Andmebaasi logo

Sirvi Autor "Lazdiņa, D." järgi

Nüüd näidatakse 1 - 2 2
  • Pisipilt
    Kirje
    Carbon content of below–ground biomass of young Scots pines in Latvia
    (2017) Jansons, Ā.; Bārdulis, A.; Ķēniņa, L.; Lazdiņa, D.; Džeriņš, E.; Kāpostiņš, R.
    Forest ecosystems play crucial role in global carbon cycling, therefore, increasing afforestation of agricultural land in Europe has been recognized as important contribution of carbon sequestration. In carbon reporting systems, root carbon content (CC) default value has been set to 50%. The study aimed to estimate CC in below–ground biomass and in relation to tree age in young Scots pine stands on forest and former agricultural land. The below–ground CC of young (8 to 40 years) managed Scots pine (Pinus sylvestris L.) stands growing on nutrient poor mineral soils in Latvia was carried out. In total 62 sample trees (43 in forest land, 19 in former agricultural land) were randomly selected for destructive sampling to estimate the CC within below–ground biomass. Below–ground biomass weighted mean CC was 49.7 ± 0.4%, being slightly lower than the default CC value used to calculate carbon budgets. Root fractions stump, small roots (diameter 2–20 mm), coarse roots (diameter > 20 mm)) differed (p < 0.001) in their CC. Stumps (50.6 ± 0.6%) had highest (p < 0.001) CC in the below–ground biomass, followed by coarse (49.5 ± 0.4%) and small (49.1 ± 0.4%) roots, which did not differ from each other in their CC. Results demonstrated age–dependent increase of CC (p < 0.001) from 48.2 ± 0.3% to 51.7 ± 0.5%, indicating overestimation of the default value during the first two decades, but underestimation for older trees (24 to 40 years).
  • Pisipilt
    Kirje
    Conversion of an industrial cutaway peatland to a Betulacea family tree species plantation
    (2019) Neimane, S.; Celma, S.; Butlers, A.; Lazdiņa, D.
    To evaluate the potential of establishing a deciduous tree plantation on an industrial cutaway peatland over an 8 ha large experimental site was established in the central part of Latvia and silver birch (Betula pendula Roth) and black alder (Alnus glutionsa (L.) Gaertn.) tree species were planted. As it is a harsh and unfavorable environment wood ash, otherwise a waste product, was used as a fertiliser and liming material in three applications (5, 10 and 15 t ha-1 ). In comparison with control, fertilised soils had higher Ca, Mg, P amounts, whilst the most substantial difference was seen in the amount of K. Application of wood ash also considerably increased soil pH from 3.5 (Control) to 5.9 (15 t ha-1 ). Even though showing reduced growth in unfertilised soil both alder and birch seedling survival rate was higher than 80%. The highest survival rate for birch was under wood ash treatment, while alder under 10 t ha-1 wood ash fertiliser treatment showed the lowest survival rate i.e. 81%. In total, more than 60 naturally occurring vegetation species were observed in the first and the second year of sites establishment after fertilisation. Species as Betula pendula, Betula pubescens, Populus tremula, Pinus sylvestris, Salix spp. often occurred from natural vegetation regeneration. Already after one year of vegetation succession increase in tree and shrub species cover was observed, suggesting perhaps such areas can be naturally afforested thus creating a more heterogeneous forest stand. In such a way sustaining economic use of land resources after peat extraction while providing other ecosystem services.