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Prescribed burning plays an important role in the management of many ecosystems and can also be used to mitigate landscape-scale fire risk. Safe and effective application of prescribed fire requires that managers have a robust understanding of potential fire behavior in order to decide on the appropriate tools and tactics for any burning operation. Shrubland ecosystems, including heaths and moors, are known to exhibit intense fire behavior under marginal burning conditions under which fire would not be expected to spread in other vegetation types. This makes developing fire behavior predictions for such systems important. Traditional managed burning is widely used as a tool in Calluna vulgaris (L.) Hull-dominated heath and moorland landscapes in northwest Europe, but in some regions, especially the United Kingdom, there is significant debate over fire use. Despite the controversy, there is general agreement on the need to (1) understand relationships between fuel structure and potential fire behavior, and (2) improve burning practice to optimize potential trade-offs between different ecosystem services. Our aim was to provide knowledge to improve management practice by developing models of potential fireline intensity and flame length. We conducted 27 burns in three developmental stages of Calluna with different stand structures and estimated fireline intensity, flame length, flame height, and flame angle. Flame properties were assessed using photographs and visual observation. We evaluated our models using a participatory research approach for which conservation and land managers submitted basic observations on fire behavior and fire weather for their burns. Fireline intensity and flame height increased significantly across age-related Calluna phases. Regression modeling revealed that fireline intensity could be adequately estimated by a combination of fuel height and wind speed, with taller fuels and higher wind speeds related to more intense fires. Predictions were, however, improved by accounting for live fuel moisture content. Flame length and height were modeled as a function of fireline intensity using standard approaches, but adequately performing models for flame angle could not be established. Evaluation data provided by land managers was noisy, but their qualitative assessments of fire behavior and estimates of flame length were significantly correlated with predictions from our models. Fire intensities and flame properties seen in northern Calluna heathlands are similar to those encountered in shrublands associated with climates and fuels more commonly perceived as representing high fire danger. The results demonstrated that our models perform tolerably well although there is substantial uncertainty in their predictions. The models were used to develop a fire behavior nomogram that can provide an indication of potential fireline intensity and flame length prior to commencing a burn.

Background: Dramatic reductions in early-spring Calluna vulgaris moisture content have been linked to extreme fire hazard and plant die-back. Aims: To investigate spatial and temporal variation in the fuel moisture content of Calluna vulgaris. Methods: Calluna vulgaris plants were sampled in different sites and seasons to examine vertical profiles in moisture content. Live moisture content was monitored throughout autumn 2003 and spring 2004. Changes were compared to trends in temperature, soil resistance and rainfall. The effect of exposure was examined by comparing shoot moisture content in sheltered and exposed locations. Results: Significant spatial and temporal variation in moisture content was observed. In spring rapid fluctuations in moisture coincided with periods of dry weather, low temperatures and frozen ground. Shoots from exposed locations had significantly lower moisture content when the ground was frozen. Conclusions: Significant declines in the live fuel moisture content of Calluna vulgari...

Background: Surveys of land management impacts (e.g. of herbivores) are carried out in the Scottish uplands to meet conservation objectives. The reliability of such assessments has seldom been tested. Aims: To assess the inter-observer reliability of impact assessments. Methods: In the upper Spey valley, central Scottish Highlands, up to 17 observers were asked to assess in 5 m by 5 m plots and 1 ha plots (a) drying and peat loss in blanket bog, (b) browsing of dwarf-shrub heath, (c) grazing and trampling of wind-clipped heath, and (d) trampling and grazing in soligenous mire. Results: Averaged across indicators, complete disagreement between any two observers (high versus low impact) was found to be very unlikely (P < 0.06, and often < 0.001). On the other hand, complete agreement was moderately likely (between P = 0.53 and 0.75). Reliability varied considerably but was greater for large test plots than for small test plots, and for wind-clipped heath and dwarf-shrub heath. Conclusions: Reliability was s...

Summary 1. Upland heaths in the UK are of significant conservation importance. Large areas are managed through prescribed burning to improve habitat and grazing for red grouse Lagopus lagopus scoticus, deer Cervus elaphus and sheep Ovis aries. Previous research has identified trends in vegetation development following burning, but has not linked this to variation in fire behaviour and severity. 2. We burned 15 experimental fires on an area of Calluna vulgaris-dominated moorland, and recorded pre- and post-fire vegetation structure and composition, fire behaviour characteristics, and several ‘proxy measures’ of fire severity. 3. We distinguished measures of fire severity, describing the immediate physical effects of burning, from the long-term ecosystem responses of substrate development and Calluna regeneration. Proxy measures of fire severity did not relate strongly to fire behaviour or ecosystem response. 4. Post-fire regeneration was strongly linked to stand age and post-fire substrate type. Fire behaviour and severity had little effect, though fire-induced ground-surface heating may promote Calluna seedling establishment. Vegetative regeneration of Calluna was extremely poor in older stands, as was seedling establishment in areas where the post-fire substrate was dominated by live or dead pleurocarpous moss mats. 5.Synthesis and applications. Significant nonlinearities exist in fire severity on heathlands, with step changes related to the depth and moisture content of moss/litter layers and peat. Younger stands, less than c. 30 cm tall, should be the focus of management if the objective is to maximize Calluna regeneration. Burning older and uneven-aged stands is discouraged except for the purposes of fire hazard management. Managers should develop landscape-level burn plans to target burning effectively and create diverse fire regimes.

Summary 1. Calluna-dominated heaths occur throughout Europe but are in decline across their range. There is growing interest in using prescribed burning for their management, but environmental and social change will impact future fire regimes. Understanding fire behaviour is vital for the sustainable use of fire, but no robust models exist to inform management. 2. Shrub fuels display complex fire behaviour. This is particularly true in UK moorlands which are unusual in their fuel structure and moisture regime, being dominated by live fuel and an oceanic climate. 3. We burnt 27 experimental fires in the Scottish uplands during the legal burning season using a replicated experimental design. Plots were assigned to one of three commonly identified growth phases. We estimated a range of prefire fuel characteristics, including heterogeneity in fuel structure. We recorded wind speed and direction and estimated rate of spread (RoS). 4. Redundancy analysis was used to investigate the relationship between fire behaviour parameters as a whole and control variables. Fuel structure and heterogeneity, wind speed and canopy fuel moisture content were strongly related to variation in fire behaviour. 5. Best subsets regression was used to generate models of fire spread based on wind speed, vegetation height, canopy fuel moisture and an index of fuel heterogeneity. RoS was determined largely by wind speed, but this interacted strongly with vegetation structure. Changes in fuel horizontal continuity and vertical structure reduced rates of spread in low wind speeds. 6. Synthesis and applications. Live fuel moisture and fuel heterogeneity play an important role in dampening fire behaviour, aspects of shrub fuels that have previously not been examined in detail. Careful use of fire for moorland management increases habitat diversity and creates fire-safe landscapes. Escaped prescribed fires burn large areas, homogenize landscapes and have severe impacts on ecosystem services. The complex relationship between fuel structure and wind speed implies that changes in behaviour can be rapid and unexpected. Models can be used to assess fire hazard prior to prescribed burning and to choose fuels that can be burnt safely under prevailing or forecast conditions.

Summary This paper describes the assessment of upland plant communities in the context of Scottish Natural Heritage's Site Condition Monitoring (SCM) programme. The quality of all notified features on all statutory designated sites will be monitored every six years, with the first national report being produced in 2005. Notified habitat features are largely defined in terms of plant communities. It is important to appreciate that plant communities are to some extent used as proxy indicators for wider interests. Upland monitoring will cover 973 specific vegetation features (grouped into just over thirty generic feature types) and 66 habitat assemblage features, spread over 223 sites and 6516 km2. Problems and solutions associated with the identification of feature boundaries, quality attributes and targets, and sampling are discussed. Three sets of assessment issues are selected for further discussion: first, appropriate species composition, and the use of direct and indirect targets; second, appropriate d...

Bracken spread could have very selective impacts on the vegetation of upland Scotland (UK). Information on this would be of value in targeting appropriate management measures. However, it is difficult to establish accurately the current distribution of bracken, so modelling bracken spread using process-based models is not possible at present. An alternative modelling approach is described which uses knowledge of the climatic, soil and topographic limits to the existing bracken distribution in upland Scotland. This knowledge is formalized as a rule-based model. This is applied through a geographical information system (GIS) to identify the maximum potential bracken niche over the whole of Scotland with a nominal spatial resolution of 1 ha. The model is validated against field data from 14 sites around Scotland. Between 64–97% of the existing bracken lies within the predicted bracken niche. Locally low accuracies are ascribed to scale-effects derived from the input datasets, the nature of the ground data, as well as the universality of the model rules. The bracken niche is differentiated into two types: continuous and discontinuous. The total area of the niche is 6036 km 2 or 7.75% of the land area of Scotland with a broad 60:40 split between the continuous and discontinuous niche types, respectively. However, there is a strong regional bias in their distribution with the discontinuous niche type principally occurring in the west of Scotland. Overlaying the potential niche on the Land Cover of Scotland 1988 dataset shows that it impacts on 70% of the national area of ‘good rough grassland’ and 31% of the ‘poor rough grassland’ category. In addition, 16% of the national area of ‘heather moorland’ is impacted. There are strong regional variations in these impacts which may have implications for future bracken management. The limitations of the approach are discussed and the potential for linking it to dynamic models is identified.

The subject of this paper is the operating experience of Aluminum Company of Canada, Ltd., with the electric drives and control systems of a high-performance 84-inch cold rolling mill. Comparative horsepower energy curves for aluminum alloys are shown, and selection of the drive motors, together with actual performance data, are discussed.

The abstract of this paper was previously published in a supplement to Forest Ecology and Management. The full paper, presented here, was available only on the CD of the conference paper. Prescribed burning of moorland vegetation in the UK is used to provide habitat for red grouse, a game bird, and to improve grazing for sheep and deer. The peak time of fire risk corresponds to the normal legal burning period of 1st November (1st October in Scotland) to 15th April rather than a meteorologically-defined fire season. Moorland fuels in the UK are unusual. They are dominated by Calluna vulgaris, which forms a dense, uniform canopy (though as stands age gaps become more frequent), and in which live material forms the majority of “available” fuel. The moisture content of live fuel plays a dominant role in determining fire behaviour. Weather in the UK uplands can vary rapidly from cold and wet, to sunny with drying winds and low atmospheric humidity. Frozen ground can prevent plants from replenishing water lost by transpiration. Fire behaviour is difficult to predict and periods of significant wildfire activity can occur. Data from 15 experimental fires were used to build empirical relationships between rate of spread, windspeed and vegetation structure. Fires in the high fuel-loads responded much more strongly to increased windspeed. The high density of the fuel-bed in younger Calluna stands may have a limiting effect on the rate of fire spread. Redundancy analysis highlights the importance of fuel moisture content and stand structural heterogeneity. We tested the rate of spread predictions of BehavePlus and the Canadian Wildland Fire Information System (CWFIS). Predictions provided by BehavePlus were relatively good. The CWFIS was unable to predict rate of spread because the moisture content of live and dead Calluna was not accurately predicted by any of the moisture codes of the CWFIS. The system did detect a period of extreme risk associated with drought and wildfires during the spring of 2003. Multiple scales and causal factors of increased fire risk are discussed with reference to seasonal variation in the fuel moisture content of Calluna.