Ever wondered what an arboriculture officer does? Are you wondering now? Good, cause the following post will give you a bit of an insight. So here’s what happened when myself (an intern at Norfolk County Council) and Andy Johnson (on work experience) joined Tom Russell-Grant, Arboricultural Officer at NCC for a tree-mendous day out.
First stop, inspecting cherry and poplar trees at Scottow Enterprise Park (previously, RAF Coltishall). After pulling out: a map, inspection sheet and a camera, we were away with the cherries. The first thing I noticed was a tree with a nasty cut in its side. This was likely the result of past branch cutting activities which had cut so close it was beyond healing over. This is because their healing and defence against disease happens in the branch collar (see photo above). When the branch collar is chopped off, the tree is less likely to heal over the wound and more susceptible to diseases.
Tom began his inspections by looking at the tree canopy and leaf cover. At the right time of year, this is a good indicator of a trees health. If you can look up from the trunk and see the sky, this can be one way of showing that your tree isn’t doing great. Some of them, sadly, did seem a bit ‘leaf’-less. Although this meant some of them had reached there end, it wasn’t all bad news. It gave the opportunity to plant in some new saplings to rise up and take their place. Plus, this gives the opportunity of replanting with more diversity, which is more likely to stand the test of time.
After a fruitful cherry inspection, we moved onto the poplars. These were significant in size, with trunks approximately 1 metre in diametre! From the outside, they looked pretty good. Hence, Tom suggested getting the hammer to look for decayed wood, which Andy obliged. The areas of decay under the bark were distinguished by a hollow sound, while healthy areas were still compact and strong, like banging a table.
Sadly, there was soon an airtight case against some of the poplars. On closer inspection, we found an issue for the future health of the tree, a bracket fungus named Ganoderma. Many fungi are great at braking down and re-cycling dead plant material and have a saprophytic relationship with trees, some fungi even help trees take up water and nutrients through the roots in a symbiotic relationship. But there are a few fungi, like certain Ganoderma species, that are able to ‘attack’ living tree tissue in a parasitic relationship. This can be a real problem, particularly if a decay causing fungi starts to attack structural roots, those anchoring it to the ground, which will over time begin to compromise the trees stability. Again, this meant that some of the poplars might have to make way for a more resilient range of species.
Next stop, Blofield Heath, for a quick look at some more cherries. Once again we picked the trusty hammer and then we were off. Interestingly these were not just one type of cherry, they were two types grafted together. One type with wonderful blossom but spreading branches stuck on top of another that has a strong rooting system and good straight trunk. This had been done in order to have the beauty of cherries, without the entangling branches blocking people as they walk or branches flying out into the road at ground level.
After looking at the canopies and listening out for any hollow trunks, Tom decided that there wasn’t any major work to be done. However, some of the trees did show some minor wounds on branches from traffic which required pruning, while the bottom of some trunks showed scars of previous run ins with lawnmowers. Damage from lawnmowers can prove to be the tipping point on a trees health, so if it can be avoided, please do.
Last but not least, we were off to a Forestry Commission Ash Dieback trial site. In February 2012, there was confirmation that Ash Dieback (Chalara) had reached these shores, arriving at a tree nursery in Buckinghamshire. Later that year, cases were found in the wild in Norfolk and Suffolk with little hope of containing the outbreak. In 2015, Ash dieback is now nation-wide, occurring in 16.6% of all 10km grid squares across the UK (See here for more details).
However, a minority of Ash have shown some resistance. Hence, the Forestry Commission began a resistance screening trial, setting up 14 locations in South-East England where Chalara is known and plant over 155,000 disease-free ash seeds from a wide variety of species. Norfolk County Council hosts two such trial sites on County farms and closed landfill sites. Hence, those showing resistance could be seen more easily. Then lab examination might be used to identify why they are resistant and produce a Chalara-resistant seed. More details here.
It was really encouraging to see the scale of the trial site and efforts being taken to ensure the long-term sustainability of our ash trees. On closer inspection, some unhealthy ash trees soon became apparent with many dead stems visible. The signs that a tree has Chalara, such as brown leaves or lesions (see diagram). Interestingly, I managed to photograph for my example, one of the only trees that had died from a disease that wasn’t Chalara. After a good look at the site, it was back to base, ending a successful day out in the field.
It had been a great opportunity to get into the field, with inspections cherry-picked for you, branching out with the pop-u-lar trees and seeing those ‘ash’-ually making a difference!