HARDWICKE'S SCIENCE-GOSSIP. 



87 



but otherwise beech can grow in Denmark on any soils 

 where the natural conditions for tree-growth are 

 present. In Jutland it forms woods as far north as 

 the soil will permit any woods to grow, close below 

 the Scaw, in latitudes where in other countries it 

 begins to be sporadic merely. Vet the beech is not 

 so absolutely dominant in Jutland towards the west 

 and the east ; though the ruling tree in many of the 

 woods to the west of the proper forest-belt, especially 

 in those of considerable, size, in many of the smaller 

 woods, composed of oak, birch and aspen, it is less 

 frequent, or quite absent. Such woods where beech 

 is scarce or absent, are not only small, but outlying, 

 and by elevation or otherwise exposed to the repres- 

 sion of the west winds, or other ills ; but in those of 

 larger extent, which do not suffer from west winds, 

 wet soil, or ill-usage, the beech is either the ruling 

 tree, or on the way to become so at no distant date. 

 It is steadily extending itself in the westerly woods ; 

 but the isolated position of certain woods renders its 

 access to them difficult. For this reason it is absent 

 from the natural woods of Bornholm, not having yet, 

 in its course from west to east, advanced so far. 



The Oak is found interspersed in beech-woods, 

 and forms also pure oak-woods in Jutland on 

 boulder-sand, and upon the islands on fertile clay. 

 In the natural oak-woods of the islands the trees stand 

 wide apart, usually lifting their broad heads above 

 dense underwood, chiefly of hazel and whitethorn ; 

 thus affording a glimpse of the form of Denmark's 

 best old oak-forests, of which our forefathers left 

 us few remains. The oaks, too, which are here 

 scattered through the beech-wcods, at the rate of less 

 than one to about five oaks to the acre, among 

 beeches of one hundred and forty years old, are the 

 offspring of those ancient woods of oak ; on the east 

 coast of the peninsula oaks are also scattered among 

 the beeches, but in general both these and oak-woods 

 are rarer than upon the islands. The free use of 

 oak timber formerly has caused the disappearance of 

 many an oak-wood, for oak does not renew itself so 

 readily as beech, the young plants being more easily 

 repressed by other kinds of trees which invade the 

 grounds. Consequently the oaks have left the fertile 

 east coast for interior sites, where the soil, being in 

 general boulder-sand, and the isolated position, check 

 the advance of the beech. Some have therefore 

 concluded that in Jutland the oak has its habitat on 

 the boulder-sand, and the beech on the boulder-clay ; 

 but such preference of the oak is opposed to its 

 habit on Zealand and the smaller islands, where the 

 oak-woods usually rest on fertile soil. In Bornholm, 

 where the oak has not come under the domination of 

 the beech, it is plentiful, and both pedunculata and 

 sessiliflora are found there, but the latter most 

 frequently. 



Of Birch there are several kinds in Denmark, 

 regarded by Linnaeus and others, not as different 

 species, but as varieties of the white birch. The 



most common is the forest-birch (Bctula verrucosa), 

 distinguished by its fissured bark and other marks 

 from the northern white birch (B. gliitinosa). To 

 the last, the dun-birch (B. pubcscens) is allied, though 

 in general it is a mere bush on the mosses ; B. Cur- 

 pathica is also allied to the white birch, and can 

 attain to a tree, but is rare. 



The birch forest, even more than the oak, has 

 suffered diminution during the lapse of time. Stems 

 found in peat-mosses witness to its great extension in 

 former ages ; but now, whether associated in woods 

 or standing singly, the birch has been excluded from 

 the best forest tracts by the nobler tree-species, and 

 only retains its hold on localities which, either from 

 isolation or sterility, are favourable to the beech. As 

 a wild forest-tree, it has almost or entirely disappeared 

 from several of the islands ; and even in Vendsyssel, 

 the most northerly part of Jutland, birkenshaws have 

 given place to beech-woods, though it maintains itself 

 on swampy grounds. It is found also in parts of the 

 interior of Jutland, but it nowhere on the peninsula 

 forms an important constituent of the woods. 



The birch of the peat-mosses is marked by striking 

 peculiarities ; its stems, often more than two feet in 

 diameter, are swathed in beautiful, smooth, white 

 bark ; while the bark of the birches now growing in 

 North Zealand (where beautiful groups exist) fissures 

 as soon as the tree attains a diameter of little more 

 than half a foot. The leaves, catkins and winged 

 fruit also of the fossil and the forest-birch differ; the 

 former agreeing most nearly with the genuine northern 

 white-birch, common to the Scandinavian peninsula, 

 the northern part of the Russian forest, and the hills 

 of Middle Europe ; while, on the other hand, the 

 forest birch (B. verrucosa) predominates on the plains 

 of Germany. It is only from the mosses of North 

 Zealand that material for a thorough comparison has 

 been obtained by Dr. Vaupell ; he notes also the 

 tendency of the birch to run into varieties. 



Alder. — The red alder (Abuts glutinosa) occupies 

 swampy parts of the forest, especially in beech- woods 

 where the small or large marshy depressions which 

 frequently occur are usually filled with alder-woods, 

 or alder-mosses. Though red alder affects moisture,, 

 yet individual trees are found on hard soil, where 

 they often attain a greater age and finer form than on 

 swampy ground. In recent times, as before intimated, 

 such mortality has befallen the alders that in many 

 wooded tracts they have quite given place to other 

 species of trees, especially on the small islands and a 

 great part of Funen and Zealand ; they still flourish 

 on the east coast of Jutland and Slesvig. 



The white alder (A Inns iiicana) is admitted into 

 the Floras as a Danish tree, and certainly no foreign 

 tree has taken faster or more flourishing hold of the 

 soil, from which indeed it is difficult to rid it ; for when 

 cut down close to the roots, these strike out so many 

 shoots that more space is covered than sufficed for 

 the parent tree. It is common in the state forests of 



