Planting trees for a dry spring
Is this year’s weather a sign of what trees will have to contend with in the future? If so, it’s important to learn a few lessons from nature to improve the survival chances of all the trees planted this winter.Irregularity of rainfall is an issue for newly planted trees. The dry spring this year was followed by a dry autumn with the occasional heavy downpours thrown in for good measure.
One answer is to plant smaller stock, such as whips or transplants, rather than going for the instant effect of planting a standard (see Section 4 of The Tree Warden Handbook, Tree planting – planning and practice).
Equally important – whatever the size of stock planted – is to use mulch to copy nature and make the soil around the trees as nutrient-rich and moist as possible.
In the forest, newly growing trees can cope because they have their roots in a rich soil, full of nutrients and covered with an insulating blanket of leaves and organic material - the perfect place to grow.
However we often plant new trees in poor soil with little organic matter and the soil surface has marked changes of temperature as it is exposed to the sun.
There’s an easy way to improve the situation - with a layer of organic mulch to mimic a more natural environment.
Mulch will suppress competing weeds, reduce water loss from the soil and keep it cooler in the summer and warmer in the winter – all desirable and simply copying nature. It can also dramatically reduce the likelihood of strimmers or lawn mowers damaging a tree.
Cost may have been a limiting factor in the past. However, with tree surgeons now having to pay to dump organic material into landfill sites, they are often grateful to find a use for waste that doesn't cost them, especially as it has an added environmental benefit. So it has never been a better time to ask around and see if you can get your mulch delivered free.
Organic mulch can be composted wood chips, hardwood and softwood bark, composted leaves and compost mixes. A layer of between 2 and 4 inches deep (51 and 101 mm) is ideal. Less than 2 inches and the soil can still dry out. More than 4 inches and the mulch layer can hold so much water that the conditions underneath become too wet and unhealthy for the tree.
Different types of mulch will last for different lengths of time and it is important to check periodically to ensure that the layer is still working and doesn’t need topping up.
It is also important that the mulch is not piled up around the base of the tree as the increased moisture can cause rot. Instead, create a slight hollow in the mulch that is immediately around the tree.
More information about mulching can be found in Section 5 of The Tree Warden Handbook, Managing and caring for trees.
New action plan to protect trees
A new drive to combat exotic pests and diseases threatening the health of UK trees was launched in October.People trying to bring potentially infected plants and cuttings into the UK will face stricter controls, and the Government is putting £7 million into research on combating new or exotic tree and plant pathogens.
The Tree Health and Plant Biosecurity Action Plan, a joint initiative between Defra and the Forestry Commission, sets out ways to tackle serious tree and plant pests and diseases. It also brings together a range of organisations to draw up the first integrated strategy dedicated to protecting our natural habitats from destruction.
The action plan focuses on four key areas – import controls; practical actions; research; and communications and public engagement. The full text is available from www.forestry.gov.uk/forestry/INFD-8LMD8C.
Launching the plan, Environment Secretary Caroline Spelman said, “If we don’t act now we could end up in a similar situation to the 1970s, when more than 30 million trees in the UK died due to Dutch elm disease.”
Welcoming the announcement, Pam Warhurst, Forestry Commission chair, said, “We have worked closely with Defra, Fera (The Food and Environment Research Agency), the devolved administrations in Scotland and Wales, the forestry and horticultural sectors and non-government organisations to develop this action plan to ensure we’re taking an integrated approach to tackling tree pests and diseases across the country. We look forward to continuing and developing this collaboration as we enter the implementation phase.”
