scholarly journals Impacts of Clear-Cutting of a Boreal Forest on Carbon Dioxide, Methane and Nitrous Oxide Fluxes

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 961
Author(s):  
Patrik Vestin ◽  
Meelis Mölder ◽  
Natascha Kljun ◽  
Zhanzhang Cai ◽  
Abdulghani Hasan ◽  
...  

The 2015 Paris Agreement encourages stakeholders to implement sustainable forest management policies to mitigate anthropogenic emissions of greenhouse gases (GHG). The net effects of forest management on the climate and the environment are, however, still not completely understood, partially as a result of a lack of long-term measurements of GHG fluxes in managed forests. During the period 2010–2013, we simultaneously measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes using the flux-gradient technique at two clear-cut plots of different degrees of wetness, located in central Sweden. The measurements started approx. one year after clear-cutting, directly following soil scarification and planting. The study focused on robust inter-plot comparisons, spatial and temporal dynamics of GHG fluxes, and the determination of the global warming potential of a clear-cut boreal forest. The clear-cutting resulted in significant emissions of GHGs at both the wet and the dry plot. The degree of wetness determined, directly or indirectly, the relative contribution of each GHG to the total budgets. Faster establishment of vegetation on the wet plot reduced total emissions of CO2 as compared to the dry plot but this was partially offset by higher CH4 emissions. Waterlogging following clear-cutting likely caused both plots to switch from sinks to sources of CH4. In addition, there were periods with N2O uptake at the wet plot, although both plots were net sources of N2O on an annual basis. We observed clear diel patters in CO2, CH4 and N2O fluxes during the growing season at both plots, with the exception of CH4 at the dry plot. The total three-year carbon budgets were 4107 gCO2-equivalent m−2 and 5274 gCO2-equivalent m−2 at the wet and the dry plots, respectively. CO2 contributed 91.8% to the total carbon budget at the wet plot and 98.2% at the dry plot. For the only full year with N2O measurements, the total GHG budgets were 1069.9 gCO2-eqvivalents m−2 and 1695.7 gCO2-eqvivalents m−2 at the wet and dry plot, respectively. At the wet plot, CH4 contributed 3.7%, while N2O contributed 7.3%. At the dry plot, CH4 and N2O contributed 1.5% and 7.6%, respectively. Our results emphasize the importance of considering the effects of the three GHGs on the climate for any forest management policy aiming at enhancing the mitigation potential of forests.

2001 ◽  
Vol 31 (6) ◽  
pp. 999-1011 ◽  
Author(s):  
T L Wurtz ◽  
J C Zasada

We present 27-year results from a comparison of clear-cutting and shelterwood harvesting in the boreal forest of Alaska. Three patch clear-cut and three shelterwood units were harvested in 1972; about 100 dispersed white spruce (Picea glauca (Moench) Voss) leave trees per hectare were retained in the shelterwoods. Units were mechanically scarified and an exceptionally large seed-crop was dispersed that year. Shelterwood trees were removed after 15 years. After 27 years, overstory treatment had no effect on the density or growth of the species we studied, while scarification had highly significant effects. In 1999, scarified areas were densely populated with white spruce seedlings and saplings (118 000 – 129 000 stems/ha, with spruce in 100% of plots). Unscarified areas had far fewer spruce stems but were nevertheless well stocked (11 000 – 15 000 stems/ha, with 87% frequency). Initially, spruce grew best on scarified surfaces, but by 27 years, growth of the tallest spruce saplings was significantly greater on unscarified than scarified surfaces. By 27 years, cover of the grass Calamagrostis canadensis (Michx.) Nutt. had returned to preharvest levels in all treatment types. Because criteria for evaluating forest management practices have changed since this study was begun, partial overstory retention systems for the management of Alaska's boreal forest deserve further study.


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>


2014 ◽  
Vol 11 (18) ◽  
pp. 5245-5258 ◽  
Author(s):  
K. Sturm ◽  
Z. Yuan ◽  
B. Gibbes ◽  
U. Werner ◽  
A. Grinham

Abstract. Reservoirs have been identified as an important source of non-carbon dioxide (CO2) greenhouse gases with wide ranging fluxes for reported methane (CH4); however, fluxes for nitrous oxide (N2O) are rarely quantified. This study investigates CH4 and N2O sources and emissions in a subtropical freshwater Gold Creek Reservoir, Australia, using a combination of water–air and sediment–water flux measurements and water column and pore water analyses. The reservoir was clearly a source of these gases as surface waters were supersaturated with CH4 and N2O. Atmospheric CH4 fluxes were dominated by ebullition (60 to 99%) relative to diffusive fluxes and ranged from 4.14 × 102 to 3.06 × 105 μmol CH4 m−2 day−1 across the sampling sites. Dissolved CH4 concentrations were highest in the anoxic water column and sediment pore waters (approximately 5 000 000% supersaturated). CH4 production rates of up to 3616 ± 395 μmol CH4 m−2 day−1 were found during sediment incubations in anoxic conditions. These findings are in contrast to N2O where no production was detected during sediment incubations and the highest dissolved N2O concentrations were found in the oxic water column which was 110 to 220% supersaturated with N2O. N2O fluxes to the atmosphere were primarily through the diffusive pathway, mainly driven by diffusive fluxes from the water column and by a minor contribution from sediment diffusion and ebullition. Results suggest that future studies of subtropical reservoirs should monitor CH4 fluxes with an appropriate spatial resolution to ensure capture of ebullition zones, whereas assessment of N2O fluxes should focus on the diffusive pathway.


2001 ◽  
Vol 31 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Sonia de Bellefeuille ◽  
Louis Bélanger ◽  
Jean Huot ◽  
Agathe Cimon

We compared utilization by the snowshoe hare (Lepus americanus Erxleben) of recent clearcuts subjected to three regeneration scenarios commonly used in boreal forest: natural regeneration, plantation with herbicide release (glyphosate), and plantation with manual release (brushsaw). Refuges for snowshoe hare, on a landscape dominated by clearcuts, were also investigated. Colonization of regenerating sites by the hare comes late in the humid boreal forest because clear-cut stands take more than 10 years to reach the sapling stage. Our sites were in the seedling stage 7–9 years after cutting, and hares avoided them year round because of an inadequate protective cover. Therefore, regeneration treatments did not affect habitat use by the hare on a short-term basis. During the seedling stage, the snowshoe hare were found in the remaining forest which occupied at least 25% of the area of each home range. The preservation of residual forests is thus essential to maintain local populations on an area dominated by commercial clearcuts.


2019 ◽  
Vol 2 ◽  
Author(s):  
Bela Tóthmérész ◽  
Tibor Magura ◽  
Szabolcs Mizser ◽  
David D. Nagy

Increased fragmentation and considerable environmental changes in native forests caused by the timber-oriented forest managements are threatening the biodiversity of forests. As a remediation, uneven-aged approach is recommended during forest management, because this is less intensive and could be less harmful than even-aged practices. We tested the effects of clear-cutting (as even-aged method) and group selection harvesting (as uneven-aged method) on carabids in lowland oak forests. Pitfall traps and litter sifting were used during the study. We found that the total number of species was significantly higher in the gaps harvested by group selection and in the clear-cut than in the mature forests (control area). The species richness of forest specialist species was significantly lower in the clear-cuts than in the other area. Our findings demonstrated that the conventional clear-cutting caused a decrease in the number of forest specialist species. Therefore, group selection method should be favoured during forest management to maintain diversity.


2014 ◽  
Vol 11 (21) ◽  
pp. 6095-6105 ◽  
Author(s):  
E. Sundqvist ◽  
P. Vestin ◽  
P. Crill ◽  
T. Persson ◽  
A. Lindroth

Abstract. Forest management practices can alter soil conditions, affecting the consumption and production processes that control soil methane (CH4) exchange. We studied the short-term effects of thinning, clear-cutting and stump harvesting on the CH4 exchange between soil and atmosphere at a boreal forest site in central Sweden, using an undisturbed plot as the control. Chambers in combination with a high-precision laser gas analyser were used for continuous measurements. Both the undisturbed plot and the thinned plot were net sinks of CH4, whereas the clear-cut plot and the stump harvested plot were net CH4 sources. The CH4 uptake at the thinned plot was reduced in comparison to the undisturbed plot. The shift from sink to source at the clear-cut and stump harvested plots was probably due to a rise in the water table and an increase in soil moisture, leading to lower gas diffusivity and more reduced conditions, which favour CH4 production by archea. Reduced evapotranspiration after harvesting leads to wetter soils, decreased CH4 consumption and increased CH4 production, and should be accounted for in the CH4 budget of managed forests.


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.


Tellus B ◽  
2007 ◽  
Vol 59 (3) ◽  
pp. 458-469 ◽  
Author(s):  
M. Pihlatie ◽  
J. Pumpanen ◽  
J. Rinne ◽  
H. Ilvesniemi ◽  
A. Simojoki ◽  
...  

2018 ◽  
Vol 41 ◽  
pp. 1-12 ◽  
Author(s):  
Per Gustav Thingstad ◽  
Marc Daverdin ◽  
James D. M. Speed

Forest management has substantially altered Fennoscandian forests through clear-cutting practices started during the 1950s. Impacts on the natural biodiversity in mature boreal forest have been inevitable. The Capercaillie (Tetrao urogallus) is often regarded as an indicator species for natural old growth forest, displaying on traditional lek sites during spring. In a heterogeneous forest landscape of two adjoining municipalities in central Norway we studied whether forest management or other environmental factors can have influenced the lek distribution. We identified 15 active leks and 12 recently abandoned leks. The maximum entropy distribution modelling (MaxEnt) was used to investigate factors associated with lek distribution at two different scales, where the scale reflecting the lek site areas gave the most adequate result. Active leks were predominantly associated with mature stands of forest. In 65% of the study area the habitat suitability for lekking was most influenced by forest management. Furthermore, the recently abandoned leks were found less frequently in low productive and mature forests than the still active ones, implying that previous leks in productive forest stands may have been lost through logging. Based on our data we have developed models for the predicted distribution and the current limiting factors, showing that altered forest management could improve lek site suitability in large parts of this boreal forest.


Sign in / Sign up

Export Citation Format

Share Document