Common Walnut Establishment Trial
The techniques required for the successful establishment of walnut in the UK have been poorly tested. The Northmoor Trust considered this to be an area where further research could usefully be conducted and the following areas of original research were considered particularly important to pursue:
- the effect of varying degrees of shelter, as provided by treeshelters of different heights, on early growth;
- the effect of applying a stumping treatment in combination with the treeshelter treatments;
- the optimum timing of pruning operations.
The appropriate height of shelters to use for successful walnut establishment was considered an important parameter that had remained untested. Previous work on the stumping of walnut, could be advanced by analysing the interaction of stumping with the shelter treatments. Once the trees were successfully established after two growing seasons, the optimum time for pruning operations would be tested in order to substantiate some of the recommendations in the literature. Finally, an additional aim was that this trial would highlight which practices could be applied in the establishment of the walnut provenance/progeny trials that were to be planted within the time-scale of this research programme. Since the seeds had been so difficult and expensive to acquire, and replacement plants would not be available, successful establishment was considered very important.
The establishment trial was planted in December 1996 at Paradise Wood. The trial was a randomised complete block design consisting of two 192-tree blocks, separated by 250 m. Each block contained twelve 16-tree main plots representing one replicate of each of the 12 possible combinations of main treatments.
- 3 treeshelter treatments of different heights were applied: no shelters, 75 cm shelters and 120 cm shelters.
- 2 stumping treatments were applied: stumped and not stumped.
- 2 sources of material were planted: the German 'Sämlinge' and French 'Lozeronne' (RA464).
Hemery, G. E. and Savill , P. S. (2001). The use of treeshelters and application of stumping in the establishment of walnut (Juglans regia L.). Visit Oxford University Press for the abstract.
