S & T - Ashridge - March 2015
Presentation on Trees and Woodlands
On
Wednesday, 25 March, the Science and Technology Group gathered at Erica’s house
to hear a presentation on trees and woodlands given by Peter Mills, a National
Trust Ranger at Ashridge Estate. Peter
explained that the park covers an area of approximately 5,000 acres, half of
which is woodland, whose structure can be described as ‘emergent’ (the tallest trees), underneath
which lies the canopy, then the under-canopy and, finally, the lowest shrub
layer. There are approximately 800
fallow deer in the park, a population that has been reduced significantly in
recent years due to culling. Around 400 deer is deemed to be a sustainable
number in the longer term.
Peter had brought along samples of tree types with their bark, as well as a deer pelt and a number of antlers found in the woodlands. He said that very few discarded antlers are found in the woodland because small mammals tend to eat them as a source of calcium.
In former times, the woodland was maintained for timber production (principally for the manufacture of furniture) but nowadays the National Trust manages it for conservation, education and access. Deer management in the woodland is particularly difficult because of public open access. A number of measures have been tried to prevent collisions between deer and cars on the roads but none has proved entirely satisfactory. It is not possible to fence the woodland entirely since it is ‘common land’.
With regard to the softwood plantations, the Corsican pines have not been faring too well. The acid soil layer on which they have been planted is quite shallow and once the roots reach the underlying alkaline chalk level, the trees start to perish. There is a plan to gradually remove the pines as they die back. On the other hand, although larch trees are prone to fungal infection, there is a reluctance to remove any of them because the firecrest has been seen to be nesting in them.
As a general principle, the Estate does not remove trees that have died and fallen naturally, unless they are a hazard to the roads or pathways. Dead trees are “full of life”, says Peter. Moreover, the felling of viable trees is only done to allow the surrounding vegetation to flourish – for example smaller trees struggling for light beneath a much larger tree. A method of preserving the health of the ‘emergent’ trees is “halo thinning”, i.e. cutting back the surrounding trees in successive 5 metre tranches to allow more air and light to penetrate. Coppicing of sweet chestnut trees is done by leaving the trunk to protrude approximately 1ft/2ft above ground, which promotes new growth around the base. The coppiced material is used for fencing posts. The Estate owns and operates a saw-mill, which cuts wood for fencing and fuel and employs three people to do the work.
A current project of the Estate is one of increasing the population of juniper trees. Apparently, the female of the species yields very few berries and it takes almost three years for them to germinate, so cuttings have been taken for propagation. However, it will be another four years before the fruits of these efforts will be fully realised.
The very rich wildlife of butterflies, plants, insects, meadow pippets and skylarks on Ivinghoe Beacon and Pitstone Hill was described.
Peter concluded his presentation with an overview of the work of the volunteers – up to 30 people at any one time, who work in teams to cut back scrub, burn unwanted material, erect rabbit-proof fencing, etc.
It was a most interesting talk given by an extremely knowledgeable Ranger. Doubtless we shall now wander through the woodlands at Ashridge with renewed interest.
Our thanks must go to Erica for her hospitality and for baking her delicious apple cake for us all.
Janet Cato
Peter had brought along samples of tree types with their bark, as well as a deer pelt and a number of antlers found in the woodlands. He said that very few discarded antlers are found in the woodland because small mammals tend to eat them as a source of calcium.
In former times, the woodland was maintained for timber production (principally for the manufacture of furniture) but nowadays the National Trust manages it for conservation, education and access. Deer management in the woodland is particularly difficult because of public open access. A number of measures have been tried to prevent collisions between deer and cars on the roads but none has proved entirely satisfactory. It is not possible to fence the woodland entirely since it is ‘common land’.
With regard to the softwood plantations, the Corsican pines have not been faring too well. The acid soil layer on which they have been planted is quite shallow and once the roots reach the underlying alkaline chalk level, the trees start to perish. There is a plan to gradually remove the pines as they die back. On the other hand, although larch trees are prone to fungal infection, there is a reluctance to remove any of them because the firecrest has been seen to be nesting in them.
As a general principle, the Estate does not remove trees that have died and fallen naturally, unless they are a hazard to the roads or pathways. Dead trees are “full of life”, says Peter. Moreover, the felling of viable trees is only done to allow the surrounding vegetation to flourish – for example smaller trees struggling for light beneath a much larger tree. A method of preserving the health of the ‘emergent’ trees is “halo thinning”, i.e. cutting back the surrounding trees in successive 5 metre tranches to allow more air and light to penetrate. Coppicing of sweet chestnut trees is done by leaving the trunk to protrude approximately 1ft/2ft above ground, which promotes new growth around the base. The coppiced material is used for fencing posts. The Estate owns and operates a saw-mill, which cuts wood for fencing and fuel and employs three people to do the work.
A current project of the Estate is one of increasing the population of juniper trees. Apparently, the female of the species yields very few berries and it takes almost three years for them to germinate, so cuttings have been taken for propagation. However, it will be another four years before the fruits of these efforts will be fully realised.
The very rich wildlife of butterflies, plants, insects, meadow pippets and skylarks on Ivinghoe Beacon and Pitstone Hill was described.
Peter concluded his presentation with an overview of the work of the volunteers – up to 30 people at any one time, who work in teams to cut back scrub, burn unwanted material, erect rabbit-proof fencing, etc.
It was a most interesting talk given by an extremely knowledgeable Ranger. Doubtless we shall now wander through the woodlands at Ashridge with renewed interest.
Our thanks must go to Erica for her hospitality and for baking her delicious apple cake for us all.
Janet Cato