title: Extreme defoliation reduces tree growth but not C and N storage in a winter-deciduous species.
abstract: OBJECTIVE
  There is a growing concern about how forests will respond to increased herbivory associated with climate change. Carbon (C) and nitrogen (N) limitation are hypothesized to cause decreasing growth after defoliation, and eventually mortality. This study examines the effects of a natural and massive defoliation by an insect on mature trees' C and N storage, which have rarely been studied together, particularly in winter-deciduous species.
  
  
  METHODS
  Survival, growth rate, carbon [C, as non-structural carbohydrate (NSC) concentration] and nitrogen (N) storage, defences (tannins and total polyphenols), and re-foliation traits were examined in naturally defoliated and non-defoliated adult trees of the winter-deciduous temperate species Nothofagus pumilio 1 and 2 years after a massive and complete defoliation caused by the caterpillar of Ormiscodes amphimone (Saturniidae) during summer 2009 in Patagonia.
  
  
  RESULTS
  Defoliated trees did not die but grew significantly less than non-defoliated trees for at least 2 years after defoliation. One year after defoliation, defoliated trees had similar NSC and N concentrations in woody tissues, higher polyphenol concentrations and lower re-foliation than non-defoliated trees. In the second year, however, NSC concentrations in branches were significantly higher in defoliated trees while differences in polyphenols and re-foliation disappeared and decreased, respectively.
  
  
  CONCLUSIONS
  The significant reduction in growth following defoliation was not caused by insufficient C or N availability, as frequently assumed; instead, it was probably due to growth limitations due to factors other than C or N, or to preventative C allocation to storage. This study shows an integrative approach to evaluating plant growth limitations in response to disturbance, by examining major resources other than C (e.g. N), and other C sinks besides storage and growth (e.g. defences and re-foliation).
authors: Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Conicyt-Regional R10C1003, Universidad Austral de Chile, Camino Baguales s/n, Coyhaique 5951601, Chile, Instituto de Ecología y Biodiversidad (IEB), Las Palmeras 3425, Santiago, Chile and Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden fpiper@ciep.cl.
authors: Frida I
authors: FI
authors: Piper
authors: Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Conicyt-Regional R10C1003, Universidad Austral de Chile, Camino Baguales s/n, Coyhaique 5951601, Chile, Instituto de Ecología y Biodiversidad (IEB), Las Palmeras 3425, Santiago, Chile and Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
authors: Michael J
authors: MJ
authors: Gundale
authors: Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Conicyt-Regional R10C1003, Universidad Austral de Chile, Camino Baguales s/n, Coyhaique 5951601, Chile, Instituto de Ecología y Biodiversidad (IEB), Las Palmeras 3425, Santiago, Chile and Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
authors: Alex
authors: A
authors: Fajardo
mesh_terms: D000818:Animals; D002244:Carbon / Q000378:metabolism*; D002677:Chile; D057231:Climate Change; D060434:Herbivory; D019684:Magnoliopsida / Q000254:growth & development* / Q000378:metabolism*; D009036:Moths / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D014197:Trees / Q000254:growth & development / Q000378:metabolism
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Climate change; Nothofagaceae; Nothofagus pumilio; Ormiscodes amphimone; Patagonia; defoliation; herbivory; insect outbreaks; nitrogen; non-structural carbohydrates; plant defences; storage.