The Multiple Uses of Lime Trees (Tilia)

Martin Crawford
Thursday, 27th October 2016

Martin Crawford explains the multiple uses of the deciduous lime/linden (Tilia), from edible leaves, flowers, and seeds to fibre, bast cordage, green manure, and timber.

The limes / lindens / basswoods are a group of trees from North America, Europe and Asia, all potentially large trees with fragrant flowers. There is a long history of the leaves of many lime species being used for food in many regions; similarly, the flowers have been used (particularly to make herb teas).

Limes: Growth, Flowers, Roots

Limes are all large trees with spreading crowns living 200-300 years+ (longer if coppiced or pollarded) originating in mixed woodlands. Trees are quite wind-firm and do not often sucker (apart from T. x vulgaris which can sucker widely.) The bark is smooth and silver-grey. Leaves are broadly heart shaped, varying in size from small leaved lime (3.5-6cm/1.4-2.4ins wide) to large leaved lime (5-12cm/2-5ins wide).

Flowers are yellowish-white, very fragrant (sweet scented), in pendulous clusters on long slender stalks with a leaf-like bract at the base (the bract assisting with seed dispersal) in summer. The flowers are insect pollinated, often by bees.

Fruits are round, 6-12mm (0.3-0.5ins) across and thin shelled; ripening in October, they are very attractive to wildlife including mice and small mammals.

Lime trees have a deep and wide-spreading root system. They have a remarkable tenacity for life and are more or less indestructible: as old stems collapse, new sprouts arise and essentially trees coppice themselves; trees which fall over often retain part of their root system and sprout not only from the base, but also from where the stems rest on the ground.

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Uses of Lime (tilia)

The young leaves are edible raw (stalks removed), being mild, thick, cooling and mucilaginous. Pleasant eating in salads or as a sandwich filling. Coppicing or pollarding may be desirable for leaf harvesting, keeping the plants shrubby and more leaves within reach; young leaves are produced throughout the growing season on coppiced plants. Small leaved lime can be pollarded every 3-4 years and large leaved lime annually to produce a bush no more than 3m (10ft) high.

The immature fruits, ground up with some flowers, produce an edible paste much like chocolate in flavour. Attempts to introduce its manufacture in the 18th century failed because the keeping qualities were poor; presumably, these could be overcome nowadays. The flowers are used in herb teas (see medicinal uses below) and in confectionery. The sap is edible, tapped and used in the same way as maples. See maples (p.120) for more details.

The flowers (collected with the bracts) have well-known medicinal properties, and when dried are pharmacologically called Tiliae flos. They contain 3% mucilage, sugar, wax, tannin, amino acids, flavonoids (quercetin and kaempferol) and traces of an essential oil. They have antispasmodic, diuretic, expectorant, haemostatic, nervine and sedative properties and calm the nerves, lower blood pressure, increase perspiration, relax spasms and improve digestion. Lime-flower tea has been used for many centuries as an antidote to fever in cold and ‘flu sufferers. It is still much used in herbal medicine for hypertension, hardening of the arteries, cardiovascular and digestive complaints associated with anxiety, urinary infections, fevers, catarrh, migraine and headaches.

The flowers are also used commercially in cosmetics, mouthwashes and bath lotions. The flowers should be picked and dried as soon as they open – they reputedly develop narcotic properties with age.

The charcoal made from the wood is specially used for smoking certain foodstuffs. It is also used medicinally (e.g. for gastric problems), being an effective vasodilator. 

Bees are extremely fond of lime flowers, feeding on both nectar and pollen, and sometimes also collect the honeydew left by aphids on the leaves. Lime honey made from the flowers is still a major commercial enterprise in many parts of Europe; it has a very pleasant slightly minty flavour and a greenish tinge to its colour. In Europe, the honey is used for flavouring liqueurs and medicines. Stands of large leaved lime can yield 250-800kg honey/ha (223-714lb/ac). Honeydew honey is golden to almost black in colour, with a rich flavour reminiscent of dried figs; some honeydew honeys are highly prized in Europe.

The young bark (or bast) was formerly much used for rope, basketry, clothing and shoes, mats and roof coverings. (See box for more details: www.green-shopping.co.uk/trees-for-gardens-orchards-and-permaculture.html) The bast fibres can also be used to make a paper: trees are harvested in spring or summer, and steamed until the fibres can be stripped; the fibres are cooked for two hours with lye, then beaten in a ball mill. The resulting paper is beige in colour.

Suckers are straight and flexible, and can be used for basketry (particularly for making handles). The foliage is much relished by cattle, both green and dried and made into hay; in Norway and Sweden this was an important agroforestry practice. It is said to impart an unpleasant flavour to the milk of lactating cows. The leaves are high in nitrogen and phosphorus, similar to those of nitrogen-fixing trees like alders and black locust (small leaved lime has 2.8% N, 0.22% P, 0.9% K; dry weight). They improve soil structure and fertility over time, acting like a green manure, and increase the earthworm population; they also reduce acidification, raising the pH.

Another factor that enriches soils beneath trees is the honeydew secreted by the lime aphid: deposits on the ground of 1kg of sugars/m2 (1.8lb/yd2) per year have been recorded, and these sugars may stimulate the growth of nitrogen-fixing bacteria around the trees. The leaf litter decomposes rapidly.

Limes are wind-firm and suitable for including in shelterbelts; it also makes a good component of a hedge, tolerating frequent cutting. Limes are major forest trees cultivated for timber in some regions. The timber has a fairly broad sapwood layer; both sapwood and heartwood are usually whitish-yellow (sometimes light brown or reddish). On drying, the timber contracts moderately to severely. The dried timber is light (560kg/m3, 35 lb/ft3 at 15% moisture – one of the lightest broadleaved timbers in Europe) and easy to handle, soft, tough, moderately strong, stable, very fine and even grained, pliable, not durable; it is susceptible to woodworm attack. It is used for making drawing and cutting boards, toys, turnery, piano keys, small boxes, barrels and chests, barrel bungs, also for carving, veneers, bee hive interiors (because of its freedom from taints) and good quality charcoal (used for artists’ charcoal and formerly for gunpowder). In Russia it is used in furniture manufacture and for many purposes for which plastics are now used. It accepts preservatives easily and can then be used as a softwood substitute for fencing etc.

Limes coppice strongly, producing long straight poles valued for sustainable fuel production and turnery uses. The coppicing rotation period is usually 25-30 years, but short-rotation coppice is feasible. Coppiced lime stools are virtually indestructible; there is one coppice ancient stool at Westonbirt Arboretum in the UK that is estimated to be 2,000 years old; its age attributed to fairly long rotation coppicing with occasional layering of arching stems.

This is an extract from Trees for Gardens, Orchards and Permaculture by Martin Crawfordwww.green-shopping.co.uk/trees-for-gardens-orchards-and-permaculture.html

For cultivation advice, see the book.

Martin Crawford is the founder of the Agroforestry Research Trust, and author of several popular books.

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