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L’objectif de cette thèse était d’identifier les principaux indicateurs de disponibilité de l’azote dans les sols forestiers et ensuite de déterminer les mécanismes impliqués dans le contrôle de la minéralisation de l’azote et de la nitrification par les essences forestières. Différents indicateurs de la disponibilité en azote des sols ont été comparés dans 50 hêtraies du Nord Est de la France représentant une large gamme de type de sol. L’effet des essences a été étudié sur un cambisol hyperdystric acide dans le site de Breuil (Morvan, France). Le potentiel net de minéralisation de l’azote est corrélé négativement avec le pH du sol et positivement avec le rapport C/N microbien. Le pourcentage de nitrification est fortement corrélé à une combinaison du pH avec le rapport C/N du sol ou à la composition de la végétation. Dans le site de Breuil, le pourcentage de nitrification du sol est élevé sous le hêtre, le pin laricio et le douglas tandis qu’il est très faible sous le Sapin, l’Epicéa et la forêt native (taillis sous futaie à base de hêtre et de chêne). La permutation des carottes de sols entre ces peuplements montre que sous les peuplements forts nitrifiants, la colonisation racinaire est lente et le pourcentage de nitrification est stimulé très rapidement (<16 mois). Sous les peuplements peu nitrifiants, la colonisation racinaire est très rapide mais la réduction du pourcentage de nitrification est assez lente (>28 mois). Par ailleurs, la coupe à blanc stimule très rapidement la nitrification sous la forêt native. L’ensemble de ces résultats converge vers un contrôle fort du cycle de l'azote par les racines, mais le mécanisme exact reste inconnu. / The aim of this thesis was to identify the main indicators of N availability in forest soils and thereafter to determine mechanisms by which tree species control soil N mineralization and nitrification. Various indicators of N availability were compared within 50 beech forests covering a large range of soil types in northeastern France. Thereafter, the effect of six tree species was studied in an acidic cambisol hyperdystric at the experimental site of Breuil (Morvan, France). Potential net N mineralization was negatively correlated with soil pH and positively with microbial C/N ratio. Percent nitrification was strongly correlated with the combination of soil pH and soil C/N or with the combination of Ellenberg’s indices of N availability or Ecoplant C/N and Ellenberg’s indices of acidity (R) based on the vegetation community composition. At the Breuil experimental site, the percent nitrification was high in beech, Corsican pine and Douglas fir plantations whereas it was very low in the Nordmann fir and the spruce plantations and the native forest stands (an old coppice with standard dominated by beech and oak). The exchange of soil cores between stands showed that under the « High nitrifying stands », root colonization was low and percent nitrification was quickly stimulated (<16 months). In « Low nitrifying stands », root colonization was very quick but percent nitrification decreased slowly (>28 months). Percent nitrification was quickly stimulated by clear felling of the native forest. Our results converge toward a strong influence of roots on the nitrogen cycle in forest ecosystems but it needs further efforts to identify the mechanism.

Flera olika arter I Sverige kan ge skador på skogen på olika vis. Där hjortviltet är en stor skadegörare på framförallt yngre tallplanteringar. Varje år kommer Skogsstyrelsen ut med information om beteskadenivåerna i landet i form av en älgbetesinventeringsrapport (ÄBIN). Skogsstyrelsen uppmanar varje år till att det ska skjutas mer älg för att få ner skadenivåerna till 5 % som är det nationella målet. Betesskador på tallplantor i tidig ålder medför en tillväxtförlust och nedklassning av framtida virke vilket påverkar den ekonomiska aspekten. Av alla olika betesskador så står toppskottsbetet för ca 75 % av skadorna, där en åtgärd för att minska betesskador är att använda viltskyddsmedel på plantorna. Syften med studien var att undersöka om det var effektivt att använda viltskyddsmedel för att minska toppskottsskador på tallplantorna, samt att undersöka om mängden RASE i bestånden hade någon påverkan på skadenivåerna på tallplantorna. Studien genomfördes som ett fältexperiment där 4 bestånd på två olika geografiska platser i norra Dalsland inventerades. På varje plats så inventerades två olika bestånd av tall med medelhöjden 1-4 meter, där ett bestånd var behandlat med viltskyddsmedel och det andra inte. Skadenivåerna mättes i 2,82 m2 stora cirkelprovytor med ett provyteförband på 60 m. provytorna lades ut objektivt i ett rutnät på analoga kartor innan inventeringen. I varje provyta så mättes stamantal, andel RASE stammar och antal toppskottsskadade tallplantor.  Resultaten visade en signifikant skillnad mellan tallbestånden, där de viltskyddsbehandlade plantorna var mindre betade på båda de olika områdena i norra Dalsland. RASE plantor hittades endast på det ena området, och där var den totala skadefrekvensen högre på tallplantorna både på de behandlade och obehandlade plantorna.  En slutsats i studien är att viltskyddsmedel har god effekt för att skydda yngre tallplantor från att bli toppsskottsskadade av hjortviltet. Men också att andelen RASE plantor i tallbestånden inte verkade ha en minskad effekt på toppskottsskadorna på tallen, det såg snarare ut som att skadorna ökade när RASE andelen var högre. Det skulle eventuellt kunna innebära att fodertillgången är för låg till storleken på hjortviltstammen i landskapet.

<p>U okviru doktorske disertacije ispitan je nutritivni kvalitet mleka magarice balkanske rase tokom laktacije. Prosečna suva materija mleka magarice balkanske rase iznosi 9,26%. Sadržaj proteina tokom laktacije kreće se od 1,40% do 1,92%. Prosečan sadržaj mlečne masti je 0,61%, a sadržaj laktoze iznosi 6,50%. Sadržaj analiziranih minerala: Ca, Na, K, Mg, P i Zn se povećava tokom laktacije i maksimalna vrednost utvrđena je 170. dana. Primenom kapilarne elektroforeze definisan je profil proteina mleka magarice balkanske rase. Identifikovane su sledeće proteinske frakcije: &alpha;s1-kazein, &alpha;s2-kazein, &beta;-kazein (A, F), &alpha;-laktalbumin (A, C), &beta;-laktoglobulin, lizozim, laktoferin, serum albumin i imunoglobulin čiji sadržaj opada tokom perioda laktacije. Sadržaj &alpha;-laktalbumina se kreće od 3090 mg/l do 1990 mg/l, a lizozima varira od 1040 mg/l do 2970 mg/l. Navedene frakcije proteina su najzastupljenije u mleku magarice balkanske rase. Laktoferin i imunoglobulin su frakcije sa najmanjim udelom u mleku magarice balkanske rase. Kori&scaron;ćenjem gasne hromatografije/masene spektrometrije utvrđen je sastav masnih kiselina mleka. Udeo esencijalne linolne kiseline (C18:2 n6) kreće se u opsegu od 7,08%, do 9,69%, a udeo &alpha;-linoleinske kiseline (C18:3 n3) varira od 5,85% do 7,83%.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Sastav mleka magarice balkanske rase kompariran je sa nutritivnim karakteristikama humanog mleka tokom 40. i 90. dana laktacije. Utvrđene su značajne razlike u sadržaju proteina mleka, mlečne masti i minerala. Odnos kazeina i proteina surutke kreće se od 0,68 do 0,75 u mleku magarice, dok u humanom mleku varira od 0,59 do 0,70. Udeo -linoleinske kiseline (C18:3 n3) je oko 2,5 puta veći u mleku magarice u odnosu na humano mleko.<br />Generalno se može zaključiti da mleko magarice balkanske rase ima specifične nutritivne karakteristike koje variraju u zavisnosti od sastava hrane za životinje i analiziranog perioda laktacije.</p> / <p>Nutritional quality of Balkan donkey milk during lactation was investigated within this thesis. The mean content of dry matter, fat and lactose in the Balkan donkey milk was 9.26%, 0.61% and 6.50%, respectively. Protein content during lactation period ranged from 1.40% to 1.92%. Content of the analyzed minerals: Ca, Na, K, Mg, Zn and P increased during the lactation period and reached their maximum value at 170th day. The protein profile of Balkans donkey milk was defined by application of capillary electrophoresis when the following protein fractions: &alpha;s1-kazein, &alpha;s2-kazein, &beta;-kazein (A, F), &alpha;-laktalbumin (A, C), &beta;-laktoglobulin, lysozyme, lactoferrin, serum albumins and immunoglobulins, whose content decreases during lactation period,were identified. &alpha;-lactalbumin contents ranged from 3090 mg/l to 1990 mg/ and lysozyme varies between 1040 mg/l to 2970 mg/l. These two protein fractions were the most abundant in the Balkan donkey milk, while lactoferrin and immunoglobulin were at least represented. The fatty acid composition of Balkan donkey milk was determined using gas chromatography/mass spectrometry. The share of the essential linoleic (C18: 2 n6) and &alpha;&nbsp;- linolenic (C18: 3 n3) acid rangred from 7.08 % to 9.69% and from 5.85 % to 7.83 %.</p><p>Nutritional quality of Balkan donkey milk has been compared with the nutritional quality of human milk during the 40th and 90th day of lactation. Significant differences in the protein content of milk, fat and minerals were found. The ratio of casein and whey protein ranged from 0.68 to 0.75 in the Balkan donkey milk, while in human milk this value varies from 0.59 to 0.70. The share of &alpha;-linolenic acid (C18:3 n3) is around 2.5 times higher in donkey than in human milk.<br />The main conclusion is that Balkan donkey milk has specific and unique nutritional quality which depend on the feed composition and on the analyzed period of lactation.</p>

A threat is that some of the tree species that are important for the biodiversity are under a lot of pressure because of the high browsing activity. The Swedish forestry agency has now together with the forest industry set an acceptable level of browsing on production forest that 70% must be non-browsed when the stands are 5 meters or higher. To protect the production forest from browsing the landowner can choose from several options, the conventional way is yet to point treat every production plant with a game repellent, but that way isn’t very time saving as to treat with this new method.This study is trying out a new method to treat the whole stand instead of point treating every production plant. The method was to use a petrol mistblower (Stihl SR200) and treat one hectare with 9 litres of water and 1 litre of the game repellent Trico viltskydd. Two inventories were made, one before treatment and one after treatment. In total 200 sample surfaces of 2,82m in radius where collected, 100 of them where control surfaces. Every tree species in the sample surfaces where record and if it was or wasn’t browsed. The result of this study shown that the increase of browsing on all tree species was reduced with the treatment method. The new method shows that it can have positive effects on preserving the bio diversity.