Presentation on theme: "ES_31_2, Spain, Galicia Dozón 2006 WP 9.1 Examples of prescribed burning and its effects."— Presentation transcript:
ES_31_2, Spain, Galicia Dozón 2006 WP 9.1 Examples of prescribed burning and its effects
Plot description Town: Dozón (Lugo) Place: Seixas Area: 2 ha Slope: 5-15% Aspect: N – NW Property: Local Community Use: Livestock, hunting Objectives: This is an experimental site in which prescribed burnings and other preventive techniques are being compared. The main objective of this study area is to analyze the effects of the use of different preventive techniques on the reconstruction of the fuel complex, on the fire behavior some years later and on soil properties (physical and chemical). Other objectives are the effects on vegetation diversity.
Plot description Vegetation structure: Typical shrubland community ( m height) in developed soils, with a good level of soil moisture. It is included in the Cirsium filipenduli-Ericetum ciliaris phytosociological association. The pre-dominant species is Erica umbellata Loefl. (L.), with other woody species such as Calluna vulgaris (L.) Hull, Pterospartum tridentatum (L.) Willk., Ulex europaeus L. and Halimium lasianthum ssp. alyssoides (Lam.) Greuter also present. This structure can be associated to a fuel model 6 and 4 (Anderson 1981).
Prescription Prescribed burns were carried out in April 2006 (five plots) after a period of rain to prevent the organic matter burning and to diminish fire severity. The objective of the treatment is to reduce a 80% the available surface fuel, and to renew shrubland vegetation.
Prescription window Midflame wind speed: 2 – 12 km/h Air relative humidity: % Air temperature: 5 – 15 ºC Number of days since the last rain (>30 mm): 3 – 12 Atmospheric stability Period of the year: December - April Dead fuel moisture: < 35% Live fuel moisture: 70 – 175% Litter fuel moisture: > 110% Soil moisture: > 30% Rate of spread: < 12 m/min Flame length: < 4 m Fireline intensity: < 4500 kw/m
Execution Prescribed burning was conducted by strip head fire technique. Ignition was initiated with dip-torches following contour lines and going downslope. Distance between lines was between 2 m. Fuel inventory was carried out by two-step sampling techniques in each plot before and after prescribed burns to estimate initial fuel complex characteristics and fuel consumptions by size range classes and stratum.
Execution Wind direction and speed, air relative humidity and air temperatures were monitored during the precribed burns, with meteorological stations and sonic anemometers.
Execution Fire behaviour was monitored during each experimental fire. Ground cameras and video captured fire development and flame characteristics and, along with observers notes, were used to determine the fire spread rate, using a network of posts as references. A grid of thermocouples connected with datologgers was installed inside the plot to provide information on flame, litter and soil temperatures, flame depth, residence time and rate of spread.
Effects A reduction of 90% available surface fuels was observed after the treatment without appreciable soil heating.