Ansfewandte Botanik. 511 



'fe 



ist in Anbetracht der freier stehenden breiter ausgelegten Kronen 

 der Alpenlarche durch die Notwendigkeit einer gröszern wasser- 

 leitenden Querfläche bedingt. Der Gang des Verkernungsprozesses 

 ist also eine Folgeerscheinung erblicher Zustände. 



5. Die Stammform der Bäume wird sowohl durch statische 

 Momente als auch durch die Bedürfnisse der gleichen Wasser- 

 leitungskapazität bestimmt. 



6. Das Holz der Sudetenlärche ist in allen Teilen wesentlich 

 schwerer als jenes der Alpenlärche; die Differenz im Holzgewichte 

 ist in den unteren Schaftteilen am grössten. Die Abnahme des 

 Holzgewichtes von der Stammbasis zur Spitze ist — den statischen 

 Momenten folgend — bei der Sudetenlärche grösser als bei der 

 Alpenlärche. Die Stammform hat eben auf die Grösse des Holz- 

 gewichtes in den unteren Schaftpartien einen entscheidenden 

 Einfluss. 



7. Im Bestände werden die dichter stehenden Sudetenlärchen 

 mehr Holz erzeugen können. 



8. Die polnische Lärche sollte einer genaueren waldbaulichen 

 Erforschung unterzogen werden. Matouschek (Wien.) 



Smith, W. G. and C. B. Crampton. Grassland in ßritain. 

 (Jour. Agric. Science. VI. 1. p. 1 — 14. 4 figs. 1914.) 



The view is adopted that grasslands have originated in many 

 places ecologically different, and that it is necessary to examine the 

 environmental conditions both from the ecological aspect and in 

 connection with agricultural problems concerned with establishing, 

 maintaining or improving the value of grassland. In Br itain the 

 oceanic climate favours grassland from sea-level to the highest 

 mountains. The present extent and distribution have been largely 

 determined by the economic requirments of farm practice, the extent 

 to which original primitive Vegetation has been displaced, and the 

 influence of grazing by sheep and cattle. Just as woodlands are 

 natural or planted, so grassland is either natural or artificially in- 

 duced. Stahle natural grasslands occur on ground subject to slow 

 geological change, where the topography prevents the growth of 

 forest or excessive accumulation of peat, and where surface infertility 

 is prevented. The natural stable grasslands of Britain are relatively 

 limited: chalk downs, exposed hüls and ridges of calcareous rocks, 

 and basic igneous hills over-steepened by glacial action. Natural 

 grasslands occur widespread on substrata which are unstable, such 

 as alluvial and spring-flushed surfaces along rivers and coastal belts, 

 and on slopes of hills; these are a temporary Vegetation which lasts 

 only so long as the conditions favour grassland, and it is replaced 

 by other types of Vegetation if the maintaining factors are removed. 

 The natural conditions which favour grassland are those which 

 prevent: 1. leaching of the surface which results in competition with 

 heath; 2. accumulation of raw humus and competition with moor- 

 species; 3. stagnancy of the soil which leads to marsh; 4. the growth 

 of forest These factors are considered in detail and a series of 

 profile diagrams illustrates the topographical distribution of grass- 

 land in Britain. The influence of grazing assists these physical 

 factors, and tends to maintain grassland in competition with other 

 types of Vegetation, e.g. moor, heath and forest. 



A Classification of grasslands is outlined, based on growth-form 

 in relation to topography: I. Turf forming types on smooth surfaces 



