OBJECTS IN TREES

As mentioned in my earlier post (Dec 6th), rooks are already building their nests.  They like to build together in rookeries.  You can tell ii it's a rookery by the noisy presence of rooks chatting away.  They used to prefer elms, and people worried when all the big elm trees were killed by Dutch Elm disease, that the rooks would have nowhere to go.  But they quickly adapted and can be found in all sorts of large trees: poplars, oaks, beeches, sycamores and even ash trees.  But ash too is destined to disappear from our landscapes with the progress of ash die-back disease.

A rookery

Another phenomenon, which is present all year but shows up more when the leaves are off is mistletoe.  Mature bunches of mistletoe are more or less  spherical, like large footballs.  Mistletoe grows on lime, robinia, poplar, apple, silver maple, and occasionally hawthorn, Norway maple and the druids' favourite - oak.  Here it is on poplar and lime.

  
Mistletoe in poplar and lime

There is a fungus that invades birch trees and causes a sudden eruption of short-lived shoots.  They die each winter and more shoots join them in the spring building a a spiky cluster known as a witch's broom. The tree can co-exist with the fungus for many years, developing more and more 'brooms'

Witch's brooms on birch

On willows some of the catkins occasionally go a bit wild and become a mass of frantic shoots like the witch's broom on birch.  These are mossy willow catkin galls.  Hiding amongst the leaves in summer they are easily missed . . . . . 

Photo: naturespot

. . . . but in winter they show up on the twigs.

Mossy willow catkin galls

All the black and white photos were taken in Thornbury.