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Harvard Forest Symposium Abstract 2013

• Title: Faith-based or risk-based? Forest conservation principles and the risks to future forest function
• Primary Author: Duncan Stone (Scottish Natural Heritage)
• Abstract:

  Faith-based or risk-based? Forest conservation principles and the risks to future forest function
  
  
  Duncan Stone, Bullard Fellow
  
  
  
  
  
  Maintaining and renewing our stock of big, old trees is perhaps the chief responsibility of forest managers in conservation or multi-use forests. Many of the functions of forests depend on an element of sufficient big old trees, and failing to maintain this element leads to the loss of these functions. Failing to continually renew it deprives future generations of the benefits we’ve inherited, as well as the inherent value of rich and complex ecosystems. Our provision of big old trees is a very long term task – typically 150-400 years – during which the growing environment for the trees must remain within their genetic tolerances. However, recent years have seen numerous examples of these tolerances exceeded through novel or unexpected tree health problems, linked to impacts of climatic conditions and introduced pests/pathogens. The drivers of this instability – insufficiently-regulated world trade and climate change – are likely to continue over the next 150-400 years in unpredictable ways that cannot be guaranteed to allow successful growth of big old trees of any given species, native or non-native.
  
  
  
  
  
  Growing trees over such enormous duration requires a degree of faith – i.e. we hope, but do not know whether our management choices will turn out to be successful. But is our faith in a natives-only approach justified, when the growing environments are going to undergo big and rapid changes? Surely we need to be considering new approaches to improve the chances of success, especially where the risks of failure already seem high, such as where serious pests and pathogens are already established, or where key forest functions depend on the future health of a single species.
  
  
  
  
  
  Despite the recent evidence of serious tree health problems, conservation organisations are still largely focussed on the exclusive use of locally native trees in forest conservation. Adopting a broader range of approaches by using a wider range of tree genotypes offers a way to increase the resilience of our forests by providing more redundancy – rather than our objectives depending on a single species, we could perhaps use two or three. Of course, insurance comes at a cost, and here the cost may be that the non-native genotypes may under current circumstances provide those forest functions less well than the native species. In this context, ‘optimized’ and ‘resilient’ are mutually exclusive characteristics.
  
  
  
  
  
  During my Fellowship here at Harvard Forest I’m developing the evidence and understanding to argue for a change in forest conservation policy - to become more flexible about the role of non-native species in providing redundancy and resilience. This is particularly relevant in my home country of Scotland, where our native forests are at the higher end of any vulnerability scale – very limited species diversity, immediate disease problems and significant other threats, all set within a ‘faith-based’ conservation and legislation framework that only allows locally native species.
  
  
  

• Research Category: Conservation and Management
  Invasive Plants, Pests & Pathogens