%0 Research note
%T Growth and stem quality of mature birches in a combined species and progeny trial
%A Viherä-Aarnio, Anneli
%A Velling, Pirkko
%D 1999
%J Silva Fennica
%V 33
%N 3
%R doi:10.14214/sf.659
%U https://silvafennica.fi/article/659
%X The growth and stem quality of silver birch (Betula pendula), downy  birch (B. pubescens) and paper birch (B. papyrifera) were compared in a  32-year-old field trial in southern Finland. The material consisted of  different unselected stand origins and progenies of phenotypically  selected plus trees of silver and downy birch from southern Finland and  differing stand origins of paper birch from the North-West Territories,  Canada. Growth, yield and a number of stem quality traits, including  taper, sweep, stem defects, heights of different crown limits and length  of the veneer timber part of the stem were measured or observed. The  native Finnish silver and downy birches were superior to paper birch in  terms of both yield and stem quality, silver birch being the best.  Progenies of silver birch plus trees were better than the stand origin,  indicating that the former are able to reach high quality veneer log  size in a shorter time than unselected material. The cultivation of  paper birch can not be considered viable in Finland.