Many of the rural properties that I work on have shelter belts. On exposed sites, shelter belts can be almost essential for establishing a garden and protecting your house from wind. Many different tree species can be used for shelter belts with varying results. Some will grow quickly but may require maintenance, others will look after themselves but take a long time to establish. There can also be differences in resistance to pests and diseases. This blog will use a case study of a job I did last summer to highlight some of the issues regarding shelter belt selection.
The property in question was a formerly exposed site at the top of a hill. A Macrocarpa shelter belt surrounded a now established garden and had done a good job of protecting the inner plants through their infancy. Unfortunately, parts of the shelter belt had succumbed to Cypress canker which is a common pest on this species in Northland due to our relatively mild winters. The owner contacted me to discuss options.
There are not any affective control treatments for Cypress canker on mature trees. Fungicide sprays do exist but their effectiveness has not been proven on larger trees. Due to the extent of the infection and age of the trees, pruning was not option either. As time goes by the effected trees will die back and begin to fail; either dropping branches and limbs of whole trees falling over. Unfortunately, once the disease is established there is not much else you can do other than removing the diseased trees in the hope of saving the healthy ones.
One end of the Macrocarpa shelter belt was more affected by the disease than the other. This end of the row of trees also had established gardens in close proximity which would restrict the size of equipment and methods we could use to do the work. It made logical sense to begin at this end with a smaller set up and then return at a later point to finish the rest of the row with larger tree removal equipment for efficiency.
I decided to use a 3 ton tipper truck and 10 inch chipper with a winch for this first section. This set is nice and compact and can easily get into a variety of spaces. My friend Nick Holmes at Treecycle has this combo and I sub-contracted him in to help me with the job.
First, we moved some small plants that were in the way, protected their roots with sacks and stored them in a shady spot. We opened a section of the hedge by dismantling some of the trees in sections. These were then winched into the chipper. Once we had enough space we used the winch to fell the rest of the row one at a time back on the stumps of the previously removed trees. Each tree was then winched to the chipper and mulched. This allowed us to work in an efficient manner whilst avoiding any damage to the garden. Once the removal of the section of shelter belt was finished we reinstated the plants and watered and mulched them.
The result was that the diseased section had been removed with zero damage to the surrounding garden. The remainder of the row has easier access and, when its time comes, a whole tree chipper and digger set up can be used for greater efficiency.
The customer was left with a big pile of mulch which will be great to use on the rest of their garden and any new trees they plant as replacements.