Tag Archives: Ash Trees

Less Carbon Dioxide Absorbed by Amazon as Trees Die Off – Part Two

Less Carbon Dioxide Absorbed by Amazon as Trees Die Off
Increased mortality rate

It is estimated that in the 1990’s the Amazon absorbed up to two billion tons of CO2 each year but since then, according to the study now absorbs less than half of that.

The study was limited to primary and undisturbed forests, which makes up about 80% of the Amazon. So it doesn’t account for carbon changes, regrowth or deforestation so more research will have to be done in order to provide a more rounded result set but Lars Hedin, a professor of ecology at Princeton University suggests that the research done thus far will form an excellent springboard for a future research and understanding.

He writes: “The CO2 component of climate change may become substantially more difficult to manage and abate in the future if the findings from the Amazon basin apply more generally to the land carbon sink.”

Ian Morgan Arb is committed to Forestry conservation and growth promotion and correctly managing the trees that we have.

Your options for dealing with a Chalara infection

Beneficiaries of our Staffordshire arb training contemplating how to address a Chalara-affected area have several options, depending on the exact location and nature of the infection.

The preferred option is generally burning on site, either on the ground or in mobile incinerators brought to site, the latter likely to be chosen due to their practicality for dealing with a large volume of leaves. Those considering this option are urged to check the relevant legislation on smoke control areas, in addition to taking into account the possible smoke nuisance risk.

Alternatively, one may bury infected leaves in the grounds of their premises. Although ground burial can be done by both private individuals and local authorities, in the latter case, it would constitute a landfill operation requiring an environmental permit, in accordance with the Landfill Directive.

Other possible approaches are less proven in their efficacy. This could certainly be said of composting on site, the lack of scientific evidence for its effectiveness meaning that any arborist training recipients contemplating it are advised to spread any resulting compost on or near the infected source wherever possible. This is as opposed to passing the compost onto third parties who may transport it elsewhere and thereby risk the spread of infection.

Another less preferred option is off-site incineration or landfill. We would always advise against the movement of infected ash leaves for purposes other than destruction. Even if leaves from affected areas cannot be dealt with on-site, secure containment of the transported waste – whether by placing it in enclosed containers or bagging – is necessary. Any transportation of leaves for incineration should also be for the shortest possible distance.

Nor would we recommend off-site composting and other biological treatment, given the uncertainty surrounding the right conditions for destroying the Chalara fraxinea fungus. Any potential residual risk can, however, be minimised if the resultant compost is only used locally.

If an area is not infected at all – and the distribution of Chalara’s spread is by no means even throughout the country – there is no need to remove the leaves, they instead able to be left where they fall.

Talk to Ian Morgan Arb today about arb training in Staffordshire that will educate you on the full range of means for addressing any Chalara infection of your vegetation.

How can arborists limit the spread of Chalara?

CHALARA SPREADSA critical element of arb training for many is knowing the best means of limiting the spread of Chalara, the fungal disease that already besets so many of our ash trees and is tipped to ultimately infect most of the country’s ash tree population, akin to the notorious 1970s Dutch Elm Disease.

The importance of minimising Chalara’s spread cannot be underestimated. The risk of the transmission of spores via infected leaves means that one must always try to guard against new areas becoming infected through the adoption of sensible biosecurity precautions.

The fungus that causes the disease, Chalara fraxinea, is capable of surviving up to a year of frost or leaf degradation, but cannot fruit if buried. Although it can be killed in some cases by the heat that composting generates, this cannot be guaranteed and it is unlikely that sufficient heat to kill the spores is generated by the smaller scale heaps seen in parks and gardens.

Recipients of our Staffordshire arborist training working on any site should always heed any requirements outlined in statutory Plant Health Notices over more general advice. Nonetheless, those intending to fell or prune infected trees are advised to wait – if possible – until leaf fall before doing so.

Infected leaves may not need to be removed at all in some circumstances – it is widely advised to leave infected mature ash trees, for example, in place. The fungus in the ash tree leaves that causes the disease is able to be spread by airborne pathways or by physical movement through human agents. It is the movement of infected material, such as plants and leaves, that generally causes the spread of Chalara into new areas.

As a general rule, the smaller the volumes of leaves being transported and the shorter the distance they are being transported, the lower the probability of the spread of the disease. If leaves that have been affected by the disease do need to be disposed of, the emphasis should be on using on-site disposal options available on or near an infected area, thereby minimising the risk of infection spreading to other areas.

Those benefitting from our arboricultural training in Staffordshire should also be aware of the low risk status of timber/cordwood that means there is no control over its movement at this time. Measures should also be taken by those that have just worked on infected trees and are set to move into other areas with no or minimal signs of infection, to remove leaves and rachis from vehicle tyres, chippers and payload.

The other pests and diseases that can be present nearby only makes the adoption of biosecurity measures all the more sensible for those enrolling in arb training in Staffordshire like that of Ian Morgan Arb.

How Chalara-infected ash trees may be managed in various circumstances

Students of arboricultural training in Staffordshire or elsewhere are advised to familiarise themselves with the wide range of circumstances and settings in which Chalara-infected ash trees often need to be managed.
You may, for example, wish to carry out works on trees that are protected by tree preservation orders (TPOs) and conservation areas (CAs), in which case, it will first be necessary to contact the Tree Officer in your local Planning Office, clearly specifying the trees involved and their locations. You will also need to describe the extent of the work that you are interested in carrying out, in addition to the reasons why you would like to carry out the work. This application will then be considered by the Tree Officer.
Ash trees on development sites may also require management, with any tree survey intended to support a planning application needing to include the categorisation of trees according to the criteria shown in Table 1 of British Standard 5837:2012. This is for the purpose of identifying the existing tree stock’s quality and value, so that informed decisions can be made with regard to the removal or retention of trees in the event of development work.
Deadwood can also occur in infected ash trees that are on or adjacent to highways and footpaths, posing a potential health and safety risk. This makes it crucial for trees in such a setting to be managed in a manner that places the emphasis on public safety, ensuring that action is proportionate so that there is no unnecessary pruning or felling. Safety considerations will be at the discretion of the relevant Highways Authority, taking priority with regard to the management of ash trees close to the highway.
Similar principles apply to ash trees in parks, public spaces and heritage sites, as well as on private property that is not woodland or protected by a TPO or CA. Meanwhile, when a site is home to significant ancient, veteran or isolated trees with particular merit, best practice is to clear away and dispose of nearby leaf litter during the autumn, so that the trees are best-protected from infection.
Finally, some trees – particularly those that are mature, stressed and/or damaged – provide various roosting opportunities for bats. The legal protection of bats and their roosts from disturbance, damage or destruction – even when bats are not actually present at the time the work takes place – makes it vital for a survey to be carried out establishing that the given tree is not being used as a bat roost.

An introduction to Chalara

Chalara infection Tree DiseaseThere’s no question of the extent to which Chalara dieback of ash – also known as ash dieback or just Chalara – represents a  bane to the lives of many of those receiving arb training in Staffordshire. This fungal disease affects ash trees, causing crown dieback, leaf loss and bark lesions. Even worse is that it is usually either directly or indirectly fatal to trees, due to the weakened tree’s consequent vulnerability to pests or pathogens.

Chalara has been responsible for the infection and death of a significant proportion of Europe’s ash trees, and since its initial discovery in the UK in nursery stock in 2009, it has become prevalent among ash trees in woods, hedges, plantations, parkland and urban areas, particularly in Eastern England. It is thought that infections first began to occur here due to fungus spores being carried on the wind from planted nursery stock on the continent.

With Chalara now well-established in Britain, all chances of the disease being eradicated from here are remote. Ultimately, most of the country’s ash trees will be infected by the disease, in a manner akin to Dutch Elm Disease in the 1970s. Ash trees with the disease can pose a major risk to people and property if they are not suitably managed by landowners.

As a recipient of arb training in Staffordshire, it is important for you to carry out regular surveys of ash trees so that you can take appropriate action. There are certain ways of minimising Chalara’s presence and rate of spread so that you can maximise the amount of genetic diversity in your ash trees and ensure as little compromise as possible to associated species, general biodiversity and timber production. Above all else, the right management will help to preserve ash in the long term.

While ash trees can have certain undesirable effects such as damaging property or risking human safety, they can also be an immensely valuable part of the overall urban, suburban and rural landscape. Where the management of ash trees is advisable, getting this process right will help to enhance the trees’ value, access and other advantages. Deadwood, for example, is not merely a hazard, but also a vital ecological attribute that is depended on by many species.

Ash trees should be retained where possible, in accordance with national guidance. Such trees should not be felled or pruned merely due to the likelihood of Chalara infection, as should be noted by anyone in Staffordshire who takes advantage of arb training.