A First Order Fire Effects Model (FOFEM) was developed to predict the direct consequences of prescribed fire and wildfire. FOFEM computes duff and woody fuel consumption, smoke production, and fire-caused tree mortality for most forest and rangeland types in the United States. The model is available as a computer program for PC or Data General computer.Current information on FOFEM

https://www.fs.fed.us/rm/pubs_int/int_gtr344.pdf

First Order Fire Effects Model: FOFEM 4.0, user's guide

Smooth brome (Bromus inermis Leyss.), a native of central Eurasia, was introduced to Canada as a forage and hay crop around 1888. Early reports of plants escaped from cultivation appear in 1903, however, based on the number of collections prior to 1920, smooth brome spread more rapidly in western Canada. Smooth brome is common along roadsides, forest margins, clearings, shorelines and disturbed areas, but its most detrimental impact is on the diversity of prairies and native grasslands. In Riding Mountain National Park, MB, plant diversity of fescue prairies recently invaded by smooth brome decreased by 70%. Vegetative proliferation through underground rhizomes is key to the invasiveness of smooth brome, but long-range dispersal of seeds is facilitated by animals, wind and the transport of hay. Smooth brome is effectively controlled using selective applications of glyphosate and well-timed clipping. However, restoration of infested areas depends on the composition of native seed banks. Smooth brome remain...

The biology of Canadian weeds. 134. Bromus inermis Leyss

Fire often increases the productivity of perennial tussock grasslands inmesic environments but can reduce growth for one or more growing seasons inaridand semi-arid environments. We examined effects of single-burns on growth andnutrient content of grasslands in sub-tropical, northwestern Australia. Thesegrasslands were dominated by Themeda triandra, a speciesoften managed by regular burning in wetter temperate and tropical zones. Burnswere in the late dry season and were replicated using small plots (5 ×5-m) within fenced areas at two sites.Total projective cover and aboveground biomass were significantly less in burntplots relative to controls for 2.5 years after burning despite four growingseasons, including the first summer, of above-average rainfall. Recovery ofburnt plots was hindered by an extended dry period in the second year,demonstrating that rainfall in subsequent seasons can be as important asrainfall in the first season in determining post-burn productivity ofgrasslandsin semi-arid environments. Greater decreases in grass cover in burnt plotsduring the extended dry period may have been due to less standing dead andlitter than controls, and therefore less insulation from extreme summertemperatures, although relationships between cover changes and cover at thestart of the period were weak. With the exception of increased pH near grasstussocks, burning had little effect on chemical characteristics of surfacesoilsin the first week. Concentrations of N, and particularly P, in abovegroundplantmaterial were greater in burnt plots four months after burning, followingsummerrains, but were either less than or similar to those in controls withincreasingly dry conditions. Significantly lower concentrations of P in greenfoliage from burnt plots during dry seasons, when uptake from soil pools wouldbe minimal, indicated that burning decreased P retranslocation from plantstores. However, we found no evidence that single-burns increased nutrientlimitations to growth because plant contents of N and P were comparable inburntand control plots during periods of adequate water supply. Our data supportprevious generalizations that prescribed burning of perennial tussockgrasslandsin semi-arid environments is mostly unnecessary because putative benefits ofincreased productivity and forage quality, characteristic of more mesicenvironments, were not realized.

Growth and nutrient content of perennial grasslands following burning in semi-arid, sub-tropical Australia

https://journals.uair.arizona.edu/index.php/jrm/article/download/20099/19727

Plant Community and Soil Environment Response to Summer Fire in the Northern Great Plains

Prescribed fire is often used to restore grassland systems to presettlement conditions; however, fire also has the potential to facilitate the invasion of exotic plants. Managers of wildlands and nature reserves must decide whether and how to apply prescribed burning to the best advantage in the face of this dilemma. Herbicide is also used to control exotic plants, but interactions between fire and herbicides have not been well studied. Potentilla recta is an exotic plant invading Dancing Prairie Preserve in northwest Montana. We used a complete factorial design with all combinations of spring burn, fall burn, no burn, picloram herbicide, and no herbicide to determine the effects of fire, season of burn, and their interaction with herbicide on the recruitment and population growth of P. recta over a 5-year period. Recruitment of P. recta was higher in burn plots compared with controls the first year after the fire, but this did not lead to significant population growth in subsequent years, possibly due to drier than normal conditions that occurred most years of the study. Effect of season of burn was variable among years but was higher in fall compared with spring burn plots across all years. Herbicide effectively eliminated P. recta from sample plots for 3–5 years. By the end of the study density of P. recta was greater in herbicide plots that were burned than those that were not. Results suggest that prescribed fire will enhance germination of P. recta, but this will not always lead to increased population growth. Prescribed fire may reduce the long-term efficacy of herbicide applied to control P. recta and will be most beneficial at Dancing Prairie when conducted in the spring rather than the fall. Results of prescribed fire on exotic plant invasions in semiarid environments will be difficult to predict because they are strongly dependent on stochastic climatic events.

Effects of Prescribed Fire and Season of Burn on Recruitment of the Invasive Exotic Plant, Potentilla recta, in a Semiarid Grassland

-Grassland communities dominated by Festuca scabrella or by Stipa curtiseta and Agropyron dasystachyum were burned experimentally in spring or autumn. Forb, shrub and graminoid biomasses were greater in the unburned Festuca community than in the StipaAgropyron type. Spring and autumn burning delayed early season growth of graminoids in both grassland types in the 1st growing season after fire. Peak green biomass was reached later in the season in burned plots relative to reference areas. Plant growth in the spring of the 2nd yr after fire was more rapid in burned plots and peak biomass was reached earlier than in the reference plots. Autumn burning reduced forb biomass significantly early in the growing season during 1 of 3 yr that this parameter was measured. No effect of burning on shrub biomass was detected. Autumn and spring burning of Festuca grassland reduced peak, green, graminoid biomass production in the 1st and 2nd yr after fire; autumn burning had the most negative effect. Reductions in graminoid biomass after burning Stipa-Agropyron stands were smaller than in the Festuca community. Nitrogen concentrations in F. scabrella shoots regrown after fire were higher than those from the reference areas. Soil water content during the growing season, and snow trapping were reduced by burning. Peak green biomass and total graminoid biomass in Festuca grassland recovered to the level of the reference plots 2-3 yr after burning. Recovery was slower in the Stipa-Agropyron community.

Impacts of Burning on Primary Productivity of Festuca and Stipa-Agropyron Grasslands in Central Saskatchewan

The impacts of autumn or spring burning on Symphoricarpos occidentalis were studied in Fescue Prairie in central Saskatchewan. Symphoricarpos density increased two- to three-fold over preburn density in the 1st 2 growing seasons following a burn. Individual shoot weights were approximately one-third those of plants in reference (un- burned) sites. Leaves that were approximately two to three times larger, combined with increased stem densities, enabled plants in burned stands to re-establish a leaf area index equal to reference sites within 2 mo of growth in the 1st growing season. Total standing crop of S. occidentalis was reduced only for the early part of the 1st growing season following burning. In the 1st growing season following burning, xylem water potentials and stomatal conductance of burned plants equalled or exceeded those of reference sites. A delayed effect of burning was expressed in the 2nd growing season, with soil moisture, xylem water potentials and turgor potentials being lower in burned plants than in the reference. Flexibility in resource allocation, with a larger proportion of biomass in leaves, and unaffected or improved water status are adaptive features that enable S. occidentalis to regain its position in the plant community the 1st growing season following disturbance by burning. One-time burning in autumn or spring should not reduce the dominance of S. occidentalis in this region.

R. E. Redmann

Papers

Impacts of Burning on Primary Productivity of Festuca and Stipa-Agropyron Grasslands in Central Saskatchewan

Standing Crop, Biomass Allocation Patterns and Soil-plant Water Relations in Symphoricarpos occidentalis Hook. Following Autumn or Spring Burning