One Tree Two Cranes

One of the main aspects I enjoy as working as an Arborists is the variety of tasks I get to do.  Some days I have my feet firmly planted on the ground pruning fruit trees, other I might be swinging in the tree tops on ropes.  On special occasions I might be working with a crane to get the tree down…  and on very special occasions I get two cranes!  This blog is a case study of a recent sub-contract climbing job I recently helped my friend Nick Holmes at Treecycle with.

This picture shows the fallen tree with the limb we had identified that was bearing much of the weight

This picture shows the fallen tree with the limb we had identified that was bearing much of the weight

Nick had been contacted by a client who had a large Pohutakawa tree situated on an embankment above their house.  The tree had failed and fallen into the house and was now precariously rested against the building. 

There were 2 other trees that were tangled up in the mess; another Pohutakawa that was resting against the main tree and a dead Puriri that was helping to support both.  In addition to this, several of the large limbs from the Pohutakawa had shattered off and were hanging free in the nest of debris.

A mess of tangled and shattered limbs on the roof

A mess of tangled and shattered limbs on the roof

The whole entanglement was a complicated, messy, puzzle.  Unlike a jigsaw puzzle this one weighed several tons and had the potential to hurt or kill you if you made a mistake. 

The crane on the right was the climbers anchor, the crane on the left lifted the sections of tree away

The crane on the right was the climbers anchor, the crane on the left lifted the sections of tree away

It was quickly decided that the tree was unsafe to climb so other methods of access would be needed.  In addition, the large branches would not be able to be removed from the building via conventional methods without causing further damage or endangering workers.  The solution was to use two cranes.   One crane was to be used as the primary anchor point for me (the climber), the other crane would be used to lift the limbs off the house as I cut them.

The site was assessed by the crane company to ensure there would be enough room to operate.  In addition to the cranes, we also decided to stabilize the fallen tree using cable winches anchored back up hill to other large trees.  The winches would provide support to the fallen tree as we removed the limbs that it was resting on.

Tree limbs being cut and lifted off the house

Tree limbs being cut and lifted off the house

The beginning of the job went very quickly and smoothly.  I began by lifting out any limbs that were not providing support along with the limbs that had shattered off and were resting on the others.  The crane would slew round and land the sections at the back of Nicks truck and chipper where he and another Arborist were able to process them before the next one landed. 

Once all the free limbs were removed and we were just left with the supporting structure things got a bit more technical.  We had to assess what was actually holding the tree up and to what degree.  This became easier as more weight was removed from the tree and certain limbs that previously were pinned down began to move more freely.

A branch landing at the back of the chipper for processing

A branch landing at the back of the chipper for processing

Towards the end of the job we were down to a large trunk that was being held in the air by one limb underneath and the cable winches.  We were also close to max distance on the crane so the lifting capacity was greatly reduced and we could only take very small sections.  We backed off one of the winches and used the other to pull the trunk onto the bank.  This involved cutting the remainder of the supporting wood at the base of the trunk.  Prior to cutting we tethered the trunk to stump further up hill to prevent the whole lot sliding down the embankment and into the house.  From this position it was easier to remove smaller sections meaning the trunk could be dealt with in a more controlled fashion.

The end result was that the tree was safely removed from the house with zero additional damage.  All of the debris was cleared as we went and Nicks’ client was left with a big pile of wood chip and firewood for several years to come.  The only casualty of the day was the crane driver responsible for crane being used as my anchor point.  She was very nearly bored to death as all she had to do was extend the boom in the morning, watch with anticipation all day, and then pack the crane away at the end of the day.

For anyone looking for an Arborist in Whangarei or further north check out Nick’s website at https://www.tree-cycle.co.nz/