City of Burnside v Poumako - [2004] SASC 385

SUPREME COURT OF SOUTH AUSTRALIA
(Full Court)
CITY OF BURNSIDE v POUMAKO & ANOR
Judgment of The Full Court
(The Honourable Chief Justice Doyle, The Honourable Justice Duggan and The Honourable Justice Anderson)
25 November 2004
ENVIRONMENT AND PLANNING - BUILDING CONTROL - COUNCIL CONSENT AND APPROVAL - MATTERS FOR CONSIDERATION BY COUNCIL - ENVIRONMENTAL MATTERS
APPEAL AND NEW TRIAL - APPEAL GENERAL PRINCIPLES - RIGHT OF APPEAL - WHEN APPEAL LIES - ERROR OF LAW - PARTICULAR CASES INVOLVING ERROR OF LAW - FAILURE TO GIVE REASONS FOR DECISION - EXTENT OF OBLIGATION TO GIVE REASONS
Appeal against decision of Environment, Resources and Development Court ("the ERD Court") granting provisional development plan consent for division of land - conflicting views of experts as to whether development likely to result in substantial tree-damaging activity to `significant trees' - whether ERD Court failed to make findings necessary to support conclusions reached by it - held reasons of ERD Court sufficient and appeal dismissed.
Development Act 1993 s 4; Burnside (City) Development Plan Principles 9, 41, 46, 48 & 51, referred to.
Pettitt v Dunkley [1971] 1 NSWLR 376; Papps v Police (2000) 77 SASR 210, considered.

CITY OF BURNSIDE v POUMAKO & ANOR
[2004] SASC 385
Full Court: Doyle CJ, Duggan and Anderson JJ

DOYLE CJ. I would dismiss the appeal. I agree with the reasons given by Duggan J.
DUGGAN J. The respondents have applied for approval to develop land at Burnside. The restaurant and function centre known as Fernilee Lodge which was situated on the site has now been demolished and it is proposed to divide the land into 15 community title allotments for residential use.
The respondents lodged an application for provisional development plan consent with the Development Assessment Commission (“the Commission”). The Commission referred the application to the appellant council which is the relevant authority for the purposes of the application. The application was refused by the appellant, but that decision was reversed on appeal to the Environment, Resources and Development Court (“the ERD Court”). The ERD Court granted provisional development plan consent to the development subject to certain conditions.
The appeal to this court complains of the finding by the ERD Court that residential development on certain allotments could be undertaken without endangering the health of significant trees growing on the subject land.
Before considering the issues raised by the appeal it is necessary to refer to relevant provisions of the Development Act 1993 (“the Act”) and the Burnside (City) Development Plan (“the Development Plan”).
The definition of “development” in s 4 of the Act includes the division of an allotment. Also included in para (fa) of the definition of “development” is –
“In relation to a significant tree – any tree damaging activity”.
“Significant tree” is defined in s 4 to mean:-
“(a)a tree within a class of trees declared to be significant trees by the regulations; or
(b)a tree declared to be a significant tree, or a tree within a group of trees declared to be significant trees, by a Development Plan.”
Section 4 defines “tree-damaging activity” to mean:-
“(a)   the killing or destruction of a tree; or
(b)     the removal of a tree; or
(c)     the severing of branches, limbs, stems or trunk of a tree; or
(d)     the ringbarking, topping or lopping of a tree; or
(e)     any other substantial damage to a tree.”
Principle 9 of the Development Plan provides that the size, shape, orientation, layout and location of the boundaries of allotments should:
“(f)provide for the conversation of trees and other special site features consistent with a functional layout of future buildings, access, services and open space; and
(g)not be likely to result in tree-damaging activity occurring to a significant tree”.
In that part of the Development Plan which sets out the principles of development control there are several provisions relating to significant trees. The following principles have potential relevance to the present appeal:
“41 Land should not be developed where the development would be likely to result in a substantial tree-damaging activity occurring to a significant tree.
46Development should be designed and undertaken to retain and protect significant trees.
48Development should be undertaken with the minimum adverse effect on the health of a significant tree.
51Land should not be divided or developed where the division or development would be likely to result in a substantial tree-damaging activity occurring to a significant tree.”
I have said that the proposed development envisages the division of the land into 15 allotments. There are a number of trees on the land which come within a class of trees declared to be significant trees by regulations made under the Act. The most contentious issue before the ERD Court was whether residential development on allotments 3, 9, 10 and 14 of the subject land could compromise the health of significant trees on or in close proximity to those allotments and, if so, to what extent.
The members of the ERD Court dealt with the issue in the following passage in their judgment:
“Significant Trees and Allotment Layout
11The respondent’s case rested principally upon the concern that, if the land were divided in the manner proposed, Lots 3, 9, 10 and 14 might not be able to accommodate residential development without compromising the health of the remaining significant trees on the site. Both parties called expert arborists to give evidence. The evidence was detailed. An extract was tendered from ‘Trees and Development’ by Matheny and Clark, a monograph which both arborists acknowledged to be the principal authority in the field of urban tree preservation.
12We approach the assessment of this aspect of the proposed development on the basis that it is necessary that we be satisfied that it is possible for a form of residential development which is broadly consistent with the relevant provisions of the Development Plan to be undertaken on each allotment. It is not necessary for the appellant to make a commitment to a precise form of development for each lot.
13Both parties approached the matter by ascribing notional tree preservation zones for each significant tree on the land and three significant trees on other properties to the north of the land. In this they followed the approach of Matheny and Clark, who wrote:-
“The consultant determines how much undisturbed space is needed for the trees to retain good health and vigor (sic) by identifying an optimal tree protection zone.”
14Mr Knight (the arborist in the respondent’s case) identified larger tree preservation zones than Mr Gibbons (the arborist in the appellants’ case) identified. There were differing views as to whether it would be permissible to build partially within the tree preservation zones using building methods designed to minimize interference with trees.
15The Burnside (City) Development Plan contains numerous provisions regarding the desirability of preserving significant trees. These were set out in detail in the statements of the planners in this matter. Principle 41 in the Council wide section of the Development Plan says:-
“Land should not be developed where the development would be likely to result in a substantial tree-damaging activity occurring to a significant tree.”
16Principle 1 for Residential Policy Area 19 – Burnside (North) says, in part:-
“Development should:
(a) conserve and enhance the character of the Policy Area, described in Objective 1, and the significant trees therein; …”
17These provisions, and the other provisions dealing with significant trees, must be read with the other relevant provisions of the Development Plan, and considered in the light of the zoning of the land.
18Having regard to all of the evidence, we are satisfied that each of the proposed allotments is capable of accommodating residential development in a form compatible with the relevant provisions of the Development Plan without endangering the health of the significant trees. We note that such development will encroach upon some of the tree preservation zones, particularly on Lot 3. It is our view that there are building methods available that permit this to happen without detriment to the health of the tree.”
The ERD Court had before it a plan of the proposed division of the land (R7). Drawn on each allotment was a “building envelope” which depicted the footprint of a dwelling. This was intended to give an indication of how the individual sites could be used to accommodate structures. As was pointed out in the ERD Court judgment, the respondents were not required to commit to a precise form of development for each allotment.
The main thrust of the appellant’s argument before this court was that the ERD Court failed to resolve the differing views of the expert witnesses, Mr Knight and Mr Gibbons, and that the reasons for decision of the ERD Court did not explain how the Court reached its ultimate conclusion as set out in [18] of the Court’s reasons for decision quoted above.
It is not in dispute that both witnesses were qualified academically and by their practical experience to give expert evidence on the issues relating to the trees. As the ERD Court pointed out, both experts agreed that it was appropriate to determine a tree protection zone (TPZ) for each significant tree. The zones considered appropriate by each expert are indicated on the plan R7. The zones suggested by Mr Knight are more extensive than those determined by Mr Gibbons.
Both witnesses referred to an American text “Trees and Development: A Technical Guide to the Preservation of Trees During Land Development”, a monograph authored by Matheny and Clark. I do not accept the appellant’s contention that the judgment of the ERD Court was incorrect in observing at [13] that both expert witnesses followed the approach recommended by Matheny and Clark. The court confined this comment to the authors’ recommendation that a TPZ be defined for each tree.
Matheny and Clark state that “little quantitative information exists about factors that may influence the response of tree species to construction impacts” (CH6 p69). Factors which are suggested as relevant in relation to individual trees are tree health, species and age. The authors concede that the question of how close it is appropriate to encroach on a tree in the course of construction is a difficult one to answer (CH6 p72). A significant unknown is the full extent of the tree’s root system.
After describing various methods of determining the extent of a TPZ the authors favour a method based on trunk diameter. They continue:
“The British Standards Institute (1991) developed tree protection guidelines, based on ranges in trunk diameter, that considered the age and vigor of the tree. That system acknowledges that old trees and those of low vigor are less tolerant of construction impacts and, therefore, need a larger protection zone. We adapted the BSI method to include species tolerance to impacts (see Appendix B for species list). The optimum tree protection zone is calculated based on the species tolerance to impacts (good, moderate, or poor) and the age of the tree (young, mature, overmature) (Table 6.2). This system acknowledges that a mature walnut can tolerate less disturbance than a young ash. The protection zone should be increased by 25 to 50 percent for low vigor trees, although retention of low vigor trees is discouraged.
This approach is intended to be a guide for planning adequate space around trees, not an absolute rule. It is a tool to help the design team. There certainly will be times when it is not possible to retain the optimum tree protection zone around each tree to be preserved. The consultant then must evaluate the minimum tree protection zone that would prevent the death, decline, or instability of the specific tree.”
Mr Gibbons said in evidence that he used the trunk diameter method and employed a ratio of 1:10 so that for every metre of tree trunk he would allow for a radius of 10 metres around the tree in determining the TPZ. He said that construction can take place within the TPZ, but careful consideration needs to be given to the type of construction. He said that the authors Methany and Clark acknowledge that this is the case. According to Mr Gibbons’ evidence, the structures could encroach on the TPZ if certain methods of construction were employed. He said in his report that it was permissible to undertake construction activity within the TPZ as long as the construction methods which were used were effective in minimising the damage done to the root system. He said that it would be inappropriate to use standard slab foundations, but that the pier and beam method could be used in those areas of the construction which were within the zone. He said cutting and filling would have to be avoided and that the footings for the piers would have to be dug by hand. He added (AB 1/157):
“… in my opinion construction of piers/piles used to support a flooring system above the ground level could be used. This system would still allow air to circulate (a requirement of tree roots) and not seriously impede ground water movement.”
Mr Gibbons was of the view that, by using these methods, buildings which occupied the areas indicated by the proposed building envelopes could be constructed on allotments 3, 9, 10 and 14 in a manner compatible with tree preservation.
Mr Gibbons agreed in cross-examination that his trunk diameter method of calculating the TPZ applied as a general rule of thumb without adjustment for individual features of a particular tree such as age, vigour and species. However, he said that care had to be exercised in adopting the standard suggested by Methany and Clark because of the different species upon which those standards were based. He said that the ratio which he had chosen did not overvalue or undervalue the root system.
Mr Knight said that he used tables provided in Methany and Clark’s book to calculate the TPZ in each case. He said he used his own experience of tolerance in different species to assist in applying the calculations. He disagreed with the rule of thumb method used by Mr Gibbons to calculate the TPZ, criticising it as too general. He said his own method involved taking into account the attributes of the particular tree.
Mr Knight was asked about construction work extending into the TPZ:
“Q.Is it possible to disturb the ground within the tree protection zone which is identified, and yet make adequate provision for the tree. In other words is it possible to do things within tree protection zones.
A.It is but it is very site specific and tree specific and it depends on what you intend to do. So there are limits on how much you can encroach upon the tree protection zone and have no impacts on the tree and certainly the style or the type of incursion is also important. So every situation would have to be assessed individually.”
The witness commented on Mr Gibbons’ suggestion of using piers and beams:
“It has been interesting to hear that pier and beams are the solution to all things, but in my opinion [it] is not. Whilst pier and beam gives us a mechanism for minimising the damage to trees, you can’t say that it has no damage. We are still having to put machinery on to these sites to put in these beams. We are digging holes in the ground nevertheless. People have to work all over the sites, there is still chemical spillage; the house has to be built above a root zone. There are a whole range of impacts that still occur, even though we are doing a good job for the tree by using pier and beam. It is not necessarily that we don’t have any impact. In this case, were we to build a house underneath the crowns of these trees as is proposed by the building envelope, we not only have impacts to the root system, but we also have then, pressure to prune on this tree which is hanging over the roof, and of a species that is known to drop branches. It is not a good idea to build underneath a tree like that.”
It is clear from the evidence that the damage which might be caused to trees by construction in their vicinity is difficult to predict. Much depends on the circumstances including the nature of the activity and the state and characteristics of the particular tree.
The proposed development must be assessed against the provisions of the Development Plan (Development Act s 33). This assessment involves consideration as to whether the development “would be likely to result in a substantial tree-damaging activity occurring to a significant tree” (Development Principle 41; see also Principle 9).
Much of the focus of the evidence was on the method of calculating the TPZ for different trees on the subject site. Leaving aside the question as to whether the formula used for this purpose should be modified by considerations relevant to the particular tree, it was not in dispute between the witnesses that individual considerations were nevertheless important. Mr Gibbons, for example, referred to the recommendation made by Methany and Clark that trained consultants work with the design team on specific construction projects.
However, I do not agree that the resolution of the case before the ERD Court necessarily turned on the differences between the two experts as to the methods by which they calculated the TPZ in each case. Given the possibility that structures erected on particular allotments would encroach on the TPZ of significant trees, the question arose as to whether it is likely that those structures would cause substantial damage to the trees. The ERD Court concluded that appropriate building methods could be employed to avert such damage.
Mr Henry, for the appellant, submitted that the ERD Court failed to make findings which were necessary to support the conclusions which it reached. He relied on authorities which stressed the importance of courts and tribunals providing adequate reasons for their decisions. He referred to Pettitt v Dunkley [1971] 1 NSWLR 376 and Papps v Police (2000) 77 SASR 210. These authorities acknowledge that the requirement to give reasons for decision and the content of those reasons depends upon the circumstances of the individual case.
In my view, it was unnecessary for the court to make a finding in relation to the methods by which the two witnesses calculated the TPZ. The calculations undertaken by Mr Knight led him to recommend a wider radius for the TPZ in the case of each significant tree when compared with that arrived at by Mr Gibbons. However, Mr Gibbons’ opinion that building methods could be employed so as not to cause significant damage to the relevant trees was not restricted to cases involving minimal encroachment on the TPZ. In the case of allotment 3 there would have to be substantial encroachment on the TPZ regardless of which estimate of the TPZ was accepted. The real issue for determination was the likely effect of such encroachment.
In the passage from the ERD Court’s reasoning, which is set out above, the members of the court referred to the nature of the assessment required in determining whether the development proposal is broadly consistent with the relevant provisions of the Development Plan. They referred to the process whereby both expert witnesses determined the TPZ for each significant tree. Reference was made to the fact that Mr Knight identified more extensive preservation zones. However, it was pointed out that the experts differed in their views as to the extent to which building within the TPZ could be tolerated having regard to potential damage to the trees. The court then reached the conclusion that there were building methods which could be employed which would not be detrimental to the trees, even though construction took place within the TPZ.

The ultimate conclusion reached by the court did not require the resolution of any controversial issues of fact. There were two competing expert views on the extent to which the building methods referred to would avoid damage to the trees. It is clear that the court accepted Mr Gibbons’ view as to the appropriateness and effectiveness of the building methods identified in his evidence. Although the court might have gone into more detail in its reasons, I think enough was said to expose the court’s process of reasoning so as to enable appellate review. Furthermore, it appears on review that it was open on the evidence for the court to accept Mr Gibbons’ view on this issue. In my opinion the failure to give further reasons does not provide a sufficient ground for setting aside the court’s decision.
The appellant and the ERD Court were required to take into account the provisions of the Development Plan. In doing so, they were required for present purposes to consider whether, if the land were developed in accordance with the proposal, the development would be likely to result in substantial tree-damaging activity occurring in relation to significant trees. Mr Gibbons’ evidence, if accepted, established that the building methods which he described would prevent such damage from occurring.
In my view, the ERD Court was correct in deciding that it was unnecessary for the respondents to commit to a precise form of development for each allotment and the appellant was content for the case to be conducted on that basis.
Nevertheless, approval will be necessary for building work and the same issue might well arise at that stage. Mr Henry expressed concern at the position of purchasers of land who may be unaware of the restrictions which could be placed on the use of these allotments. I think that concern is well-founded and it is important that potential purchasers be made aware of the likelihood of such restrictions. However, I do not think that this consideration should stand in the way of approval for the present application for provisional development plan consent.
I would dismiss the appeal.
ANDERSON J. I agree with the reasons of Duggan J and I would also dismiss the appeal.