Q2. What if my trees are older and greater than 1.3 m in height?
Recommendation: Cut, treat stumps and optionally burn
Cutting and immediately treating cut stumps is likely to be the most cost effective option for older plants greater than 1.3 m in height. All stumps should be cut below the lowest live branch, but left tall enough to be visible.
Treatment: Cut trees and apply a 10% solution of a 360 g/l glyphosate or similar product to the cut stumps. Ensure you follow the application rates detailed on the product label. (Further guidance is provided in FC Field Book 8 – The use of herbicides in the forest.)
Disposal: Cut stems and branches may be left in situ, or be disposed of by burning on site for improved biosecurity. This is the preferred option, where allowed, under legislation on smoke control areas and subject to the potential risk of smoke nuisance. Chipping of whole trees or branches and leaving the chipped material on site is not currently a recommended treatment for infected sites because of uncertainties over the risk that this may have in spreading the disease. However, chipping and removal for use as biofuel is safe, as long as the material is removed quickly from the site, and stored under cover, or dried to <20% moisture content, before burning.
Timing: Cut and spray in November – mid March for optimal control, avoiding the period of spring sap flow. Applications at other times are also possible, but are likely to be somewhat less effective, particularly during April – early June. Where it is intended to immediately burn the arisings then treatment in the period July-September/October is preferable to waiting until November as it will destroy the current season’s leaves before autumn fall.
Application: Applications should be made to saturate the stump surface, paying particular attention to the outer circumference of the stump containing the phloem. Avoid run off to surrounding ground. Applications should not be made to frozen stumps. Ideally, for optimum control spraying should take place within 1 hour of cutting, although a reduced level of control may still be possible if applications are made within 24 hours of cutting. If spraying cannot take place within these time frames, the stems should be re cut prior to application. The use of a dye marker such as Dysol Turquoise (50% Acid Blue 9) @ 2% of final spray volume can be helpful in ensuring all cut stumps are properly treated.
Monitoring: Signs of re-growth from the stumps should be monitored and a repeat treatment made if necessary.
Product: Examples of suitable effective herbicides for cut stump treatments include Montsanto Roundup (Pro Biactive, 360 g/l glyphosate); and Dow AgroSciences Triclopyr (Timbrel, 480 g/l triclopyr;).
From here:
Forestry Commission - Chalara ash disease - Disposal and removal
And more here:
Forestry Commission - Plant Health - Chalara grants and guidance