Self-replacement after small-scale partial crown dieback in austral Nothofagus dombeyi forests affected by an extreme drought

SUAREZ, MARÍA LAURA; LLORET, FRANCISCO

CANADIAN JOURNAL OF FOREST RESEARCH

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Año: 2018 p. 1 - 9

0045-5067

The spectrum of structural response in drought-induced mortality (degree of partial crown mortality) could play a keyrole in pervasive changes in plant composition, as individual openings could reset self-replacement dynamics or trigger shifts invegetation. Here we capture the community pattern 17 years after a drought episode over a range of canopy responses inNothofagus dombeyi forests. We applied a widespread demographic approach to address evidence of species shifts vs. selfreplacementand to relate partial dieback to understory structure and composition. Assuming that the outcome of growthrelease of the understory components can be observed 17 years after canopy loss, this study reveals evidence of self-replacementin N. dombeyi forests heavily affected by drought. Alternatively, when the co-dominant species A. chilensis is widely present in theunderstory and large gaps are opened, a compositional shift may be possible, with a potential change in forest functionality.Individual partial openings do not favor more shrubby communities or a shift toward a new community. Thus, partial crowndieback contributes to self-replacement mechanisms by hampering strong growth release in understory shrubs, as evident inplots with high mortality, and by facilitating the growth of dominant tree species.