© 2003 Heron Publishing—Victoria, Canada
Root turnover and root necromass accumulation of Norway spruce (Picea abies) are affected by soil acidity
Douglas L. Godbold (1, 2), Heinz-Werner Fritz (3), Georg Jentschke (3), Henning Meesenburg (4) and Peter Rademacher (4)
1. School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, U.K. / 2. Author to whom correspondence should be addressed (d.l.godbold@bangor.ac.uk) / 3. Forest Ecosystem Research Centre, University of Göttingen, Büsgenweg 1, 37077 Göttingen, Germany / 4. Forest Research Institute of Lower Saxony, Grätzelstr. 2, 37079 Göttingen, German / Received August 14, 2002; accepted February 1, 2003; published online August 1, 2003
Summary
Fine root distribution and turnover were investigated in ca. 40-year-old pure Norway spruce (Picea abies Karst.) stands in Germany, growing on four sites that differed in soil acidity (Ebergötzen < Barbis < Fichtelgebirge = Harz).
The density of fine root biomass and necromass in different soil horizons differed among the sites. At one of the most acidic
sites (Harz), fine root density in the humus layer was more than twice that at the least acidic site (Ebergötzen). At the
two most acidic sites, Fichtelgebirge and Harz, the ratio of biomass to necromass was significantly lower than at Ebergötzen
and Barbis, particularly in the subsoil layer. In each stand, clear vertical gradients in fine root length density and root
tip density were observed. Most of the roots and the root tips were in the humus layer and in the first mineral soil horizon
(0–10 cm). There was a significantly different decrease in specific root length (cm gDM−1) and specific root tip density (root tips gDM−1) in the more acidified stands Fichtelgebirge and Harz compared with Ebergötzen and Barbis. Fine root production estimated
by ingrowth cores and a net method was approximately twice as high in the more acidic stands Fichtelgebirge and Harz compared
with Ebergötzen and Barbis. Rates of living fine root biomass turnover were higher at the Fichtelgebirge and Harz sites than
at the Ebergötzen site. Rates of necromass turnover were similar at all sites. The results suggest that the accumulation of
necromass was not due to a slower disappearance at the more acid sites, but to earlier root death. Roots contributed 46% to
root + needle litter and 32% to root + total aboveground litter at the Harz site in 1997.
Keywords:
fine roots, litter fall, root necromass.
