Whangarei District Council STATEMENT OF EVIDENCE OF STUART GREGORY BARTON

Transcription

1 UNDER of the Resource Management Act 1991 IN THE MATTER of Plan Change 139 to Whangarei District Council to schedule two rimu trees at 1 Apirana Avenue, Regent, Whangarei BEFORE Whangarei District Council STATEMENT OF EVIDENCE OF STUART GREGORY BARTON 1. INTRODUCTION Qualifications and experience 1.1 My name is Stuart Gregory Barton. I hold a Certificate in Arboriculture from Waikato Polytechnic (1989), a Diploma of Horticulture and a Diploma of Parks and Garden Technology from Lincoln University (1986 and 1987, respectively), and a National Certificate in Horticulture (Amenity) from the Royal New Zealand Institute of Horticulture (1989). I have been working within the Arboricultural and Horticultural industries in New Zealand and the United Kingdom for the past 34 years. 1.2 I am a member of the New Zealand Arboricultural Association and the International Society of Arboriculture. I am trained in the use of quantified tree risk assessment (QTRA) and have an International Society of Arboriculture s tree risk assessment qualification (TRAQ). 1.3 I am the Managing Director of Arbor Connect Ltd an arboricultural consultancy company. Prior to this, I was a consultant arborist and the General Manager of The Specimen Tree Company Ltd for 21 years. I have extensive experience in using STEM and similar systems as an evaluation and valuation tool including for Waikato District Plan Franklin Section Plan Change 21 and Auckland City Council Plan change 305. As an arboricultural consultant, I have been involved in a range of projects that include tree assessments, surveys, risk analysis and reports. Involvement in project 1.4 I was engaged by Vivek Deshwal, Director of Archpoint Ltd on behalf of his clients DC Empires Ltd to prepare a report on the Whangarei District Council s (WDC) proposed Plan Change 139 (PC139) in relation to the two rimu trees located at 1 Apirana Ave, Regent, Whangarei. These Page 1

2 two trees have the identification number 378 in the PC139 schedule of notable trees. My role was to assess the two rimu trees using the Standard Tree Evaluation Method (STEM) and to comment on the threshold used by WDC to assess trees to be added to the Notable Tree schedule and whether or not the trees have significant amenity, historical, ecological or cultural values. Photographs of the trees are attached as Appendix A Photos I visited the site on 20 June 2018 to assess the two trees, after my site visit I produced a report for DC Empires in relation to the trees dated 2 October In preparing this report I reviewed the following documentation: Plan Change 129 Notable and Public Trees, Section 32 Evaluation Report for Whangarei District Council by Barker and Associates dated March Purpose and scope of evidence 1.7 The purpose of my evidence is to provide an overview of the STEM assessment by the WDC and myself and a rationale for the removal of the two rimu trees from the proposed PC129 schedule of notable trees. 1.8 Specifically, my evidence will: Describe the methodology adopted in the assessment of the trees and the use of STEM to describe trees with significant, historical, ecological or cultural values (Section 3); Comment on the WDC STEM assessment of the two trees (Section 4); Provide a STEM assessment and discuss the rationale behind the scoring (Section 5); Discuss the use of STEM to classify trees notable trees (Section 6); Comment on the officer s report (Section 7). Set out my conclusion (Section 8). 1.9 A summary of my evidence is contained in Section 2. Expert witnesses code of conduct 1.10 I confirm that I have read the Code of Conduct for Expert Witnesses contained in the Environment Court s Practice Note I have read and agree to comply with that Code. This evidence is within my area of expertise, except where I state that I am relying upon the specified Page 2

3 evidence of another person. I have not omitted to consider material facts known to me that might alter or detract from the opinions that I express. 2. SUMMARY OF MY EVIDENCE 2.1 I assessed the two rimu trees as a group using STEM and scored them 114 points this was 12 points more than the 1996 WDC assessment. 2.2 None of the scores in the function, stature, visibility of tree, proximity of other trees, role in setting or climatic influence criteria indicated that the group of trees had significant amenity, historical, ecological or cultural values. 2.3 The use of 100 points or more using STEM is to low a threshold for the scheduling of notable trees. A threshold of points is a more appropriate. 3. ASSESSMENT METHODOLOGY 3.1 In the preparation of my report, I inspected the two trees from the ground and measured their height with a Nikon Forestry Pro ranger finder and the trunk girths were measured with a trunk diameter tape. 3.2 I evaluated them as a group using the Standard Tree Evaluation Method (STEM). 3.3 I reviewed the WDC Proposed Notable and Public Trees Provisions objectives particularly Objective and the Criteria for Notable Tree Classification (NPT.1.8). 3.4 I reviewed the district plans of 39 councils in New Zealand for councils that reportedly use the STEM evaluations as a tool for protecting trees. 4. WDC STEM ASSESSMENT 4.1 The two trees were evaluated in 1996 and were given a STEM score of 102 attached as Appendix B. This score is above the WDC threshold of The WDC assessment sheet has simplified the descriptions of each feature headings in that the same feature heading has been used for each criterion, that is Poor (3), Fair (9), Good (15), Very Good (21) and Specimen (27). Whereas STEM has differing feature headings to better describe the assessment, for example, Occurrence of species is described as Predominant (3), Common (9), Infrequent (15), Rare (21) or Very Rare (27). It has been assumed that the original STEM descriptors were used in the WDC assessments otherwise it would not have been possible to assess the trees properly. Page 3

4 4.3 The only comments made by the assessor was under Vitality Brown leaves towards the centre of the trunk and age which was scored a 9 (20yrs +) but the scorer questioned if it could be scored 15 points (40yrs +). 4.4 Of the 10 categories, 8 of them were scored at 3 or 9 points while two (Stature and Proximity to other trees) were scored 21 points each. 5. ARBOR CONNECT STEM ASSESSMENT 5.1 I assessed the two trees as a group using STEM and gave them a score of My score and the WDC score differ in the categories for Vitality, Age, Stature, Proximity of other trees and climatic influence. Some of the differences can be contributed to changes in the trees and surrounding areas in the 22 years between assessments. A summary of my scoring and with the WDC scoring as a comparison: Arboricultural Criteria Arbor Connect score WDC Score Form 9 9 Occurrence of species 9 9 Vitality 15 9 Function 9 9 Age 21 9 Subtotal Amenity Criteria Stature Visibility of tree 3 3 Proximity of other trees Role in setting 9 9 Climatic influence 9 3 Subtotal Total Points The rationale for my scores is as follows: Form Moderate 5.4 The form of the trees is not noteworthy. The northern tree main stem bifurcates producing a potentially weak union and the southern tree has been pruned in the past and looks to be over thinned with an open canopy which is not typical of this species. See photos 5 and 8 attached as Appendix A. Page 4

5 Occurrence of the species Common 5.5 Rimu occurs naturally in Northland and can be found growing in many areas in and around Whangarei. Vigour and Vitality - Good 5.6 Both trees are exhibiting good vigour and vitality. A score above 15 is not warranted as there is no evidence that the trees are healthier than an average specimen. Function Useful 5.7 Being native trees, they have some usefulness in providing a food source, however rimu are dioecious (separate male and female trees) and the sex of the two trees has not been determined so the amount of fruit that the trees bear is dependant upon at least one of them being a female and that there are male trees in the neighbourhood to fertilise the female flowers. They will be part of a wildlife corridor, however, if these trees were not here it would be a not be a major detriment to the ecosystem. They have some physical usefulness mainly acting as a screen between the property and the busy road although the canopies have been lifted so that they do not provide a complete screen. They do have a negative impact on the property in that they produce a shaded area in the southern corner of the property that is not inviting and would not be used much especially in the winter. Age 80+ years 5.8 The aerial photo dated 28/5/1942 attached as Appendix D shows the existing house and what appears to be a row of trees in the southeast corner of the property. The resolution is not good enough to have any idea of the size or species but it is assumed that at least the southern Rimu tree, which is the larger of the two rimu trees, is in this group which would make it over 76 years old. The existing house was constructed prior to the 1940s and it is conceivable that the trees seen on the aerial were planted at the time of the construction of the house. 5.9 The southern rimu tree has a trunk diameter at 1.4m of 990mm. This is consistent of a rimu tree of around 80 years old. The northern rimu tree has a noticeably smaller trunk diameter of 580mm and it is possible that it was planted at a later date Based on these assumptions the southern tree would score 21 points (80+ years) and the northern tree would score 15 (40+ years). There is not a mechanism in STEM to score an average of two trees so I have had to score the age of these trees as 21 (80+ years). Page 5

6 Stature 15 to 20m 5.11 The height of the northern tree was measured at 15.2m and the southern tree at 16.4m. These heights fall within the 15 20m criteria and results in a score of 15. Visibility 0.5km 5.12 I tried to view the trees from beyond 0.5km at several locations but was unable to see them so awarded a score of 3. Proximity to other trees Group There are at least 18 trees within and adjacent to 1 Apirana Avenue that form a wider group that I believe these two trees are a part of. Being in a group of 10+ trees results in a score of 15. Role in setting Moderate 5.14 The two trees do provide some value to the role in this particular setting. They provide some visual amenity between the busy Bank Road and the existing property and provide amenity value to the continuous tree line that occurs on this section of the road. If these trees were not in this location it would be noticeable that the trees were missing only to those people viewing the trees in the immediate vicinity of them. If there was a greater opportunity to view these trees then I would have scored them higher. I am not aware of there being any cultural, commemorative or traditional role that these trees may have to the setting. Climate influence - Moderate 5.15 These two trees would have some influence over the climate mainly by influencing the wind flow and provide a cooling influence on the immediate area. If these two trees were removed from this group of trees the effect on the local climate would not be adversely effected. 6. THE USE OF STEM TO CLASSIFY TREES AS NOTABLE TREES 6.1 One of the objectives of the Proposed Notable and Public Trees Provisions (NPT.1.3.1) is that: Notable trees and notable groups of trees with significant amenity, historical, ecological or cultural values are retained and protected from inappropriate subdivision, use and development. Page 6

7 6.2 The NPT goes on further to explain the Criteria for Notable Tree Classification (NPT.1.8) and that the threshold for classification of a tree or group of trees as notable would be a score of 100 points or greater using the STEM evaluation. 6.3 It is my contention that the two rimu trees, when assessed as a group, do not have significant amenity, historical, ecological or cultural values. If they had significant values, they would have to have scored 21 or more points in the function criteria (for ecology) under the Condition Evaluation, 21 points in any of the Amenity Evaluation Criteria or achieved any score in the Notable Evaluations. 6.4 A STEM score of 100 points or more as criteria for a tree to become a notable tree, in my opinion, is to low of a threshold for a tree to be considered worthy enough to become a notable tree. 6.5 The STEM scoring system starts at 3 and increases in steps of 6 points to 27, therefore the possible scores are 3, 9, 15, 21 and 27, with 3 having descriptions such as Poor and Minor and is a score given to trees with little merit under the particular criteria, whereas a score of 27 has descriptions which include Specimen, Very Rare, Excellent and Major and is used for trees that have outstanding attributes of a particular criteria. It is my understanding of STEM that a tree that has significant attributes would achieve scores of 21 or more as it has descriptors such as Significant, Very Good and Rare. The only criteria that I have scored 21 is Age and even then, that age is not conclusive but I have erred on the side of caution for the southern tree and the northern tree could be less than 80 years old. Age is not specified in the NPT objectives. It could be argued that age is captured in the Historical value but just because a tree is 80 years old does not necessarily give it historical context. 6.6 The WDC use of a threshold minimum of 100 points means that trees or groups of trees that are below a medium are scheduled. The minimum points a tree or group of trees can score is 30 and the maximum points are 270 and a tree that scores the medium points of 15 in each category would score 150 (I have disregarded the Notable evaluation as it is used for trees of major importance only). I believe that a minimum score of 100 is to low and it captures trees that although could be good specimens are not necessarily above average. 6.7 A threshold of 100 points or greater throws up the possibility that a mediocre tree growing by itself in a residential back garden could score 9 points, which has descriptors such as Moderate, Common, Some and Useful, in all categories other proximity where it scores 27 because it is a solitary tree giving it a score of 108 points but it would qualify as notable tree. Page 7

8 6.8 There are 39 other councils in New Zealand that have been recorded as using STEM 1, and I researched the websites and district plans of these 39 councils and could only find information of 15 councils that use STEM in a similar way that WDC does, that is scoring trees or groups of trees using only the criteria in STEM and having a threshold of points that a tree or group of trees must reach or past before it can be scheduled as notable. A list of those councils that I could find using STEM in this manner and their point threshold is attached as Appendix E. 6.9 I found 15 councils using STEM points system that can be directly compared to the way that WDC use it. The highest threshold of points was 170 (Thames Coromandel District Council) and lowest was 100 (Upper Hutt City Council). The average was points with a median of of the 15 had a threshold of 130 or greater I believe that a more realistic threshold for scoring notable trees should be around points. A score in this range or greater would capture trees that would be considered as trees that for one or more reasons above average trees. 7. COMMENTS ON SECTION 42A REPORT Use of 100 point threshold. 7.1 Mr Simon MilIer in his evidence (Attachment 6 Statement of Evidence Simon Miller paragraph 22, page 3) states that the 100 point threshold is appropriate without expanding on what makes it appropriate other than to say that it has been in place since the inception of the first generation District Plan. I have addressed my reasons that the 100 point threshold is inappropriate in Mr Miller states in paragraph 23 that in STEM a tree does not need to be a specimen or rare or significant to score 100 points or more and he is of the opinion that this appropriate. I am of the opinion that having a low STEM threshold is not appropriate as it does not achieve the WDC objective of protecting trees with significant amenity, historical, ecological or cultural values. I have addressed this in Use of STEM by other councils 7.3 In paragraph 24 Mr Miller states that over 35 councils in New Zealand use STEM to evaluate trees. I have addressed this in and Partridge, Jez, Amenity Tree Evaluation Methodologies in New Zealand paper presented to NZ Arboricultural Conference 8 November 2018 Page 8

9 7.4 He also notes in paragraph 24 a quote from the Royal New Zealand Institute of Horticulture that appears to endorse the STEM system. I concur with the statements, however, would like to point out that it does not mention the use of STEM to identify significant trees using a score threshold. WDC STEM assessment In response to the DC Empires submission, Mr Miller visited the site and concluded that the trees were still worthy of scheduling. (Attachment 6 Statement of Evidence Simon Miller Appendix 2 PC129 Submission Notable Trees STEM assessment report ). His conclusions are repeated, in part, in the Section 42A Hearing report (Paragraph , Page 22). Mr Miller notes that the trees meet the criteria for scheduling and that the STEM assessment does not require all criteria to achieve a significant score in order to score sufficient STEM points to be included on the Heritage Tree register. I concur with these statements, however as addressed in 6.4 to 6.10 I disagree with the 100 point threshold and have concluded that these two trees have no significant amenity, historical, ecological or cultural values. 7.6 Mr Miller assessed the two trees on 3 October 2018 and scored them at 117. Mr Miller's score is only 3 points more than my assessment and is less than the points that I believe would be a more appropriate threshold for scoring notable trees. 7.7 A comparison of my scoring and the 1996 and 2018 WDC scoring is: Arbor Connect score WDC Score 1996 WDC Score 2018 Arboricultural Criteria Form Occurrence of species Vitality Function Age Subtotal Amenity Criteria Stature Visibility of tree Proximity of other trees Role in setting Climatic influence Subtotal Total Points I have obtained Mr Millers scoring attached as Appendix E. In general, the total score is not disputed, however, it is noted that three of the criteria, Function, Role in setting and Climatic influence were scored 12 points each. It is my understanding that it is not possible to score any different than the scores given in the evaluation sheets. In the Standard Tree Evaluation Method Page 9

10 publication page 13 it states Only those point option scores set out on the form may be used. I believe that the trees should be reassessed for these three criteria and am of the opinion as outlined in 5.7, 5.14 and 5.15 above that they should each be scored CONCLUSION 8.1 In my opinion, the two rimu trees do not merit being included in the proposed WDC PC129. Although they have reached the 100 point threshold I am of the opinion that this threshold is to low a score to warrant a tree or group of trees as being significant and that a threshold of points is more appropriate. 8.2 There are no significant amenity, historical, ecological or cultural values that can be attributed to these two Rimu trees. 8.3 For these reasons, I do not agree to the two rimu trees at 1 Apirana Avenue to being included in the notable tree schedule. Stuart Barton 23 November 2018 Page 10

11 Photographs Appendix A Photo 1 The two trees from Bank Street. The southern tree is on the left. Page 11

12 Photo 2 - The two trees from inside the site. The southern tree is on the right. Page 12

13 Photo 3 - Google street view September 2017 looking north. Northern rimu arrowed Page 13

14 Photo 4 - Google street view September 2017 looking south. Trees are arrowed Page 14

15 Photo 5 - Northern tree showing stem bifurcation (arrowed) which is a potential weak union Page 15

16 Photo 6 Southern tree showing thinner than normal canopy. Page 16

17 WDC Tree Evaluation 1996 Appendix B Page 17

18 Arbor Connect Tree Evaluation 2018 Appendix C STEM - Full Tree Evaluation Score Sheet Assessor: Stuart Barton Date: 20 June 2018 Botanical Name: Dacrydium cupressinum Common Name: Rimu Address 1 Apirana Ave, Regent, Whangarei ID Number: 378 CONDITION EVALUATION Points Score Form Poor Moderate Good Very Good Specimen 9 9 Occurance Predominant Common Infrequent Rare Very rare 9 9 Vigour & Vitality Poor Some Good Very Good Excellent Function Minor Useful Important Significant Major 9 9 Age (yr) Subtotal Points 63 AMENITY EVALUATION Points Score Stature (m) 3 to 8 9 to to to Visibility (km) Proximity Forest Parkland Group 10+ Group 3+ Solitary Role Minor Moderate Important Significant Major 9 9 Climate Minor Moderate Important Significant Major 9 9 Subtotal Points 51 NOTABLE EVALUATION Recognition Local District Regional National International Points Score Stature - Feature 0 Stature - Form 0 Historic - Age Historic - Association 0 Historic - Commemoration 0 Historic - Remnant 0 Page 18

19 Historic - Relict 0 Scientific - Source 0 Scientific - Rarity 0 Scientific - Endangered 0 Subtotal Points 0 TOTAL POINTS 114 Page 19

20 Aerial Photographs Appendix D Group of trees at 1 Apirana Ave circled - Detail of aerial taken 28/05/1942 sourced from Page 20

21 Location of the two rimu trees are indicated by the green dots. The southern tree is lower of the two dots. Page 21

22 Council STEM Thresholds Appendix E Council Threshold score Thames-Coromandel District Council 170 Hastings District Council 160 Palmerston North City Council 160 Horowhenua District Council 150 Kaipara District Council 150 Marlborough District Council 150 Dunedin City Council 145 Kapiti District Council 140 Matamata-Piako District Council 140 South Taranaki District Council 130 Tauranga City Council 130 (for native species) Hutt City Council 120 Queenstown Lakes District Council 120 Upper Hutt City Council 100 Whakatane District Council 108 Average Threshold Score Page 22

23 WDC 2018 STEM ASSESSMENT APPENDIX F Tree Evaluation Score Sheet TREE # 378 ADDRESS : DATE: TREE TYPE : 1 Aprina Ave Dacrydium cupressinum (Rimu) 1.0 Arboricultural Condition Evaluation Points scored Score 1.1 Form Poor Moderate Good Very Good Specimen Occurrence of species Predominant Common Infrequent Rare Very Rare Vitality Poor Some Good Very Good Excellent Function Minor Useful Important Significant Major 12 Large canopy trees; of some merit within the ecology and extent of the forest remnant/ stand; habitiat for native birds and vertebrates; also ref: /science Proximity of other native trees adjacent lowers score somewhat. 1.5 Age 10yrs+ 20yrs+ 40yrs+ 80yrs+ 100yrs+ 15 Size and girth of trees indicate trees 40 years+ old Well formed, balanced canopies Relatively common tree Well foliated canopies in a tree that sometimes suffers in urban areas Sub-Total Amenity Criteria Points scored Score 2.1 Stature 3 to 8 9 to to to Visibility of tree Canopies are obscured by adjacent trees 2.3 Proximity of other trees Forest Parkland Group 10+ Group 3+ Solitary 15 Trees stand in a group of adjacent trees 2.4 Role in location Minor Moderate Important Significant Major 12 The location and prominence of the trees/ stand are an arboricultural link to native forest that once occupied this area. Their roadside loaction mitigates and softens busy arterial road and commercial area. 2.5 Climatic influence Minor Moderate Important Significant Major 12 Similar to its function, the trees play a moderate to important role (due to the proximity of other trees) in temperature, wind and pollution moderation; similarly with soil and water conservation. Sub-Total Outstanding Criteria Points scored Score Recognition District Regional National International 3.1 Stature Feature Form 3.2 Historic Age Association Commemoration Remnant 3.3 Scientific Rarity Source Height measured Sub-Total 0 Total 117 Page 23