Kingston University Biodiversity Action Group

26-02-2014 : Dorich delights once again

We had a full class for this year's orchard maintenance afternoon at Dorich House with the London Orchard Project.
Lewis McNeil from the London Orchard Project enthuses about the need for healthy soil

Three years into our collaboration with the London Orchard Project, our little orchard at Dorich House Museum offered the perfect example for Lewis to explain why such spaces are important. We have a good mix of new and old trees which is crucial for continuity and habitat diversity; we are situated in the outskirts of a town allowing urban dwellers the chance to witness and get involved in food growing; we manage the site with minimal chemicals which keeps the soil healthy, productive and supportive of a variety of wildlife; and have seen the beautiful (and tasty!) rewards of careful maintenance in recent years.

A traditional orchard, managed in this way often has a proliferation of lichen - a combination of algae and fungus - which is sensitive to environmental conditions. As primary producers, they are part of the food chain providing sustenance to many invertebrates and birds.

Our old orchard is home to an array of wildlife, such as this lichen
The knarled and cracking bark produced as a result of healing wounds/breaks, in addition to rotting wood inside older trees provides perfect sheltering spots for invertebrates and even bats, thus completing the food chain from primary producer to predator. Owls living in the large trees of Richmond Park overlooking the orchard most likely predate these bats, pushing the trophic level one stage higher again. So to maintain this biodiversity in and around the orchard we need to keep the ecosystem balanced - we need to work with nature.

Setting the scene, Lewis tells volunteers why we need to care for our old fruit trees even though they are in decline
Fundamentally this means ensuring the soil is rich in nutrients and fungally dominated. Grass favours bacterially dominated soil and thrives in those conditions, so to reduce competition from the surrounding lawn, we have created large mulch pits around all the trees using woodchip. This increases the right kind of fungus in the soil which helps the trees take up nutrients. Many trees work in symbiosis with such fungus - known as mycorrhizal fungi. This means each gets something out of the relationship without harming the other: trees get nutrients and the fungi gets sugars from the tree's photosynthesis process. We added to the woody material in the mulch pits with new wood chip and the cut up young prunings from the trees.
Lewis explains that we should attempt to create a goblet shape when pruning fruit trees
The young trees need to be guided into the correct shape as they mature - this is called formative pruning. The ideal form for any fruit tree is goblet shaped, letting in plenty of light and air to prevent a humid micro-climate building up - the perfect environment for the wrong kind of fungus and disease to set in which would spell trouble for our trees.
Volunteers trimmed any branches that were heading the wrong way back to buds facing in the preferred direction to encourage growth in that way in the new growing season.

Kate and Sania try their hand at some formative pruning

Spring has sprung early this year so we are right at the end of the dormant season when work like this should take place. Soon sap will start rising in the branches to spur on growth, but this makes them heavy. And of course when the leaves and fruit appears this can be too much for some of the older, more fragile branches. We tried to identify vulnerable trees and cut back overhanging branches and unbalanced shapes to strengthen the form and encourage new growth once more. This meant tying down new shoots in some cases while they were supple, to encourage growth in a new direction. The string need only stay on for a year or so as the branch will soon harden-off in the desired position.

The long handled pruning saw was useful for those hard to reach places
This all took a variety of tools, including long handled pruning saws and secateurs. Although a bit fiddly to being with, they were worth the effort as it meant we didn't need to use ladders and risk serious injuries! Other volunteers worked with regular secateurs to prune out old, dead fruits on the tree, and congested branches, others retied old stakes and one pair planted a new pear!
Robin, Nicole and Kate refresh the ties on the younger trees

Lewis was impressed with the growth the young trees have put on in the last year.

We had installed a new training wire next to the wall ready to take our new tree to be trained as an espalier. Despite all the love and attention we paid to getting the right depth of hole, ensuring none of the roots were squashed or cut off, and giving it a blanket of lovely mulch, we were all shocked to hear Lewis wanted to cut most of it off! Poor Adrian had the cruel task to perform - but we were assured that it was in the best interests of the tree as its current shape was not going to work on our espalier - its branches had hardened off in the nursery and we would put too much tension on them if we tried to bend them down. A younger specimen would have been more suitable, but alas none were available when we bought this one. Still, a brutal cut now will encourage new growth very soon and give us something to work with.

Lewis psyches Adrian up for a drastic cut to this maiden pear tree - 'it's for it's own good' he says!

As we got down to ground level to look at the tree ties on the young trees we spotted something else had taken an interest in them. What looked like teeth marks were evident on the plastic sheath and obvious damage to the bark underneath had occurred. What could it be?

Mystery damage - something has been chewing through the plastic guard and into the bark. Could it be a playful young fox?
After a final spruce up with mulch around all the trees to keep weeds at bay, retain water and provide vital nutrients, we headed indoors for tea.

Smart and orderly the young trees have been dressed with fresh mulch to give them a spring boost!
We clearly hadn't exhausted Lewis of all his knowledge as he entertained us for another half an hour with a presentation about organic growing and how to encourage nature into your orchard to help overcome problem pests. We learned about earwig houses, moth pheromone traps, comfrey tea and bulb barriers - a wealth of ideas anyone could implement and certainly food for thought for the future of the Dorich House orchard. Volunteers were inspired and packed full of new knowledge and skills, plus the orchard was ship-shape again - what more could you ask of a biodiversity volunteer event?!

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