This study focuses on how established shrub seedlings (Salix myrsinifolia x phycilifolia and Vaccinium vitis-idaea) develop in historical milking grounds. Historical milking grounds are cultural remains from the intensive reindeer herding era when the Sami migrated with closely controlled herds. Although the places were never fenced, the high concentration of reindeer close to the tenting grounds created patches of grass and forb dominated vegetation in areas outherwise dominated by deciduous or ericoid shrubs. Despite about 100 years of abandonment the shrubs have not come back and the milking grounds are still clearly visible in the landscape. One theory why the former milking grounds are so stable is that shrubs cannot establish from seedlings due to unfavorable abiotic conditions, or due to competitive dominance of already established forbs and grasses. I tested this hypothesis by planting shrub seedlings in the milking grounds and in reference areas, with and without neighboring vegetation and investigated seedling survival and growth. The results show that shrub seedlings are able to both survive and develop in milking grounds suggesting that the seedling state is not the limiting factor in shrub encroachment in the milking grounds.

Urban greeneary is an integral part of the urban environment of the city. Beside buildings, technical infrastructure and services, urban greenery is an important component of any urban space. It is a part of environment od human and it is a great part of good psychical ease of man. Many features and kinds of public green are known. Trees and shrubs create architectural elements in grassy fields. Planting, maintaining and resorting vegetation must belong amongst priorities of development of any city.

At this moment there is a gap in information regarding the affect roots might have on 210Pb distribution in peat cores and in turn the obtained chronologies by 210Pb dating. Therefore, four peat cores were collected from the snow manipulation study site within the mire complex Storflaket (68°20048″N, 18°58016″E). Two cores from snow fence plots, which has experienced root growth due to permafrost thaw, and 2 cores from control plots. 210Pb distribution and the provided 210Pb chronologies were then compared with root content within and between the cores. In two of the cores (C5 and SF2) did subsurface peaks in the 210Pb activity profile follow the distribution profile of the dwarf shrub roots. The same pattern was not seen with Eriophorum roots. This indicates that presence of dwarf root with their shallow and horizontally growth can affect the 210Pb profile by horizontal translocation of 210Pb. The chronologies obtained by the CF:CS and CRS dating models could not be validated for the C5 core which suggest that dwarf shrub roots also can affect the 21oPb dating.

Die derzeitige Markt- und Preisentwicklung bei Schnittblumen gibt neue Impulse für eine Eigenproduktion. Besonders für Einzelhandelsgärtnereien bietet sich die energie- und investitionsarme Produktion im Freiland an. Innerhalb des Projektes 'Sortimentssichtung und Erarbeitung von Anbauverfahren zur Erzeugung von Freilandschnittblumen und -schnittgrün von Stauden mit Absatzschwerpunkten vor und nach den Sommerferien' im Fachbereich Gartenbau Dresden-Pillnitz der LfL konnten Anbauhinweise und Sortimentsempfehlungen für den Freilandschnittanbau unter hiesigen Bedingungen erarbeitet werden. Die über einen längeren Zeitraum ermittelten Ertragskennzahlen am vollsonnigen Standort sowie die Daten zur Aufbereitung, zur Schnittblumenqualität und Vasenhaltbarkeit der Stauden ermöglichten die Zusammenstellung der in der Schriftenreihe dokumentierten umfang- und abwechslungsreichen Empfehlungssortimente. Sie erleichtern dem Erwerbsanbauer die Arten- und Sortenauswahl entsprechend der betriebsspezifischen Bedingungen, betriebswirtschaftlichen Überlegungen und des Kundenklientel. Im Mittelpunkt stehen dabei Stauden für die absatzstärkeren Zeiträume vor und nach den Sommerferien. Bei ausgewählten Arten und Sorten kann der Rückschnitt des Austriebes Mitte Mai zur Blühterminverspätung genutzt werden. Diesbezügliche Versuchsergebnisse sind den Sortimentsempfehlungen im Bericht angefügt. Innerhalb des Projektes wurden auch intensive Anbauversuche mit Montbretien und Clematis als Schnittblume erfolgreich durchgeführt. Als Ergebnis werden Sortimentsempfehlungen und Hinweise zum Kulturablauf und zur Produktion im Freiland gegeben. Wertvolle Anbauergebnisse bezüglich des Einsatzes von Xylit als Mulchstoff zur Reduzierung des Unkrautaufkommens runden die Projektergebnisse ab.

At this moment there is a gap in information regarding the affect roots might have on 210Pb distribution in peat cores and in turn the obtained chronologies by 210Pb dating. Therefore, four peat cores were collected from the snow manipulation study site within the mire complex Storflaket (68°20048″N, 18°58016″E). Two cores from snow fence plots, which has experienced root growth due to permafrost thaw, and 2 cores from control plots. 210Pb distribution and the provided 210Pb chronologies were then compared with root content within and between the cores. In two of the cores (C5 and SF2) did subsurface peaks in the 210Pb activity profile follow the distribution profile of the dwarf shrub roots. The same pattern was not seen with Eriophorum roots. This indicates that presence of dwarf root with their shallow and horizontally growth can affect the 210Pb profile by horizontal translocation of 210Pb. The chronologies obtained by the CF:CS and CRS dating models could not be validated for the C5 core which suggest that dwarf shrub roots also can affect the 21oPb dating.

Forage kochia (Bassia prostrata, [L.] A. J. Scott) (Synonym = Kochia prostrata [L.] Schrad.) is a perennial semi-shrub that is valued for its forage quality and ability to restore degraded rangeland. However, establishment success of forage kochia plantings in western North America has been erratic. These failures leave the land vulnerable to erosion and invasion of undesirable plants. This research focused on the germination dynamics of forage kochia accessions as it relates to harvest date, planting date, age of seed, and environmental conditions. The effect of planting date, age of seed, and environmental conditions on forage kochia germination was elucidated by planting recently harvested (2010) and year-old, cold-stored seed (2009) monthly, during a four-month period at two locations. Two entries were tested, Immigrant, the standard subspecies virescens cultivar, and an experimental line, Sahsel, of subspecies grisea. Regardless of planting date, location, or age of seed, Sahsel exhibited higher germination percentages than Immigrant. The age of the seed lots used also significantly affected (P<0.05) the germination percentage. Field germination averaged over location and planting date of year-old Immigrant seed was 89.5% less than the current-year fresh seed, and similarly year-old Sahsel seed had 83.6% less germination than current-year seed. Although the two locations were subjected to very different weather patterns, the germination percentage of seeds at each location was not significantly different (P=0.3156). In the year we conducted our study (2011), the germination percentage from planting in February was significantly higher (P<0.05) than January, which was significantly higher (P<0.05) than both March and April. In the final set of trials, different harvest dates were tested by collecting seed in October, November, and December from seven forage kochia accessions. Measurements for total seed yield, 100-seed weight, and germination were collected from seed harvested each month. The month of harvest, accession, and month × accession interaction were significant (P<0.05) for each measurement in the study. Two accessions, Pustsel and KZ6Xsel, matured the earliest and had peak seed production at the October harvest (15.1 and 13.4 g plant-1, respectively). The remaining accessions had maximum yield and viable seed from the November harvest.

The nitrogen budgets of Eurotia lanata (Pursh.) Moq. and Atriplex confertifolia (Torr. and Frem.) S. Wats salt desert shrub plant communities were investigated. In each, a complete biomass and organic nitrogen inventory was made. In addition, investigations of the nitrogen fixation potential of soil surface microflora and inorganic soil nitrogen relationships were carried out. Greater total biomass and organic nitrogen was found in the above-ground portions, annual shoot productivity, and litter of the Atriplex community. However, the Atriplex community was exceeded by the Eurotia community in root biomass. Roots accounted for 74 and 87 percent of the plant biomass and 83 and 90 percent of the associated organic nitrogen in Eurotia and Atriplex communities respectively. Root biomass distribution at various depths was markedly different in the two communities. Differences between communities in relative amounts of various plant parts and litter are related to contrasting plant growth habit, and differences in soil texture and soil salinity. Total plant biomass estimates, which were 18,480 and 17,300 kilograms per hectare for Eurotia and Atriplex communities, were not significantly different and reflect the overriding influence of macroclimate and associated moisture limitation. Under laboratory conditions the soil surface microflora of the Atriplex community was able to fix significant amounts of atmospheric nitrogen while that of the Eurotia community did not. Nitrogen fixation potential in the Atriplex community was associated with the presence of abundant lichen cover and associated heterocvstcontaining blue-green algae of lichen interspaces. Differences between communities were found in rates of mineralization, downward flux, and pattern of utilization of inorganic soil nitrogen. Soil salinity appeared to strongly limit inorganic soil nitrogen mineralization as well as root growth and nitrogen uptake in the lower part of the Atriplex soil profile; however, this lack of biological activity was compensated for by a greater downward flux of inorganic soil nitrogen from decomposing litter and surface soil in the Atriplex community. Shoot and root litter appears to be the most readily available source of inorganic soil nitrogen for plant growth in salt desert shrub plant communities.

A short duration-high intensity grazing trial was conducted in spring of 1985 to determine whether shrub establishment in crested wheatgrass pastures could be enhanced through spring grazing by cattle, or by fertilization of shrub seedlings. Data was collected on diet selection by cattle during spring grazing, and on subsequent shrub growth and survival. Shrubs studied were transplants of sagebrush, Artemisia tridentata, fourwing saltbush, Atriplex canescens, bitterbrush, Purshia tridentata, and one year old bitterbrush seedlings. Cattle did not browse sagebrush or fourwing saltbush transplants, but utilization of bitterbrush transplants and seedlings averaged 15 and 42 percent, respectively. Shrub selection by cattle was unaffected by grazing pressure or fertilization. Fertilization increased growth of sagebrush transplants but had no effect on survival. Trampling of shrubs was greater than anticipated. Trampling reduced growth in sagebrush, and reduced survival of both bitterbrush and sagebrush transplants. Browsing reduced growth of bitterbrush seedlings, but increased growth and survival of bitterbrush transplants. Despite adverse effects from trampling and browsing on some shrubs, the overall effect of spring grazing of crested wheatgrass by cattle was to enhance establishment of fourwing saltbush and bitterbrush transplants. Spring grazing had no measurable effect on establishment of sagebrush transplants or on survival of one year old bitterbrush seedlings.

Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure seed production on 13 sites ranging from 10-33 years post-fire. We hypothesized that seed rain (mean seeds produced/ m2) would peak before stand density had maximized due to decreasing individual plant fecundity (mean seeds produced/ plant) in high density stands. We measured population density and individual plant fecundity for three size classes of MBS and used forward stepwise regression analysis to identify environmental factors influencing seed production over time. Density for small (basal stem diameter (BSD) <1 cm) and medium-sized (BSD=1-3 cm) plants was consistently low and was not affected by time since fire (TSF), while large-sized (BSD > 3 cm) plant density increased steadily with TSF (p=0.0002). Plant fecundity decreased with TSF for all three size classes (p range = 0.019 – 0.0506), with large plants dominating reproductive output. Small and medium-sized plant fecundity was negatively correlated with winter precipitation (p range = 0.0106-0.0174), while large plant fecundity was positively correlated with winter precipitation (p<0.0001) and negatively correlated with elevation (p=0.0001). Despite losses in plant fecundity over time for all size classes, steady recruitment in population density resulted in increased seed rain (p=0.0039), suggesting that increases in stand density compensated for losses in individual plant fecundity. Results partially support our hypothesis that the time required for MBS seed rain to be maximized was not tightly bound to indicators of stand maturation. Understanding the factors that influence post-fire seed production can help land managers better manage for successful recovery by providing them with tools for evaluating seed production capabilities of MBS communities.

Climate changes have been observed in the Northern Hemisphere during the last century, causing a longer growing season and upslope expansion of forest, tree, and shrub limits. Here, a long-term historical perspective was used as a tool for investigating how climate change has impacted woody plants at the forest, tree, and shrub limits across the study region. For this, historical data about plant communities were used, including the position of the forest, tree, and shrub limits, gathered by the Reindeer Commission in Troms County (1914-1915). The historical data were compared to contemporary data from a re-visit study in 2022. In addition, variations in microclimatic factors were investigated by looking at the growing season length, distance to coast, slope, and aspect. Importantly, the growing season length was found to have increased across the study region with the largest increase along the coast. The increase in the growing season length led to an upslope shift in the vegetation limits, although not significantly so for the forest limit. The field layer had shifted from meadow to heath around the historical shrub limit, and non-significantly for the forest and tree limit zones, indicating that the alpine tundra is the most sensitive to the observed warming. Distance to coast and slope did not impact the shift in vegetation limits, while aspect impacted the forest limit shift. The results from this thesis indicate that future studies should expand their research beyond climate variables and explore factors such as herbivory and land use change