The decline of Austrocedrus chilensis forests in Patagonia, Argentina: soil features as predisposing factors

Manna, Ludmila La; Rajchenberg, Mario

doi:10.1016/j.foreco.2003.10.025

Cited by 31 publications

(27 citation statements)

References 14 publications

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“…Alternatively, stands that establish on low elevations sites with poor soil water drainage (La Manna and Rajchenberg, 2004;La Manna et al, 2008a) as well as those at moderate elevations with greater precipitation (Baccalá et al, 1998) undergo periodic tree mortality during all development stages. This mortality process, locally known as 'mal del ciprés' (cypress sickness), was first detected more than five decades ago (Varsavsky et al, 1975;Hranilovic, 1988) and currently affects forests throughout the range A. chilensis in Argentina.…”

Section: Introductionmentioning

confidence: 99%

Stand development patterns as a consequence of the mortality in Austrocedrus chilensis forests

Amoroso

Larson

2010

Forest Ecology and Management

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Section: Introductionmentioning

confidence: 99%

Stand development patterns as a consequence of the mortality in Austrocedrus chilensis forests

Amoroso

Larson

2010

Forest Ecology and Management

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“…Serm. & Bizarri (ciprés de la cordillera) are being affected by ''mal del ciprés'', a syndrome caused by a poorly known agent (Filip and Rosso 1999;La Manna and Rajchenberg 2004;Greslebin and Hansen 2006) that causes root death and standing mortality followed by mass canopy collapse owing to root weakening and increased susceptibility to windthrow. At the landscape scale, poor soil drainage controls the occurrence of patches of standing dead trees of diverse sizes plus logs and fallen branches on the forest floor that appear interspersed in a matrix of healthy forest (La Manna et al 2008;Fig.…”

Section: Introductionmentioning

confidence: 99%

Effects of introduced ungulates on forest understory communities in northern Patagonia are modified by timing and severity of stand mortality

2008

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Natural disturbances such as fires, windstorms, floods, and herbivory often act on plant communities, affecting their structure and the abundance and composition of their species. Most research has focused on the effects of single disturbances on plant communities whereas the synergistic effects of several disturbances have received less attention. In this study, we evaluated how timing and severity of tree mortality modified plant use by introduced deer and early post-mortality successional trajectories in northern Patagonian conifer forests. We sampled understory composition and deer use in Austrocedrus chilensis (ciprés de la cordillera) forest stands undergoing varying timing and severity of forest mortality as reconstructed using dendroecological techniques. In addition, we evaluated the effect of fallen logs on plant composition and deer use of plants by monitoring areas of massive dieback where fallen logs had been removed for fire hazard reduction, and nearby control areas not subjected to such removal. Stepwise regression analyses showed that history and severity of tree mortality strongly influence plant composition and deer use of plants. For deer use (with pellet counts and browsing index as response variables), results showed a positive relationship with degree of stand mortality and a negative relationship with cover of fallen logs. Similarly, cover of unpalatable shrub species was explained by canopy mortality history, whereas cover of palatable shrub species was positively associated with severity of canopy mortality. In areas where fallen logs had been removed, pellet counts were six times higher than those in control areas. Though total shrub species cover was similar between log removal and control areas, proportion of unpalatable shrubs increased in areas where fallen logs had been removed. In conclusion, deer use of plants was strongly limited by tall fallen logs, allowing palatable species to establish and grow. Fallen log removal accelerated deer entrance and changed understory composition toward more browse-resistant and unpalatable species. These results underscore the importance of considering the dynamics (timing, severity, and extent) of fallen woody debris influencing understory herbivory and post-disturbance succession. In addition, experimental results underpin the importance of maintaining snags and large woody debris in disturbed landscapes where salvage logging is a routine procedure.

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“…Areas affected by cypress mortality are generally classified as disaggregated or aggregated (La Manna and Rajchenberg, 2004a). Disaggregated spatial pattern presents a distribution of affected trees fairly uniform over the area; on the contrary, in aggregated pattern the symptomatic trees form hot spots clearly separated from the asymptomatic neighbourhood.…”

Section: Discussionmentioning

confidence: 99%

Temporal progression trends of cypress mortality at permanent plots in a National forest reserve of Austrocedrus chilensis (Patagonia, Argentina)

Mujtar

Andenmatten²,

Perdomo³

et al. 2011

For. syst.

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Longevity is a characteristic of forest trees that influences their responses to challenges by biotic and abiotic stresses and the temporal development of symptoms. Monitoring programs have been extensively used to detect the impact of climatic change, air pollution and outbreaks of pathogens on forest health, growth and dynamics. In Argentina, forests of Patagonian cypress are affected since mid twenty century by a mortality process called «mal del ciprés» (cypress mortality), but information about their temporal progression is scarce. In the present work we used a database from a program of dasometric permanent plots to analyse the temporal development of cypress mortality on plot and tree level, and determine qualitatively the spatial distribution of affected trees. Particular pulses of appearance of affected trees shared by all plots, rapid or slow progress of mortality at tree level and a homogeneous distribution of affected trees without a clear pattern of expansion from a central point were determined. The results indicate that the episodic appearance of affected trees can be related with warm and dry climatic periods and suggest that the individuals affected by cypress mortality share some special characteristics such as genetic background, developmental conditions or physiological mechanisms for drought responses.Key words: symptoms development; monitoring; spatial distribution; drought; mortality pattern. ResumenTendencias en el desarrollo temporal del mal del ciprés en parcelas permanentes de una Reserva Forestal Nacional de Austrocedrus chilensis (Patagonia, Argentina)La longevidad de las especies arbóreas afecta la respuesta a estreses bióticos o abióticos y, en gran medida, determina el desarrollo temporal de los síntomas. Por tal motivo, los programas de monitoreo se han empleado para detectar el impacto del cambio climático, la polución ambiental o estallidos de patógenos en la sanidad y dinámica de los bosques. En Argentina, los bosques de Austrocedrus chilensis sufren desde 1945 una mortalidad masiva conocida como «mal del ciprés»; sin embargo, hay escasa información sobre su progresión temporal. En el presente trabajo una base de datos de un programa de parcelas permanentes se empleó para analizar el desarrollo temporal de la mortalidad a nivel de parcela e individuo y la distribución espacial de los árboles afectados. Se determinó que la aparición de síntomas sigue un patrón de pulsos compartido por todas las parcelas, con mortalidad rápida o lenta a nivel de individuo y una distribución homogénea de la mortalidad sin un patrón de expansión desde un punto central. Los resultados indican que los episodios de afectación pueden ser relacionados con períodos climáticos cálidos y secos, sugiriendo que los individuos afectados comparten características tales como background genético, condiciones de sitio o respuesta a la sequía.Palabras clave: desarrollo temporal de síntomas; monitoreo; distribución espacial; sequía; patrón de mortalidad.

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The decline of Austrocedrus chilensis forests in Patagonia, Argentina: soil features as predisposing factors

Cited by 31 publications

References 14 publications

Stand development patterns as a consequence of the mortality in Austrocedrus chilensis forests

Stand development patterns as a consequence of the mortality in Austrocedrus chilensis forests

Effects of introduced ungulates on forest understory communities in northern Patagonia are modified by timing and severity of stand mortality

Temporal progression trends of cypress mortality at permanent plots in a National forest reserve of Austrocedrus chilensis (Patagonia, Argentina)

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