1 GLOBAL CHANGE SYMPOSIUM 15 MARCH Physiological ecology of understorey trees in alternative management systems Sophie Bertin Physiological ecology of understorey trees in alternative management systems Sophie Bertin Maurizio Mencuccini 1, John Grace 1, Mike Perks 2, Nigel Straw 2 & Bill Mason 2 1 University of Edinburgh & 2 Forest Research PhD project Co-Sponsored from the Forest Research Innovation Fund & the Torrance Bequest for Plant Ecology

2 GLOBAL CHANGE SYMPOSIUM 15 MARCH  CCF : increasingly common alternative management system for British forests  Sitka spruce : dominant commercial tree species in the UK  Limited knowledge of desirable conditions for seedling regeneration and growth under CCF Continuous Cover Forestry & Sitka Spruce

3 GLOBAL CHANGE SYMPOSIUM 15 MARCH  Main defoliator of Sitka spruce  Sap feeding insect  Prediction: climate change is likely to enhance aphid population growth and therefore declines in Sitka spruce productivity (Straw, 1995). Green Spruce Aphid & Climate Change (I)

4 GLOBAL CHANGE SYMPOSIUM 15 MARCH Green Spruce Aphid & Climate Change (II)  Life cycle of the green spruce aphid

5 GLOBAL CHANGE SYMPOSIUM 15 MARCH Research Question Low light conditions GLOBAL CHANGE SYMPOSIUM 15 MARCH 2006 Aphid attack & ? How are Sitka spruce seedling growth and survival affected by the interactions between

6 GLOBAL CHANGE SYMPOSIUM 15 MARCH General Aim and Hypothesis  General aim Understanding seedling tree ecophysiology within CCF systems  Hypothesis Low light level & aphid attack = poorer Sitka spruce seedling growth and survival

7 GLOBAL CHANGE SYMPOSIUM 15 MARCH Methods (I)  2006: Exploratory experiments  Short-term pot-plant shade/aphid experiment, NRS nursery, Roslin  Transect investigations of natural regeneration and treated trees in CCF sites, Borders  : Detailed experiments  Full field shade/aphid experiment, Roslin  Large scale field manipulation experiment, Wales NRS Borders Wales

8 GLOBAL CHANGE SYMPOSIUM 15 MARCH Methods (II)  Layout of short-term pot-plant experiment 2006

9 GLOBAL CHANGE SYMPOSIUM 15 MARCH Assessment Protocols (I)  Aphid population size (Straw and Green, 2001)  Plant allometry (architecture) and needle densities

10 GLOBAL CHANGE SYMPOSIUM 15 MARCH Assessment Protocols (II)  Plant Physiological measurements  Photosynthesis  Chlorophyll fluorescence kinetics

11 GLOBAL CHANGE SYMPOSIUM 15 MARCH Research Outcomes  Guidelines for natural regeneration under CCF management systems  Implications for the impact of green spruce aphids on Sitka spruce  Development of chlorophyll fluorometer techniques to assist CCF stand manipulation

12 GLOBAL CHANGE SYMPOSIUM 15 MARCH  Mike Perks (NRS)  Maurizio Mencuccini (UoE)  Forest Research staff  University of Edinburgh Acknowledgments