The complicated sex life of the Knopper gall wasp

Almost three hundred species of insect are associated with the oak tree. And that doesn’t include over 400 species of mites. One of these is a tiny wasp, Andricus quercuscalicis, which lays its eggs in the Spring in the buds of our native oak tree. This results in a woody growth or gall being formed between the acorn and its cup. This gall resembles the knobbled German hat that was in fashion in the 17th century called a knoppe hence its name the knopper gall. The galls are just turning brown and hard and will soon drop in the Autumn gales to the woodland floor. In the Spring a tiny female wasp will emerge and fly off to find  a different species of oak, the Turkey oak, where it will lay her eggs on the male catkins. These eggs will produce wasps of both sexes and it is their eggs that will be laid in the buds of the native oak to restart the cycle.

Turkey oaks are an 18th century reintroduction into Britain. They were in fact present before the last ice age. The Knopper gall wasp first made its appearance in the 1960s and is considered a threat to the fertility of our native oaks.

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Oak Leaves

I was watching Springwatch last night and I’m sure I heard Chris P say that there are between 750,000 and 1,000,000 leaves on an oak tree. Mental calculations whilst walking in Cliff Ridge Wood tonight justified that figure. Ten leaves on a spring, ten sprigs on a branch the thickness of a pencil, ten branches the thickness of a pencil on one the thickness of a finger and so on.  A bit crude but hey …

But Google says a different figure for an average oak tree, 250,000.  Who to believe?

What is certain is that the oak is the tree or shrub which has the greatest number of insect species associated with it – 284. Plus 139 species of mites and 324 lichen.

The oak has been long associated with the gods of many religions. Thor (Norse), Zeus (Greek), Jupiter (Roman) and Dagda (Celtic). The Druids sacrificed white bulls beneath the canopy of oak trees.

May Blossom

In Nottingham in the early 60s I remember me mam saying “naer cast a clout till May is out” to me when I tried to go out in the Spring without my duffle coat or string vest. I thought, and I think me mam thought too, that “may” referred to the month of May but it really means the blossom of the May tree, one of many names for the Hawthorn. Other names are Whitethorn, Thornapple and Hawberry as well as the Faerie Tree since fairies live close by.

Indeed Hawthorn is steeped in folklore, being frequently associated with bad luck. To bring it into the house is sure to incur illness and death and a wedding while the May is blossoming does not bode well. This association with misfortune may be because Hawthorn was supposedly used for Jesus’s crown of thorns.

On the positive side 149 species of insect have been recorded as being supported by Hawthorn and the berries, the haws, are a rich source of food for birds. The tree can be very long lived with 700 year old specimens recorded.

Bluebells, Cliff Ridge Wood

Ever since seeing the first blue buds appear three or four weeks ago I have been waiting patiently for the purple haze. I feel sure the bluebells in Newton and Cliff Riidge Woods are late this year. Maybe the recent cold spell has set them back a bit. At least when it does come it will be free, not like at Ashridge, another of National Trust’s many properties where you now have to pay to view the spectacular blue carpets.

The reason the National Trust have given for introducing the charge is to pay for extra rangers because the “bluebells are being trampled and the ground is being compacted”. They are a pretty sight but we must remember that great swathes of bluebells are not really a natural sight. Bluebells have evolved to withstand trampling and grazing by large herbivores such aurochs, elk and red deer. The large carpets that are common today are the result of removal of these animals so it could be argued that a bluebell wood is what the scientists call a plagioclimax habitat. That is an ecosystem in which the influence of the humans prevents it from developing further. But then there are not many habitats which are not influenced by man.

It is a common belief amongst gardeners that deer do not eat Bluebells but research by the Forestry Commission has shown that deer do in fact have an impact on woodland biodiversity with tree and understorey species both being vulnerable to browsing including bluebells. Muntjac deer, themselves an introduced species,  have a particular predilection for the little blue flowers.

Bluebells are a species of deciduous woodland, blooming early before the tree canopy shades out the wood floor. Two species are found in the British Isles. The Common Bluebell is native whereas the paler Spanish Bluebell is an introduced species. The two hybridise readily and produce fertile offspring leaving our native Common Bluebell at risk. For this reason it is protected a  under the Wildlife and Countryside Act 1981 making it a criminal offence to remove any wild bulbs.

In folk medicine the bulbs of bluebells have been used as a diuretic or styptic to stop bleeding and as a remedy for leucorrhoea.

Aerial Ropeway Bases, Cliff Rigg Wood

Among the leaf litter of beech trees, two concrete bases that supported one of the steel towers for an aerial ropeway that ran from Ayton Bank Ironstone Mine to sidings at the west end of Cliff Ridge where the ore was loaded into railway trucks. There is actually a third base which has been buried by the slope. The holding down bolt can just be seen poking out of the leaf litter (a bit of a trip hazard).

The mine and ropeway was operated by the Tees Furnace Company which also operated the Roseberry Ironstone Mine. The ropeway was short lived, in use from 1913 to 1921. it was built by the Aerial Ropeways Ltd. of London. In the booklet “Mineral Tramways of Great Ayton” by R. Pepper and R. J. Stewart, 1994, (which is still available on Amazon) there is a advertisement photo from 1920 which is believed to be of the Ayton ropeway. Unfortunately I can not find a copy on line.

Cliff Ridge Wood

It’s amazing how a bit of overnight snow transforms an otherwise mundane scene. This is Cliff Ridge Wood on the National Trust’s Roseberry Property.

Geggamoja

The north of North Yorkshire has got off fairly lightly with the recent floods but the month of incessant rain is taking its toll. All footpaths are heavy going as the racecourse stewards would say. This is a footpath through Cliff Rigg Wood, a National Trust property. It is typical and very hard work. I’m almost tempted to go on the roads as a respite.

I always think of a Swedish word when I’m wading through mud: Geggamoja. Such a lovely word. Gegga  is the proper word (which Google translates as “goo”), the moja suffix makes it child friendly. I guess it’s a bit like referring to a horse as horsey.

And if you should get stuck you could always sing the Flanders and Swann song:

Mud, Mud, glorious mud
Nothing quite like it for cooling the blood!
So follow me, follow
Down to the hollow
And there let us wallow
In glorious mud