Pit and mound topography and its influence on storage of carbon, nitrogen, and organic matter within an old-growth forest

Liechty, H.O.; Jurgensen, M.F.; Mroz, G.D.; Gale, M.R.

Pit and mound topography and its influence on storage of carbon, nitrogen, and organic matter within an old-growth forest

1997

Liechty, H.O. | Jurgensen, M.F. | Mroz, G.D. | Gale, M.R.

Pit and mound microtopography created by tree windthrow is a dominant feature in many old-growth forests in the Great Lakes Region. This study investigated whether stand-level quantities, or processes which control quantities, of carbon nitrogen, and organic matter in forest floor and mineral soil have been altered by changes in microtopography caused by windthrow. Comparison of flat or relatively undisturbed surfaces with the areas that contained mounds, pits, and flat features combined indicated no changes in the amounts of carbon, nitrogen, or organic matter in the forest floor or mineral soil as a result of pit and mound microtopography. However, there was an increased mixing of forest floor organic matter within mineral soils of mounds as compared with pits. Decomposition potential after 10 weeks, as indicated by cotton strip assay method, was 116% greater within the mineral soils of mounds than in pits. The decomposition rates in the mineral soil in the mounds were related to greater amounts of organic matter, temperatures, and moisture contents within this feature. Changes in sink sizes related to organic matter mixing or alteration by decomposition were minimal. Thus long-term stand-level storage carbon, nitrogen, or organic matter in forest floor or mineral soil pools was not found to be significantly altered by changes in microtopography resulting from windthrow disturbance levels found within this study area.

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