Starch content of eucalypts as affected by season, ringbarking and chemical stump treatments.  J. D Kellas and R. O. Squire.  July 1983.  10 pp. (unpubl.)

SUMMARY

Observations of seasonal variations in sapwood starch content were made in stems and roots of Eucalyptus obliqua L'Hérit. (messmate stringybark), E. cypellocarpa L.A.S. Johnson (mountain grey gum), E. radiata Sieber ex DC. (narrow-leaf peppermint), E. globulus ssp. bicostata (Maid. et al.) Kirkp. (Gippsland blue gum) and E. viminalis Labill. (manna gum). For all species, sapwood starch levels of stems and roots generally peaked in September or October and subsequently declined through to February.

Sapwood starch levels in stumps and roots of E. obliqua were determined periodically following the application of TORDON 105^† (5% w/v picloram and 20% w/v 2,4,5-T) or ammate (ammonium sulphamate) to the stump surface. Comparisons were made with untreated stumps (stumps and roots) and ringbarked and healthy trees (stems at breast height and just below stump level, and roots). The application of TORDON 105 and ammate to stump surfaces did not significantly reduce sapwood starch content of roots, below that occurring after ringbarking or felling. Accordingly, these treatments offer little promise, at present, for control of the invasion by Armillaria luteobubalina Watling and Kile (armillaria root rot) of root systems of felled trees in forests susceptible to attack by this fungus.

^†Registered Trade Name. Use of this name does not constitute an endorsement of any product to the exclusion of others that may be equally suitable nor does it imply that the uses discussed have been registered.