BrownhillsBob's #365daysofbiking

On a bike, riding somewhere. Every day, rain or shine.

Posts tagged ‘oak’

#365daysofbiking A good crop

August 17th – With my fascination with galls, it’s easy to overlook the fruiting of the oaks as it should be, and I’m happy to report this year that the crop of acorns – even though it’s been hit very heavily by knopper gall wasps – is plump and profuse.

The heathy acorns I’ll later gather to spread in hedgerows and on edge lands as is my tradition look better this year than they have for years. I guess a warm but wet season was good for them, if not so much for me.

I always have a dilemma here though: I can collect acorns solely from trees unaffected by knoppers, and assume they have so resistance, but in spreading solely those am I harming the wasp ecology? I suppose I should just spread any acorns I find, but it’s an interesting conundrum…

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#365daysofbiking From tiny acorns grow


August 1st – The various varieties of wasp gall that form on oak trees are necessarily seasonal. Rosy, marble and apple galls form from wasp eggs injected into leaf notes, so grown from them in spring and early summer, and by now are largely vacated and spent.

Knopper and artichoke galls form from eggs laid in acorn buds, corrupting the fruit into a gall from the crop, so don’t start appearing until late summer. Right now they’re developing well, forming a protective, curiously shaped home for the wasp larva to hatch in and develop.

Galls are fascinating things for sure, and are markers of the passing year.

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#365daysofbiking From little acorns

July 15th – More galls: I mentioned knopper galls recently and pointed out these wasp galls deform acorn buds to form a home for the wasp larva within. I found an illustration of this in Victoria Park Darlaston.

This is a knapper gall starting to form. The acorn cap is normal, but where the smooth, rounded nascent acorn should be, there is a knobbly, textured growth which will expand to form the gall.

The DNA of the acorn has literally been corrupted or reformed to grow a home for the wasp egg within by a chemical the egg was coated with.

How does such a mechanism evolve? It’s truly wonderful.

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#365daysofbiking Flown

July 8th – The galls that formed on the oak trees in spring that looked like rosy apples have now served their purpose and are dead, their bodies spongy and containing many holes where the wasps that grew from larvae within ate their way out to freedom and maturity.

Galls fascinate me: Corruptions of the tree’s buds by a parasitic, tiny wasp, they grow as host to the wasp’s offspring and take many forms.

These expired galls signal the passing of the season and soon we’ll start seeing knapper and artichoke galls which form on acorn buts, but have the same genesis.

Parasites are fascinating.

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#365daysofbiking Long live the King!

April 15th – At the end of February, I was sure I would never see this fine gentleman again, for it seemed the flat where Sam, the elderly, toothless and thoroughly grumpy Kings Hill Park cat lived had been vacated.

I was heartbroken, and wished him well in this post.

I needn’t have worried. I spotted the old grump a couple of weeks ago in the bay window of the flat BELOW the one being refurbished, snoozing as one would expect. I obviously couldn’t take a picture, but was so relieved this venerable old lad was not gone – after all, his sleeping habits last summer entertained me on many a day and I’d become, well, somewhat attached to him.

I finally found him today in the roadside garden of the flats complex where he lives. He’s thinner, but his coat has a beautiful gloss and his wonky eyes were bright and keen. His whiskers were immaculate and Sam clearly is reclaiming his place as monarch of the Kings Hill summer.

I think he might have remembered me, or perhaps not. But I’m glad though that this old cat can sleep, hopefully undisturbed – through another warm, peaceful summer dreaming of his kittenhood and youthful exploits.

A fine lad whose return I am very glad to see.

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#365daysofbiking Welcome snowflakes

April 4th – A break in the rain, and I made a dash for it, mostly avoiding getting too wet, but oh my goodness it was cold.

Not cold enough for snow, though.

Warm enough for spring snowflakes, as I found this clump growing and flowering beautifully at Sandhills. Gorgeous white flowers with delicate green tipped petals, snowflakes look a lot like snowdrops, but are bigger and bushier and flower later.

A real treat on an awful day.

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#365daysofbiking Unshed

February 4th – I’ve always been puzzled why it might be that some deciduous trees don’t shed their dead leaves in autumn; the summer growth dies and goes brown, but doesn’t drop.

Someone asked the same question on social media over the weekend, so I thought I’d look into it.

The characteristic is called marcescence, and is exhibited mainly by oak, beech and hornbeam in the UK. It’s not clear what the evolutionary purpose of this curious feature is; it could be to shelter leaf buds from browsing animals like deer, and indeed, some oaks are only marcescent on lower boughs. Another theory says that the leaves attached to the beaches have their goodness absorbed back into the tree over winter, which is more efficient than them dropping and relying on conversion from leaf litter.

So I’m not really much wiser, but at least it has a name – and this marcescant oak was showing it’s dead leaves well beside the cycleway in Telford as I passed this morning, making me smile.

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August 23rd – I don’t know what it is in the season, but the acorns this year are prolific and absolutely huge. With the dry summer I’d have expected the opposite, but they are absolutely huge. 

The fecundity of the crop is, however, being affected by the large amount of knopper galls, that from from acorns attacked by the knopper wasp. Also a peculiar seasonal phenomenon, they are very,. very red this year, whereas it’s usually just tinges of colour. 

Wonder why?

August 13th – At Hortonwood in Telford, I found a small wayside oak sapling, which was growing round, large acorns. they were generally healthy and surprisingly large, with only a handful affected by knapper galls – and where they were, the actual effect of the acorn remained small.

The ants were clearly interested in the acorns, but I have no idea why, and I’m wondering if the low gall-count and manner of development is maybe signifying and evolved defence to these parasites.

Certainly is fascinating. Going to be a good crop of acorns this year I think, and a bumper hedgerow harvest generally from what I can see so far.

July 25th – These oak knopper galls actually took me by surprise a couple of days ago, but the photos I took weren’t great, so I revisited the saplings they’re growing on today.

I spotted them on a tree near Victoria Park in Darlaston and I don’t think there’s a single normally formed acorn on that tree at all, and yet several adjacent ones have no knoppers at all.

These mutations of normal acorns are of course caused by a tiny wasp that lays eggs in the acorn buds earlier in the year. A secretion the eggs are coated in causes the acorn bud to mutate and grow in a distorted form, forming a gall, with the wasp egg at the centre. 

The larva hatches, and eats it’s way out of the gall, which provides it enough nourishment to grow to maturity.

Insect galls like this don’t hurt the tree, but of course, do affect it’s fecundity.

Isn’t nature amazing?