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Schmid, J.M; Mata, S. A. 1996. Natural variability of specific forest insect populations and their associated effects in Colorado.

Analysis of data from seven specimens revealed a composite fire interval in ponderosa pine of 2.4 years from 1745 to 1876 (122 years), a shorter interval than previously reported. In all cases, composite fire intervals were shorter than individual specimen intervals.

Flood-Plain Zone 1 (Very shallow water table-0-4 ft) Flood-Plain Zone 2 (Shallow water table-4-8 ft) Flood-Plain Zone 3 (Medium water table-8-20 ft) Flood-Plain Zone 4 (Deep water tablebelow 20 ft)

A dense, immature ponderosa pine stand was thinned in 1962, 1972, and 1982 to six growing stock levels (30, 60, 80, 100, 120, and 150). Except for height, average tree growth characteristics (diameter, crown length, and width) were negatively correlated with residual stand density. Stand basal area and volume increment were positively related to stand density.

Verbenone capsules were stapled to trees in mountain pine beetle infested stands of ponderosa pine at densities of 10, 20, 40, and 68 capsules per acre. None of the treatments were effective in reducing the number of attacked trees. The effectiveness of the treatments may have been compromised when above-average temperatures followed early placement of the capsules, which may have degraded the verbenone before peak beetle emergence.

A good seed crop, coupled with a prescribed burn, designed to reduce fuels in an undisturbed stand of ponderosa pine (Pinus ponderosa Laws.), resulted in the establishment of many pine seedlings. In addition to an adequate seed source which was being dispersed during the fall burning, conditions that appeared to favor germination and survival included a more receptive seedbed, increased nutrient availability, and more favorable conditions of soil moisture and temperature. lU Z o' i~2.

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