Post-fire resprouting strategies of woody vegetation in the Brazilian savanna

Abstract

Post-fi re response by vegetation may refl ect the severity of the damage suff ered, but we still know little about the species-specifi c nature of responses to fi re or their predictors. Here, we evaluated 26 woody species before and after a fi re event in an Cerrado sensu stricto area (typical Brazilian savanna-type) in order to evaluate mortality rates and the type of resprouting (epigeal, hypogeal or epigeal + hypogeal). We evaluated the relative importance of stem diameter, height, and bark thickness as predictors of the type of post-fi re resprouting, using a sequential logistic regression model (SLRM). Mortality was 4 %, while epigeal resprouting was recorded in 57 % of the individuals, hypogeal resprouting was recorded in 24 %, and epigeal + hypogeal resprouting in 15 %. Our SLRM analysis indicated that bark thickness, followed by stem diameter, were the best predictors of the type of resprouting. Th ere was a greater than 60 % probability that individuals with bark thicker than 1.6 cm resprouted only epigeally. Our results confi rm the resistance (low mortality) and resilience (high resprouting capacity) of the woody vegetation of the Cerrado sensu stricto to fi re, and that thick bark is an eff ective protection against fi re damage.

Responses of Plant Biomass in the Brazilian Savanna to Frequent Fires

“…Tree biomass recovers more rapidly after one fire event (1F) than other vegetation strata, as tree individuals are generally more protected from fire damage, because of higher height, trunk diameter, and bark thickness Souchie et al, 2017). Therefore, damage caused by fires is generally associated with partial damage to individual trees, such as topkill (Hoffmann and Solbrig, 2003;Hoffmann et al, 2009;Souchie et al, 2017) and this permits more rapid regeneration through sprouts produced from the trunk or tree crown (Moreira et al, 2008;Souchie et al, 2017). However, for smaller individuals (< 2 m), such as shrubs, fire can cause complete death of the trunk due to greater exposure to higher temperatures, making regeneration more difficult (Moreira et al, 2008;Hoffmann et al, 2009;Gomes et al, 2014).…”

“…On the other hand, the recovery of tree biomass declines with increased fire frequency, as the 2 year fire intervals (2 BF) may not be sufficient for the thickening of bark or for trunk growth above the height of greatest exposure to flames (Souchie et al, 2017;Keeley and Pausas, 2019). Other studies also demonstrate the decline in tree biomass in Brazilian savanna after three (Rios, 2016;da Silva Rios et al, 2018) and five biennial fires (Sato, 2003;Sato et al, 2010).…”

Diversity of functional trade‐offs enhances survival after fire in Neotropical savanna species

“…Two clear trade-offs emerged: investing in increased growth rate, height and bark density vs. investing in bark thickness and higher wood density; and investing in outer vs. inner bark. The choice between investing in growth and building a tall canopy vs. investing in thick insulating barks to resist fire is a relatively well explored plant strategy trade-off (Gignoux et al, 1997;Hoffmann et al, 2009;Keeley et al, 2011;Lawes et al, 2013, Souchie et al 2017. A thick…”

Conexões biogeográficas de savanas brasileiras: partição da diversidade marginal e disjunta e conservação do trópico ecotonal setentrional em um hotspot de biodiversidade

“…Uma vez que a predominância do domínio das terras do Cerrado é privada, os desmatamentos e incêndios ocorrem cada vez mais de forma acelerada. Souchie et al (2017) esclarece que o fogo historicamente influenciou a extensão e composição dos ecossistemas de pradarias e savanas tropicais, mas dentro de certas restrições físicas naturais e que o aumento nessas taxas evidencia o descuido do poder público e a necessidade de uma gestão mais verticalizada e eficaz para a preservação do patrimônio ambiental do Cerrado.…”