Its nearly three weeks since I last visited my oak tree – where has the time gone? Now signs of spring are well and truly in evidence, despite today’s cold.

Buds on the tree continue to swell and the scars left by last year’s leaves, when they fell, seem even more livid in the brighter light.

But it’s in the understorey than the difference is most apparent; the ground is now covered in a green haze.

At first glance this looks like a mat of bluebells, Hyacinthoides non-scriptus. The most precocious of these already have flower buds nestling in the centre of the rosette of leaves. Not long to wait now until the woodland floor is a sea of blue.

This year’s flower bud (left) and bluebells flowering in High Wood last May (right)

Bluebells are in a race against time with the trees above them – in order to have enough light to grow and reproduce successfully, they must complete their growth cycle before the leaf canopy is full. By the time the oak and beech trees in High Wood are at their June best, new bulbs will have been produced beneath the ground and the bluebell leaves will have died back for another season.

Of course the understorey is not all bluebells – I can already see wood sorrel, tiny cleavers, ferns and cow-wheat and there will be plenty more to come. The cow-wheat is another opportunistic plant; a hemiparasite, obtaining some of its nutrients from tree roots, rather than a holoparasite such as the Orobanche and Dodder we saw in Malta (see Parasitic plants), though it is from the family Orobanchaceae. Cow-wheat is a good indicator of ancient woodland; the seeds are dispersed by ants (myrmecochory), which take them to their nests to feed their young, but will rarely carry them more than a few metres. It is also an important food plant for the larvae of the rare Heath Fritillary butterfly though, sadly, this does not make it as far north as Durham.

Cow-wheat (Melampyrum pratense)

There is plenty of evidence of other woodland fauna though – two more barn owl pellets on the lump of rotting wood where we found one in January. These are much drier and more compact than the one we saw before and are clearly made up largely of fur.

Barn owl pellet

We also found a neat little wood mouse hole by the base of my oak which may explain why the barn owl likes to hang around here!

When I finally got the bottle we found in January cleaned up, I was in intrigued by the irregularities in the glass as much as I was delighted by its lovely turquoise colour.