This week the Common took on all its Spring finery: oaks are bright green and with a such a profusion of glorious pollen-laden blossom from the chestnuts, rowans, hawthorn and apples, you may also expect the odd sneeze or two. Down at ground level garlic mustard joins cow parsley and in the acid grassland, two of our indicator species are making an appearance: sheep sorrel (Rumex acetosella) and cat’s ear (Hypochaeris radicata) – often mistaken for dandelion. Surprise sighting of the week was a Mandarin duck on the cricket field. Also seen were bats at dusk and green hairstreak butterflies.
Willow
There are three types of Willow (Salix) on Barnes Common. Two are true natives, one a more recent hybrid. All are members of the Salicaceae family and closely related to Poplars. Poplars will be addressed in a separate article.
Goat Willow (Salix caprea) was one of the first trees to recolonise after the Ice Age and one of the earliest known engravings shows a goat eating its foliage. It can grow to a tree of up to 15m but is more often shrubby. Carried on the wind, seed spreads easily, can travel long distances and likes to settle into disturbed ground. It particularly loves moist soil and is often found near streams. Willows are dioecious, with male and female catkins (flowers) appearing on separate trees. The male produces the classic golden pussy willow catkins in Spring. A self-seeded example can be found near the path south of Ranelagh Avenue. This appeared after ground was disturbed when the reed bed was created a few years ago. The unremarkable clump growing near the path across ‘Maisie’s Meadow’ (the large meadow over the little bridge from the Green) where children love to play, is an example of a female plant.
Crack Willow (S. fragilis) is the other native found on the Common and arrived a little later. Again, it likes very moist soil and is one of the common trees of riversides. The leaves are long, thin, pointed, glossy green and well-spaced. The bark is a dull brown, criss-crossed with thick ridges. The trees grow rapidly and can reach 25m, with substantial trunks, but more often than not the weight will be too much and either the branch will split until it touches the ground and supports itself, or the whole tree can topple due to ground heave or a weak trunk. The tree will root again where it touches the ground and fresh vertical shoots will grow. Indeed, so easily does crack willow root, that many trees along a river will have grown from twigs that have floated down and simply settled into the mud. FoBC uses this characteristic to help manage the banks of the brook, as well in the creation of the ‘living fence’ around the reedbed. Seen by some as a ‘messy’ tree, it possesses a powerful sculptural beauty (Featured image. Photo M Hildesley)
Weeping Willow (S. x sepulcralis var. chrysocoma) is most likely an artificial hybrid between S alba ‘Vittalina’ and S babylonica. ‘Chrysocoma’ comes from the ‘golden locks’ of its branches in winter.
Traditional uses of willow: Due to its fragility, willow is not suitable for construction and is a positive danger for firewood, as it spits copiously. However, these properties also make it is a useful tree for other reasons: when coppiced, willow grows long straight shoots very rapidly that are supple enough to be woven easily to produce baskets for produce, fish traps and a host of purposes. Livestock were contained with wickets woven from willow. Wickets being just one of its connections with cricket, the other its use for cricket bats. The wood has a springiness capable of taking the sting out of being hit by a hard object, particularly the ‘bat willow’ (S. alba var. caerulea) first found in East Anglia. Much of the wood for ‘daub and wattle’ construction was willow, although other wood was also be used. Mud mixed with horsehair and straw is squeezed into a woven wattle and smoothed off. It dries to provide a well-sealed ‘plaster’ wall, typically within a wooden framed building. Protected with lime wash, examples of this simple mud cottage construction can last centuries.
Renewed interest: The beds of willow grown for these uses were called Osier beds, and they were often planted along streams. The 1838 Tithe Map shows extensive osier beds where Westfields now stands, as well as between Barn Elms and Putney Lower Common, where the Beverley Brook used to meander towards its outfall into the Thames. At that time people probably did not realise the additional benefit such beds gave to the water quality of the stream. Today, willow and reed are often used in natural sewage treatment and its rapid growth makes it a feature of some biomass projects. Sadly, I know of one osier bed, operating when my mother was a child, that fell into disuse. When the village wished recently to renew it as part of a waste water treatment programme, planning consent was refused as the trees had grown so large the planners thought they should not be cut down – result a multi-million pound pumped sewage project and trees which are already collapsing under their own weight!
Medicinal: Chewing on the bark of some willows and willow-bark tea has been long recognised, and certainly recorded in classical times, as a means of alleviating pain. Willow bark contains the compound salicin which metabolises in our bodies to form salicylic acid. From this you can manufacture acetyl salicylic acid, the active ingredient in aspirin which became the foundation of the German pharmaceutical company Bayer. Obviously, we do not recommend taking bark off any of our trees or ‘trying this at home’.
Next Week: Chestnuts on the Common.