Cold damage and plant mortality in experimental provenance plantations with Scots pine in northern Sweden

Föreliggande arbete behandlar köldskador och plantdöd resp. överlevnadsförmåga hos tallplantor i en proveniensförsöksserie utlagd 1952-1955. Denna serie omfattar 30 planteringsytor fördelade större delen av Sverige med en sammanlagd areal av 36 ha. Här har endast material från 20 försöksytor kommit till användning, nämligen från de ytor, som är belägna norr om 60' N. I denna del av Sverige har under perioden 1953-1964 inträffat betydande köldskador, vilka observerats icke blott på försöksytorna utan även i andra planteringar och på träd intill en ålder av 20 år. Inom vissa områden var planteringarna mycket skadade och i några fall har de t. o. m. helt gått ut. Orsaken till köldskadorna och till den stora avgången har tillskrivits olika faktorer. Detta arbete har i främsta rummet avsett undersökning av den typ av köldskador, som har betecknats såsom "basal stem girdle" eller "strangulering" ("strangulation sicknes", "Trocken Gürtel", "Einschnürung") och dess samband med extrema klimatforhållanden under vissa år. Även förekomsten av andra slag av köldskador och skador förorsakade av andra klimatfaktorer har emellertid beaktats

Variation between and within populations in a provenance trial of Pinus sylvestris at Nordanås, lat. 64 19', long. 18 09', alt. 400 m

Data on survival, stem height, stem volume and yield per hectare from a provenance trial with Scots pine (Pinus sylvestris) at Nordanås, lat 64o19', long 18o09', alt 400 m, are presented in this report. Regression analyses were carried out to test the influence of transfer on the parameters studied. For the most important characteristics, yield per hectare and survival, it was found that a transfer by 1-2 latitudes southward will imply an improvement. Since the progenies from individual trees within the populations were kept apart the variation within populations could be analysed. This variation was found to be considerable both for survival and height in some of the populations

Severity index and transfer effects on survival and volume production of Pinus sylvestris in northern Sweden

By means of results from provenance trials in northern Sweden, a map of severity index for various latitudes and altitudes was drawn up. The severity index is defined as the expected percentage plant mortality rate in the local population during the first 20 years after establishment of the plantation. By combining transfer effects based on data from all trials, a general trend of the transfer effect was calculated. The regression obtained showed that, at constant altitude, each degree of transfer southwards meant an increase in survival of 10.8 percentage units; at constant latitude, every 100 metres of downward transfer implied an increase in survival of 3.0 percentage units. By means of a graph combining severity index with transfer effects, it is shown how optimum transfer can be estimated. Optimum transfer is defined as the transfer giving maximum volume yield, which equals 70-80 per cent survival