When the survey was performed
The survey was done annually during July and August and the completed forms sent to Forest Research by the end of September.
How survey plots were selected
To qualify for this survey a plot had to:
- Contain six species of tree from a list of 17 chosen genera (see table below)
- Have at least five representatives of trees of each of these six species (unless stated in the table below)
- Within each species, have all the trees that were assessed around the same age and in the same general area.
Each plot therefore included around 30 trees although some volunteers choose to assess more.
|Tree species||Allowable combinations|
|All species||Excluding any ‘coloured’ foliage (non-green) varieties|
|Acer platanoides||These Acer spp. could be included as two separate species|
|Aesculus x carnea||Only one Aesculus sp. allowed per plot|
|Betula pendula||Only one Betula sp. allowed per plot|
|Crataegus monogyna or oxyacantha||These two Crataegus spp. could be combined if necessary but not chosen as two separate species|
|Fraxinus excelsior||Only one Fraxinus sp. allowed per plot|
|Platanus x hispanica||Only one Platanus sp. or hybrid allowed per plot|
How the assessment was recorded
The trees on each plot were assessed using a special form. On this form a number of easily recognised pests and diseases were scored, together with non-specific symptoms of ill-health such as crown thinness.
There were species-specific assessment forms for Acer, Aesculus, Crataegus, Fagus, Ilex, Prunus, Quercus, Sorbus and Salix as there were a number of specific diseases that we wanted to be looked out for. A blank form was used for other species.
Assessing pests and diseases
To assist in the assessment, volunteers were provided with their own copies of:
- "Diagnosis of Ill Health in Trees" by R.G. Strouts & T.G.Winter
- A pocket photo-guide (PDF-1247K) showing the particular pests and diseases that we wanted to be assessed as part of the survey.
Monitoring and advice
To help make sure that the data was assessed correctly and to provide advice on-site, a member of Forest Research arranged a visit to each plot at least once during the five years of the survey. Advice was available at most other times from the area co-ordinator or Forest Research.