Lodgepole Pine at Crater Lake: History and Management of the Forest Structure
II. Important Characteristics of Lodgepole Pine
Lodgepole pine at Crater Lake is Pinus contorta subspecies murrayana. Some of its ecological characteristics important here are: (1) it is a relatively small, short-lived conifer with sparse foliage; (2) it appears to tolerate a variety of harsh environments (wet, cold, low nutrients) which few other trees can, but (3) its growth is considerably slowed by such conditions; (4) it is intolerant of heavy shade; (5) its small, winged seeds are released soon after the cones mature; (6) it is very susceptible to dwarf mistletoe, although few trees die as a direct result of infection; (7) it is quickly killed by mountain pine beetle; (8) it has very thin bark, even when an old tree, rendering it susceptible to kill by fires of low intensity; (9) trees are very subject to heart rot introduced through wounds such as fire scars; (10) fire-affected trees appear to be very susceptible to secondary bark beetle attack; and (11) dead trees lose their bark rapidly and form a hard sheath, and thus logs appear to decay relatively slowly.
Our lodgepole pine thus differs considerably from ponderosa pine, which has thick bark even when young, gets much larger and survives much longer, appears to be more resistant to bark beetles and can be scarred repeatedly without rotting. It also differs significantly from its relative in the Rocky Mountains, P. contorta ssp. latifolia in at least one way of importance to our study (no. 5 above): many Rocky Mountain trees are serotinous, having cones which remain closed for years until subjected to a high temperature, usually from fire. Thus, in the Northern Rockies, the seed crop of many years is released directly on a site following fire in lodgepole pine. In our area, seed for regeneration must be dispersed from surviving trees or the edge of the burn, only one year’s crop at a time. This probably results in slower, more sporadic regeneration in this area than in the Rockies, especially near the center of large burns.