Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 4 uppsatser.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 5 uppsatser.

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Angl. resumé

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This dissertation presents research results of Norway spruce (Picea abies L. Karst) populations in timberline ecotone of the Hrubý Jeseník Mts. The work is presented in the form of five scientific articles, 3 of which are accepted for publication, or already printed. Two articles are in the form of submitted manuscripts. The first article describes the biometric and age structure of spruce populations, including the assessment of the possibility of their vegetative as well as seed-based reproduction and compares these characteristics between two vertically connected sections of timberline ecotone. The second article analyzes the influence of dwarf pine stands of different cover on the ability of vegetative reproduction of spruce and their height growth. The third article deals with the historical dynamic of spruce trees establishment within timberline ecotone. This are correlated with both temperature characteristics and agricultural land abandonment during the last 100 years. The fourth article deals with measurements of the quantity and directions of sap flow in layering branches as well as parent and daughter trees in Norway spruce clonal groups. The article evaluates the importance of sap flow quantity in layering branch to the total amount of water use by parent and daughter trees. The fifth article substantially extends the fourth article of measurements on more interconnected tree pairs within a longer time series. Additionally, this article includes the drought stress experiment in the daughter tree and subsequent monitoring of changes in sap flow in layering branch.

The effect climate change has on forest trees is a large scaled topic. It is to believe that one of the largest threat to the environment today is global warming (IPPC, 2007). The use of fossil fuels seems to be the big threat with its greenhouse gas (GHG) emission and therefore forest is of interest. Forest contributes in several ways. Forest trees work as a renewable source of numerus materials and as it takes up CO 2 from the greenhouse gasses it gives us oxygen (O2). The important process of photosynthesis, to able production of more trees and creation of more forests, tells us the vitality of understanding the tree physiology to the fullest. The response of photosynthesis to temperature is a central facet of trees’ response to climate change. With its photosynthesis plants play a large role in the carbon cycle as they store the hazardous carbon dioxide helping us humans to deal with problems directly linked to climatic change and in the same time they build up biomass that can be used as a renewable source. To understand, and to find the key, how plants can achieve optimum potential of photosynthesis several observations were made using plant material from fertilized and unfertilized Picea abies. Well acknowledged leaf gas exchange measurements were used to see the limitations of photosynthesis, observing the net CO2 uptake rate (Anet), the maximum Rubisco carboxylation (Vcmax), maximum rate of electron transport for regeneration of RuBP (Jmax) and their unique response to temperatures. For three days observations were conducted at the Slu Asa field research station in Lammhult, Sweden. In addition to gas exchange measurements, nitrogen (N), phosphorus (P) and chlorophyll content was measured in needles of the fertilized and unfertilized P. abies to see if the content somehow made an impact on photosynthetic parameters and the influence nutrients might have on the specific leaf area (SLA). Results from the observations showed that optimum temperature for photosynthesis varies to be by fertilized 22°C and unfertilized 19°C. The net photosynthetic rate responded to the influence by added fertilizers to almost a double, 9.10 μmol m−2 sec−1 than of the unfertilized, 5.36 μmol m−2 sec−1. These results indicate that a fertilized P. abies has a greater potency to capture carbon than of an unfertilized P. abies. The result also reveals the future prospect of adding fertilizer to a P. abies as a potential of growth in biomass as well as a carbon sink when atmospheric CO2 levels rise. There were no great differences in the behaviour between Vcmax and Jmax to the added or non-added fertilized P. abies. Perhaps the fact that given fertilizer contained both nitrogen and phosphorous could have in their combinations influenced the sensitivity of the relationship between them two and therefore also the result. The presence of N and P in the fertilized P. abies affected the concentration of chlorophyll positively, paving the way for photosynthesis, accumulated biomass and possibly for trees defence against abiotic stress factors.