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Federal Biological Research Centre for Agriculture and Forestry www.bba.de
Economic and environmental impact assessment for ornamental and forest plants – the case of P. ramorum
Long-term growth of perennials – substitution of damaged plants hardly to calculate / problem of appropriate discount rates
Ideal values of ornamentals or forests may not be accounted with market prices and are hardly to be estimated
Different use-values of forests (current and future) like recrea-tional land use, aesthetic, production or ecological value
Difficult evaluation of (impacts on) biodiversity Phytophthora ramorum damages a broad range of ornamentals and forest trees (examples in table 1) and is actually being evalua-ted within the European Union framework 6 project on Risk Analysis for P. ramorum threat to Europe (RAPRA,www.rapra.csl.gov.uk). Impacts of the fungus in Europe are mostly on crop production in nurseries and to a limited extent outside nurseries in plant societies where Rhododendron are present. Details on possible impacts and methods for their assessment shows table 1.
Foto: S. WerresFig. 3: Branch dyback and foliar lesions on Rhododendron caused by P. ramorum
Foto: S. WerresFig. 4: Stem canker on Quercus agrifolia
Fig. 1: What is the recreational value of a rhododendron park?
Foto: Axel Oehler
Hella Kehlenbeck
Federal Biological Research Centre for Agriculture and Forestry, Department for National and International Plant Health
Stahnsdorfer Damm 81, D-14532 Kleinmachnow, Germany; [email protected]
The example of P. ramorum shows that the economic and environmental impact assessment for ornamental and forest plants as needed within Pest Risk Analysis requires a broad range of economic methods and tools. Since economic and environmental con-sequences depend on a number of biological, environmental and ecological data, these disciplines have all to be linked together.
Example: Phytophthora ramorum in Europe
Problem
Pests and diseases cause a variety of direct and indirect impacts. The assessment of these impacts on perennial ornamental and forest plants as needed for a decision on measures (SPS agreement) and their evaluation with cost-benefit analysis differs very much from the assessment for annual crops (wheat, corn). It remains very often with a high degree of uncertainty. Important points are:
Table 1: Examples for important host plants of Phytophthora ramorum in Europe, possible impacts and proposed methods for impact assessment
Host Plants (examples)
Where impacts mainly occur
Possible impacts Possible methods
- Calluna vulgaris - Rhododendron - Viburnum - Camellia
nurseries, home gardens
- direct losses in production
- additional plant protection products
- trade restrictions
- cost calculation
(concept of willingness to pay1 for home gardens)
- Rhododendron - Camellia
public gardens and parks
- loss of valuable plants
- loss of special recreation areas and hobbies
- cost calculation
- concept of willingness to pay1
- Arbutus unedo - Castanea sativa - Fagus sylvatica - Laurus nobilis - Pieris spp. - Quercus spp.
forests, heathland and maquis,
public green,
home gardens,
also nurseries
- direct losses in wood production
- additional plant protection measures
- losses in international trade with wood or plant material
- changes in use-values
- changes in biodiversity
- loss of human recreation areas
- cost calculation
- concept of willingness to pay1
- market price method2
- travel cost method3
1 concept of willingness to pay: is based on the estimate how much people would be willing to pay for specific environ-mental services.
2 market price method: applicable to products or services (of ecosystems) that are bought and sold in commercial markets.
3 travel cost method: assumes that the value of a site is reflected in how much people are willing to pay to travel to visit the site.
Conclusion
Fig. 5: Shoot dyback on Vi-burnum caused by P. ramorum
Foto: S. Werres
Foto: www.suentelbuchen.de
Fig. 2: What is the use-value of an old tree?
A proper impact assessment for ornamental and forest plants requires:
Experience in practical application of the complex and very special methods Consultation with experts in economics More interdisciplinary investigations and projects Use of qualitative data where quantification of monetary terms is not
possible
