting in high-latitude regions by comparing the importance of biogeophysical (albedo) and biogeochemical (carbon dioxide release) changes in Sweden. The hypothesis is that the albedo effect of high-latitude clear-cutting can reduce climate warming.</p><p>Data on incoming and reflected shortwave radiation was obtained from four-component net radiometers installed in the forest and neighbouring clear-cut sites, in southern (56°N), central (60°N) and northern (64°N) Sweden. The study site pairs along a latitudinal gradient were chosen to account for different climatic conditions. Data at these station pairs covered a continuous period of three (2016-2018), five (2014-2018) and one year (2014), respectively. Due to lack of clear-cut measurement stations in close vicinity to the northernmost forest site, the shortwave radiation data was retrieved from an open mire, where albedo and its temporal dynamics are similar to a clear-cut. All the forest stations and the mire station are part of ICOS Sweden network. Data on carbon dioxide release from clear-cutting was estimated as a difference in the aboveground carbon stock of the standing biomass between forest and clear-cut sites. The estimated carbon dioxide release was translated into an equivalent change in absorbed shortwave radiation and compared to the radiative forcing by albedo difference between forest and clear-cut sites.</p><p>Our results underline results from previous studies showing that the magnitude of the net radiative forcing by clear-cutting varies considerably depending on the latitudinal position of the examined sites. Based on available data, clear-cutting in southern and central Sweden had a warming effect on the climate while in northern Sweden clear-cutting had a net cooling effect. However, large inter-annual variability (central Sweden) and lack of available continuous data (northern Sweden) resulted in high uncertainty of the climatic effects of changes in net radiative forcing due to clear-cutting. Our study indicates that the albedo effect has an essential role in the estimation of the climatic effect of clear-cutting and should thus be incorporated in future forest management strategies.</p>


2007 ◽  
Vol 85 (12) ◽  
pp. 1158-1170 ◽  
Author(s):  
Sybille Haeussler ◽  
Yves Bergeron ◽  
Suzanne Brais ◽  
Brian D. Harvey

Southern boreal forests dominated by trembling aspen ( Populus tremuloides Michx.) are notable for the biological richness of their plant communities. We used 12 plant community and plant functional group indicators to test the hypothesis that natural dynamics-based silvicultural systems better maintain biodiversity in aspen plant communities than conventional clear-cutting. Using CA ordination, box-and-whisker diagrams, and ANOVA, we compared the range of variability of our 12 bioindicators among five experimental stand types of the sylviculture et aménagement forestier écosystémiques (SAFE) project: mature (78 years) uncut; mature 1/3 partial-cut; mature 2/3 partial-cut; young (3 years) unburned clear-cut; young burned clear-cut; and three closely matched aspen stand types of northwest Quebec and northeast Ontario: old (105 years) uncut; young unburned clear-cut; young wildfire. Burned clearcuts partially emulated wildfires by reducing tall shrub abundance and regenerating post-fire specialists, but snags were lacking. The dual disturbance also retarded aspen regrowth and caused a 7-fold increase in non-native plants. Partial-cuts retained most attributes of mature uncut stands, but after 3 years showed little evidence of accelerating development of old stand characteristics. We concluded that SAFE natural dynamics-based silviculture better recreated the range of variability of naturally disturbed aspen plant communities than conventional clear-cutting. Improvements, including alternative burn prescriptions and snag or green tree retention in clearcuts, are nontheless warranted.


1983 ◽  
Vol 61 (5) ◽  
pp. 970-980 ◽  
Author(s):  
Arthur M. Martell

Changes in small mammal communities following logging were monitored in clear-cut and strip-cut upland black spruce (Picea mariana) stands and in selectively cut mixed wood stands in north-central Ontario. Clear-cutting and subsequent scarification essentially eliminated the vegetative cover. Much of the ground cover recovered within 5 years and shrubs within 12 years, but mosses and lichens took much longer. The small mammal community in both clear-cut and strip-cut stands changed over the first three years after logging from one dominated by southern red-backed voles (Clethrionomys gapperi) to one dominated by deer mice (Peromyscus maniculatus) and then remained relatively stable for up to 13 years after harvest. That shift was not apparent in selectively cut mixed wood stands where the composition of the small mammal community was similar between uncut stands and stands 4–23 years after harvest. There was relatively little change in total numbers of small mammals after logging. In general, the diversity and evenness of small mammals increased or remained stable in the first 1–3 years following harvest, decreased on older (3–16 years) cuts, and then increased to values similar to those in uncut stands on the oldest (19–23 years) cuts.


2016 ◽  
Vol 359 ◽  
pp. 65-73 ◽  
Author(s):  
Therese Johansson ◽  
Joakim Hjältén ◽  
Jörgen Olsson ◽  
Mats Dynesius ◽  
Jean-Michel Roberge

2007 ◽  
Vol 363 (1501) ◽  
pp. 2339-2349 ◽  
Author(s):  
Seppo Kellomäki ◽  
Heli Peltola ◽  
Tuula Nuutinen ◽  
Kari T Korhonen ◽  
Harri Strandman

This study investigated the sensitivity of managed boreal forests to climate change, with consequent needs to adapt the management to climate change. Model simulations representing the Finnish territory between 60 and 70° N showed that climate change may substantially change the dynamics of managed boreal forests in northern Europe. This is especially probable at the northern and southern edges of this forest zone. In the north, forest growth may increase, but the special features of northern forests may be diminished. In the south, climate change may create a suboptimal environment for Norway spruce. Dominance of Scots pine may increase on less fertile sites currently occupied by Norway spruce. Birches may compete with Scots pine even in these sites and the dominance of birches may increase. These changes may reduce the total forest growth locally but, over the whole of Finland, total forest growth may increase by 44%, with an increase of 82% in the potential cutting drain. The choice of appropriate species and reduced rotation length may sustain the productivity of forest land under climate change.


Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1542
Author(s):  
Nadezhda V. Genikova ◽  
Viktor N. Mamontov ◽  
Alexander M. Kryshen ◽  
Vladimir A. Kharitonov ◽  
Sergey A. Moshnikov ◽  
...  

Bilberry spruce forests are the most widespread forest type in the European boreal zone. Limiting the clear-cuttings size leads to fragmentation of forest cover and the appearance of large areas of ecotone complexes, composed of forest (F), a transition from forest to the cut-over site under tree canopy (FE), a transition from forest to the cut-over site beyond tree canopy (CE), and the actual clear-cut site (C). Natural regeneration of woody species (spruce, birch, rowan) in the bilberry spruce stand—clear-cut ecotone complex was studied during the first decade after logging. The effects produced by the time since cutting, forest edge aspect, and the ground cover on the emergence and growth of trees and shrubs under forest canopy and openly in the clear-cut were investigated. Estimating the amount and size of different species in the regeneration showed FE and CE width to be 8 m—roughly half the height of first-story trees. Typical forest conditions (F) feature a relatively small amount of regenerating spruce and birch. The most favorable conditions for natural regeneration of spruce in the clear-cut—mature bilberry spruce stand ecotone are at the forest edge in areas of transition both towards the forest and towards the clear-cut (FE and CE). Clear-cut areas farther from the forest edge (C) offer an advantage to regenerating birch, which grows densely and actively in this area.


Author(s):  
George Montopoli ◽  
Hank Harlow ◽  
W. Smith, MD ◽  
A. Wheeler, MD ◽  
Andy Byerly ◽  
...  

Advancing global climate change and associated desiccation of temperate and boreal forests, exacerbated by extensive clear-cutting, may increase poisoning of aquatic ecosystems with high levels of contaminants, especially Hg. We report on contaminants identified in nestling bald eagles and wildland firefighters of the Teton Ecosystem (Grand Teton National Park (GTNP) and the Snake River Unit (SRU), Wyoming) during summers of 2006, 2007 and 2008. In bald eagles, we focus primarily on mercury (Hg), lead (Pb), and selenium (Se) because each was detected in all nestlings during all summers at moderate levels. In wildland firefighters, we report primarily on Hg due to potential contamination from Hg when fighting fires and ingesting smoke and particulates produced by those fires. We feel that studying Hg both in the eagles and humans simultaneously is a better indicator of the general health of the environment than studying them separately. Both humans and bald eagles occupy top tiers on the food web, and intricately reflect the status of the environment. Results of the bald eagle analyses showed trends indicating increases in Hg and Pb from 2006 to 2007, and decreases from 2007 to 2008. Selenium essentially remained constant from 2006 to 2007 and increased from 2007 to 2008. In wildland firefighters, Hg appears to be elevated in those firefighters who are exposed to significant levels of smoke and particulates, both in 2007 and 2008. Conjectures about firefighters, however, are not statistically significant due to small sample sizes and logistical problems. Encouraging trends in bald eagle contaminant levels from 2007 to 2008 suggest reduction (or stabilization) of contaminant concentrations in the Teton Ecosystem. We also encourage the continued elimination of Pb attributable to humans (lead ammunition, lead shot, etc.) from the Teton Ecosystem. We encourage periodic monitoring of contaminants in the Teton Ecosystem, minimally at five-year intervals (Harmata 1996), unless unexpected events mandate more immediate monitoring. In wildland firefighters, we suggest a well-designed, comprehensive research study for summer 2009, to immediately address future ecological issues that are emerging due to climate change.


2019 ◽  
Vol 101 (3) ◽  
pp. 42-47
Author(s):  
Thomas R. Guskey

Opinions about whether comments, grades, or both are the most effective forms of feedback vary widely among teachers, school leaders, and even grading and assessment consultants. Thomas Guskey maintains that the truth is not as clear-cut as some suggest. He reviews the research, going back to the 1950s, to better understand when certain types of feedback are most useful. He concludes that grades and comments are not, in and of themselves, beneficial to student learning. Effective feedback, whether in the form of grades or comments, must give students a sense of where they are and what they need to do to improve.


2020 ◽  
Vol 50 (7) ◽  
pp. 608-614
Author(s):  
Ronei Baldissera ◽  
Suiane Oliveira de Quadros ◽  
Gabriela Galeti ◽  
Everton Nei Lopes Rodrigues ◽  
Luan M.V. Lazzarotto ◽  
...  

Habitat loss is one of the main consequences of landscape transformation by humans. Monitoring biodiversity changes in areas under different management strategies is fundamental for species conservation. Our study is the first to assess the role of forest disturbance history on spider (Araneae) biodiversity in the westernmost portion of the Atlantic Forest. We analyzed taxonomic and functional aspects of spider assemblages in understories in a large forest fragment in southwestern Brazil. Spiders were sampled in five 30 m × 5 m plots over three seasons in three areas with different management histories: clear-cutting, selective logging, or native plots. We also characterized tree basal area, tree density, and canopy openness. The clear-cut plots showed more canopy openness and low habitat heterogeneity due to the high density of one pioneer native tree species. Forest structure in selective logging and native plots was similar. Spider richness, abundance, and functional richness were affected only by the season. Species composition also differed among the areas depending on the season. The abundance of web-building species was mainly associated with clear-cut areas in winter and spring. These results highlight the importance of natural regeneration in the Atlantic Forest after disturbance for the conservation of regional spider biodiversity.


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