0000000000138950
AUTHOR
Oskars Krišāns
Species composition modulates seedling competitiveness of temperate tree species under hemiboreal conditions
Abstract Mixed stands are advised for reduction of impacts of natural hazards, and species composition can largely affect sustainability and productivity of the stands. Early development of a stands after a stand-replacing disturbance can have considerable legacy effects on growth via alterations in the diversity-productivity relationships. Accordingly compatibility of growth and competitiveness of different species is one of the key issues for susceptibility of mixed stands. A two-year chamber experiment was conducted to assess early growth and intra- and inter-specific competition for light and soil resources among the seedlings of temperate tree species simulating the predicted effect of…
Gravu attīstība un mūsdienu eksodinamiskie procesi Nurmižu gravu rezervātā
Bakalaura darba izstrādes gaitā veiktie pētījumi un iegūtie rezultāti sniedz informāciju par Nurmižu gravu rezervāta gravu erozijas tīkla un Raganu katla attīstību. Darba gaitā autors iepazinās ar pieejamo literatūru par Gaujas senielejas un tai pieguļošās teritorijas ģeoloģisko un ģeomorfololoģisko uzbūvi, gravu erozijas un sufozijas procesu attīstību. Veica Raganu katla topogrāfisko uzmērīšanu, ģeoloģisko urbšanu, objektu lauka apsekošanu un fotografēšanu. Lauka pētījumos iegūtie dati tika apstrādāti ar grafisko programmu Bentley Microstation V8 XM Edition. Tā rezultātā ir izveidots Raganu katla topogrāfisks plāns un Kaktiņu gravas gultnes ģeoloģiskais griezums. Darbu veido 4 nodaļas. Pir…
Lineārās erozijas tīkla attīstība un morfoloģija Nurmižu gravu rezervātā
Maģistra darba izstrādes gaitā veiktie pētījumi un iegūtie rezultāti sniedz informāciju par Nurmižu gravu rezervāta lineārās erozijas tīkla attīstību un morfoloģiju. Darba gaitā autors iepazinās ar pieejamo literatūru par Gaujas senielejas un tai pieguļošās teritorijas ģeoloģisko un ģeomorfoloģisko uzbūvi, gravu erozijas procesu attīstību un ģeogrāfisko izplatību. Pētījuma laikā ir veikta Kaktiņu gravu erozijas tīkla tiešā uzmērīšana, ģeoloģiskā urbšana un iznesu konusa nogulumu granulometriskā analīze, objekta lauka apsekošana un fotografēšana. Lauka pētījumos iegūtie dati tika apstrādāti ar grafisko programmu Bentley Microstation V8 XM Edition, bet pieejamo kartogrāfisko materiālu analīzē…
Wind Resistance of Eastern Baltic Silver Birch (Betula pendula Roth.) Suggests Its Suitability for Periodically Waterlogged Sites
Storms and wind damage are the main cause of biomass loss in forests of Northern Europe, as well as they are synergic with the disturbances causing intense water and temperature stress. This highlights the necessity for climate-smart management at landscape level coupling ecological demands of forestry species with their wind resistance. Silver birch (Betula pendula Roth.), which is highly plastic species, appears to be promising for a wider application under such conditions, as it is believed to tolerate wide range of weather conditions. Though silver birch can be sensitive to water deficit and windthrow, local information on its wind tolerance in sites with different moisture regimes is a…
Non-linear regional weather-growth relationships indicate limited adaptability of the eastern Baltic Scots pine
Abstract Under changing climate, temporal and spatial stability (stationarity) of growth responses of trees to weather and climate, which has often been presumed without explicit testing, is crucial for prediction of productivity and sustainability of forests. However, considering evolutionary adaptation of tree populations to wide spatiotemporal ecological gradients, extrapolation of linear responses, which could be observed in limited parts of the gradients (certain locality), can result in biased results. Accordingly, the plasticity of responses of tree-ring width of the eastern Baltic populations of Scots pine (Pinus sylvestris L.) to meteorological conditions across the regional climat…