Fire, logging and establishment patterns of second-growth forests in south-central Chile: implications for their management and restoration

Abstract

M.E. González, P. Szejner, P.J. Donoso, and C. Salas. 2015. Fire, logging and establishment patterns of second-growth forests in south-central Chile: implications for their management and restoration. Cien. Inv. Agr. 42(3): 427-441. Second-growth forests represent the greatest potential resource for forest management and large-scale ecological restoration in many regions. In south-central Chile, second-growth forests include those dominated by Nothofagus obliqua, N. dombeyi, Drimys winteri, and a mixture of evergreen species, especially hardwoods. This article examines the influence of fire and logging on the establishment patterns and development of second-growth forests in south-central Chile. We characterize the size structure and composition of these four types of forests with sampling plots. The identification of the type of disturbance and its date of occurrence was determined from evidence such as fire scars and even-aged pulses of tree establishment. The size, structure and species composition of these forests indicate an intermediate state of development with an average density and basal area ranging from 1294 to 5038 trees ha-1 and from 59 to 85 m 2 ha-1 , respectively. Logging and/or devastating fires that occurred in the early decades of the 1900s promoted the relatively rapid establishment and growth of pioneer species (Nothofagus obliqua, N. dombeyi, D. winteri). In the Mixed Evergreen second-growth forests, mid-shade or shade tolerant species (e.g., Gevuina avellana, Eucryphia cordifolia, Amomyrtus luma, and A. meli) became established mostly through vegetative sprouting. Fires and logging have been pervasive factors in determining the structural and compositional uniformity of the native forests of south-central Chile. Ecological restoration at a landscape level, either by ecological processes (i.e., a reduction in fire frequency) and/or the structure and composition of second-growth forests, provide a relevant approach to accelerating the generation of attributes of old-growth forests, therefore meeting manifold societal demands for forest goods and services.

Consequences of land-use change and the wildfire disaster of 2017 for the central Chilean biodiversity hotspot

“…However, their study does not cover plant mortality. Finally, González et al (2016) have shown that wildfires transform Chilean forests from primary to secondary forest, which may host a reduced biodiversity.…”

Differentiating Structural and Compositional Attributes across Successional Stages in Chilean Temperate Rainforests

“…The two Nothofagus-dominated secondary forests (NoSg and NdSg) can be considered in the "understory reinitiation" stage (sensu [48]), with larger trees and basal areas and lower tree densities, but still similar heterogeneity. The great differences among these two successional stages, as expressed in this study), are the result of differences in few decades since establishment, in growth rates of dominant species (Nothofagus species are among the fastest in Chile, [15,16,49,50]), and also in the type and magnitude of the disturbance that generated these forests [32], which, for example, determined the differences in species composition. In general, second-growth forests in the stem exclusion stage of stand development will have less commonalities with structural characteristics of old-growth forests than when comparing forests in the understory reinitiation stage of stand development with old-growth forests, but there may be exceptions, such as with dead wood.…”

“…The other three second-growth forests were dominated (i.e., at least 50% of the basal area in one species), respectively, by Drimys winteri (DwSg), Nothofagus dombeyi (NdSg), and Nothofagus obliqua (NoSg), but all were also mixtures and had common late-successional tree canopy species such as E. cordifolia, L. philippiana, A. punctatum and D. winteri (Table 1). The MESg and DwSg forests were mostly established between 1940 and 1970 (they were on average close to 60 years old), and NoSg and NdSg forests were mostly established between 1910 and 1940 (they were on average 90 years old; [32]). The remaining successional forest (NdM) was also dominated by N. dombeyi and was also originated by human-caused fires as observed in the field.…”

“…These old-growth forests (EgOg and NoOg; Table 1) were dominated by the same canopy species (Aextoxicon punctatum, Eucryphia cordifolia and Laureliopsis philippiana) but the one in Rucamanque also had some emergent Nothofagus obliqua trees. The successional forests (Table 1) included four second-growth forests that were established following human-caused fires, with ages between 60 and 100 years [26,31,32]. The MESg was a mixture of several hardwood evergreen species, including some short-lived pioneer species of the Proteaceae family, but among successional canopy species was dominated by E. cordifolia, L. philippiana and D. winteri.…”

Cambios en cobertura y regeneración arbórea en bosques siempreverdes en diferentes estados sucesionales en el sitio experimental de Llancahue, Cordillera de la Costa de Valdivia, Chile

“…Dos de los bosques muestreados corresponden a bosques nativos secundarios en distintos estados sucesionales (temprano e intermedio) y uno a un bosque adulto (BA) en un avanzado estado sucesional. El bosque en un estado sucesional más temprano corresponde a un bosque secundario mixto siempreverde (BSMS) que fue originado por madereo y presumiblemente fuego a inicios de los años 30 del siglo veinte, y el bosque secundario dominado por N. dombeyi (BSNd) fue originado luego de un incendio severo que ocurrió cerca de 1914 (González et al 2015). Diversos atributos de composición y estructura de estos bosques son reportados en Ponce et al (2017).…”