Oak Tree decemation

[Matthew Arnold]

In one of the local FC woodlands the Oaks are being hammered by little green caterpillars. Last summer my dad and i noticed a large number of small white moths flying around the crowns. I did wonder if it was OPM but the caterpillars are hairless. The remaining leaves are dry and curled up. I havent got any pics yet but will do when in the woods next.

[sloth]

Green oak tortrix (Tortrix viridana)?

[Fungus]

Or Operophtera brumata ?

[Matthew Arnold]

Or Operophtera brumata ?

 

Looks like that and has completely defoliated most of the trees.

[charlie]

i believe oak trees produce a second flush of leaves called lammus leaves!?!

[Fungus]

i believe oak trees produce a second flush of leaves called lammus leaves!?!

 

Correct, in Dutch it's called St. John's leaves, after St. John's nameday, about the date of reappearing of the leaves.

Once the second flush of leaves appears, in The Netherlands often an infection of the young leaves with the anamorph of the aok mildew Microsphaera hypericacearum develops, which diminishes the fotosynthesis in the leaves by more then 30 %, resulting in further reduction of the energy reserves of the oak, which already were not fully produced and stored, because the first appearing leaves were completely lost.

[janey]

Looks like that and has completely defoliated most of the trees.

 

On the plus side, it should be a good year for fledglings down your way with all that extra food available.

[Matthew Arnold]

On the plus side, it should be a good year for fledglings down your way with all that extra food available.

 

Yep. Plenty of deadwood habitats in there for the woodpeckers and tree creepers to utilise. There is a big Oak that is slowly falling apart. I counted 5 species of bird using the various holes and cracks.

[Fungus]

On the plus side, it should be a good year for fledglings down your way with all that extra food available.

 

Janey,

Food being caterpillars, you mean the great and blue tits, not the woodpeckers and treecreepers, I presume ?

[Graham]

One of the great wonders is that tits time the hatching of their eggs to coincide with the first great flush of caterpillars.

Also the pupae hatch just on budburst as the old leaves contain too much tannin.

 

How do they all do that?

Edited May 8, 2011 by Graham
addition