ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

Figure 2.-- ReZative yield capabiZity estimates of the experimentat sites
based on Pfister and others (1977) and R.A. Grah (persona2 comni-
ca-bion) .
Recycling of accumulated organic matter is regulated by temperature and
moisture gradients as reflected in the rapidity of the decay process and fire
frequency. In recent years fire protection and timber harvesting also have
influenced organic matter accumulation. Figure 3 compares accumulations of soi 1
organic matter on the experimental sites. These measurements show substantial
accumulations on warm, moist, productive sites, and good reserves on intermediate,
productive sites. The lowest organic reserves appear on the cold Teton site and
the relatively productive but dry Lubrecht site, which also has a prolonged
harvesting history. How much, if any, effect past logging at Lubrecht may have
had on the accumulation of soil organic matter, particularly wood, is not known.
However, the disproportionately small amount of wood compared to soi 1 humus may
indicate that harvesting had significant effects. The relatively large accumulations
of tree stem residues not incorporated into the soil on the Teton site (Benson
and others 1980) indicates the decay process is extremely slow and that large
fuel accumulations and associated severe fires may be responsible for the low
soil organic matter accumulations.