<body bgcolor="#ffffff" text="#000000" link="#0000ff" vlink="#800080" alink="#ff0000"> <TABLE width="85%" border="1" cellspacing="0" cellpadding="4"> <TR> <!-- Row 1 Column 1 --> <TD > <img src="spacer3.gif" width="351" height="5" alt="white space"> <DIV align="center"><B>Responses to specific points raised by Colin O'Donnell</B> &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; Page 5.</DIV> <HR WIDTH="95%"ALIGN=center> <center>by <I>Dr Henrik Moller</I></center> <HR WIDTH="95%"ALIGN=center> My comments refer to numbered locations marked on Appendix 4 (attached - see rhs column), continuing at Section 3 before returning to the Summary & Recommendations (Section 1) at the end. <P> <B>7.0 &nbsp; Beech tree harvesting rates and mitigating effects on wildlife</B><P> <U>7.3 &nbsp; Problems with TWCL harvesting rates</U><P> <font color=#ff0000><B>35. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; There has been no demonstration that these numbers of holes are required.<P> <font color=#ffffff>.<P> </font> <font color=#ff0000><B>36. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; A formal simulation model is now planned to test these hypotheses.<P> <font color=#ffffff>.<P> </font> <font color=#ff0000><B>37. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The DoC Critique has emphasised and added assumptions that all work to increase perceived potential risk. No error limits are presented and these are likely to be wide (see point 26 for the effect of error limits on just one part of the extrapolation). Calculations are presented only for tree removals &gt; 80 cm DBH rather than running two scenarios (in which all trees &gt; 80 are left c.f. all trees &gt; 110 are left). There has been no demonstration that a significant risk exists, let alone that retention of trees &gt; 110 cm DBH "seems likely to be inadequate".<P> <font color=#ffffff>.<P>.<P> </font> <font color=#ff0000><B>38. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The model now proposed could simulate a series of trade-offs between leaving different sized trees for biodiversity risk simulation c.f income from timber extraction. Estimates of the proportion of defective trees in each size class <U>after single tree selection criteria</U> have been applied can then be predicted.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>39. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; There is no evidence for such competition in New Zealand forests so far. This does not necessarily mean that it does not exist, just that we do not know one way or the other. It is another example of useful follow-up research for consideration by TWC and/or DoC.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>40. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The vast majority of common wasp nests are in the ground (Moller <I>et al.</I> 1991), and rats and starlings nests are not always in tree holes. It is unknown whether these other introduced species significantly reduce tree cavity availability.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>41. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The simulation model now proposed will separate out these two classes of trees to track their fates.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>42. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; Research in search of a reliable technique for detecting cavities would be valuable so that foresters can avoid felling defective trees and risks to biodiversity are minimised.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>43. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The logic for this assertion is not spelled out, but Colin O'Donnell informs me <I>in litt.,</I> 5 October 1998) that he is concerned that the foresters will compensate for felling defective trees by taking more than the allotted cut.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>44. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; Again, this figure has been used from a putative compensatory increase in number of trees felled if many are found defective (Colin O'Donnell <I>in litt.,</I> 5 October 1998). <P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>45. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The model now proposed should be able to formalise this expectation.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>46. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; Such areas are likely to be relatively very small because the use of helicopters obviates the need for much new roading. The exact amount could presumably be estimated by TWC to remove all doubt.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>47. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; Use of a sensitivity analysis in a model to set likely limits from current best knowledge, follow-up monitoring, and an active adaptive management approach (Walters & Holling 1990, Parma 1998) all safe-guard environmental values. TWC have recognised these risks and plan all these approaches to safeguard against them. The formal hypotheses for test in an adaptive management framework need to be spelled out and formalised as part of the process and audit cycles. Adaptive management represents best professional practice and risk management, and is equally needed for interventions from DoC managers (Several risks apply to conservation management interventions on reserved land as well). <P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>48. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The philosophical approach taken by TWC is to accept current ecological processes and productivity levels occurring naturally in the forest (rather than to force the system for maximum timber production), including leaving of slash and rotting hollows etc for pinhole borer and other hole-generating microbes and invertebrates in the forest.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>49. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; Natural gap formation will indeed continue, but not necessarily at the previous rate if compensatory processes are triggered by live-tree extraction. These aspects should be modelled and monitored for long-term predictions, and their impacts on tree cavity availability.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>50. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; In most instances ca 3 to 5 trees will be felled in one gap. The only instances of 10 trees will be when many small trees are grouped together (Kit Richards, pers. comm.). Such small trees rarely have trees cavities (Elliott <I>et al.</I> 1996b). Where very large trees are logged usually only one or two trees are removed (Kit Richards, pers. comm.). This expectation needs to further emphasised (sic) in TWC plans because Colin O'Donnell was not assured that 10 very large trees might be felled in the one gap (Colin O'Donnell, <I> in litt. </I> 5 October 1998). If he was unaware, so too will other readers be unaware. On average ca 3 gaps will be created per hectare of forest in each logging event (every 15 years). Most passerines have territories in the order of a hectare, and bats in the order of 10s of square km, so localised effects are unlikely to be significant. The assertion that up to 70% of the cavities could be felled in "one patch" is alarmist.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>51. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; This statement is unproved and relies on several assumptions; speculative scenarios could easily be built to negate the concern altogether (see points 20 & 27 above). <P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>52. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; See point 20 for the assumptions behind this assertion.<P> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ff0000><B>53. </B></font> &nbsp; &nbsp; &nbsp; &nbsp; The whole importance of food limitation for forest bird populations is unproved, and even more difficult to evaluate than the hypothesis that tree hole availability limits the population. Again from first principles, if predation has depressed the populations it seems most unlikely that they could now be limited by food levels. Evidence for the mechanisms for the effects of past logging methods on bird numbers is almost completely lacking - removal of foods and nesting hollows are mentioned but we do not know which, if any, of these are important. Indirect mechanisms such as the effects of logging on predation have not even been considered. Without this knowledge of mechanisms it is much harder to guess at the likely impact of small group tree removals when the bigger/older trees are left in place. However, the same general argument about the likely impacts of predation apply to the food limitation hypothesis i.e. when severe predation occurs, especially of adults as in the kaka case, food is most unlikely to be a limiting factor. Just as assumption can not rule food limitation in, so too it can not rule it out. The monitoring and adaptive management approach promised by TWC act as an overall safeguard for these risks, however remote they might seem. Similarly, the same large trees left <I> in situ</I> by the group-tree selection protocols to safeguard availability of cavities will also help ameliorate potential food impacts because the largest trees are also the favoured feeding trees for many species of bird (O'Donnell & Dilks 1994).<P> <font color=#ffffff>.<P>.<P>.<P> </font> </TD> <!-- Row 1 Column 2 --> <TD > <img src="spacer3.gif" width="351" height="5" alt="white space"> Page 5 of the DoC Critique written by Colin O'Donnell. <HR WIDTH="95%"ALIGN=center> <DIV align="center"><h3>7.0 &nbsp; Beech Tree Harvesting Rates and Mitigating Effects on Wildlife</h3></DIV> <HR WIDTH="95%"ALIGN=center> <U>7.3 &nbsp; Problems with TWCL harvesting rates</U><P> On first analysis the harvesting rates proposed by the TWCL forest growth model appear to be well developed (if the 15 year rest between rotation is adhered to). However, from the wildlife point of view there are still some significant concerns. In reality, harvesting rates or harvesting impacts may be much higher than prescribed. Concerns are listed below:<P> 7.3.1. &nbsp; The sum of cavity bearing trees which we predict would be required by long-tailed bats, kaka and parakeets amounts to a minimum of 14.2/ha with the majority being &gt; 80 cm DBH (Table 1). Thus there is a high probability that any trees &gt; 80 cm DBH selected for harvesting would be trees<P> <font color=#ff0000><B>(See comment 35)</B> required by </font><P> these threatened species. The logging regimes <P> <font color=#ff0000><B>(See comment 36)</B> proposed would have a disproportionate impact on tree of this size because of higher mortality rates (MSMP, Table 5.1). The forest growth models indicate these trees will go through a bottleneck at least over the first 3 - 4 rotations, </font><P> reducing the available pool of suitable trees below the predicted minimum requirements. Therefore, TWCL's assertion that retention of trees &gt; 110 DBH will minimise likely impacts on birds (BSM, p. 70; & note they did no assessment for bats) <P> <font color=#ff0000><B>(See comment 37)</B> seems likely to be inadequate. </font><P> Specific research undertaken in North Westland red beech forests would improve predictions.<P> <font color=#ff0000><B>(See comment 38)</B> Setting the maximum harvesting limit of beech at 80 cm DBH (rather than 110 cm) would mean that the majority (ca 80%) of cavity breeding and roosting sites for threatened species would be retained. This would reduce the harvest by a maximum of 10% - but would probably have a lesser impact on wood volumes recovered because a high proportion of wood from trees &gt 80 cm DBH will be "defective". </font><P> 7.3.2. &nbsp; The above calculations do not provide any estimates for other cavity-using species in the Maruia forest (Table 1. viz. short-tailed bat, robin, morepork, rifleman, yellow-breasted tit, paradise shelduck; see Heather & Robertson, 1996, O'Donnell et al . in press). Wildlife ..<P> <font color=#ff0000><B>(See comment 39)</B> may </font><P> compete for cavities because none of the species in New Zealand actively excavate new cavities. Therefore, the requirements for cavity bearing trees to be exempt from felling will be greater than the 14.2/ha estimates for threatened species.<P> 7.3.3. &nbsp; The above calculations do not provide any estimates for other cavity-using pest species in the Maruia forest <P> <font color=#ff0000><B>(See comment 40)</B> (e.g. rats, wasps, starlings) </font><P> which may out-compete indigenous species seeking cavities for breeding. Starlings have been recorded displacing bats in studies in other countries (Rieger, 1996a; Maeder, 1974), and occupying roosts in New Zealand (Sedgeley & O'Donnell unpubl. ms.). This will further increase the required cavity rate/ha and increase the number of trees/ha which should be exempt from harvesting.<P> 7.3.4. &nbsp; The MSMP estimates that 40% of trees in the working circle will be "defective" in terms of merchantibility (sic), only 67.3 trees/ha will be merchantibile (sic) (Table 3.8, p.33), and ca. 50% of trees &gt;80 cm DBH will be unmerchantible (sic) (MOP, p. 55). <P> <font color=#ff0000><B>(See comment 41)</B> It is the so-called "defective" trees which eventually provide the cavities which so many wildlife species require. </font><P> Therefore, <P> <font color=#ff0000><B>(See comment 42)</B> unless there is a fullproof (sic) technique for determining if a tree is suitable for processing before it is felled </font><P> then excess trees may still be felled and discarded. The MARVL quality criteria (MSMP, Appendix 1) would not identify a high proportion of suitable cavity-bearing wildlife trees. The prescribed harvest rate <P> <font color=#ff0000><B>(See comment 43)</B> <I> could double as a result,</I></font><P> again increasing the probability of felling a critical tree. The MSMP states that "where a tree is marked as merchantible (sic) and is upon felling found internally defective, its status will remain and the stem deducted from the merchantible (sic) proportion of the permissible cut" (p.52). However, this regime is still likely to have a disproportionate impact on trees &gt;80 cm DBH, because this cohort has a much higher frequency of cavities and 50% of trees are "defective" in terms of merchantibility(sic). &nbsp; If <P> <font color=#ff0000><B>(See comment 44)</B> 50% of these trees </font><P> were inadvertently felled as part of the permissible cut, then this would have a huge impact on wildlife habitat.<P> 7.3.5. &nbsp; In addition 2.36 immature defective stems per ha per yr will be removed for "improvement felling" (MSMP, Table 5.5. pp.52, 80). <P> <font color=#ff0000><B>(See comment 45)</B> "Over time, there should be a slow improvement in the quality of trees with a gradual reduction in the number of malformed trees" (p. 43). While this is sensible in terms of silvicultural management, it means that the numbers of trees which will develop into breeding and foraging trees in the future (with well developed cavities in them) will become progressively fewer over each felling cycle. </font><P> Younger trees with the beginnings of rot or broken branches are assets in terms of the development of wildlife habitat. Research on the ontogeny of cavity development in forests needs to be undertaken to determine whether "improvement felling" would sustain enough wildlife cavities.<P> For example, the impact of improvement felling on red beech is that 17.4 trees (19% of the pool of 90 young trees and biassed towards "deformed" stems), will be felled per rotation. This would carry through a significant impact on the occurrence of cavity bearing trees to future generations.<P> <font color=#ff0000><B>(See comment 46)</B> 7.3.6 &nbsp; The prescribed harvest rate per ha may be further increased by the removal of trees for roads (MSMP, p.64). landings (p.63), and firewood (p.84). Trees damaged during felling of other trees will be felled irrespective of quality (p.56) but will hopefully be included as part of the permissible cut. There is a higher probability of felling standing dead trees during normal operations, especially if additional trees are being felled for health and safety reasons (BSM, p.82). The plans do not indicate what this harvest rate would be, nor why removal of firewood is necessary. </font><P> <font color=#ff0000><B>(See comment 47)</B> 7.3.7. The MSMP acknowledges that research on recruitment of new trees in these beech systems is required ("At the present time TWC does not have the data to determine (recruitment) functions for its beech forests", pp 73-73). Without this research, no-one will be able to properly assess if the annual rate of felling (especially in the larger tree size classes) will in fact mimic natural processes and be sustainable.</font><P> The MSMP estimates survival rates at 3%. However, if mortality rates mimic the changes in the number of trees/ha between each tree size class present (Table 5.1, p.73) then mortality rates between different tree size classes would vary markedly. For example, tree densities were reduced by 97% between the seedling and sapling classes; by 12.2% between the 30-40 cm and 40-50 cm DBH classes, and by 42.9% between the 80-90 and 90-100 cm classes. In reality there is no average mortality rate per year. Sustainability models must take into account very variable mortality rates depending on the age of the beech tree.<P> <font color=#ff0000><B>(See comment 48)</B> 7.3.8. While there is currently no specific management for pinhole borer being proposed (MSMP, p.88), if future research indicates a need to treat live or standing dead trees then this has implications for wildlife. Wood borer is one mechanism leading to the formation of cavities, as well as providing food for forest parrots.</font><P> 7.3.9. Group felling of trees has been prescribed in the plans, where 1 - 10 trees in a patch are felled at once (MSMP, p. 41, 43). <P> <font color=#ff0000><B>(See comment 49)</B> Natural gaps will continue to be formed as well. </font><P> <font color=#ff0000><B>(See comment 50)</B> In a worst-case scenario &gt;10 trees per ha could be felled in one patch; the <I>local </I> impacts of harvesting would be much higher than the 1 tree/ha prescribed.</font><P> Felling will also be concentrated in a few close-together compartments each year, again localising the impacts (MOP, Map 2B).<P> 7.3.10. Unlike birds, bats roost together in tight clusters within trees hollows. Unless long-tailed bat roosting areas in the managed forests are identified prior to harvesting, then patchwork felling would increase the probability of <P> <font color=#ff0000><B>(See comment 51)</B> devastating bat populations.</font><P> Long-tailed bats roost in relatively small patched of forest, usually in cluster of trees. Bats move trees almost everyday, particularly lactating females with young. They move in closed social groups (O'Donnell 1995). <P> <font color=#ff0000><B>(See comment 52)</B> Thus removing relatively small clusters of trees at one site could fell trees containing the whole social group. </font><P> 7.3.11. The above predictions have been based on impacts of harvesting on cavity bearing trees used for breeding and roosting. There have been no studies in the North Westland area which have determined which size classes of trees are <P> <font color=#ff0000><B>(See comment 53)</B> required for foraging by forest birds.</font><P> It is not known if the harvesting regimes proposed will leave sufficient habitat for foraging. <P> .<P> <font color=#ffffff>.<P>.<P>.<P> </font><font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> <font color=#ffffff>.<P>.<P>.<P> </font> </TD> </TR> </TABLE>