Selection of species and clones for biomass willow forestry in Finland.

In sections 1-3 of this report, brief reviews are presented of the genus Salix and its use (especially for biomass) in Finland. In section 4, the results from early breeding programmes in Finland (1910-79) are analysed. In section 5, selection of biomass willows in the 1980s is reviewed. Some 63 exotic willow clones (mainly S. burjatica and S. viminalis) from Sweden were screened at the Kopparnas willow research site, S. Finland, from 1983 to 1989. S. viminalis showed consistently high yields. The yield variation of S. burjatica was large because of an outbreak of rust (Melampsora sp.), followed by lowered winter hardiness. Three S. viminalis clones were recommended for S. Finland: 78-0-183 (Sweden), E7888 (Somero, Finland) and 78-0-21 (Sweden). Selection of indigenous species and clones was based mainly on a collection of 375 clones of the Foundation of Forest Tree Breeding and a collection of 566 clones of the Finnish 4H-organization. The clones were grown at Suomusjarvi, Nurmijarvi, Kannus and Haapavesi. S. myrsinifolia was the most productive; 5 clones were recommended: E6631 (Kulaa), K2322 (Heinavesi), E6695 (Hartola), V75 (Mikkeli) and V78 (Loppi). S. phylicifolia was the second most productive species and the most promising clones were E6682 (Juva), V766 (Pieksamaki) and V754 (Kuru). Willow hybridization studies have also been carried out. Further intraspecific crossings of geographically distant S. myrsinifolia clones are recommended. Based on research results from 1910 to 1990, S. viminalis is recommended for biomass forestry in S. Finland and S. myrsinifolia is recommended for research in other areas. A list of Salix species, subspecies, varieties, forms, hybrids and synonyms is given in an appendix (pp. 44-58)