Klinškalnu priedes (Pinus contorta Dougl. var. latifolia Engelm.) introdukcijas perspektīvas Latvijā = Perspectives of Lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) introduction in Latvia

As the demand for wood as a renewable resource is increasing, it is necessary to evaluate all possibilities to boost productivity of forest stands, including the use of introduced tree species. The aim of the thesis: to evaluate Lodgepole pine provenances characteristics (productivity, resistance, suitability for timber or biomass production) in comparison to Scots pine provenances parameters and recommend suitable P. contorta provenances for usage in Latvia. The doctoral thesis has been developed from year 2009 to 2012. The thesis researches tree species of North America – Lodgepole pines – productivity, growth rate, and also resistance to biotic and abiotic environmental factors in the climatic conditions of Latvia. Biomass volume, moisture of biomass components and also wood mechanical properties of Lodgepole pine are analysed separately. The data for the doctoral thesis were collected from the 18 Lodgepole pine provenance trials in Kuldīga, Ugāle, Tukums, Zvirgzde and Kalsnava that were established by Dr. silv. Imants Baumanis. Data for the comparison with Scots pine were collected by measuring trees from the Scots pine control lots that are included in the experiments, or from the identical age Scots pine stands right next to the experiment.During the research it was established that Lodgepole pine productivity is 25% higher than for Scots pine grown in identical conditions, also survival of this pine species is 10% - 20% higher. The average tree height and diameter of Lodgepole pine in comparison to Scots pine is statistically significantly (p=0.05) higher, furthermore, both species are responding similar to factors that influence growth rate. However, it is determined that Lodgepole pine has statistically significantly (p=0.05) higher proportion of trees with spike knots and double leaders, its wind hardiness is lower and this pine species is damaged more often by artiodactylia. The Lodgepole pine biomass volume of dry wood in average is 1.7 times higher than for Scots pine. Also tree mechanical properties – breaking strength and modulus of elasticity for this pine is statistically significantly (p=0.05) higher. For the conditions of Latvia the most productive are provenances from 50º, 53º, 55º-56º north latitude in Canada, 50º and 54º north latitude of Sweden’s Lodgepole pine stand progenies and the Lodgepole pine progeny stands of Latvia in Skrīveri and Bukulti with unknown origin. The doctoral thesis consists of 122 pages; information is summarized in 36 tables and 55 pictures, bibliography sources 153. In the final part of the theses 7 conclusions are formulated.