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29 Nov 2022

Crathes Garden blog #19: The cycles of life

Written by Susan Bennett, garden guide at Crathes Castle, Garden & Estate and author of Notes from Crathes blog
A close-up of a branch of a rose bush in autumn. Its leaves are a deep yellow with a dark green pattern on them.
‘Rosa rugosa’ leaves in the Rose Garden
Our expert garden guide has been sharing a blog offering a behind-the-scenes glimpse at what the team are working on in the garden at Crathes. This month, she considers the role the garden can play in improving biodiversity in the years ahead.

On a dull day at the end of October I contemplate the trees that are preparing for the coming winter. Large flat leaves become a problem for the trees as temperature and light levels dip and winter storms threaten. By dropping these leaves, the broadleaf trees can reduce water loss and wind damage until the kinder days of spring return. However, before the leaf drops, the tree re-absorbs some of its goodness. As it does so, it may create the most delightful patterns. The green chlorophylls are absorbed first, then the red and purple anthocyanins and orange carotenes. We all depend on these photosynthetic chemicals which store the sun’s energy, as they provide us, and the animals we may eat, with food.

There are not many folk about on this gloomy day, but I see volunteer Jenny tidying and weeding in the Camel Garden. She is quite happy working away by herself, savouring the peace of the garden that gives her a break from a busy life.

On another day, the sun is shining on the remaining autumn colours: the gold and copper of the beech, the silver bark and golden triangular flakes of the silver birch leaves. After the recent winds, most of the leaves are gone, but the Cotinus leaves in the garden hang on in a spectacular show. Yet another mild November means there are still some of the summer flowers to enjoy.

In the native plants area outside the Woodland Garden, gardeners and volunteers are planting oak saplings. Although there is some natural regeneration of oaks, the tiny saplings tend to be swamped by sycamore seedlings (see my earlier blog Sycamores can be a nuisance). There is not enough time to weed them individually, so the saplings that are being planted – North East oaks from Castle Fraser – will have a head start. A little bone meal and a mix of soil and compost is added to each sapling, which will be caged for protection from rabbits and deer. The sycamore seedlings can then be strimmed away. Steve is planting an oak that has been growing in a pot for some years in the yard. There is a feel-good factor to planting oaks, and releasing this tree from its pot so that its roots can spread out and connect with the mycorrhizal fungi of its neighbours is very satisfying.

A lot of time is spent removing leaves in the garden at the moment, but the thousands (perhaps millions) of leaves that cover the estate will be reincorporated into the soil by natural processes brought about by a host of invertebrates, fungi and bacteria. Much of the summer bounty decays and is returned to the soil. The leaves collected in the garden will also be recycled as leaf mould and used as a mulch.

A man holds a small oak sapling that has just been taken out of a pot.
Steve prepares to plant the oak sapling from Castle Fraser.

With the unseasonably high November temperatures, we cannot avoid thinking about the natural cycles of life and how they have been disrupted by the climate crisis – a crisis brought on by our own actions.

A year on from the Glasgow COP26 agreement to keep global temperature rises below 1.5 degrees, the future is looking bleak. In the last year we have seen a range of catastrophic weather extremes from the floods of Pakistan and the droughts of Africa to the wildfires of California and Australia. Even in the UK we have had some idea of the future as drought and storms have affected our lives. And yet with the world in political disarray there seems little chance of keeping the Glasgow pledges.

Some hope can be garnered: there is a growing realisation that home-grown renewables are the answer to oil and gas dependence. In gardens, there is a move to stop spraying and to cater for wildlife. There is a new passion for growing our own fruit and vegetables thereby producing fresh healthy food, reducing food miles and boosting our well-being. Agriculture too is beginning to put its house in order.

Thinking about the summer drought, I ask James if the water situation has moved on and if there has been any development of the dipping pool potential? (See A global perspective and Challenges) The answer was yes – although not exactly in the way expected. An expert North-East drainage firm advised that, considering all the probable underground water flow in the area near the gardeners’ yard and the old well, the best solution would be to sink a borehole. This would provide water whenever needed. The borehole should be sunk where most of the underground water courses converge; this location could be found by a water diviner. The drainage firm employs a diviner who apparently has a 97% success rate in locating water. To a divining sceptic like me, this is extremely interesting. How on earth does it work? Even when a plan is developed, there is the matter of funding. However, with the rising costs of metered water, just a few years of free water in a drought situation is likely to pay for the project.

A pipe drips water into a concrete, square pool, with several layers built up around the edge.
Even in a drought, the underground water from the garden and beyond drains into the dipping pool.

This month I watched a brilliant film, Riverwoods, about the lifecycle of the salmon, which emphasised our dependence on the natural cycles of abundance and decay. The film demonstrates the paucity of the Scottish landscape, but also gives us hope that changing tactics might return the land to something closer to its previous abundance of biodiversity. The numbers of the Atlantic salmon (Salmo salar), once plentiful, have now declined dramatically, and this has affected the health of the land in ways we did not previously understand. Some of the problem lies at sea, but much is wrong with our rivers. The adult salmon spawn in the upper reaches of the rivers, where the young fry grow for a few years until ready to migrate to the sea. In the burns and rivers they are vulnerable to predators, but they thrive in habitats that offer shade from overhead trees (thus reducing the water temperature) and have fallen trees and branches that provide nutrients and shelter from predators. Having made their way downstream to the estuary, the salmon, now called smolt, then migrate to the seas around Norway or maybe Iceland.

It will be about four years before they return, using their sense of smell, to the river in which they were born – an incredible feat. These adult salmon return nutrients from the ocean back to the land, because after spawning they die and are eaten by a variety of animals such as ospreys, badgers or otters. Alternatively, they are merely left to rot and decay back into the forest, where trees and vegetation absorb the nutrients originally taken from phytoplankton in the oceans. The animals that eat the salmon leave their droppings throughout the forest to further the cycle. Other animals, such as roe and red deer, will browse the trees and vegetation that have gained nutrients from the soil – in time, the deer too will rot and return to the soil.

What Scotland lacks now is trees and some keystone animals. Beavers have already been reintroduced to some parts of Scotland, making suitable habitats in which the salmon can thrive – and also contributing to flood management. As their population spreads, biodiversity will increase, the salmon and other wildlife will benefit, and carbon will be sequestered. Over the centuries, excessive numbers of deer – both red and roe – have impoverished Scottish landscapes by denuding it of trees because there are no apex predators. Maybe it’s time for the lynx to make a comeback. The story of river ecosystems is complex and more than I can do justice to here, but it’s crucial that we realise the complexity of the issue so that the healing can begin.

A burn rushes through a woodland.
The Coy Burn in the Crathes Estate

I have previously written about some of the Deeside projects that are helping (The mysteries of time). Salmon have already returned to the Beltie Burn, so just a short time can make a big difference, although the newly planted trees will take some years to provide shelter and summer temperatures will be critical. Crathes also has a role to play; that is why it is so important that the millpond restoration is done correctly. The Coy Burn, already well wooded, is one of many tributaries draining into the Dee and providing good habitat in which salmon and trout can breed. As the rivers and burns heal and the salmon return, it will not just be anglers and the tourism industry that benefit; it will be a restoration for the land and the whole Deeside ecosystem.

I recently read an interview with Peter Cairns, who is the co-founder of SCOTLAND: The Big Picture, the rewilding charity that made the Riverwoods film. Here is a quote from that interview:

‘Talk of loss has been the stock-in-trade of conservation communication for decades – it’s easy and can be evidenced, which makes conservationists comfortable. Hope is more nebulous but, equally, much more powerful. You have to tell the story of loss to provide a platform but if you want to enable change, hope is the key.’

Let us follow the hope.

Updates

  • Mike and Joanna have been on a course to enable them to enter garden plants onto the new database created for the PLANTS project (see Home and away). The PLANTS team are now back at Crathes for winter work to finalise their records. I find Nikki in the garden checking up on some deutzias. We look at some of the fruits of the blue sausage tree (Decaisnea fargesii). The seeds remind me of watermelons.
  • The Rose Garden contractors have finished and the wall has been re-built.

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