American giants and English oaks

It was a glorious day at the end of 2021 and unusually mild – 12 degrees Celsius. The car park was almost full and families were making the most of the erratic weather walking those trails that had reopened after the storms. A bad back had prevented me from stravaiging about in the usual way and I had not ventured further than the walled garden for some weeks. On this day my aim was to check on the specimen trees that grow around the castle. I had heard that the old walnut tree had gone in the gales. I had seen from the carpark that the giant sequoia and the massive Douglas fir to the north of the castle were still standing, but that the sequoia looked a bit sparse on one side.  Passing by the sequoia I saw the mighty branch that had fallen from the tree. Roughly twelve metres long, it lay on the ground looking like a tree trunk itself. It impressed on me just how big the tree is – and just a youngster compared to those that grow in North America. The branch had annihilated a lovely dogwood, Cornus kousa, splitting the dogwood down the middle as it rocketed to the ground.  

The native range of the giant sequoia, Sequoiadendron giganteum, is limited to groves on the western slopes of the Sierra Nevada in California – the groves extending to about 28,000 acres. One particular tree, known as General Sherman, is the most massive non-clonal tree on the planet, its bulk easily surpassing that of a blue whale.* General Sherman is thought to be over 2,000 years old.** Such enormous trees sequester huge amounts of carbon. Despite the fact that the wood is not of good quality, a history of logging and clearing has diminished these groves so that there is now real concern about their future.  Giant sequoias have evolved to benefit from moderate fires: the spongy bark can cope with a certain amount of heat; occasional fires burn off excessive debris, reducing fuel that might cause more intensive fires and producing small clearings for regeneration; the heat helps to open the cones so that the seeds can be released to germinate in the newly created ash that fertilises the forest floor. However, with the recent extreme weather events of the last two years severe fires have killed many trees and their seeds.  Increased erosion and drought has contributed to the environmental damage thus decreasing the likelihood of natural regeneration.

The giant sequoia quite likes the Scottish climate – the tallest in the UK is to be found at Benmore (RBGE) where the high rainfall suits it well. In the UK the trees were known as Wellingtonias; in the USA as Washingtonias. They first came to Britain in 1853 and there is some evidence to suggest that Crathes and other Deeside estates were among the first recipients.*** Many of those early plantings are still standing – sequoias rarely blow over because of their buttress shaped trunks, but the shedding of side branches can be dangerous.

Robert, son of the 10^th baronet of Leys, was sheep-ranching in California following the gold rush and the opening up of the West. In 1859 he sent a parcel to Crathes that contained the seeds of thirteen different American conifers; these seeds were to make dramatic changes to the landscape of the estate.

As I approach the conifer glade I can see that it has not suffered too much damage, but to the north of the glade is a row of four ancient oaks and one lies sprawled across the ground. These four oaks are of the species Quercus robur, the pedunculate or English oak – so called because it is commoner in southern parts of the British Isles. It was usual to plant the pedunculate oak on Scottish estates. It is easy to identify if you can find the acorns which have long stalks as opposed to those of the sessile oak, Quercus petraea. The sessile oak also grows at Crathes and the two species are known to hybridise. Both species are excellent for biodiversity, providing a habitat for hundreds of different species. A tree survey estimates that at least two of these four oaks date to the eighteenth century and they appear to be individually depicted on the 1^st Ordnance Survey 25 inch to the mile map of Crathes (surveyed 1864-5 and published 1866).  

Surveying the damage, I took time to take it in pondering on the amount of wood that lay about whilst remembering that all the twigs and smaller branches had already been removed. Three hundred years or more of living. A couple of wrens chirruped about the fallen wood. Oddly the fourth oak in the row, which looks more than half dead, is still standing. If you look carefully at the 2013 photograph you can just see the beefsteak fungus, Fistulina hepatica, at its base. This fungus causes brown rot in the tree – sometimes attractive for furniture makers.

I wondered what it might have been like on the night of the storm for those living on the estate. Andy says he could feel his house vibrating as the wind took its toll. James had been away and arrived home in the middle of the storm likening it to entering a war zone. He was unable to use the main drive due to fallen trees. He managed to get up Butler’s Avenue before the beech fell, but could see that the walnut had fallen. He was scared to look on the following day and there was much to think about, but he and Davy had to concentrate on clearing the roads for access. He says it took him fully two or three days to digest the extent of the damage. On reflection he says: ‘I am very reassured and proud of the Crathes team’s abilities and response in the clear up operation given the level of destruction. The Brodie team were also excellent and saved us many weeks work with their generous help. For me this underlines the importance for the NTS of ensuring the investment in these specialist skills within the organisation, not to mention the huge financial savings.’  

In the 2013 photograph of the four oaks you can see the stump of the Lawson’s cypress, Chamaecyparis lawsoniana. This tree was one of the most successful of Robert’s seeds. An annotation on Robert’s list records that 42 were ‘very fine’. Because Lawson’s cypress was only introduced to Britain in 1854 no-one would have known either how to grow it or what to expect of the mature tree. Hundreds of cultivars have been developed from the Lawson’s cypress, many of them dwarf forms that are now popular in small gardens. It is likely that the Lawson’s cypress represented by the stump was one of those 1859 seeds sent from California. It was planted at the entrance to the glade, but got damaged in another earlier gale. There is a replacement tree, but it will be many years before it looks proportionate to its opposite number – the western red cedar.

But the western red cedar, Thuja plicata, is not a cedar at all; it is a cypress and looks very similar to Lawson’s cypress, though it smells more fruity, perhaps of pineapple. This entrance glade specimen has produced a small grove of trees by natural layering. This restricts the height of the mother. As I notice that one of the younger trees in the group has been damaged a small child runs by calling to her friend that it is her favourite tree. The curved layering branches make wonderful places for children to play.

The first American giant to come to Crathes was the Douglas fir, Pseudotsuga menziesii, which had been discovered by Archibald Menzies and introduced by David Douglas in 1827. It has been planted extensively on Deeside for its impressive growth and valuable wood. There are quite a number at Crathes that must date from the 1850s or earlier. I was relieved to see that all of the major Douglas firs on the main drive and in the conifer glade are still standing. The noble fir, Abies procera, probably another of Robert’s trees, is also standing proud.

I had seen from the drive that there were pockets of blown trees in different parts of the estate and as I walked beyond the conifer glade I saw more individuals blown over. One fine oak tree had landed in the leaf mould heap.

Another day I looked around the viewpoint, admiring the young monkey puzzle and a lovely yellow witch hazel. Despite the mild weather, the Daphne bholua ‘Jacqueline Postill’ is not yet in flower, but the buds are ready to burst and will be making a fine show in the coming weeks. It was definitely flowering by mid-January in 2019. A red squirrel scurrying up a nearby tree made the day extra special. Red squirrels are fairly common at Crathes but they never fail to brighten up the day.

A new year, a new beginning? Well hardly; plenty of unfinished work due to the storms. There are, however, new and exciting projects ahead. Andy and volunteers, Alyson and Sheila, have been removing viburnums from the Rose Garden in preparation for the new design. A piece of the viburnum has been retained for replanting elsewhere. The Rose Garden project, funded by a generous benefactor, has been in the planning for some time; watch this space!

Updates

Work has been going on in the Millpond. Working with the Dee Fisheries Trust, the pond is being surveyed prior to installation of new sluices. This will entail draining the pond for a short length of time.

James and Steve have been working on the drain by the entrance building.

Joanna has been cleaning and painting in the glasshouses.

Almost all the trails are now open, but expect some diversions.

*Some trees, like aspens, will sucker so that a whole wood may be the same organism. Giant sequoias sometimes layer but generally have a single trunk.

**Archangel Ancient Tree Archive is a good source of information.

***Bennett, Susan, The Gardens and Landscape of Crathes Castle (2019) for more information about the American conifers and their introduction to Crathes and Deeside.