ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

I Newly formed, small-dimension residues (1 eaves, twigs, and small branches up to
2 to 3 cm in diameter) are relatively high in available carbon, nitrogen, and
macroel ement nutrients. Initial colonization of these materials at the Lubrecht
site was by Athelia epiphylla Pers. (figs. 11 and 12), while at Coram the prevalent
fungi were ( i n order of frequency) Athelia epiphylla, Leucogyrophana pseudomollusca
arm.) Parm., and corticium lepidum Rom. Primary colonization occurred under
psychrophilic conditions (fig. 11). Leaves were more frequently colonized than
small woody materials, The impact of these fungi on small dimension materials may
be expressed directly by changes in nutrient content of needles (table 5) and in-
directly by observations on amounts of fungal biomass produced.
Table 5.--Apparent effect of the association of Athelia epiphylla on
nutrient losses of over-wintered need1 es of subal pine fir,
Abies lasiocarpa (Hook. ) Nutt, , Coram Experimental Forest,
Montana, May, 1975.
- . - . . -
A. epi ph y ll am C a Mg K P Ash C N C/N
Present* 17,200 71 0 1,9.75 0.086 6.6 34.7 1.18 29:l
Absent 14,500 1,090 5,750 .14 6.1 44.88 1.18 38:1
Si gni ficance ns** ns p=0.001 p=0.001 n s n s ns p=0.01
*Values corrected for weight loss of affected foliage.
**Not significant.
DISCUSS ION AND CONCLUSIONS
We have attempted to characterize one part of the organic resource of Rocky
Mountain forests in some detail. The characteristics and amounts of wood in the
soil are significant (Jurgensen and others 1980; Harvey and others 1980) in terms of
their effects on soil quality and function. It is apparent from existing (or
formerly existing) forest ecosystems that ecosystem perturbation, where biomass is
removed either by fire or indiscriminate harvesting practices, may be directly
reflected in the organic resources of the site, whether they be parent materials or
end products.
Brown-cubical decayed wood on a1 1 investigated sites is interchangeably functional
with himus, but the functional importance increases with the dryness of the
site. Reasonable guidelines for biomass utilization can be established using
biomass productivity estimates, estimates of decay rates, and assessments of optimal
volumes of necessary soi lwood (Harvey and others 1980) . These guide1 ines, however,
only address one form of residue, i .e. those large enough (0.2 to 0.5 meters) to
emerge as recognitabl e and persistent brown-rotted wood in soil . Significant impacts,
at present lacking adequate assessment, could occur by harvesting or premature
burning small-dimensional materials, Deleterious effects on site nutrient resources
would be observed because the nutrient capital in small-dimension materials is
1 arge.