Eri tekijöiden vaikutus metsänuudistamiseen MHY Karhun alueella vuonna 2013

Tavoitteena opinnäytetyössä oli selvittää eri tekijöiden vaikutusta metsänuudistamisen onnistumiseen metsänhoitoyhdistyksen toimialueella. Tekijät, joiden vaikutusta metsänuudistamiseen selvitettiin, olivat kasvupaikkaluokka, maanmuokkaus, maalaji ja uudistamisesta vastannut taho. Puulajeista mukana olivat mänty ja kuusi. Lisäksi uudistusaloilla huomioitiin kivisyyden, märkyyden, pintakasvillisuuden ja lehtipuuston esiintymistä. Työssä sovellettiin aiheeseen liittyvän kirjallisen aineiston lisäksi metsänhoitoyhdistyksen tietokannasta saatua materiaalia, joka mahdollisti työhön sisältyneiden maastomittausten toteuttamisen. Maastomittaukset suoritettiin 40 uudistusalalla, jotka arvottiin kaikkien vuonna 2013 paakkutaimilla istutettujen uudistusalojen joukosta. Maastomittauksista saadut tiedot analysoitiin vertailukelpoisen aineiston aikaansaamiseksi. Saatujen tulosten perusteella taimitiheydet jäivät alle tavoiteltujen perustamistiheyksien pääosalla työssä mukana olleista uudistusaloista. Männyllä metsänuudistamisen laatuvaihtelut olivat pienempiä kuin kuusella. Varsinaisesti kehityskelvottomaksi todettuja taimikoita ei kuitenkaan tavattu, kuin yksi, kuuselle istutettu uudistusala. Työssä mukana ollut aineisto jakautuu melko pieniin kokonaisuuksiin, joten saaduista tuloksista muodostettuihin johtopäätöksiin on syytä suhtautua hieman varauksella.When I was working in practical training in the Forest management association, Karhu, I asked the possibility to make my thesis for Karhu. They were interested in finding out succeeding the forest regeneration and different factors which impact to it. My aim was to find out the impact of different factors to succeeding forest regeneration in the district of forest management association. Factors which were taken into this study were: reformer, category of growing place, soil cultivation and soil type. Species of trees were: pinus sylvestris and picea abies. In addition in seedlings factors like stoniness, wetness, ground vegetation and deciduos trees were taken into account. In this thesis was used different research of the same topics and the database of forest management association which allowed to carry out the field measurement. The field measurements were done in 40 seedlings which were chosen by change among all the seedlings which were done in the year 2013 and in which were used seedlings. The facts of field measurement were analysed to find combarable Data. The results show that the frequency of seedlings was lower than expected. Pinus Sylvestris had lower quality variation than Picea Abies. But only one seedling which was not developable was found and that was seedling of picea abies. The data of this study is diveded into relatively small entities and that must be taken into account when making conclusions of these results

Petrographic, mineralogical and geochemical study of the Mäkärä Au-Fe mineralization, Tanaelv belt, northern Finland

The Mäkärä mineralization is located in the Tanaelv Belt next to the Lapland Granulite Belt. It is a hydrothermal vein-type deposit enriched in gold and iron. The aim of this study was to provide a geological and mineralogical overview of the mineralization and classify the associated rock types and their alteration styles. In addition, a formation model, mineral paragenesis and possible classification of the mineralization are discussed. Geochemical data, hand samples and thin sections were provided by the Geological Survey of Finland (GTK). A total of 20 thin sections were selected for petrographic study, which was done in Oulu Mining School. In addition, chemical analysis was made on selected minerals from 11 thin sections with a field emission scanning electron microscope (FESEM) in the University of Oulu. Geochemical data were utilized in studying the correlation of different elements with gold. A lithological map and a W-E cross section were compiled from the research area using geophysical, drilling and bedrock observation data of GTK. The results of petrological, geochemical and FESEM studies showed that the major vein minerals are hematite, quartz, pyrite, and magnetite. Multiple vein generations with variable mineral assemblages were recognized. The major rock types hosting ore-bearing veins are arkose- and granite gneisses, arkose quartzite, and amphibolite. Sericite, quartz, propylitic, carbonate and limonite alterations were observed. Gold occurs as native microscopic (≤20 µm) grains and is hosted by pyrite and limonite in ore veins. Silver and iron were detected in gold grains in FESEM analyses. In whole-rock compositions, gold correlates with silver, bismuth, iron, tellurium, and tungsten. The results also suggest that gold has been remobilized after brittle deformation and/or vein recrystallization. The Mäkärä mineralization could not be assigned to any specific gold deposit class. The most feasible analogues are distal granitoid-related IRG, IOCG, or epithermal Au ± Ag occurrences related to porphyry Cu systems. The genesis of the Mäkärä mineralization is probably related to the ca. 1.77 Ga Nattanen granite intrusions