Long-Term Effects of Silvicultural Practices on Groundwater Quality in Boreal Forest Environment

2012 ◽  
pp. 192-199 ◽  
Author(s):  
E. Kubin
2020 ◽  
Author(s):  
Julia Schneider ◽  
Kristina Höhler ◽  
Paavo Heikkilä ◽  
Jorma Keskinen ◽  
Barbara Bertozzi ◽  
...  

<p>By triggering the formation of cloud ice crystals in the atmosphere, ice-nucleating particles (INP) strongly influence cloud properties, cloud life cycle and precipitation. Describing the abundance of atmospheric INPs in weather forecasts and climate projections remains challenging, as the global distribution and variability of INPs depend on a variety of different aerosol types and sources. Although widespread field measurements have been conducted, neither short-term variability nor long-term seasonal cycles have yet been well characterized by continuous measurements. In 2018, the University of Helsinki and the Karlsruhe Institute of Technology (KIT) initiated a field campaign HyICE to perform comprehensive long-term INP measurements in the Finnish boreal forest. The campaign took place in Hyytiälä, Southern Finland at the University of Helsinki SMEARII research station (Hari and Kulmala, 2005). KIT provided the INSEKT (Ice Nucleation Spectrometer of the Karlsruhe Institute of Technology) to analyse the INP content of ambient aerosols sampled on filters. INSEKT is able to measure INP concentrations in the immersion-freezing mode at temperatures between 273 K and 248 K. The measurements started in March 2018 and ended in May 2019, which provides a unique continuous long-term time series of INP concentrations for over more than one year with a time resolution of about one to three days. This long-term observation record is used to examine systematic seasonal trends in the INP concentrations and to find meteorological and aerosol related parameters to describe the observed trends and variabilities. These findings will enable to find new parameterizations of atmospheric INP concentrations, as current parameterizations do not reproduce the observed seasonal cycle yet. In addition to INP concentration measurements, heat treatment tests of the aerosol samples have been conducted providing additional indications about the INP types dominating the INP population in the boreal forest, also in dependence on the season. Finally, this contribution will summarize and discuss major findings and implications from the HyICE long-term INP observation.</p><p> </p><p>Hari and Kulmala (2005), Boreal Environ Res. 14, 315-322.</p>


2008 ◽  
Vol 84 (5) ◽  
pp. 741-747 ◽  
Author(s):  
Ian D Thompson ◽  
James A Baker ◽  
Christopher Jastrebski ◽  
Jennifer Dacosta ◽  
John Fryxell ◽  
...  

Much of the southern boreal forest is composed of second-growth stands that have been subjected to a variety of silvicultural treatments ranging from cut and leave to scarification, planting, and tending with herbicides. We have limited understanding of the effects that these treatments may have on wildlife species, as a result of changes to forest structures and species composition. Forest amphibians, generally, and the American marten (Martes americana) are species for which there has been long-standing concern about the effects of forest management. We examined the long-term effects at stand and landscape scales of a range of silviculture intensities on these species by comparing the relative abundances of some amphibians and habitat use by marten in forests that were about 32 to 50 years old. American toads (Bufo americanus) appeared to be unaffected by long-term changes in habitat structure and composition owing to silvicultural techniques. We observed lower relative abundance of wood frogs (Rana sylvatica) in treated stands 20 to 30 years old than in all other stands including uncut old forests. However, abundance in treated stands more than 32 years old did not differ from untreated or uncut stands. This effect may have resulted from lower moisture levels in treated young stands. Marten seemed to positively respond to post-harvest planting and tending treatments, suggesting that basic silviculture provided habitat attributes, notably a higher conifer content, which was favourable to marten. Key words: post-harvest silviculture, marten, wood frog, American toad, herbicide, boreal, woody debris, Ontario


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