• IMMEDIATE FIRE EFFECT ON PLANT
• DISCUSSION AND QUALIFICATION OF FIRE EFFECT
• PLANT RESPONSE TO FIRE
• DISCUSSION AND QUALIFICATION OF PLANT RESPONSE
• FIRE MANAGEMENT CONSIDERATIONS

IMMEDIATE FIRE EFFECT ON PLANT:

Pinegrass is usually top-killed by fire [95]. Fires that consume the duff layer may kill pinegrass rhizomes [18,96,114]. In the northern Rocky Mountains, pinegrass is seldom, if ever, eliminated from a site even after severe wildfire [141].

DISCUSSION AND QUALIFICATION OF FIRE EFFECT:

No entry

PLANT RESPONSE TO FIRE:

Pinegrass sprouts from rhizomes and establishes from seed following fire. It may bloom profusely for the 1st 2 or 3 postfire years, allowing rapid colonization of burned areas. It can also invade burned areas from off-site sources. Pinegrass generally increases in response to fire, often exceeding preburn levels [20,27,32,72,74,128,138,139,142].

DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:

Following the Pattee Canyon Wildfire in a Douglas-fir type near Missoula, Montana, pinegrass bloomed profusely in the 1st postfire summer. Subsequent seedling establishment was observed in the following 2 years, along with vegetative spread from rhizomes. Pinegrass responded rapidly to the July wildfire. Even on severely burned sites it became the most abundant native species. Pinegrass cover increased from 0.6 to 8.5% on upland sites, and from 1.0 to 1.3% on ravine sites from postfire year 1 to postfire year 3 [33,34].

Johnson [74] summarized pinegrass response to several fires in the mountains of northeastern Oregon. Pinegrass responded quickly and positively to low, moderate, and high severity fires in grand fir, Douglas-fir, ponderosa pine, and in ninebark-common snowberry shrublands. In all cases, pinegrass sprouted from rhizomes and reproduced from seed, often with dramatic increases over preburn cover. Pinegrass recovery was most delayed following severe fires in ponderosa pine types.

In western Montana, pinegrass cover increased following the high severity Sleeping Child Fire in seral Rocky Mountain lodgepole pine communities within subalpine fir/beargrass and subalpine fir/grouse whortleberry habitat types. Cover values (means from 11 transects) were 0.3% in postfire year 1; 11.6% in postfire year 12; and 19% in postfire year 21 [89,90].

The following coverage class values (2=6% to 25% cover; 3=26% to 50% cover; 4=51% to 75% cover) were reported for pinegrass following moderately severe prescribed fires in a western quaking aspen and quaking aspen-mixed conifer type in the Caribou National Forest, Idaho [20]:

Type	Untreated	Postfire Yr 2	Postfire Yr 4
Quaking aspen-mixed conifer	4	4	3
Pure quaking aspen	3	3	2

In these study areas, pinegrass produced more biomass, uniformly flowered, and produced seed on severely burned sites. Pinegrass also produced many new culms in burned areas, but few were produced in unburned areas [40].

Pinegrass followed a general trend (increase in frequency and/or cover) in the first 17 years following the Waterfalls Canyon Fire in Grand Teton National Park. The fire occurred in a subalpine fir-Engelmann spruce dominated area, with some lodgepole pine contributing to the overstory. Cover and frequency were temporarily reduced in postfire year 1 on moderately burned and severely burned sites, as compared to an adjacent stand that had burned 43 years earlier and an adjacent unburned stand. Pinegrass increased by continued sprouting and seedling establishment from abundant postfire seed production, with greater cover in burned stands compared to unburned stands during most of the successive 17-year period. Mean percent frequency and cover, respectively, for pinegrass during the course of the study follow (frequencies were not provided after postfire year 1) [10,43]:

Site	Postfire Yr 1	Postfire Yr 2	Postfire Yr 3	Postfire Yr 9	Postfire Yr 17
43-yr-old Burn	78 (12)	---  ---	---  ---	---  ---	---  ---
Unburned	42 (7)	---/(7)	---/(9)	---/(5)	---/(5)
Moderate Burn	7 (1)	---/(2)	---/(3)	---/(13)	---/(9)
Severe Burn	15 (1)	---/(4)	---/(3)	---/(27)	---/(9)

FIRE MANAGEMENT CONSIDERATIONS:

Fire suppression in the Pacific Northwest has caused a downward trend in range condition where pinegrass has historically played an important role. The invasion of Douglas-fir and grand fir into ponderosa pine communities has caused an overall increase in crown cover which in turn has caused a decrease in pinegrass production. The highest densities of pinegrass in the region are found in fire-maintained ponderosa pine stands [63].

According to Johnson [74], low- and moderate-severity fires are best for pinegrass enhancement in Douglas-fir/pinegrass associations of the Blue Mountains and Wallowa Mountains in Oregon.

Prescribed fire guidelines have been developed for Douglas-fir/pinegrass habitat types in Montana that are adjacent to grasslands where shrub enhancement for wildlife is important [58].

Stout and Brooke [143] developed an equation for determining the relationship between culm height and leaf area for pinegrass. Total leaf blade area (y) was predicted from culm height (x): y=0.39375 + 0.051604x + 0.00419223x² (R²=0.97). This may be useful in predicting fuel loading. Others have evaluated the National Fire Danger Rating System grass fuel models [129], compiled photo guides for appraising fuel loading in Rocky Mountain habitat types with pinegrass indicators [47,48], estimated fuel weights for pinegrass [21], and developed surface area to volume ratio models as indicators of flammability [19,22]. Fuel loads have been estimated for the Douglas-fir/pinegrass habitat type in northwestern Montana [4].

Related categories for SPECIES: Calamagrostis rubescens | Pinegrass