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Age and Growth Development of Norway Spruce (Picea abies (L.) Karst.) In a Heterogeneous Forest In Västerbotten County
PI: Sara Jäger
This masters thesis is a collaboration between The University of Gothenburg and The Swedish University of Agricultural Sciences, SLU. The main focus during 2 semesters is to investigate the correlation between age and growth development of Norway spruce, growing in a heterogeneous forest.
PI: Reimo Lutter
According to the recent estimation for Northern Europe, about 1.8-2.6 M ha of agricultural land is available for afforestation and intensive biomass production (Rytter et al. 2016). However, the long-term effects of different species C sequestration potential are unknown on former agricultural land. For the basis of current project, the growth data was obtained from tree species (hybrid aspen, poplar, birch, spruce, larch and willow) experiments on five former agricultural sites along a latitudinal gradient in Sweden (56° to 64°N). Site index curves were calculated to predict the potential production for each tree species and different long-term scenarios were tested to investigate each species climate benefit potential on former agricultural lands. More detailed information about the experiment: Rytter, L. and Lundmark, T. 2010 Trädslagsförsök med inriktning på biomassaproduktion [Tree species trial with emphasis on biomass production]. Skogforsk, Arbetsrapport no 724, Uppsala, 24 p.
PI: Reimo Lutter
The aim of the project is to describe the radial distribution of deuterium in Scots pine tree rings in order to develop a sampling methodology in 2H2-labeled water experiments . The experiment is located in Rosinedal experimental forest where 2H2-labeled water was added to soil. Tree ring samples were collected from two trees close to the labeled area in 2019. The sampling was carried out in four different heights (ground level, 1.3m, 2.0m and from the beginning of the living crown). From each height, 16 core samples were taken around the stem. In addition, core samples were taken from coarse roots.
Does long-term nitrogen deposition lead to increased microbial mining for phosphorus in organic and mineral soils, and what is the consequence for the soil carbon sink? This project use the long-term nitrogen addition experiment at Svartberget and ingrowth cores with needle litter, humus, and mineral soil with and without elevated phosphorus content. Substrates were collected in a phosphorus addition experiment in the Tönnersjöheden research forest in Halland.
This project made an inventory of the soil microbial communities in the organic layer of the D (n=6) and E (n=6) plots at the Svartberget nitrogen addition experiment in 2016, after 20 years of annual N addition at 12.5 and 50 kg N ha-1 yr-1. We used PLFA profiling and fungal DNA sequencing to study shifts in the microbial community structure, and used enzyme assays to study the impact of nitrogen on the soil metabolism targeting key components of soil organic matter and litter, including cellulose and hemicellulose, organic nitrogen in peptides and microbial necromass, phosphates, and lignin.
This project made a comprehensive inventory of element stocks of carbon, nitrogen, and phosphorus in the organic layer, 0-10 and 10-20 cm into the mineral soil in 2017, after 13 years of annual N addition rates at 3, 6, 12, and 50 kg N ha-1 yr-1 (n=&). 10 cores were collected in each plot and subsamples analysed by IRMS and spectrophotometry.
This project utilised the Åheden long-term nitrogen addition experiment with five nitrogen addition rates and a trenching/tree root isolation treatment in a split plot design. We measured decomposition in needles and humus incubated in the soil and profiled the microbial communities using a combination of PLFA and fungal DNA sequencing.
Nitrogen deposition can enhance above ground carbon sequestration, but most of the carbon in boreal forest soils are stored in soils. A higher above ground growth enables a higher input of above ground litter to soils, potentially increasing soil carbon stocks. However, a large flux of carbon is entering soils through roots, where it is used to produce and maintain root biomass, as well as exported into microbial biomass such as ectomycorrhiza. Root and microbial biomass production and turnover is an important source of soil carbon, but labile carbon in the root zone is also driving decomposition processes. In this project, we use the Åheden long-term low to high N addition rate experiment to study the consequence of different rates of N input on the soil C balance. We combine above ground flux measurements including the input of above ground litter and output of CO2 by respiration, and below ground measurements on fine-root and ectomycorrhizal fungal biomass production to understand how different rates of nitrogen addition influence the amount, form, and location of carbon inputs to soils, with the overall goal to understand how N deposition influence the boreal forest carbon sink.