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

Leonardo Gallo,Verónica Andrea El Mujtar,Ernesto Andenmatten,Federico Letourneau,Oscar Grau,Marcelo Perdomo

doi:10.5424/fs/2011202-8916

Abstract

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.

Highlights

Longevity is a characteristic of forest trees that influences their responses to challenges by biotic and abiotic stressors
Similar diameter distributions were detected for PP16 and PP12 whereas PP26 had a lower contribution of diameter class I (Fig. 1)
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 (Dobbertin et al, 2001; Solberg, 2004; Badea et al, 2004; Bussotti and Ferretti, 2009; Klos et al, 2009; Brown and Allen-Díaz, 2009)

Summary

Introduction

Longevity is a characteristic of forest trees that influences their responses to challenges by biotic and abiotic stressors. The impact of cypress mortality on dynamics of A. chilensis forests was studied using dendrochronological tools to determine temporal development of the radial growth at the tree and stand levels (Amoroso, 2009). Years with warm and dry weather conditions were dendrochronologicaly related with the beginning of decrease in radial growth on symptomatic trees (Calí, 1996) and on trees selected by a matchedpair case-control strategy (Mundo et al, 2010). This decrease on radial growth precedes the development of the external symptoms in the crown. Satellite images were used to construct a map of the spatial distribution of patches of cypress mortality and to quantify the affected forest surface, the methodology was only used on a special area and time (La Manna et al, 2008)

Methods

Results

Conclusion