Forestry is an important industry in Sweden, with clear-cut as the most commonly used method for harvesting. Here the long-term impact of clear-cut on lake water quality (dissolved organic carbon (DOC), nitrogen, phosphorus and pH) has been investigated, based on 23 lakes sampled during autumn. Data for additional 15 lakes sampled for the Swedish monitoring program were also used. Lakes were classified as 5, 25, 40 and 60 year based on data of the forest age in the catchment, gathered from the Swedish national forest inventory. Clear-cut lakes were classified as 5 years (>20% of the catchment clear-cut during the last 10 years). The results showed that DOC and total nitrogen (TN) concentrations decreased with increasing age of the forests. In clear-cut lakes (5 year) average DOC- (20.5 mg/L) and TN concentrations (477 µg/L) were higher than the average concentration in lakes with older forests (25, 40 and 60 year) (i.e. DOC 13.5 mg/L and TN 351 µg/L). Also the quality of DOC were changing (measured as changes in absorbance at 254) with forest age, with more bioavailable (low molecular weight) DOC in clear-cut lakes. A greater clear-cut area compared to the catchment area did not significantly result in higher concentrations of DOC and TN in clear-cut lakes. In conclusion, the concentration of TN, and the concentration and quality of DOC, in small boreal lakes are affected by clear-cutting and are changing with the age of the forest stand. Thus, highest concentrations and more bioavailable carbon compounds are found in clear-cut lakes where forests recently has been removed (<10 year).

The Soil and Water Assessment Tool (SWAT) was used to quantify the potential impacts of clearcutting on hydrologic and water quality components, and assess potential forest biomass production and perform sensitivity analysis of crop parameters to predict forest biomass in the Upper Pearl River Watershed. Results based on clearcutting indicated that the hydrologic and water quality components increases with increase in percentage of forest area harvested. The most significant effect was observed from 55% and 75% harvesting scenarios. The results based on SWAT’s performance to simulate potential forest biomass production showed satisfactory performance and revealed that the watershed has the potential to produce approximately 49 tons/ha of annual forest biomass. The results also revealed that predicted forest biomass was sensitive to three out of the seven crop parameters: Fraction of maximum leaf area index, corresponding to 1stpoint on the optimal leaf area development curve, Radiation use efficiency and maximum LAI.

Tyrimų tikslas - Nustatyti beržynų atsikūrimo galimybes plynose kirtavietėse. Darbo objektas – Šiaulių miškų urėdijos 4 ir 6 metų amžiaus plynos kirtavietės Lc, Ld, Ud, Pcn ir Pdn augavietėse. Metodai – Beržo žėlinių kiekybiniai tyrimai atlikti stačiakampėse apskaitos aikštelėse, kurios atidėtos vadovaujantis miško atkūrimo ir įvesimo nuostatais. Tyrimai atlikti kiekvienoje augavietėje atliekant bent po 3 pakartojimus. Apskaitos aikštelėse nustatytas žėlinių tankis, o išmatavus aukštį, žėliniai suskirstyti į 4 aukštumo grupes: iki 0,5 m aukščio, nuo 0,5 iki 1,0 m aukščio, nuo 1,0 iki 1,5 m aukščio ir virš 1,5 m aukščio. Nustatytas žolinės dangos agresyvumo laipsnis žėlimui ir suskirstytas į 6 grupes. Gretimo medyno įtaka nustatyta atidedant apskaitos aikšteles 15, 35, 55 metrų atstumu nuo vakariniame kirtavietės pakraštyje esančio medyno. Žėliniai vertinti pagal augimo vieta: ruoštoje ar neruoštoje dirvoje. Nustatyta atsikūrimo galimybė skirtingose augavietėse, dirvos paruošimo, konkuruojančios augalijos įtaka žėlinių tankiui ir gyvybingumui. Gyvybingumas nustatytas pagal miško atkūrimo ir įveisimo nuostatus. Rezultatai – Palankiausios sąlygos natūraliam žėlimui nustatytos Lc ir Pcn augavietėse. Nustatyta vakariniame kirtavietės pakrašyje esančo medyno sudėties įtaka žėlinių tankiui. Didėjant beržo kiekiui minėtų medynų sudėtyje, žėlinių tankis didėja. Optimaliausias atstumas, nuo vakariniame kirtavietės pakraštyje esančio medyno, yra 35 metrai. Išaiškinta teigiama dirvos... [toliau žr. visą tekstą] / The aim of our investigation – To determine abilities of birch regeneration in clear cut areas. The object of investigation - 4 and 6 age clear cut areas in Lc, Ld, Ud, Pcn Pdn forest sites of Šiauliai State Forest Enterprise. Methods – Quantitative research of birch seedlings was carried out in rectangular sample plots according to the methodology of statute of reforestation and afforestation with 3 repetition in each forest site. There were determined: density of seedlings, height (seedlings were classified in 4 groups: up to 0,5 m; from 0,5 m to 1,0 m; from 1,0 m to 1,5 m and more than 1,5 meter in height), shading degree of herbal plants for birch regeneration was classified in 6 groups. Smaple plots were set out in 15, 35 and 55 meters from the edge of western side stand for detemination the influence of it. Besides, it was determine the influence of soil preparation, possibilities of birch regeneration in different forest sites, shading plants influence on vitality and density of birch seedlings. Results – it was determined that the most favorable conditions for birch regeneration was in Lc and Pcn forest sites. The higher content of birch in adjacent stand caused the higher density of birch seedlings in clear cut areas. The most optimum distance for birch regeneration was 35 meters from the adjacent western side stand. Besides, it was determined the positive influence of soil preparation on birch seedlings density (unprepared soil had 25 % less seedlings)... [to full text]

Land-use history has been recognized as an important factor in shaping biological communities in clear-cuts. Many solitary bees and flower beetles (Cerambycidae: Lepturinae) are commonly found in clear-cuts, which serve as early successional habitats. I analyzed the effect of land-use history on the abundance and species richness, as well as the preference for land-use history in specific species, of solitary bees and flower beetles in coniferous clear-cuts in southern Sweden. Additionally, the effect of site-specific environmental factors was examined. Insects were caught with blue, white and yellow pan-traps in 48 clear-cuts, of which half were meadow and half were forest in the 1870s. With few exceptions, the species found did not show preference for any land-use history. Furthermore, land-use history had no significant effect on the abundance or species richness of solitary bees or flower beetles. This may be due to pan-traps being less attractive in flower-rich locations, a bias in the sampling method. However, species richness and abundance of solitary bees was higher in young clear-cuts (2-4 years old), probably best explained by more exposed soil and higher frequencies of flowering plants in newer clear-cuts. Abundance of flower beetles was higher in old clear-cuts (6-8 years old). This may be due to larger amounts of more strongly decomposed wood in older clear-cuts, which is used in the flower beetles´ larval development. I conclude that solitary bees are likely to benefit if clear-cuts, particularly with meadow history, are kept more open by introducing disturbance regimes, as suggested by previous studies.

Forests in boreal and temperate forest-ecosystems have importance for carbonbalance since they sequester large amount of atmospheric carbon by uptake ofcarbon-dioxide during photosynthesis, and transfer and store carbon in the forestecosystem. Forest material can be used for bio-fuel purposes and substitute fossilfuels, and supply wood products, which can replace carbon-and-energy-intensivematerials. Therefore it is vital to consider the role of forests regarding today´s aimto mitigate climate change. This thesis assess (i) how climate change affects futureforest carbon balance, (ii) the importance of different strategies for forestmanagement systems, and biomass production for the carbon balance, (iii) how theuse of forest production affect the total carbon balance in a lifecycle perspective,and (iv) how the Swedish carbon balance is affected from the standpoint of boththe actual use of forest raw material within Sweden and what Swedish forestryexports. The analysis was made mainly in a long-term perspective (60-300 years) toillustrate the importance of temporal and also the spatial perspective, as theanalysis includes stand level, landscape level, and national level. In this thesis, forestry was considered a system. All activities, from forestregeneration to end use of forest products, were entities of this system. In theevaluation, made from a systems perspective, we used life-cycle analysis toestimate carbon stock in different system flows. Different forest managementsystems and forest production were integrated in the analyses. Different forestmanagement scenarios were designed for the Swedish forest management incombination with the effect of future climate change; (i) intensive forest practiceaiming at increased growth, (ii) increased forest set-aside areas, changes in forestmanagement systems for biomass production, and (iii) how the use of forestproducts affect the total carbon balance (construction material, bioenergy and otherdomestic use). The results showed that future climate changes and intensive forest managementwith increased production could increase the biomass production and the potentialuse of forest raw material. This has a positive effect on carbon stock change in theforest biomass, litter production and below ground carbon stock and help reducingcarbon-dioxide emissions. Increased forest set-aside areas can increase the shorttermcarbon stock in forest ecosystems, but will reduce the total long-term carbonbalance. The net carbon balance for clear-cut forestry did not differ significantlyfrom continuous-cover forestry, but was rather a question of level of growth. Mostimportant, in the long term, was according to our analysis, how forest raw materialis used. Present Swedish forestry and use of forest raw material, both withinSweden and abroad, reduce carbon-dioxide emissions and mitigate climate change.The positive effect for the total carbon balance and climate benefit mostly takeplace abroad, due to the Swedish high level of export of wood products and thehigher substitution effects achieved outside Swedish borders. One strategy is toincrease production, harvest and use Swedish forest raw material to replace morecarbon intensive material, which can contribute to significant emission reduction.Carbon-dioxide mitigation, as a result of present Swedish forestry, was shown tobe almost of the same level as the total yearly emission of greenhouse gases. Thetotal carbon benefit would increase if the biomass production and felling increasedand if Swedish wood products replaced carbon intensive materials. This thesis shows also that, by changing forest management, increase thegrowth and the use of forest raw material and export of forest material we cancontribute to even larger climate benefits. In a long-term perspective, thesubstitution effects and replacement of carbon-and energy-intensive materials areof greater significance than carbon storage effects in forests. A more productionoriented forestry needs to make balances and increase the prerequisite forbiological diversity, improve recreation possibilities, and protect sensitive landareas and watersheds. Climate benefits, from Swedish forestry, are highly dependent on policydecision-making and how that can steer the direction for the Swedish forestry.

Šiame darbe buvo įvertinta žėlimui paliktų plyno kirtimo biržių jaunuolynų formavimosi priklausomybė nuo motininio medyno rūšinės sudėties. Tyrimo tikslas: Ištirti savaiminio žėlimo intensyvumą ir žėlinių rūšinę sudėtį, priklausomai nuo augavietės ir motininio medyno rūšinės sudėties. Tyrimo uždaviniai: Ištirti savaiminio žėlimo intensyvumą ir jo eigą 5 metų plyno kirtimo biržėse Šiaulių miškų urėdijoje priklausomai nuo augavietės. Ištirti žėlinių rūšinę sudėtį ir jos kitimą, priklausomai nuo motininio medyno rūšinės sudėties. Tyrimo objektas: VĮ „Šiaulių miškų urėdijos“ miškai Iš urėdijos plynų kirtimų registracijos knygų išrinktos 302 2000 -2004 m. plyno kirtimo kirtavietės ir sudarytas jų sąrašas. Detalesni tyrimai atlikti 14 biržių, jose išskirti tyrimo bareliai. Tyrimo metodai: Pagal 1995 m. ir 2006 m. miškotvarkos medžiagą pateikiama buvusio motininio medyno ir augančių jaunuolynų taksacinė charakteristika, bei analizuojama jaunuolyno rūšinės sudėties priklausomybė nuo augavietės tipo ir motininio medyno rūšinės sudėties. Detalesni tyrimai buvo atliekami remiantis lauko tyrimais atsienojant laikinas tyrimo aikšteles. Tyrimo rezultatai: Tyrimo eigoje nustatyta, kad motininio medyno rūšinė sudėtis turi didžiausią įtaką savaiminiam žėlimui ir atsikūrusio miško rūšinei sudėčiai. Beržynai formuojasi, kai motininio medyno rūšinėje sudėtyje, buvo 1 dalis beržo ir greta auga derantys beržynai. Juodalksnio jaunuolynas susiformuoja, kai motininio medyno sudėtyje 5 ir daugiau... [toliau žr. visą tekstą] / The aim of present study was to evaluate relationship of young self-generating stand from previous generation stand after clear cut. The object of this study is situated in Šiauliai forest enterprise forest stands. Also there were clear-cutting registration papers and forest inventory of year 1995-2006 analyzed in this study. It was found that bigger area is after clear-cutting for self generating and species composition of previous generation stand has the main influence to self generating and species composition of new self generating stand.

During the summer of 2013 the environmental office at Lycksele Municipality received a complaint, regarding algal blooms at the stream outlet between the lakes Kalven and Byssträsket in the southern parts of Lycksele Municipality. No deeper studies were made to ensure what could have caused the bloom. The purpose of this report was to examine if there was a specific source contributing to high levels of nutrients in the stream, mainly focusing on clear-cuts and a small dam by the stream inlet, and if the nutrient status differed along the stream flow. Therefore, suitable sites were picked for examination, following the stream flow between the two lakes, and in a stream not affected by clear-cuts for reference. Water samples were picked at each site, determining the status of the parameters total-nitrogen, total-phosphorus, nitrate, ammonium, pH and conductivity. The result showed quite high levels of total-phosphorus (ranging from 40-50 µg/l) and total-nitrogen (ranging from 350-450 µg/l), but low levels of ammonium and nitrate. The results showed no sign of a nutrient input from a specific location. The conclusion of this study is that the present nutrient levels could be high enough to result in a bloom, though probably dependent on contributing factors, such as warmer weather and lower water levels. An alternative explanation is that the nutrient levels could have been higher 2013, deriving from new clear-cuts, but that these clear-cuts stopped leaching nutrients due to older age. Hence, due to lack of previous studies no exact assumption can be made

Emissions of greenhouse gasses, such as carbon dioxide, have been shown to be strongly connected global warming. In 2020 the European Union adopted the goal of reducing emissions of greenhouse gasses to a net of zero before year 2050. This is essential for keeping the average global temperature rise below 1.5 degrees. A large source of carbon dioxide emissions in Sweden is the forestry sector. The carbon balance in ecosystems is usually disturbed due to clear-cutting, which is the main silvicultural system used in Sweden. Introducing more sustainable silvicultural systems, such as continuous cover forestry, is a measure that authorities advocate. This study aimed to examine emissions of carbon dioxide from two timber sources that may be used for a bridge construction in Skellefteå. The timber would either come from a local clear-cut, transported by truck, or from continuous cover forestry in Lithuania, transported to Sweden by ship. The result is based on literature and calculations on data from previous studies. The results showed effects on carbon balance due to different silvicultural systems are complex, though the alternative with continuous cover forestry seemed to contribute to less emissions, despite the timber not being locally produced. The main factor between the systems, and therefore the different levels of emissions, seems to be highly dependent on how much of the harvested trees that is suitable for timber. However, emissions will also depend on local conditions such as timber storage. Therefore, it is important to take this into account when comparing silvicultural systems.

Habitat loss and fragmentation due to agricultural practices are causing worrying declines in insect diversity and biomass. Agricultural intensification, among other things, have led to a decline in semi-natural grasslands. Forest in the surrounding landscape can have a positive effect on species abundance in grasslands. Clear-cut forest have been identified as a supporting habitat for grassland species as they contain important resources. Clear-cuts can also support a wide variety of insects, both grassland species and forest species. In this study, I examined how different land covers in the surrounding landscape affected species abundance on clear-cuts in southeastern Sweden. Using data of insects collected in three previous studies, I tested the hypothesis that insects on clear-cuts benefit from other clear-cuts in the surrounding landscape. I also tested at which spatial scales the surrounding landscape mainly exerted its influence. The results were not in line with the hypothesis and showed that forest in the surrounding landscape had a positive effect on species abundance on clear-cuts, whereas clear-cuts had a negative effect. There were no clear patterns over different scales, although the smallest scale of a 250 m radius produced the highest number of significant results. A lot of insects recorded on the clear-cuts were generalists associated with both forest and agricultural landscape. The reason for the negative effect of clear-cuts needs further investigation.

No description available.