Rapid Soil Development After Windthrow Disturbance in Pristine Forests

Abstract

We examined how rapidly soils can change during secondary succession by observing soil development on 350-year chronosequences in three pristine forest ecosystems in southeast Alaska. 2 Soil surfaces, created by different windthrow events of known or estimated age, were examined within each of three forest stands (0.5-2.0 ha plots; i.e., a within-stand chronosequence method). Soil surfaces are more likely to have developed under common climate and vegetation conditions within stands than in the spatially separated ecosystems used in traditional chronosequence studies. 3 We observed rates of change that were higher than those previously reported for secondary succession, and were similar to those described for primary succession. Well-developed spodic and albic (podzol) horizons with characteristic C, Fe, and Al signatures were found in soil surfaces less than 150 years old. Carbon accumulated linearly at 21 g m-2 yr-1 ; mineral P and N became increasingly immobilized in the spodic horizon as time passed. We found no trend toward an equilibrium in C or N accumulation over the 350-year chronosequences in any of the three stands examined. 4 These rapid changes in soil and a shift in rooting from mineral to organic horizons appeared likely to reduce productive capacity of the soil during a single generation of trees. Windthrow or disturbances that mimic windthrow may be required at intervals of about 200-400 years to maintain soil productive capacity in these ecosystems.

Impact of tree species on nutrient and light availability: evidence from a permanent plot study of old-field succession

“…Similar rates of SOC accumulation have been reported for northern ecosystems (Bormann and Siddle 1990;Bormann et al 1995;Hooker and Compton 2003); in many cases the forest floor turned out to be a major sink for carbon after agricultural abandonment (Hooker and Compton 2003). In our study, the decrease in SOC in the top 10 cm within the first five years of abandonment and the initial decrease in the lower soil were not sustained.…”

Soil carbon stock increases in the organic layer of boreal middle-aged stands

“…Soil carbon accumulation of 8 g C m −2 yr −1 in the organic layer was reported in the chronosequence of windthrow pits in Alaska (Bormann et al, 1995), and long-term accumulation of the organic layer without fire resulted in an increase of 5 g C m −2 in Sweden (Wardle et al, 2003). Peltoniemi et al (2004) measured and simulated 64 sites in boreal coniferous stands in Finland and obtained a 4.7 ± 1.4 g C m −2 yr −1 increase in carbon in the simulations, and a 4.2 ± 1.2 g C m −2 yr −1 increase in the organic layer in measured chronosequency data.…”

SILVAQUA - Auswirkungen forstlicher Bewirtschaftungsmaßnahmen auf den Zustand von Gewässern in bewaldeten Einzugsgebieten am Beispiel der Oker im Nordharz

“…Da die N-Dynamik an den C-Kreislauf gekoppelt ist (GUNDERSEN et al 2006 (AHRENDS 2008b, BERENDSE et al 1998, BERG et al 1995, BILLET et al 1990, BORMANN et al 1995, DE KOVEL et al 2000, TIETEMA 2004, TURNER u. LONG 1975.…”