• 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:

DISCUSSION AND QUALIFICATION OF FIRE EFFECT:

PLANT RESPONSE TO FIRE:

Inkberry response to prescribed fire: Inkberry sprouts quickly and prolifically following fire. Following a February prescribed burn in a Georgia longleaf pine/slash pine community, inkberry responded with a rapid increase in biomass from the end of April to early June. From June to early August, the growth slowed. From August to the end of October, the growth curve flattened, with little biomass increase recorded.  Growth ceased in November [82].

On the southeastern coastal plain, inkberry may act as a major inhibitor of herbaceous plants in longleaf pine/wiregrass understories. A temporary reduction in the percent cover of inkberry by fire may provide an opportunity for expansion and colonization by herbaceous species, increasing understory plant species richness and diversity as well as the biomass productivity of grasses and shrubs. In a Georgia longleaf pine/wiregrass forest, percent cover of inkberry was significantly reduced (p<0.05) by annual, biennial, and triennial prescribed fire treatments, from 50% cover on unburned plots to 35% on burned plots [20]. Prescribed burns at 3- to 4- year intervals restrict the presence and cover of inkberry, though it resprouts quickly [66,192]. Lewis and Hart [119] observed that where inkberry stems were burned to the ground, resprouts were half as tall as unburned stems within 9 months. On 1 site in Georgia, the number of inkberry stems was significantly greater (p<0.05), though percent cover was significantly less (p<0.05), on burned versus unburned plots 9 months postfire; on a 2nd plot, no significant differences were reported [119]. During the 2nd postfire year on sites in Florida, Georgia, and South Carolina, Hilman [81] recorded number of inkberry stems per acre:

In Florida longleaf pine/slash pine stands, prescribed fire treatments significantly reduced (p<0.01) inkberry canopy coverage below 4.9 feet (1.5 m), from 14.7% to 11.1% approximately 1 postfire year [137]. In saw-palmetto-dominated shrub vegetation of Florida, inkberry cover values reached or exceeded preburn values within 3 years. Information on mean inkberry percent cover is summarized in the following table [172]:

Another study conducted on the lower coastal plain of Georgia found that slash pine-harvested sites were dominated by inkberry 6-years postharvest and remained dominated by inkberry following prescribed fire. No difference was found in the frequency of inkberry pre- and postfire. Inkberry on these sites strongly competed with slash pine seedlings, and 6-year-old slash pine seedlings competing with inkberry were significantly smaller in diameter (p<0.025) than those not subject to the same competition [197].

Even without burning, inkberry persists and often increases [69,199,209], reducing forage production [199]. In Georgia flatwoods, inkberry foliage cover increased 3-fold during 20 years of continuous fire exclusion. In 1 series of plots unburned for 30 years, inkberry occurred as a dominant shrub [69]. On plots in Georgia last burned in 1941, inkberry percent cover increased from 7% in 1942 to 14% in 1951 and 39% in 1963 [80].

Seasonal patterns of carbohydrate levels in roots and stems of inkberry are unaffected by season of burning. Recovery of carbohydrates occurs within 1 year, regardless of the time of year inkberry is burned [69,80].

DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:

FIRE MANAGEMENT CONSIDERATIONS:

Contribution to fuels: Without frequent fire, the herbaceous understory of southeastern pine flatwoods is replaced by highly flammable species, including inkberry [34,169,198], which is dangerous to treat with fire due to its volatility. This may result in continued accumulation of wildland fuel loads and increasingly difficult and dangerous conditions for fire suppression [198]. A general increase in the size, number, and severity of fires accompanies increasing age of vegetation in the gallberry-saw-palmetto/wiregrass fuel type. This increase is attributed to fuel accumulation as the vegetation ages, and frequent burning may help manage these hazardous fuel levels [169]. Experimental burns in longleaf pine forests with an understory dominated by inkberry produced "very hot fires" [76]. On areas protected from fire in longleaf pine forests, inkberry attains much greater size than on frequently burned areas [79]. On sites in Georgia, prescribed fire reduced vegetative inkberry fuel 0 to 70% [83].

Following an initial burn on a longleaf pine site in Florida and longleaf pine and loblolly pine sites in South Carolina, fuel weights of inkberry were recorded. Total (total litter fuel plus total understory fuel) mean weight of inkberry is presented below in pounds per acre. On the Florida site, inkberry fuels increased for about  6 years before leveling off, while in South Carolina, fuel weights continued to increase. On these sites, inkberry represented 1.8 to 6.6% of the total fuels measured [168].

In uniform 4-year-old saw-palmetto-inkberry roughs, headfire spread rates can exceed 0.5 mph (0.8 km/hr) with flame lengths in excess of 20 feet (6 m) and fireline intensities of 2,000 Btu/ft/s under "good" burning conditions [195].

Inkberry forms specific fuel types with wax myrtle [210] and saw-palmetto [200]. A model for predicting particulate matter emissions from fires in the saw-palmetto-inkberry fuel type has been developed [200].

Inkberry control using fire: Campbell [29] states that annual winter burning in longleaf pine forests may alleviate inkberry competition with longleaf pine seedlings, and over a 20-year period, annual winter burning resulted in a significant decrease (p<0.05) in inkberry crown spread [117]. Following a winter burn in South Carolina, inkberry relative percent cover was recorded at 4.0%, contrasted with 12.1% on the control site [59]. However, Clewell [34] found that summer prescribed burning provides better control of inkberry than winter burning. Spring and summer prescribed burning reduces the frequency and size of inkberry plants, thinning out dense clumps that can shade out grasses and forbs [52]. Inkberry thrives with frequent winter burning [69,93]; though fire top-kills the plants, within a few months as many or more new sprouts grow [93]. Hilman and Hughes [80] found that resprouts of inkberry burned in January appear in late February, growing most rapidly from mid-April to mid-May and averaging 2 feet (0.6 m) in height by November.

Though fire will not eliminate inkberry, annual summer burning may be effective in retarding growth [80,93]. In 1 study, inkberry stands were burned for 3 consecutive years in each of the following months: January, April, June, August, and October. Regardless of the month of burning, the number of stems increased following the initial burn and remained fairly stable for the next 2 years, with sprouts growing approximately 2 feet (0.6 m) the 1st year after the initial burn. The effects of these consecutive burns are presented in the following table according to month treated [93].

However, in a study of longleaf pine communities in Alabama, inkberry contributed 60 to 78% of shrub biomass on winter, spring, and summer burn treatments, as well as on control plots. There was no difference between the effects of dormant season and growing season burns [110]. Repeated burning, even at the most vulnerable time, is not likely to eradicate inkberry [93,161].

Related categories for SPECIES: Ilex glabra | Inkberry