Abstract
Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation.Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain.Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model.Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena.Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed. p>ERRATUM PDF
Highlights
Crown fires display extreme fire behaviour (Werth et al, 2016) as the fire spreads through both the surface and tree canopy fuel layers, with the surface and crown fire phases more or less linked (Alexander & Cruz, 2016)
The aims of this paper are as follows: (1) to present the main results of the first full-scale crown fire experiment conducted in a Mediterranean conifer stand in Spain; (2) to compare the results obtained for crown fire initiation and propagation in Mediterranean conifer forests (Pinus pinea L. and Pinus pinaster Ait.) with current crown fire models by using data from field and laboratory experiments; (3) to obtain information on pine crown ignition in the absence of wind-forced convection; (4) to assess the flame residence time during crown fires in Mediterranean conditions
The model proposed by Cruz et al (2002) was developed in boreal forests characterized by low surface fuel load and lower Crown bulk density (CBD) than in the P. pinea stands under study here
Summary
Crown fires display extreme fire behaviour (Werth et al, 2016) as the fire spreads through both the surface and tree canopy fuel layers, with the surface and crown fire phases more or less linked (Alexander & Cruz, 2016). There are two main reasons for the difficulties in modelling crown fires: (i) the extreme complexity of the physical phenomenon (Rothermel, 1991), due to the heterogeneous fuel involved and the multiple influencing factors such as wind, slope, relative humidity, fuel moisture, atmospheric stability and surface fire intensity; and (ii) the complexity of conducting experimental crown fires (Stocks et al, 2004a) These difficulties are common throughout the world, including the most advanced countries where crown fire experiments have been carried out in a limited extension (for a review, see Alexander & Cruz, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
