Puistojemme puu- ja pensasvalikoima 1950-luvulla

Plants strongly affect the atmosphere of and the general feeling produced by amenity landscapes. To preserve the original impression when maintaining or renovating a landscape site, it is essential to know the plant assortment available at the time of construction. Our aim was to find out which landscape plants were popular or typical in Finland in the 1950s and how they were used in ornamental plantings. The study was confined to woody plants in public and semipublic green areas, such as parks, street plantings, playgrounds, cemeteries and shared yards. The back volumes (1950 to 1959) of the Finnish horticultural magazine Puutarha and a few other publications on garden plants and landscape design were used as the main source of information. The relative popularity of different taxa was judged by the frequency they were referred to in the literature. The results showed that even if the assortment of woody ornamentals was rather scanty in the 1950s, there were such taxa on the market that are no longer common in Finland. Domestic nurseries prospered and there seemed to be enthusiasm for trying new, sometimes not quite winter hardy species, such as Ligustrum vulgare, which was often advertised for hedges in the fifties. Some of the most popular ornamental plants were Crataegus grayana, Caragana arborescens, Syringa vulgaris and its cultivars, Salix alba sericea 'Sibirica' and the glaucous-leaved forms of Picea pungens. Hardwoods were favoured in urban settings and Tilia were the most common taxa in street tree plantings.Non peer reviewe

Mansikantaimien lisäystapa ei vaikuta niiden talvenkestävyyteen

Mansikan talvivaurioihin on kiinnitetty viime aikoina entistä enemmän huomiota. Osittain tämä johtuu uusien, oloissamme arkojen lajikkeiden yleistymisestä viljelyssä. On herännyt myös kysymys, miten taimityyppi vaikuttaa mansikan talvehtimiseen. Tutkimuksessamme verrattiin erityyppisten mansikantaimien - valiotaimet, tervetaimet ja tilataimet - talvenkestävyyttä.vo

Mansikkalajikkeiden talvenkestävyyden mittaaminen

ei saatavill

Quantifying carbon stocks in urban parks under cold climate conditions

Removing CO2 from the atmosphere and storing carbon in vegetation and soil are important ecosystem services provided by urban green space. However, knowledge on the capacity of trees and soils to store carbon in urban parks - especially in the northern latitudes - is scarce. We assessed the amount of organic carbon stored in trees and soil of constructed urban parks under cold climatic conditions in Finland. More specifically, we investigated the effects of management, vegetation type and time since construction on the amount of carbon stored in park trees and soil. We conducted two tree surveys and collected soil samples (0 to 90 cm) in constructed parks managed by the city of Helsinki. The estimated overall carbon density was approximately 130 t per park hectare, when the carbon stock of trees was 22 to 28 t ha-1 and that of soil 104 t ha-1 at the very least. The soil to tree carbon storage ratio varied from 7.1 to 7.5 for vegetated, pervious grounds and from 3.7 to 5.0 for entire park areas. The effects of park management and vegetation type could not be entirely separated in our data, but time was shown to have a distinct, positive effect on tree and soil carbon stocks. The results indicate that park soils can hold remarkable carbon stocks in a cold climate. It also seems that park soil carbon holding capacity largely exceeds that of forested soils in Finland. Preservation and augmentation of carbon stocks in urban parks implies avoidance of drastic tree and soil renovation measures.Peer reviewe

Pohjoiset taajamapuut

ei saatavill

Irreversible diameter change of wood segments correlates with other methods for estimating frost tolerance of living cells in freeze-thaw experiment: a case study with seven urban tree species in Helsinki

International audienceAbstractKey messageWe assessed tree frost tolerance using electrolyte leakage and a method based on irreversible diameter change of branches. It was shown that irreversible diameter change correlates with electrolyte leakage and USDA hardiness rating and is a good indicator of frost tolerance.ContextThe number of potential tree species for urban green planning is low in northern latitudes where cold tolerance is a critical factor. High cost of urban tree establishment calls for reliable and preferably non-destructive methods for determining their cold tolerance.AimsWe studied the cellular damage occurring during freezing and thawing in branches of seven broadleaved tree species using electrolyte leakage and a method based on branch diameter changes.MethodsCellular damage in branches was studied during the cold-hardy stage in winter and the dehardening stage in early spring in laboratory conditions using both monitoring of frost-induced diameter changes and the common electrolyte leakage method during temperature decrease to −25 °C.ResultsFrost-induced irreversible diameter shrinkage correlated positively with electrolyte leakage. Out of the seven studied species, Quercus palustris and Crataegus monogyna had the highest frost tolerance during the dehardening stage in early spring, whereas Pterocarya fraxinifolia was the least frost tolerant.ConclusionIrreversible shrinkage of branch diameter due to freezing stress is a good and non-destructive method to indicate frost tolerance. It also correlates well with the USDA plant hardiness rating that is based on the minimum temperature range in which the studied species prevail in the USA

Modelling human choices: MADeM and decision‑making

Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)