© 2007 Heron Publishing—Victoria, Canada
Fine root morphological adaptations in Scots pine, Norway spruce and silver birch along a latitudinal gradient in boreal forests
Ivika Ostonen (1, 2), Krista Lõhmus (1), Heljä-Sisko Helmisaari (3), Jaak Truu (4) and Signe Meel (1)
1. Institute of Geography, University of Tartu, Vanemuise 46, 51014, Estonia / 2. Corresponding author (ivika.ostonen@ut.ee) / 3. Finnish Forest Research Institute, Vantaa Research Unit, PL 18, FI-01301 Vantaa, Finland / 4. Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51014, Estonia / Received August 21, 2006; accepted January 22, 2007; published online August 1, 2007
Summary
Variability in short root morphology of the three main tree species of Europe's boreal forest (Norway spruce (Picea abies L. Karst.), Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth)) was investigated in four stands along a latitudinal gradient from northern Finland to southern Estonia. Silver birch
and Scots pine were present in three stands and Norway spruce was present in all stands. For three fertile Norway spruce stands,
fine root biomass and number of root tips per stand area or unit basal area were assessed from north to south. Principal component
analysis indicated that short root morphology was significantly affected by tree species and site, which together explained
34.7% of the total variability. The range of variation in mean specific root area (SRA) was 51–74, 60–70 and 84–124 m2 kg–1 for Norway spruce, Scots pine and silver birch, respectively, and the corresponding ranges for specific root length were
37–47, 40–48 and 87–97 m g–1. The range of variation in root tissue density of Norway spruce, Scots pine and silver birch was 113–182, 127–158 and 81–156
kg m–3, respectively. Sensitivity of short root morphology to site conditions decreased in the order: Norway spruce > silver birch
> Scots pine. Short root SRA increased with site fertility in all species. In Norway spruce, fine root biomass and number
of root tips per m2 decreased from north to south. The differences in morphological parameters among sites were significant but smaller than
the site differences in fine root biomass and number of root tips.
Keywords:
adaptive strategies, Betula pendula, fine root biomass, Picea abies, Pinus sylvestris, specific root length.
