South Sister St. Marys, Tasmania
LEAMANS GEOPHYSICS
GPO Box 320
Hobart, TAS. 7001
COMMENTS ON FOREST PRACTICES BOARD CRITICISMS
(by P D McIntosh)
OF MY APPRAISAL OF INITIAL FOREST PLAN ON SOUTH SISTER.
Dr McIntosh sustains the record of the Forest Practices Board for considered deviation from the real issues. The crucial topics of protection of water supply, and the actual protections afforded by the Forest Practices Code, are completely glossed over. It appears that I 'overstated the risks' but nowhere are we given any evidence that this was so. Indeed, close examination shows that I wrote fairly and honestly.
It is also interesting to learn that a forest plan (of May 16th 2003) existed, that the area was inspected by McIntosh (Oct 14), and yet the people most likely to be affected by the plan – the scattered individuals around South Sister – were neither advised or consulted about this nor given copies. I call that official arrogance and contempt of the highest order.
Although the point was not conceded by McIntosh, because he sought to deny my report any credibility, I did in fact conclude that the zone along Dublin Town road must be protected – for precisely the reasons he quotes.
McIntosh's comments, however, demonstrate an ignorance of Tasmanian geology and a level of inconsistency in his comments that mean the official protection zone is too narrow and will prove quite inadequate. It is the narrowest possible reading and not a true reflection of slopes above the road.
First he suggests that my summary of the geology is false. Perhaps he would like to read some publications of Mineral Resources Tasmania (geological map sheet, St Marys: Coal Resources Bulletin, Gravity Survey of East Coast Coalfields) where he would find that the great bulk of the Nicholas Range is composed of a lithic series of rocks known as the coal measures. I was co-author of one of the publications and just happen to know something about the area. These rocks are exposed around South Sister but have a broad cover of patchy and variable talus deposits, which are important to stability and hydrology. Permian rocks are virtually non- existent. McIntosh has no appreciation of the importance of the lithic rocks to water supply and its high quality (see also MRT publications on water supply, including my study of the Coal River Basin). This failure to understand the fundamentals of the geology causes him to misinterpret the area and all else follows.
Second, it is indeed gracious of McIntosh to suggest I might be right about something, such as the origin of the topography. But, when he has seen as much of dolerite and dolerite products as I have(refer to my book The Rock which makes Tasmania, 2002) then he might be more careful about the humpiness evident around South Sister. I did note, and he fails to credit, that the failures were generally old. The issue of present risk is transformed if we change the vegetation or hydrology of the area – matters that he fails to address or discuss. One must ask why.
Third, contrary to McIntosh's assertion about failure scales he should actually read my text and quote it in full. I described various types of large to very large failures, some clearly involving bedrock. Some are arguably in thick talus wedges and he seems unaware that a columnar face need not be in place. I covered the zone with his 'large' failure and suggested it be excluded from operations. This is hardly an error. He, to the contrary, has not covered enough of the slopes to offer any assurances in this eastern region.
Fourth, the Forest Practices Code - much worshiped in many quarters - does ignore failure realities or the effect of previous failures which always lower angles. Nor does it consider the effect of changed hydrology. What might be stable now. May not be stable if we mess with it. Further, McIntosh's belief that the area is, and has been, stable other than in the NE corner of the coupe area blinds him to the general situation. He believes that failures have to be large, have toes and scarps etc. It is not so. Failures have occurred here at lower angles; the humps across the south face especially, prove it. It is just that most of then have not been very recent. Perhaps the question is, when is a landslip zone not a landslip risk? The legislation dealing with subdivision for other purposes is quite clear about this: and South Sister could not be zoned in those terms. This is an example of forest practices operating in splendid isolation for their own purposes.
Fifth, the Forest Practices Board is supposed to educate contractors on minimal damage working and to ensure working to Code. Does McIntosh really want me to catalogue all those sites where this has not happened and ground disturbance has been atrocious? He could start in the far south with coupes off Fortescue Bay Road. I simply made an observation that too many coupes are a mess and perhaps should not be. I would be happy to provide the information if I thought it might do some good and that proper teaching or penalties might apply. I have no such confidence.
Sixth, whilst harvest on dolerite soils may 'generally' be one of the lowest impact operations would he care to define how low the impact is? He goes on to suggest no impact and then becomes wholly inconsistent. He overlooks the fact the dolerite talus does fail and is a variable medium. His presumptions are just that: presumptions. I dispute the comment 'general stability of slopes surrounding dolerite outcrops'. It is a nonsense. Several of these fail every year, somewhere. Then we read the finest of inconsistencies. He associates failure with the base of the talus. This is a prime source of failure. But it is rarely the underlying, impermeable rocks which fail – it is the talus itself. There it is. The talus does fail. He says so. Now, match this to all his other comments and realize that it is all misleading and irrelevant.
Seventh, my statements about South Sister being a 'dry' mountain in a high rainfall area are not contradictory. He ignores my explanation which contrasts 'surface' water with 'subsurface' water. It is a matter of appearance and hidden reality. This is a clever, rather desperate and misleading criticism.
Eighth, the reader should note that McIntosh wholly avoids discussion of protection zones, exclusion of equipment, or regional protection of intakes.
It is quite clear from his original report, and his comment on mine, that he believes the mere 10m exclusion zone (really only 5m) is adequate protection. Well, I do not, and nor do the wise and more sensitive authorities I quoted. It is also clear that the Forest Practices Board intends to ignore the rights and protections afforded under Section D.2.2 (page 58).
It was news to read in his report of possible regeneration after a light burning. I understood that thinning was the goal in this coupe. Question: just what does the forest plan involve? This needs to be spelled out. I further note that the word thinning does not appear in either of his reports.
McIntosh claims that a good environmental outcome is likely. Really? Evidence please. No demonstrations or examples of water protections are given. Ever.
Why is there no comment on any of the sensible recommendations about vetting the demands and location of current water users and their requirements? There is no offer of any protection since the protected zone does not cover the catchments even of the Dublin Town Road intakes.
McIntosh, in both his reports, completely ignores those residents on the south side of South Sister dependent on the mountain. Since the preparation of my original report I have spoken to some of those with intakes above St Marys. These people have been completely overlooked and there needs ignored. A giant gamble is to be taken with their water supplies and there is no sense of any duty of care toward them. Not that there is much toward those on the east side of the mountain either.
I do not believe that I overstated any risks. I believe that McIntosh and the Forest Practices Board have understated them. When livelihoods and vital water supplies to individuals are involved some caution would seen warranted. We should also expect to be shown real data and some evidence in support of assurances. Forestry Tasmania and the Board never offer any. Why not? They happily deny data presented by others ...
I wrote that the Code of Practice does not guarantee water supplies and McIntosh offers no hope since the risks are dismissed. He writes that this is a coupe on dolerite. It is not. It is a coupe on talus over coal measures and is susceptible to failure and alteration with implications for water supplies. Why has section D.2.2 been discounted?
I repeat my suggestion that residents fully monitor water supplies and, if necessary, take legal action for any resulting losses should they occur and be demonstrated.
D.E. Leaman, B.Sc., Ph.D.
December 4, 2003
50419-6042 (2, 17, 37, 86)