%0 Research article
%T Coarse root architecture of three boreal tree species growing in mixed stands
%A Kalliokoski, Tuomo
%A Nygren, Pekka
%A Sievänen, Risto
%D 2008
%J Silva Fennica
%V 42
%N 2
%R doi:10.14214/sf.252
%U https://silvafennica.fi/article/252
%X Root system architecture determines many of the vital functions of a  tree, e.g. stability of anchorage and resource uptake. The shoot:root  ratio is determined through the allocation of resources. Studies on  below-ground architectural elements in boreal mixed forests are  relatively scarce despite the fact that knowledge on below-ground  interactions and allocation changes in relation to stand developmental  stage and soil fertility is needed both in ecological and silvicultural  research. In this study, sixty tree root systems of three different tree  species, Betula pendula, Picea abies and Pinus sylvestris, were  excavated in five mixed forest stands in order to quantify differences  between the species and sites in terms of rooting behaviour. Root  architecture differed greatly between the species, implying different  solutions for the functions of root systems. Half of the P. sylvestris  had developed a taproot as a response to anchorage needs, while P. abies  correspondingly had pronounced secondary growth of proximal roots.  Betula pendula had the most extensive root system, illustrating the  greater demand of deciduous trees for water. Betula pendula was also the  most sensitive to soil fertility: it favoured exploration on the  poorest site, as illustrated by the high total root length, whereas on  the most fertile site its strategy was to efficiently exploit soil  resources through increased branching intensity. The results obtained in  this study provide basic knowledge on the architectural characteristics  of boreal tree root systems for use by forestry professionals and  modellers.