Poplar Trees' fate

The Queenstown Lakes District Council will be asked to approve a recommendation to remove a line of aging Poplar Trees on Lower Shotover Road at next week’s full council meeting, QLDC parks manager Gordon Bailey said.

Last week during high winds, one of the trees fell, tragically killing a local farmer.

“We have now received an aborist’s report advising that a number of the trees in the row are in questionable health. With a line of trees like that it is not possible to remove one or two as that undermines the entire row. Under the circumstances we are seeking to remove the rest of the trees,” Mr Bailey said.
He said whilst the death had been a real tragedy, he would be reminding Councillors that the tree fall had to be viewed as a ‘freak accident’.

“In a strong equinoctial wind any tree either in good health or poor can succumb,’ Mr Bailey said.
On the meeting agenda, Councillors would also be asked to approve work on the preparation of an ‘issues and options paper’ for the future management of trees on and adjacent to roads.

“Potentially the job of cataloguing and managing the thousands of trees that line roads throughout our district is enormous but it’s something we need to give further consideration to,” Mr Bailey said.

The agenda item also sought to encourage the community to report potentially hazardous trees through the council’s recently overhauled request for service system.

“It’s as easy as a phone call to a Council customer service advisor. That request is then formally entered into the system and allocated to a staff member or contractor who is tracked and accountable,’ Mr Bailey said.

The removal of the Lower Shotover trees was expected to cost between $50,000 to $80,000.

A landscape impact assessment would be tabled at next week’s meeting.

 

 SUBMITTED BY: Gordon Bailey – Parks Manager

REPORT DATED: 17 September 2009
POPLAR TREES ON LOWER SHOTOVER ROAD

PURPOSE
To inform the Council about the safety - based on an arborist’s report - of a line of Poplar trees along Lower Shotover Road and to generate discussion on the wider issue of trees on rural road reserves. Given the short timing since a recent tragic accident, this latter aspect should be seen as only starting the debate.

BACKGROUND
Following the tragic death of a local farmer on 14 September, caused by a falling Poplar tree on Lower Shotover Road, Council commissioned an arborist’s report on the safety of the approximately 66 remaining Poplar trees in the shelterbelt.

The report indicates that a number of the trees are in questionable health. It is recommended that these trees should be removed.

A landscape assessment report by Dr Marion Read will be available before the meeting. This information is important as trees on or adjacent to rural roads is part of the amenity of the District and decisions on trees have to have that aspect in mind.

The tragedy highlights the wider issues regarding roadside trees although Council should be mindful that this was a freak accident attributed to strong equinoctial wind, to which any tree either in good or poor health can succumb.

SIGNIFICANCE OF DECISION
This is not significant in accordance with Council’s Policy on Significance.

ATTACHMENTS
Arborist report

RELEVANT COUNCIL POLICIES
QLDC Tree Policy

QLDC Partly Operative District Plan - these trees are NOT protected.

 

DISCUSSION

It has now been established that the Poplar trees are standing on the legal road reserve, as are many thousands of other trees along the more than 800km of roading the Council controls. Like so many others around the district and New Zealand, these trees have been planted not by the Council but a previous adjacent land owner, generally to provide shelter or screening. In the case of these particular trees, planting occurred probably in excess of 100 years ago.

Many Councils have clear policies for trees obviously planted by someone other than Council on a road reserve where they are the responsibility of the adjoining landowner as the benefit they accrue is directly relevant to that property. In later years this Council has entered into a number of Licence to Occupy agreements allowing certain plantings on some road reserves. It’s very difficult to enter into these retrospectively especially when the adjacent owner didn’t plant the trees and would be rightly wary of the maintenance liability that might accrue to them.
Given that the Lower Shotover trees are on road reserve and given the outcome of the Aborist report, I would recommend that the Council take action to mitigate any further risk.

With regards to Lower Shotover the Council also has to weigh up the safety issue and possible removal of these trees (which clearly takes priority) with the wider landscape effects, consultation with affected parties and possibly the wider community.

Since the Lower Shotover tragedy the Council has had two other calls suggesting potentially unsafe trees on road reserve in various parts of the district. These trees will also need to be inspected and it gives rise to a wider question.
At present we are aware of mature trees that are listed as being protected, however we are somewhat reliant on the community to report any roadside trees of concern. In not all cases would the Council agree that the said trees should be felled and there are several cases to illustrate this.
The task of creating and monitoring a schedule of all road reserve trees is a major undertaking and would come with significant cost to the community. The job would require accurately determining all the legal road boundaries, assessing the vegetation growing within that reserve area and weighing that up with risk potential. In considering removing trees we must also consider whether a planting programme to replace them, perhaps with more appropriate species, should also be pursued. Formulating and consulting on some form of policy around this issue may be a more long term option to consider.

 

For completeness I would also record that the Council has addressed the issues of safety and amenity for reserve trees and urban street trees through recent annual plan provisions and the Asplundh contract.

As a minimum, given that trees have a life span, the Council will need to provide budgets in future years in the roading area for the removal of dangerous trees on road reserves in rural areas.

 

FINANCIAL IMPACT

In terms of dealing solely with the Shotover Road situation, a rough estimate of cost is in the vicinity of upwards of $50,000.00 although it is more likely that tendered prices will be nearer to $80,000.00 and would be funded from the roading budget. Clearly this will mean some other projects will not be funded in order to keep within budget. The Roading and Finance Managers will be present at the meeting to provide options.

With regards to the wider issue of potentially cataloguing and monitoring all roadside trees, further work would need to be undertake to understand the cost implications if that was the desire of the Council.

CONSULTATION
The only consultation undertaken to date has been with a representative of the owners of the property adjacent to where the tree fell. They felt the trees were for Council to act on.

In the event that the Council formulated any policy on the matter, it would seek comment from the community.

DELEGATIONS REGISTER REFERENCE
This is an unbudgeted item of expenditure that requires Council approval. Funding will require the reallocation of some other budget to accommodate the work.

RECOMMENDATION
It is recommended that the Council:

Receive this report and the recommendation of Option 2 in the Asplundh Arborist report dated 17 September 2009;

Approve that the trees be removed forthwith;

Request the Roading Manager, the Parks Manager and Policy staff to
prepare an issues and options paper for future management of trees on and adjacent to roads in time for the 2010/11 annual plan;

That the community be encouraged to report trees adjacent to rural roads that they believe to be dangerous through the RFS system; and

That the CEO be authorised to commit budget without further resolution of Council to the removal of trees on rural road reserves identified by the Parks Manager as being hazardous.

 

Tree Inspection Report – Lower Shotover Road, Queenstown

Prepared by: Rob Slater
This report has been prepared for Gordon Bailey QLDC.

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The purpose is to determine the health and safety of the avenue of Populus nigra 'Italica' (Lombardy poplar) Poplar trees (Approx 66) that are growing on QLDC road reserve on Lower Shotover Road, south of RD 311.

The recent loss of one of these Poplar trees that fell over in strong winds has caused concern for the future safety of traffic and pedestrians in this area for the line of trees still standing. A brief explanation on the health of the tree that fell over has also been included in this report as Tree #1
As part of this assessment, only a visual ground based inspection was carried out.

In my capacity as an arborist I have undertaken to produce an independent and unbiased evaluation.

Location:

The Poplar trees are located on road reserve land located in Lower Shotover road south of RD number 311.
Hazard targets in the vicinity include public roads, farm fencing and the general public.
General Overview:
The Poplar trees growing in this location (approx 66) are spread in an avenue on road reserve land spaced consistently.
Populus nigra 'Italica' (Lombardy Poplar)

The landform is flat and even with public road on one side of this avenue of trees and private land on the other.
No official public walking tracks or footpaths have been developed in this area. However the general public walk along the road edge of this avenue of trees.
A high percentage of these trees have major dead wood, hangers and large dead limbs that are visible. Overall the health status of the trees growing in this location is considered to be poor.

Tree Inspections:
A visual assessment was undertaken of all trees in the locality to determine their safety and health status. Due to the urgency of this assessment a visual inspection was only possible due to the sheer number of trees.

From this assessment it was determined that approximately 85% of the living specimens show some immediate signs of deadwood and decay, indicating that this avenue of trees is in decline.
The result of the inspections has been detailed below.

Tree # 1 This tree is lying on the ground approximately 1/3 distance along the avenue of poplar trees. At first inspection this tree has been cleared from the road, and is placed in segments on the road reserve verge.

Estimated age 80-120 yrs
Tree Characteristics:
Species: Populus nigra 'Italica' (Lombardy Poplar)

Height: Approx 24-30 metres DBH: approx 87cm

Canopy spread: 3 metres

General Condition: A fallen tree with poor overall health.

Pruning History: Unknown.
Butt and Roots: The base of the tree is located on flat even ground. It shows good root development, but there was dry rot in the buttress roots and basal flare. The tree’s buttress and trunk were hollow in many areas that were available for inspection. Some surface roots were exposed but these don’t appear to be undermined or unstable. There are no indications of any root plate movement prior to this tree falling over.
Trunk: A single main stem had developed. One can assume that smaller side stems had also formed as this is typical with poplar trees’ form and growth habits.
Branches: N/A as only the main trunk and butt was available for inspection.

Canopy: Taking into consideration all the other poplar trees in the immediate vicinity, one can assume this tree’s canopy had numerous dead wood and hangers in the canopy
Hazard Evaluation: N/A as this tree had already fallen

Summary: This particular tree had major dry rot in the lower main stem and lower trunk. The lower trunk was hollow and the dry rot was prolific in the lower part of the tree. The tree’s root system did not fail in this instance, but the buttress and trunk failed in the lower 2 metres of this tree. The tree’s age has a part to play in the tree falling over as poplar trees do not age well compared to some other trees. Any poplar tree in this age bracket is more likely to be prone to disease and rot.
Specialist equipment is required to determine if the tree’s inner core is rotten or in decline. If this specialist equipment is not available and there are no examples of a tree that has previously fallen, or any external signs that are evident to suggest the tree's inner core is compromised, then it is very hard to determine the tree’s structural strength.

Tree # 2 Approximately 66 Poplars (Populus nigra 'Italica' (Lombardy Poplar)

Location: The Poplar trees are located on road reserve land; this is located in Lower Shotover road south of RD number 311.

Hazard targets in the vicinity include public roads, pedestrians and farm fencing.

General Overview:
There are approximately 66 Poplar trees growing in this location, and they are spread in a line (avenue) on road reserve land; they are all spaced evenly and generally consistent in height and health.

These trees are in a straight line about 4metres from the road edge. The trees’ form and shape look fine as you drive by. It is only when you stop to have a look at these trees do you notice the numerous amounts of dead wood and decline in each tree.

Estimated age - All trees were planted at the same time. They are around 80-120 years old.
Tree Characteristics:
Species: Populus nigra 'Italica' (Lombardy Poplar)

Height: Approx 24-30metres DBH: approx 75-110cm Canopy spread: 2.5-4metres

General Condition: A majority of trees in this line have poor overall health.
Pruning History: Unknown. There appears to have been limited pruning in the past on this line of trees. Maybe some cutting back from the road and farm fencing at the lower levels of these trees has taken place.

Butt and Roots: The base of the trees are all located on firm flat even ground. A large majority of the trees in this line show good root development.

A large number of these trees have decay or rot in the buttress roots and basal flare. There is also cracking in the bark on the basal flares. Some of the trees’ buttress and trunk have small hollow or soft areas that indicate rot and decline. Due to the hawthorns growing around the poplar trees, I could not get access to the basal root or flares to examine the condition of some trees.

Some surface roots were exposed but they do not appear to be undermined or unstable. As a group, the trees’ roots generally seem to be in good condition. There appears to be no indications of any root plate movement on the trees. The long grass and Hawthorn undergrowth did hamper my observations, so not all trees could be checked.

Trunk: A majority of the poplar trees have a single main stem with other smaller side trunks / branches forming from the main trunk. A high percentage of the trees’ trunks had major dead wood and in some cases minor dead limbs coming of the main trunk. This major dead wood is cause for concern if it falls off.

Branches: Due to the growth habits of these trees, most side branches are all vertical and come from one or two of the major trunks. A high percentage of the poplar trees had branches in decline or they were dead.

Canopy: 75% of the poplar trees had stag heading in various stages of development. (Stag heading is a sign that a tree is in decline for various reasons). Approximately 30% of the trees had a hanger or two still in the canopy, some small and some very large up to 4-5 metres in length. All hangers pose a threat to persons and road below should they fall.

Approximately 90% of the trees had dead wood present, this posing a hazard to persons or vehicles below
Hazard Evaluation: The avenue / line of poplar trees in Lower Shotover Road do pose a serious threat to both pedestrians and the road below them. With this first tree splitting out earlier this week, it brought these trees to QLDC’s attention while providing evidence of rot and disease. Unfortunately, this is the first sign that this line of trees is a hazard and will continue to be a hazard until they are removed.

With evidence shown from the fallen tree and so much rot in the tree’s main trunk, controlled removal of these trees is very hazardous itself.

Summary:
Currently, the trees while looking as magnificent as they do are a significant hazard.
A Poplar tree’s health and longevity is generally short, and at this grand age they are generally in decline. This is the case with this avenue of Poplar trees in Lower Shotover Road. Large amounts of stag heading combined with major dead branches and smaller dead wood are still cause for concern. Anything above two inches in diameter if it falls from height from one of these trees will go through a car windscreen. The size of some of the dead wood and hangers in these trees is over 2-3 metres in length.

The visual inspection under taken in my opinion is enough to establish that a large majority of the trees are in decline, and do pose a hazard currently. Specialist equipment is available if required to determine 100% if the trees’ inner core is rotten and the extent of the interior rot. In this case the tree that has fallen to date provides evidence in conjunction with other external signs to suggest the majority of these populus trees’ inner cores are compromised and that these trees are in decline and have poor or failing health.

In my opinion the trees need to be managed and the only safe way to do this is by either of the following suggestions:
Option1 (extreme) - Close the road indefinitely to traffic and retain the trees in their natural state.
Option 2- Removal of all of the popular trees to ground level. Do not retain any trees in this avenue.
Please Note: Removal of individual trees from this avenue rather than removal of the whole line of tree will result in possible wind throw of the trees left in situ. Total removal of these trees is the only option in my opinion.

Please contact me if you require further information or clarification of any of the points raised.