The occurrence of large and recurring forest fires has long been associated with fire-prone environments, but this perception has been shifted rapidly in recent decades as Earths' landscapes have become increasingly threatened by severe and unpredictable fires as a result of climate changes. In this regard, the flammability of trees is a topic of great interest for ecology, management, and the development of sustainable restoration and rehabilitation plans. Tree species differ in regard to flammability, and many plant functional traits contribute to flammability at species, community and vegetation level. The relationship between plant traits and flammability at species level is important for a broader understanding of the vegetation-fire dynamic at the local and landscape scales. This review summarizes the current state of knowledge regarding the impact of individual plant traits of tree species on flammability components. By keywords-based searching of academic databases, 85 research papers were collected and analyzed. The literature synthesis shows: i) main issues addressed in studies on plant trait-based tree flammability, ii) general research output and biogeographic regions studied, iii) inventory of tree taxa investigated, iv) relationships between plant traits and flammability components, v) the most relevant plant traits that determine the flammability-related differences between species.
Shrubland is a Mediterranean biome characterized by densely growing evergreen shrubs adapted to fire events. To date, scientific research has focused on the impact of vegetation on soil erosion mainly through the control that plant biomass or plant cover exerts on sediment delivery and runoff discharge, being the individual plant species influence on hydrological and erosional processes not achieved in detail. The objective of this research is to determine: i) runoff and soil losses in a shrubland-covered rangeland at Sierra de Enguera, Spain; and ii) how four plant species affect soil and water losses. We measured soil cover, soil properties, runoff discharge and sediment yield under natural rainfall for five years (2010-2014) in a typical shrubland burnt in 1999. Four plant species were selected with 4 plots each: Ulex parviflorus Pourr., Pistacia lentiscus L., Quercus coccifera L. and Rosmarinus officinalis L. Despite that the soil properties and plant cover did not exhibit statistically significant differences among plant species, the runoff discharge was lower on Q. coccifera (4.87%, SE 0.24) and P. lentiscus (6.24%, SE 0.51) than on U. parviflorus (13.41%, SE 0.58) and R. officinalis (13.84%, SE 1.23). Sediment concentrations were, respectively, 3.91, 4.33, 4.31 and 4.88 g l-1, and the differences between R. officinalis and the other species were statistically significant. The runoff discharge determined differences in soil erosion rates among the plant species with lower rates on P. lentiscus (1.36 Mg ha-1 y-1) and Q. coccifera (1.53 Mg ha-1 y-1), than on U. parviflorus (3.17 Mg ha-1 y-1) and R. officinalis (3.85 Mg ha-1 y-1). This long term in situ study indicated that Q. coccifera and P. lentiscus are more efficient in controlling runoff discharge and soil losses than U. parviflorus and R. officinalis one decade after a fire. We discuss these results in light of the recent findings by the scientific community of the role of the canopy cover (rainfall interception), soil macropore and root system, and the water repellency that control the hydrological response of the soil (e.g. runoff generation, infiltration). The information supplied by 5 years of research is relevant for restoration and rehabilitation programs and advise that Q. coccifera and P. lentiscus are the most efficient plant species to control soil and water losses within the Mediterranean shrubland. This is an applied science approach for a better management of rangelands.