Forestry Commission Booklet No. 20 H M S O : 15s. od . n e t Know Your Broadleaves Forestry Commission ARCHIVE Cover picture By CHARLES TUNNICLIFFE, R.A. Photographs The photos on pages 21, 33, 51, 78, 100, 128 and 133 are from the Forestry Commission collection, and were taken by 1. a . a n d e r s o n and MRS. T. K. EVANS. Plate I and the photos on pages 5, 11, 14, 25, 40, h i , 131, 137 and 140 are b y jo h n MARICHAM. Those on pages 12, 17, 43, 56, 59, 72, 74, 80, 84, 91, 103, 108, 113, 116 top, 118 and 124 are by m . n i m m o . Those on pages 27, 30, 37, 47, 62, 66, 88, 94, 97 and 1 17 are b y e r ic h o s k in g . That on page $2 is by l. s . p a t e r s o n and that on page 69 b y Le o n a r d and m a r jo r ie g a y t o n . m r . it. s t o t t took the pictures of osier willows on pages n o , 116 (foot), and 117 (foot). Drawings All the drawings are by Ch r is t in e d a r t e r , except for the small sketches of tree seedlings, which are by He r b e r t l . e d l in , and the picture of the elm crowns on page 141, which is by ALAN MITCHELL. FORESTRY COMMISSION Booklet No. 20 Know Your Broadleaves Text b y Her b e r t l . e d l in , b .sc . Forestry Commission Drawings by Ch r is t in e d a r t e r , b .s c . LONDON: HER MAJESTY’S STATIONERY OFFICE 1968 PLATE I Lombardy poplars beside the Thames, KEY TO COYER PICTURE Horse Chestnut Beech English Elm tree Rowan Ash Lime tree Silver Birch tree Hazel Sycamore Sessile Oak Contents In alphabetical order by scientific names 6 INTRODUCTIONASH P a g e 53 Fraxinus excelsior L. MAPLES AND SYCAMORE 9 Acer campestre L H O L L Y 12 Acer platanoides L. 57 Ilex aquifolium L. 15 Acer pseudoplatanus L. WALNUT HORSE CHESTNUT 60 Jugians regia L. 19 Aesculus hippccastanum L. PLANE ALDER 63 Platanus acerifolia Willd. 22 Alnus glutinosa L. POPLARS STRAWBERRY TREE 67 Populus alba L. 26 Arbutus unedo L. 70 Populus canescens Sm. 73 Populus nigra L. BIRCHES 75 Populus nigra variety italica du Roi 28 Betula pendula Roth. 77 Populus ‘Regenerata’ Rehd. 31 Betula pubescens Ehrh. 79 Pcpulus ‘Serotina’ Hartig. 81 Populus tacamahaca Mill. BOX 82 Populus tremula L. 35 Buxus sempervirens L. WILD CHERRY HORNBEAM 86 Prunus avium L. 38 Carpinus betulus L. OAKS SWEET CHESTNUT 89 Quercus borealis L. 41 Castanea sativa Mill. 92 Quercus cerris L. 95 Quercus ilex L. HAZEL 98 Quercus petraea Lieb. 44 Corylus avellana L. IOI Quercus robur L. BEECHROBINIA 48 Fagus sylvatica L. 105 Robinia pseudoacacia L. 4 W IL L O W S ELMS P age 109 Salix alba L. P age 129 Ulmus glabra Huds. 112 Salix alba variety coerulea Smith 132 Ulmus hollandica. Spath. variety vegeta Rehd. 114 Salix caprea L. 134 Ulmus procera Salis. 118 Salix fragilis L. 140 Ulmus stricta Lindl. ROWAN 142 INDEX OF ENGLISH NAMES 121 Sor bus aucuparia L. LIME 125 Tilia europaea L. >’ ■* V ,'C- ‘ V ' - ■ r_ - ^ PLATE II Aspen poplars. 5 Introduction The broadleaves, or hardwood trees, are the leading feature more water than the roots could replace, and the tree would in the British landscape of woods and hedgerows. In the die of drought. past they were the country’s main source of building Such seasonal changes in warmth and moisture explain material, fencing, and fuel. Today, when we have other the marvellous rhythm of growth that we find in the life sources of heat and power, and steel and concrete play so of every deciduous broadleaved tree— that is, one which large a part in building, the hardwood timbers of these loses its leaves in autumn. In spring, as the land warms up, attractive trees are less important to our economy. But it expands a new set of leaves from opening buds, clothing there is still a very substantial trade in good sound oak, its branches with fresh, bright green foliage. All summer beech, ash, sycamore and elm, for the better classes of through these leaves carry out their essential function of furniture making and joinery, while poplar is used for winning organic food from the air, by the wonderful pro­ matches, and willow for cricket bats. cess called photosynthesis. Every leaf holds in its tissues a To a growing extent, the country’s needs of timber in remarkable substance called chlorophyll, which gives it its bulk are nowadays met by the conifers, or softwood trees, green colour. In sunlight, and in the presence of sufficient which have been described in detail in the companion moisture and mineral salts, this chlorophyll “fixes” some volume Know Your Conifers (Forestry Commission Booklet of the carbon dioxide gas that is always present in the air. 15, H .M .S.O ., 5s. od. net). Once fixed, the carbon dioxide is transformed by intricate chemical processes into sugars, and eventually into all the Most forest planting today is done, inevitably, with other complex materials that make up the tree’s substance these conifers. But the landscape, shade and shelter values — wood, roots, flowers, and seeds, as well as the leaves of the broadleaves are so great that they are always likely themselves. to play the larger part in hedgerows, as street trees, and in general amenity planting. Most of them are natives, and In autumn, the tree withdraws all the mobile food these are firmly established in old natural, or semi-natural, material from its leaves, which slowly change colour from woodlands throughout the British Isles. green to brown or orange. Then, their work done, they fall away from a definite point of union with the twigs, Our broadleaved trees form part of the vast natural leaving behind them small leaf scars. Already the tree has broadleaved forest of Northern Europe, which once made preparations for a fresh crop of leaves in the ensuing stretched, almost unbroken, from the Atlantic to the spring, and the buds from which these will spring can be steppes of Russia. Similar forests are found in eastern seen already formed, waiting for their long winter rest. Asia, on the upper slopes of the Himalayas, and right across North America. The key feature of all these woods The falling leaves, drifting to the forest floor, decay to and trees is, as the name implies, the broad leaf, which is make a rich mould, still holding mineral nutrients. This shed each autumn as the colder weather approaches. leaf litter forms a fertile addition to the soil in which the trees’ roots live and feed; in fact it returns to the ground The Leaf and its Work the vital minerals won earlier. To put it very simply, the broadleaf tree carries on its life A few of our broadleaved trees are evergreen, and their processes throughout the summer months, as though it leaves have a longer cycle of life. Some of them, like the were living in the warm moist tropics. It has at that time holly, are native to our milder western districts where cold enough water and heat for this, and the long summer days winters are exceptional; others come from southern Europe, of the northerly latitudes are all in its favour. But when or from other countries with a “Mediterranean” climate of winter approaches and the temperatures of the soil and warm moist winters. Each leaf on an evergreen broadleaf the air fall, it is no longer able to draw water from the soil. tree lasts for several years; every year new ones are added, Its growth processes slow down, and it is obliged to shed and a few of the older ones fall, but the tree as a whole is its foliage; if the leaves were retained they would give out never leafless. 6 The timber of broadleaved trees is known as hardwood, features of the local species which may be different to those because in most kinds, though not in all, it is physically we know in Britain. much harder than that of the conifers, or softwood trees. Whenever possible, work with two or more features Its structure, as seen under the microscope, is very com­ from every tree that you wish to name. Single characters, plex, and varies a great deal from one kind of tree to the such as buds, may be much alike, but a combination of next. This results in a fascinating variety of appearance bud, leaf and fruit is unique for any of our common trees. and working properties, which makes certain timbers far more suitable for certain work than others. Ash, for ex­ ample, makes tough axe handles, whereas elm is used for Key Characters of Tree Genera chair seats since it never splits. To identify trees you must examine each of their features on a predetermined plan, knowing just what you are looking How to Know the Broadleaves for. The illustrations in this booklet are designed to bring out key characters in a comparable way. Leaves, twigs, and All broadleaved trees belong to the great natural order of buds on both very young and very old branches may not plants called the Dicotyledones, which are distinguished by be true to type; look therefore at specimens from average having two seed-leaves or cotyledons in every seed.