Betula pubescens

• White Birch

Sap - raw or cooked. A sweet flavour^[1][2][4]. Harvested in early spring, before the leaves unfurl, by tapping the trunk. The flow is best on sunny days following a heavy frost. The sap is often concentrated into a sugar by boiling off the water. Between 4 and 7 litres can be drawn off a mature tree in a day and this will not kill the tree so long as the tap hole is filled up afterwards^[5]. However, prolonged or heavy tapping will kill the tree. A beer can be fermented from the sap. An old English recipe for the beer is as follows:- \"To every Gallon of Birch-water put a quart of Honey, well stirr'd together; then boil it almost an hour with a few Cloves, and a little Limon-peel, keeping it well scumm'd. When it is sufficiently boil'd, and become cold, add to it three or four Spoonfuls of good Ale to make it work...and when the Test begins to settle, bottle it up . . . it is gentle, and very harmless in operation within the body, and exceedingly sharpens the Appetite, being drunk ante pastum.\"^[6]. Young leaves - raw or cooked^[2][4]. Young catkins^[2]. No more details are given.

A pioneer species, it readily invades old fields, cleared or burnt-over land and creates conditions suitable for other woodland trees to become established. Since it is relatively short-lived and intolerant of shade, it is eventually out-competed by these trees^[8][11]. A tar-oil is obtained from the white bark in spring. It has fungicidal properties and is also used as an insect repellent^{[12][13][9][14]}. It makes a good shoe polish^[9]. Another report says that an essential oil is obtained from the bark and this, called 'Russian Leather' has been used as a perfume^[15]. A glue is made from the sap. Cordage can be made from the fibres of the inner bark. This inner bark can also be separated into thin layers and used as a substitute for oiled paper^[12]. A decoction of the inner bark is used to preserve cordage, it is rich in tannin. The bark contains up to 16% tannin^[16]. A brown dye is obtained from the inner bark. An oil similar to Wintergreen oil (obtained from Gaultheria procumbens) is obtained from the inner bark^[7][9]. It is used medicinally and also makes a refreshing tea^[7]. The young branches are very flexible and are used to make whisks, besoms etc^[17]. They are also used in thatching and to make wattles^[12]. The leaves are a good addition to the compost heap, improving fermentation^[18]. A black paint is obtained from the soot of the plant^[9]. A high quality charcoal is obtained from the bark. It is used by artists, painters etc.

The bark is diuretic and laxative^[22]. The inner bark is bitter and astringent, it is used in treating intermittent fevers^[12]. An oil obtained from the inner bark is astringent and is used in the treatment of various skin afflictions, especially eczema and psoriasis^[12][19]. The bark is usually obtained from trees that have been felled for timber and can be distilled at any time of the year^[19]. The buds are balsamic^[22]. The young shoots and leaves secrete a resinous substance which has acid properties, when combined with alkalis it is a tonic laxative^[12]. The leaves are anticholesterolemic and diuretic^[22]. They also contain phytosides, which are effective germicides^[22]. An infusion of the leaves is used in the treatment of gout, dropsy and rheumatism, and is recommended as a reliable solvent of kidney stones^[12]. The young leaves and leaf buds are harvested in the spring and dried for later use^[19]. A decoction of the leaves and bark is used for bathing skin eruptions^[12]. The vernal sap is diuretic^[12]. The boiled and powdered wood has been applied to chafed skin^[10].