treeblog Set D: collection and pre-pretreatment of rowan seeds

Looking into the canopy of the Whitwell Moor rowan. [Photo: 12 Sep. ‘09]

On Saturday the 12th of September I went for a late summer’s wander with my father. The weather was beautiful, the scenery was stunning, and our route just happened to pass by a couple of special trees: two rowans from which we collected berries to plant for treeblog’s Set D, one on Whitwell Moor and one overlooking Oaken Clough high up in the Ewden Valley.

Berries on the Whitwell Moor rowan. [Photo: 12 Sep. ‘09]

I previously collected berries from the Whitwell Moor rowan in autumn 2008 which I planted as part of treeblog Set C this spring (along with berries from another rowan, downy birch seeds, and sweet chestnuts), then replanted as Set C-r on the 12th of May. None of those seeds have germinated to date, presumably because I never pretreated them before planting them - something I didn’t realise was necessary. Without the pretreatment they still ought to germinate, but a whole year later rather than in the same year like I expected. So treeblog is expecting rowans from both Set C and Set D to germinate in spring 2010!

The Whitwell Moor rowan on the day of my Set D berry collection: the 12th of September 2009.

I discovered the Oaken Clough rowan this summer on the 18th of July. When I first lay peepers on it I knew that it had the biggest girth of any rowan I’d ever seen. I measured it on the berry run: 3.4 m (11 ft 2 in.) in circumference at about shin height. That gives a diameter of 1.1 m (3 ft 7 in.). These figures might not sound very impressive, but for a rowan they are well impressive. Unfortunately, this monster of a rowan has suffered a catastrophic collapse. Most of the collapsed boughs nevertheless remain alive, and since this incident the tree has put out a lot of new growth. There’s no reason why it shouldn’t keep on going for many years to come.

The Oaken Clough rowan. Massive yet collapsed. [Photo: 18 Jul. ‘09]

After I’d picked my berries, I sort of forgot about them for a couple of weeks. I just couldn’t stomach the upcoming task…

The Oaken Clough rowan berries. The black ones have gone bad. [Photo: 20 Sep. ‘09].

Then last week I got around to removing the seeds from the berries. This was a long, time-consuming process. I estimate it took me four or five hours, and that was only working with about half of the berries! The other half had gone rotten because I’d waited so long to act. I should have removed all of the seeds when the berries were fresh, but then ten hours of seed extraction would have sent me pathologically insane. Whatever, the outcome is I have plenty of seeds.

The Whitwell Moor rowan berries. [Photo: 20 Sep. ‘09].

This afternoon I removed any bits of husk still attached to the seeds. How nice and clean they look!

The clean extracted rowan seeds earlier today. The Oaken Clough rowan’s seeds appear to be slightly larger than those of the Whitwell Moor rowan.

Right. Now the seeds are all ready for pretreatment. To improve my chances of Set D success, I’ll be trying out not one, not two, but three methods of pretreatment. My two piles of seeds will be split into thirds, and each pair of thirds will undergo a different method of pretreatment. These methods are laid out in a Forestry Commission practice guide, and an upcoming post will detail what they are. The pretreatment has actually already begun for one pair of thirds: they are currently being soaked for 48 hours to rinse off any germination-inhibiting chemicals!

N.B. As each of the three Set D species are being planted on different days, I’m going to describe the rowans as belonging to Set D-r, the beeches – which were planted on Wednesday - as belonging to Set D-b, and the sweet chestnuts – which I have yet to collect – as belonging to Set D-c. That’s just to make things easier when I say blah blah blah Set D-r, Day XX.


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The fortieth edition of the Festival of the Trees is over at local ecologist. Go read!


Posted in Gone for a walk + The treeblog trees










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