Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniversitet, 2007. / Härtill 4 uppsatser.

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

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

Swedish forest takes up and stores 60 million tons of CO2 every year. Which is a great climate benefit. Fertilization of forest results in a growth increase beacuse of the added nutrients supplied to the trees. This leads to an increased amount of needles that can produce a higher photosynthesis. The purpose of this report has been to examine the possibility of growth increase of norway spruce (Picea abies) with frequency fertilization in young stands. Earlier studies have shown that this is an efficient way to increase the stemwood production. The study has one hypothes, the growth increase in frequency fertilized young stands results in a yearly growth increase of 10 m3 per hectare compared to unfertilized stands. The material of this study is prepared from assessments from trials in Tranemo and Toftaholm in southern Sweden. The results have been compared to data from earlier assessments in the trial stands. Tranemo and Toftaholm is fertilized six times since 2003. The fertilizer dose is optimized after a needle analysis before every fertilizing occasion. The results show that the volume, diameter, basal area and individual stem volume is higher in the fertilized areas than in the unfertilized areas for both Toftaholm and Tranemo. The growth increase at the fertilized areas has increased significant compared with the unfertilized areas. The growth increase at the fertilized areas is 24-25m3 per hectare and year. The growth increase at the unfertilized areas is about 15m3 per hectare and year. Fertilization of young stands results in a high growth and shortens the rotation period considerably, the trees reach higher dimensions in shorter time. This study indicates that the number of stems per hectare has an impact on the growth increase in fertilized stands.

This thesis deals with the exploration of the influence of various phytohormones, primarily the influence of abscisic acid on the process of maturation and the influence of auxin and gibberellin on the process of germination of two types of conifers, Abies alba and Picea abies, often used as a material in the discovery of somatic embryogenesis. Each genotype prefers specific concentration ABA. 15 uM and 45 uM is the most effective for the cell lines Abies alba; 15 uM and 30 uM ABA for Picea abies. Auxin (IBA) and gibberellin (GA3) did not support the growth of roots of Abies alba. The interaction between fungal cultures Paxillus involutus and Amanita muscaria and between the embryos during the germination was studied as well. Fungal culture Paxillus involutus had very fast speed of growth on the germination medium. Fungal culture Amanita muscaria was growing very slowly. The effect of fungi on the germination has not been observed.

Disturbances have a major impact on the dynamic of forest ecosystems. However, there is lack of its exact consequences for mountain spruce forests in Central Europe. In 2007 heavy windstorm damaged a lot of stands in Šumava NP, subsequent bark beetle outbreak resulted in a large-scale dieback of spruce stands in this area. We took advantage of this opportunity. This study is focused on disintegration and structure of stands after the severe disturbance and in next step is focused on density and structure of natural regeneration in these stands. In addition we dealt with spruce regeneration (Picea Abies (L.) Karst.) on decaying logs. We compared two localities, disturbed (NP Šumava) and undisturbed site (CHKO Jeseníky). We concentrated on the change in saplings densities and on impact of decaying logs characteristic on this change. Finally we wanted to determinate impact of decaying logs characteristic on density of spruce regeneration. In area of Trojmezná we recorded 99 % mortality of parent stands. We founded only a few of adult tress which survived the disturbance, in addition we found several new trees, most of them with diameter about 10 cm. Live trees (DBH > 7 cm) reach density 16 trees per ha. The amount of dead wood was 2.5 times higher than before 10 years, one third were lying logs. Only natural regeneration of Norway spruce and rowan (Sorbus acuparia L.) was founded. Regeneration recruitments occurred in sufficient numbers, mostly on mosses (32 %), dead wood (27 %) and the nearest neighbourhoods of living mature trees or snags (28 %). Advance regeneration occupied 88 % of all regeneration. The density of individuals was similar along the elevation gradient. But in lower elevation of study area was situated higher regeneration recruitment then in the higher parts. With increasing elevation gradient regeneration was more homogenous in height and was lower. Best conditions for spruce regeneration provides logs with the largest diameters and logs with presence of white fungi Armillaria spp. or Phellinus nigrolimitatus. On the other hand logs with presence of Fomitopsis pinicola do not provide a suitable microsite for saplings. When we compare change in regeneration density on dead wood between the disturbed and undisturbed site, our results show significant increase in regeneration density at disturbed site (by 33 %). The increased regeneration density observed at the disturbed site was mostly associated with the smallest saplings on logs with the largest diameters. Three years after death of the parent stands no significant effect was recorded on the growth rate and survival of established spruce saplings on dead wood.

Evaluation of the circumference increment of Norway spruce focused on the effect of inter-tree competition in the mature spruce stand was made at the study site of Rájec (Drahanská vrchovina Highland) over a 5-year period. Data were collected from 49 trees, which were monitored continuously with mechanical band dendrometers from 2010 to 2014. The dependency of the circumference increment on competition index, diameter at breast height, Lang's rain factor, mean temperature of various periods and sum of precipitation of various periods was evaluated. Climatic conditions of the study site are characterised with warm and wet summers and cold-dry winters. In 5 years average around 61 % of the annual precipitation falls during growing season. There was highly significant correlation between relative increment and temperature (p=2.324e-13) and significant correlation between relative increment and precipitation (p=0.0439). The performed results confirmed that inter-tree competition and diameter at breast height are sufficient variables for circumference increment estimation of unmeasured trees in the particular year. Coefficient of determination reached 0.25 - 0.63 for competition and 0.40 - 0.84 for tree diameter at breast height. The present investigation brings important results about tree growth and seasonal growth dynamics and its relation with competition and microclimatic conditions in mature spruce stand. It is obvious that unsuitable climatic conditions for spruce can lead to stem shrinkage during growing season. Here we assume that these responses are caused mostly by water storage deficit in stem and this leads to decreasing of the tree vitality. Such phenomenon will have significantly negative ecological and economic consequences in expected climatic changes in the future.

No description available.