Analysis of fire frequency on the Talladega National Forest, USA, 1998-2018

Fire is an essential ecological process and management tool for many forested landscapes, particularly the pine (Pinus spp.) forests of the southern USA. Within the Talladega National Forest in Alabama, where restoration and maintenance of pine ecosystems is a priority, fire frequency (both wild and prescribed) was assessed using a geographical process applied to a fire history database. Two methods for assessing fire frequency were employed: (1) a simple method that utilised the entire range of years acknowledged in the database and (2) a conservative method that was applied only the date of the first and last fires recorded at each location. Analyses were further separated by (a) method of mean fire return interval calculation (weighted by area or Weibull) and (b) fire season interval with analyses conducted on growing season and dormant season fires. Analyses of fire frequency for national forest planning purposes may help determine whether a prescribed fire program mimics ecological and historical fire frequencies and meets intended objectives. The estimated fire return interval was between ~5 and 6.5 years using common, straightforward (simple) methods. About one-third of the forest receives no fire management and about half of the balance has sufficiently managed fuels.

Annual Fire Return Interval Influences Nutritional Carrying Capacity of White-Tailed Deer in Pine–Hardwood Forests

Prescribed fire is a cost-effective habitat management tool in pine stands to enhance the quantity and quality of forage available for white-tailed deer (Odocoileus virginianus). Management recommendations typically suggest a 3- to 5-year burn rotation in mixed pine–hardwood stands to increase quality forage production, but as fire frequency increases, forb and legume biomass increases, and woody browse decreases. A more frequent burn rotation may be a viable management option for deer managers, but there is still a lack of information regarding preferred forage and nutritional carrying capacity response to prescribed fire at these intervals. We measured the production and nutritional quality of forage within mature pine–hardwood stands after a 1- or 2-year fire-return interval during three nutritionally stressful periods for deer on a 640-acre (259-hectare) enclosure located in east-central Alabama during 2014 and 2015. These stands had previously been burned annually for over 15 years, resulting in an abundance of herbaceous vegetation. We then compared forage class biomass, nutritional carrying capacity estimates, and digestible protein between burn treatments. A 1-year fire return interval improved habitat quality to a greater degree than a 2-year fire return interval by increasing the production of forage able to support greater nutritional planes. An annual burn rotation is an effective option for managers to increase protein availability in pine–hardwood stands, but other factors such as decreased cover availability and soft mast production should also be considered.

A New Method for Evaluating the Visual Quality of Loblolly Pine (Pinus Taeda L.) Forest

<p>Most of the forested lands in the south-eastern United States were largely the result of the frequent, low intensity, non-lethal fires that swept through the pre-settlement forests. In the absence of fire, forested stands develop a thick undergrowth of broad-leaved species and herbaceous vegetation. In this study, we compared the influence of prescribed fire on the understory vegetative cover of loblolly pine stands in relation to visual quality assessment. To examine the visual quality of prescribed fire management, a box-counting method was used to analyze photographs of prescribed fire management. The photographs were taken from: a) one-year fire return interval, b) two-year fire return interval, c) three-year fire return interval, and d) no-burn. The objectives of this study were: 1) develop a comparison of aesthetic value of the different fire return intervals of fire management with areas not experiencing prescribed fire; and 2) provide an estimate of enhancing visual quality of forest stands with prescribed fire management. The results showed that one-year interval prescribed fire application stands had more abundant grass cover (Andropogon sp.) than two- and three-year interval treatments. There was a significant decrease in grass cover between one-year and two-year prescribed burning. A positive relationship was also found between frequency of fire treatment and abundance of grass. No burn areas were covered by woody vegetation which may have a negative impact on scenic beauty and visual quality.</p>

Relationship between fire-return interval and mulga (Acacia aneura) regeneration in the Gibson Desert and Gascoyne–Murchison regions of Western Australia

A study of 26 burnt mulga (Acacia aneura) stands was conducted from 2003 to 2012 in the Gibson Desert and eastern Gascoyne–Murchison region of Western Australia to assess the effect of fire interval on seedling regeneration. Tree-ring analysis and Landsat satellite imagery identified mulga stands with fire intervals ranging from 3 to 52 years. Results show fire-return intervals less than 20 years produce 2–3-year-old seedling regeneration lower than 50% of the original adult stand population (average juvenile-to-adult ratio=0.49). In total, 6 of the 26 stands sampled had reburnt within 3 to 10 years of the previous burn, a consequence of increased plant growth associated with higher rainfall. For all fires, summer fires were larger and more frequent (24 of 35 fires recorded, median fire size=150km2) than spring fires (median fire size=91km2). This study emphasises the important role of fire in maintaining the diversity and vigour of the mulga–Triodia ecosystem but indicates a minimum fire-return interval of 26 years to maintain mulga populations.