Unasylva
welcomes letters from readers on any topic related to forestry and the environment. Letters should be reasonably short and legible. English, French or Spanish is preferred, but other languages will also be considered. Please address letters to: Editor, Unasylva, FAO Forestry Department, Via delle Terme di Caracalla, 00100 Rome, Italy.
Accumulation of eucalypt litter
When first reading FAO Forestry Paper 59 (The ecological effects of eucalyptus) I did not give high priority to commenting on the reported evidence from Malawi that eucalypt litter breaks down less readily than that of indigenous Brachystegia. It is the requoting of the statement in Unasylva 38 (152) ("Are eucalypts ecologically harmful?") that has finally moved me to write.
Dr C.A. Jocqué was responsible for the original statement as a result of short-term observations during his study Malawi. A terrestrial baselines study of the Visphya pulpmill project area, a FAO internal report, which is quoted in Forestry Paper 59. The report is now not accessible to me but, if I recall it correctly, Jocqué observed an accumulation of litter in the eucalypt plantations near Chinteche - a locality with the warmest, wettest environment in Malawi. Jocqué observed no such accumulation of litter in the surrounding semi-evergreen Brachystegia forest, and suggested that different biological activity was the reason for the difference in the litter buildup.
What he fatted to note was that the Brachystegia forest is given a controlled burn every year if possible and it had received such treatment about two months before he made his observation. Showers and a new growth of herbs had superficially removed the signs of the control burn in which all litter is consumed. The eucalypt plantations had been successfully protected from fire since they were first planted.
When the Department of Forestry saw his report, I wrote as Chief Conservator of Forests to Dr Jocqué to point out the significance of fire in his observations on the comparative rates of litter accumulation. At our next meeting, I formed the impression that he was going to amend his report. It would appear that Poore and Fries referred to the unamended version when they compiled Forestry Paper 59.
One would expect biological activity to be more intense in an ecologically diverse indigenous forest than in an adjacent eucalypt plantation. However, I do not think that the non-woody component of the Chinteche eucalypt litter was failing to break down to a more-or-less homogeneous mass in much more than 12 months in the humid conditions.
Certainly, the eucalypt litter layer did not appear to get deeper as more years continued without fire.
I would not wish to overpraise the eucalypts: the species currently available to us in dry, cold, mountainous Lesotho certainly cause graziers, soil conservation staff, and foresters some concern over their effects on the indigenous light-demanding herb flora. Neither would I wish to see eucalypts for warm humid areas maligned because of incorrect conclusions drawn from very short-term observations in Malawi.
E.D. May
Maseru, Lesotho
