Woodlands Historic Woodlands After the last Ice Age, some 10,000 years ago, the floor of the Lea Valley was undoubtedly covered in marshy woodland. However, early human settlers would soon have discovered that the rich soils, moderate climate and plentiful supply of wood and water made the valley sides a good place to live. The woodland of the valley floor would steadily have been cleared and replaced for the most part by meadows and marshes. The area was kept open by hay cutting and grazing by cattle, horses and sheep. River Lea The river rises in Luton at Leagrave and runs about 50miles to the Thames. Rather than follow a single deep channel, the river would have been made up of a number of different channels that constantly changed their route over the years. During the wet months of the year there would be regular flooding. Although the nutrients in the silt that was washed down with the floodwater maintained the richness, ditches were dug to ensure that the water was able to drain off as soon as the river level dropped. This flooding continued to be a feature of the valley, particularly the area around Waltham Abbey, right up to the middle of the twentieth century. Development of the Woodland In the 18th century the northern parts of the site that were not then being used in connection with gunpowder manufacture were densely planted with Alder, Crack Willow and Alder Buckthorn. Once they became established, these were regularly coppiced ( cut back to just above ground level every 15 years or so) over a period of 150 years to make high quality charcoal -one of the principal ingredient of gunpowder. Coppicing stopped more than 50 years ago and the trees have now grown up and matured into woodland with a high canopy. The woodland comprises an area of nearly 120 acres, most of which is designated by English Nature as a Site of Special Scientific Importance (SSSI). The new woodland management plan proposes that about a fifth of the woodland will be brought back into a coppice regime. One of the first (experimental) areas to be re-cut is behind the Moulding House. Despite their considerable size the trees have responded reasonably well and are sending out new growth from the stumps. We are, therefore, confident to proceed with further coppicing as and when resources permit. Other trees on the site that are worthy of note are Sycamore, Poplar hybrids, Walnut, Ash and Alder. Trees on Site Alder - These are the bulk of the trees on the site. Despite being broad-leafed these trees bear small cones. The leaves are unusual in that they are either rounded or have a notch at the tip. The leaves, twigs and bark are unpalatable with the result that unlike many other trees and shrubs they are not eaten by deer or rabbits. They regenerate very easily from seed in damp, open conditions, as can be seen around the acid factory and the corning mill. They naturally occur in damp conditions, but there is a disease called Phytophthora or Alder Blight that is spreading across the country and occurs on the site. This seems to particularly affect trees with their roots actually in water. This disease, which is invariably fatal to the tree, is closely related to that (Potato Blight) which caused the Great Irish Famines. The retention of such a large area of alder trees is, therefore, of great importance. Alder Buckthorn - This large shrub (which is not related to Alder!) is also known as 'Black Dogwood' (although it is not botanically a Dogwood either!). It used to grow more extensively on the site and often grows in the same sort of area as Alder, but as the other trees grew up it was shaded out. A large block has now been replanted on the east side of the Burning Ground. Apart from needing plenty of light, it is susceptible to browsing and during its early life needs to be protected with a tree-guard. It is the principal food plant of the caterpillars of the Brimstone butterfly. Its charcoal was much sought after as an ingredient for gunpowder and for making fuses, because of its even, slow-burning properties. Ash - This tall fast growing tree with widely spaced branches, has an upright, open character that casts only a little shade beneath it. Like the Walnut the leaf is made up of a central stalk with 6 or more separate leaflets each side. All these leaflets are more or less the same size and have long tips. The bark is pale fawny-grey, or the colour of Ash, and splits into vertical cracks. The black buds stand out against the pale bark and are very noticeable at any time of year. The fruit form in bunches about 6in across, which hang at intervals along the branches. Each fruit is a single seed with a wing that helps it fall away from the parent tree. Vast numbers of seeds are produced each year. The young growth of this tree is palatable to browsing animals, and further spread of it is like to be controlled by the deer. So far as we know this light but strong wood was not used for the production of charcoal at WARGM. It seems to have been self-sown early in the 20th century and specimens occur allover the site. Crack Willow - This tree gets its name from the brittle nature of the twigs. The charcoal made from the tree is conversely far from brittle and is much prized by artists as well as in the manufacture of gunpowder. The tree grows by the waterside and has long narrow leaves, but the branches are not pendulous like Weeping Willow. Because the new growth is very palatable to browsing animals it is usually pollarded (i.e. similar to coppicing but cut about 7 feet above the ground). The prefix 'H' on buildings refers to the name Hoppet, which was an area where Crack Willow was grown. A remnant of this plantation survives in the area to the north of the car park, and there are numerous other specimens around the site. Those most easily seen are to the right hand side of the track by the southern part of the acid factory .A block has been planted on the west side of the Burning Ground. Elder - Commonly called the elderberry this is often shrub-Iike but on suitable ground it can reach gm. It grows vigorously, especially where the nitrogen content of soil is high. Typically, it colonises abandoned dwellings and can be seen growing around and even on many of the old building remains. The stalked leaves are opposite, consisting of 5-7 leaflets which have a distinctive smell that many found offensive. The stems have a large centre filled with a spongy pith which is easily removed resulting in a hollow stem which has been used by children to make whistles and peashooters. The small white flowers grow in erect, fiat-topped umbels with a heavy, sweet scent. When the berries form they droop downward, turning from green to black. Both the flowers and the ripe fruit are used for making wine and jams and are rich in vitamin C. Different parts of the tree have also been used to make dyes; green from the leaves, black from the bark and blue from the flowers. Hawthorn - There are 2 species of Hawthorn in Britain, but only the common hawthorn has been found on the site. The seeds were undoubtedly brought in by birds from the surrounding countryside, and grew up as scrub in small clear areas. Although usually thought of as a bush or shrub, most of the Hawthorns have grown up in competition with surrounding vegetation and it appear as rather wispy trees. Unless the surrounding woodland is coppiced, many of these trees will steadily lose out to taller trees and die from lack of light. Horse Chestnut - Introduced into Britain from the Balkans in the late 16th century, this tree is one of the best-known species with its sticky brown buds, magnificent white 'candle' flower spikes, its very large leaves with 5-7 stalkless leaflets and its spiny rounded green fruit contain-ing the much prized 'conkers'. Generally a large spreading tree with arching branches that are usually turned up at the ends. Mature trees reach a height of some 35m. The bark is red-brown or dark grey-brown and scaly. The wood is very light and weak and is used for making fruit trays and fence panels but little else. It grows rapidly on most soils but requires plenty of space. A fine example can be seen towards the southern end, with a small stand planted towards the northern end, of Queens Mead. Lombardy Poplar - There are two of these trees on the eastern edge adjacent to the cafe. These were probably planted purely for decorative and windbreak reasons. Easily recognised by the long narrow outline with all its branches sweeping almost vertically upwards. It bears alternate, hairless leaves which are roughly triangular. A fast growing tree reaching a height of 30m. Early in the 18th century cuttings of a male tree were brought from Lombardy, in northern Italy, giving rise to its name. It is now thought to be originally a native of Asia. The Lombardy poplar is not affected by soot and smoke and since the dense, high crowns form an excellent screen it is commonly planted in a line to hide industrial structures. It is also used as a windbreak around orchards and other crop growing fields. London Plane - A single large specimen is growing on the Island Site, immediately to the north of old Mixing House and Saltpetre Store. Many London planes were planted over 200 years ago and are still surviving in the squares of London. It is a fast growing hybrid between the western, or American, plane and the oriental plane, first described in 1670 from a specimen in the Botanic Gardens at Oxford. It is very pollution resistant with its shiny leaves easily washed by rain. The bark is shed regularly in patches which prevents grime from accumulating and brings about the familiar mottled appearance. The leaves are similar to the sycamore but grow alternately instead of in opposing pairs. Male and female flowers grow on the same tree either singly or in clusters. It bears bobble-like fruit which remain on the tree throughout the winter. Oak - The English or Common Oak is a basic part of the English countryside and is used in major construction work, paneling and furniture. The shape can vary greatly depending on its habitat. A lone oak usually has a short, broad base, spreading into many sizeable branches to form a large rounded crown. Close grown specimens may well have long straight trunks with very little branching. Maximum height is generally around 35m. The leaves are alternate and deeply lobed. The fruit (acorns) are often in pairs on long stalks. Very few oaks are present on the site but two close grown trees can be seen on the canal bank opposite the main exhibition hall. Recently a number have been planted on the most easterly New Hill area. Poplar - These trees are located at the northern end of the site and in the bend of the Old River Lea just north of the Burning Ground. Although they can naturally propagate themselves, Poplars tend to be either planted or grow from suckers. They would only have grown naturally when the woodland was much more open than it is now. They grow very rapidly and produce a tall tree with arching branches. It is difficult to imagine why they would have been planted as their timber would have been of little use on the site, and they are far from ideal for charcoal production. Some of them are favoured by Herons as bases for nest building. During the early summer months the down from the trees' flowers forms a carpet on the ground beneath. Silver Birch - Its silvery white trunk and pendulous branches make this one of the most decorative and easily recognised of Britain's native trees. It is one of the world's hardiest trees, despite its delicate appearance. In young trees the bark is reddish rather than the black-marked white of older trees. It displays a delicate tracery of drooping branches and usually grows to about 15m although some reach up to 30m. The thin, shiny leaves are ragged and alternate on slender stalks. Purple-brown male catkins and pale green female catkins open in April. The fruiting catkins stay on the tree until winter when they break up into scales and wind-borne seeds. A small stand can be seen on the northern edge of the Burning Ground and two on the river bank opposite the main Exhibition Hall. Sycamore - This large maple needs no introduction. All these trees are thought to date from early in the 20th century when a few were self-planted or introduced to the site. Regrettably this tree is extremely invasive, producing huge numbers of winged seeds that easily colonise new areas, rapidly germinate and quickly grow into large, mature trees. The large leaves cast a dense shade that inhibits the growth of less vigorous species. The seedlings and young growth are very palatable to rabbits and deer, but unless large numbers of these browsers exist they grow out of their reach in only a few years. This species was much more widespread on the site, but in the preparations for opening huge numbers were cut down and their stumps treated to prevent re-growth. The woodland management plan proposes the steady reduction in the numbers with other species being allowed to take their place. Walnut - This tree is rarely seen growing in the wild in Britain, as its timber is so sought after. Although a native tree, it is on the northern edge of its distribution and usually only occurs where it has been planted. In its early years the Royal Small Arms Factory at Enfield Lock was a subsidiary part of the Royal Gunpowder Factory. When there was a need to ensure good quality wood for rifle stocks, the planting of Walnut trees was encouraged in a number of locations, including this site. In recognition of these facts a group of these trees has been planted about half way up the left-hand side of Queens Mead. The tree can be recognised by its leaf. Like the Ash tree each leaf is made up of a central stalk with separate leaflets either side. In the case of the Walnut there are usually 7 leaflets, which get larger towards the tip of the leaf. Weeping Ash - This unusual tree can be seen at the southernmost tip of the Island Site by the canal bridge. Similar in most respect to the common ash except in its weeping habit with long, drooping branches sweeping almost to the ground. This specimen has been pruned on the bridge side but on the canal side the branches reach down to the water.