Observatree Visit to Shibden Hall Park

On an exceptionally hot and unseasonal spring morning the Observatree North of England volunteer group organised a visit to the picturesque park and ornamental gardens of Shibden Hall on the outskirts of Halifax.  The half-timbered hall dates to 1420 and is probably most famous for the diarist Anne Lister, better known as ‘Gentleman Jack’.  The park around the hall is a mixture of formal gardens and informal wooded pleasure grounds set around a lake which were laid out in the 1830s by Ann Lister.  The park was purchased by the local authority in the 1920s and has since been open to the public.

Although the weather tricked us into thinking it was midsummer, the foliage of the broadleaf trees reminded us we were still start of spring. We saw a number of interesting trees, trees with health issues and pest and diseases.

Walkabout

After meeting at the park café at 10.30am, we set off on a circular walk of the park to take in as many different types of planting as possible. The gentle stroll uphill towards the Hall was spent discussing the extent of soil erosion on tree root formation, the successful establishment of both self-seeded and planted beeches and identifying specimen planting around a long defunct ornamental waterfall.  After walking around the ramparts which surround the Hall, we set off back down towards the lake where we surveyed the condition of some of the more interesting species and more recent planting. Two examples stand out - a mature Acer, most likely A. amoenum or A. cappadocicum ‘Rubrum’, which had presumably once been a pair flanking the path to the Hall from the main road. North of this was the remnants of a line of flowering cherry trees and what can best be described as ‘randomised’ planting, including a handkerchief tree (Davidia involucrata). In the strong sunlight, the fruit/seed pods were far more obvious than the flowers and it wasn’t until we were virtually under the tree that we were able to confidently identify it. There were quite a number of other planting oddities spread across what we assumed to be a former miniature golf course that appears to be taking on a new role as an impromptu arboretum.

Tree Health issues

We agreed that whilst most of the mature trees looked to be in good condition, many (the majority perhaps?) of the substantial number of new trees which had been planted were ailing. A large number could best be described as being the ‘wrong tree in the wrong place’, i.e., in sites that were too windy, too dry, too damp, with no mulching and no tree guards. Most were planted into long grass which was outcompeting the tree roots and those that didn’t were near universally suffering from the dreaded mower damage to their lower trunks. The young trees of Shibden Park have had a hard start to life for sure!

Amongst the wide-ranging environmental damage described above, we saw two especially weird growth forms. One was in a common beech (Fagus sylvatica L.) - pictured opposite - and an ornamental Whitebeam (Sorbus Aria ‘Lutescens’) alongside the Red Beck which flows parallel to the lake at the bottom of the valley. Both trees showed similar epicormic proliferation at the main union which is uncommon in beech and unusual (or rare?) in whitebeam, certainly we had not seen this before. In addition, the whitebeam showed prolific root suckering in all directions - it was not grafting root stock as the leaf was true to the principal tree. There were no bleeds evident, but there was cankering on the whitebeam. Both trees suffered from some serious compaction and erosion over the majority of their root plates, and we are sure this has somehow played a part in predisposing the trees to further infection or injury.

Pests and Diseases

Across the park, there had been a number of relatively recent plantings of Mountain Ash (Sorbus aucuparia) that had broken into foliage, and a couple were even in full flower already. On one of these, we found the characteristic symptoms of European Mountain Ash Ring Spot Associated Virus which is an Observatree Priority Pest.  Although early in the year, the characteristic yellow mottling could be seen in addition to the early symptoms of Eriophyid Mites characterised by the light-coloured swellings on the underside of the leaf.  In the Northern Region, symptoms of this virus would not normally be seen till later on in May, but the warm weather has accelerated the flush of the foliage.

Other unidentified ‘leaf-rolling’ insects were seen on at least two other Rowans in the same area, the leaflets being deformed into neat rosettes to protect the feeding ‘critters’.

We also saw a few trees with ‘bleed-like’ symptoms, not surprisingly on Horse Chestnut where this is quite a common occurrence. This is caused by either bacterial or fungal-like pathogens, but even the worst affected tree looked in reasonably good health overall. 

There was a noticeably oozing bleed on a rather sickly-looking Bird Cherry (Prunus padus). It appeared as though damage may have entered through a side branch that had been pruned incorrectly/incorrectly timed.

The result was the formation of a deep-seated canker leading to dieback and epicormic shoot growth lower down the trunk in response to the damage.

Other examples of trees that took our interest included a single oak by the lake with historic bleed spots. At first these were difficult to see, but after carefully checking around the tree, it was quite clear that there had been at least half a dozen in recent years. There were also various cracks and growth adaptations throughout the trunk and major branches. There did not appear to be any exit holes of any shape or size and it was concluded that the bleeds were probably the result of some kind of fungal or environmental stressor.

A final check along the beck side resulted in no signs of Phythophthora sp., despite being lined quite densely in places with Rhododendron ponticum with canopies trailing in the water.  

After a cup of tea back at the café, we agreed that all in all, we had had a very interesting morning in Halifax and we look forward to meeting up again to visit new sites within the region, share our knowledge and to continue to develop our tree identification and pest and disease recognition skills.