Monday, 17 March 2014

Buds are starting to break

The unfurling of buds is one of the most critical events on the wildlife year. Among the first to show its leaves is the elder, Sambucus nigra. 
Elder in early leaf. Byfield Pocket Park.
17 March, 2014

Despite the comments in my last blog (sorry about the dreadful pun) some elders are permitted to flourish and, indeed are welcome for their fruits, but their new leaves seem to attract no interest among browsers, miners or nibblers. This is hardly surprising as they are poisonous, containing some thoroughly unpleasant - and carcinogenic - glycosides. They thrive, uneaten, around rabbit burrows.

Hazel leaves start to unfurl in Byfield
Pocket Park  17 March, 2014

Hazel, Corylus avellana, also breaks into leaf quite early. It is generally part of the shrub layer in deciduous woodland and so perhaps needs to get on with the task of photosynthesis before the canopy of oak, etc, closes above it to drastically reduce the sunlight. John Clare made the point when he wrote:

     'Neath Oxeye Hazel bowers
     As near Hazels I have stood
     In the gloomy hanging wood,
     Whence the sunbeams filtering small
     Freckling through the branches fall.

                           Clare's Village Minstrel, 1821

Trees such as birch tend to occupy more open ground and therefore leaf-bud opening can be delayed. It is a beautiful tree but, as spring advances...

                                 ... the birchen bud doth spring
                                 That makes the schoolboy cry.

                                        Beaumont and Fletcher: "The Knight of the Burning Pestle"

As a schoolboy I frequently made painful contact with bamboo canes, wielded by practised hands, but not, as far as I can recall, with a birch stick!

Silver Birch in the burial ground adjacent
to the pocket park.
Byfield, 17 March, 2014
The Silver Birch, Betula pendula, is indeed, "a dainty lady"; it is one of two species of birch found in our county. The second one, the Downy Birch, Betula pubescens, is rather uncommon and confined to acidic soils; I have yet to find a specimen. 

The Silver Birch is the usual source for anyone wishing to make birch sap syrup. Holes are drilled into the bark and the sap is tapped off into a suitable container. Once home the sap is gently heated to drive off up to 80-90% of the water and the resultant syrup may be used on pancakes, etc. There is plenty of information on the internet including an article from The Guardian which first brought this interesting product to my attention.

It is an excellent tree for supporting wildlife, with over 300 species of insect making use of birches in the UK. Watch out for the Bronze Birch Borer, Agrilus anxius, a beetle which apparently also relishes the sap. It is a recent American invader, capable of causing great damage and is currently a matter of concern in Britain.

I will monitor the whole process (of bud-break, not syrup production) because, with tender leaves come hungry caterpillars and bugs. Bring them on! 


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