‘Alder than the rest!’
I was reading a blog about Alder when it came to me that I had not expanded my work on our local Alder up the Gelt valley where I had lived since 1986. Yes I know there is only one species found in Britain but what I know of this Geltsdale area is that there are at least 3 types. There is the typical Alder found in river side growth. There is the Alder/Ash woodland also often found on flood plains. There is the Alder wood caused by ‘poaching’ the ground by cattle where a large number of suckers appear creating a thick woodland which will be invaded by Ash and other trees and then the ancient Alder found mainly in the Upper Gelt.
I sent a few pictures of these older trees to Murray who wrote the article and the question came back about ‘pollarding’. This is not a common feature of Alder as the timber is not so well used like Ash and certainly the bark is not eaten by cattle or sheep when cut and left on the ground like Ash. So then came the thought of ‘natural pollarding’. This seems a funny question but given the age of many of the Alder up stream it was worth investigating.
Not only were the trees worth looking at but the question of other trees actually growing on these old trunks was worth looking at. The picture that I had sent to Murray included an amazing tree from the New Water where a Rowan had grown up through the Alder but as rot had set in to the Alder the Rowan had fallen out of the tree down wards and then started growing back upwards again. This shows that the once roots can become stems/trunk in a very twisted way!
I started my search in Knotts Wood and Binney Banks moving to the New and Old Water where smaller areas of the trees are found with one named Hensay Wood in the New Water. Knotts Wood have some very old Alder and a recent ‘non grazing’ scheme has allowed many to regenerate from the base of the trunk showing grazing by sheep was removing this growth. Cattle now graze the area and some nibbling is taking place but few stems are effected.
One Alder outside the wood has a girth of over 5 meters and looks ‘pollarded’ but it may well be natural growth. A Rowan grows right through the middle of this tree. It looks like the tree has become a ‘sacred’ tree as bells and pictures of Hindu gods are found around the tree. This is amazing as the tree is well off the main track and can only be found by walking up the river side. In the wood itself many trees look as if they would have died out if there was not this reprieve from grazing. This is the last place to find Sessile Oaks with around 4 large stemmed trees. Both Ash and Woolly Birch are hanging on with no regeneration other than the planted Ash and Alder of the early 1990s by the once ‘East Cumbrian Countryside project’.
Here are a number of Crab Apples which have been planted with some large trees found in especially Binney Banks. A single Field Maple sits on a boundary bank here at Knotts Wood suggesting that stock was restricted in this wood hundreds of years ago. This tree is a rare tree this far north! The upper part of this wood is full of Hazel where the name of the wood came from which is a miss spelling of ‘nuts’! Here again large amounts of base trunk growth shows how the trees were grazed by sheep.
Binney Banks is yet another amazing wood with old Alder but areas of many old Birch. Natural Regeneration is non existent unless growing out of old Alder leaving more open areas than Knotts Wood. Many trees especially Birch have been removed for firewood once they fall down while the Alder have some growth from their base saving many from dying out. There are examples of Rowan which have kept growing years after the alder has disappeared. Rings of old roots now part of the trunk show that the trees once germinated in the Alder. One Rowan even shows ‘natural’ pollarding! There is one Birch that has fallen out of an Alder but Birch are rare as this type of regeneration . Birds must deposit the Rowan seed onto the Alder while Birch seed is wind blown and may have problems establishing on these often rotting trunks.
As you move upstream the number of Alder with Rowan growing inside them increase. In fact in the Old Water Wood there is evidence of a very large Alder which may even be the oldest in Britain. This tree has new growth from the base creating a width of around 20 metres which is 14 metres larger than the record in Britain. The difference being this new growth looks like individual trees not as one. Small leaved Limes are often found to represent the old trunk like this and are several hundred years old.
Two Rowan look short trees but again have the remains of dead Alder around them with pulp left over at the side of one tree in a very wet hollow. Here the % of Rowan in the Alder is as high as 80% while over in Hensay Wood in New Water 60% of the trees have Rowan growing out of them. The age of all this growth is very varied with young trees around 10 years up to trees that could be well over 100 years with them self pollarding.
Small numbers of Alder are found beyond Old Water Bridge but non seem to have any Rowan growing in them while no Alder grow beyond Hensay Wood in New Water. A single Grey Willow is growing in an Alder at New Water bridge next to the water works house. This is another wind blown seed and given the numbers blown from local trees you would expect more to develop this type of growth but like the Birch may be they have trouble germinating in such trees where Rowan has the extra advantage of semi digestion thinning their shell and a drop of fertilizer to start them off!
The conclusion of this work is that more work needs doing on aging these Alder and a ‘news letter’ sent out by the North Pennines AONB will ask for any other valleys in the area that might have such old Alder trees containing Rowan or other trees growing in them. With the removal of sheep from Geltsdale natural regeneration of Alder is starting to show especially along the river sides but may be Alder needs taking to the top of these waters so that when mature their seed also can colonies the river banks.
High numbers of Roe Deer are certainly preventing many Birch from regenerating with areas around Talkin Fell where I have seen new trees coming, have now been grazed off. Recent planting schemes in New Water in bracken are mainly Alder, Birch and Rowan so will increase the seed sauce. Hopefully the future for Geltsdale is going to be a better place for trees.