In The Walks you can see an exceptional display of Mistletoe (Viscum album). It seems to grow mainly in the lime trees, although you can also see it in poplar, willow, maple and sorbus trees and traditionally it has been associated with apple orchards – mainly in the west of England. Nowadays it appears to be spreading across the UK and is becoming common in East Anglia.
One reason may be warmer wetter winters, but there may be other reasons. Mistletoe is generally spread by birds who eat the berries. Two key species are the Mistle Thrush (which, although numbers have been declining nationally, are resident in Lynn) and Blackcap (whose numbers have risen greatly in recent years). Additionally, Blackcaps used to migrate south in winter, but nowadays seem to be happy to reside here all year.
Mistletoe is a ‘hemi-parasitic’ plant – which means it uses photosynthesis to feed itself, but also draws water and nutrients from the host tree. Generally, there appears to be a happy balance in this relationship.
However, there is now some evidence that warm, wet winters are allowing Mistletoe to grow unchecked to the extent that it can weaken or kill the host. Apple farmers in Herefordshire have been reporting this, although other factors may also be at work. (Tree species can be stressed by drought summers or wet winters, but perhaps Mistletoe is coping better with these changes?) Heavy Mistletoe growth may also lead to trees being physically damaged in wind.
There is certainly evidence that the lime trees with mistletoe along Tennyson Avenue are declining in health and may need replacing in coming years.