468 BOTANICAL GAZETTE [JUNE 
destruction of the vegetation carpet as to have given rise to further and more 
serious loss through erosion. The peak of this destruction has been in the 
spruce-fir basins, above gooo ft., where slopes are steep and summer grazing 
is excellent. Deferred and ftation grazing are necessary to prevent the 
destruction of these areas for grazing purposes; once erosion has set in, graz- 
ing should be abandoned, and an attempt made to re-create good grazing con- 
ditions by terracing, planting, and the construction of dams. 
In connection with these bulletins there may be mentioned one on the 
general principles underlying range management in the National Forests,’ 
in which such topics are considered as the determination of the class of stock 
to which the range is best suited, grazing periods, grazing capacity, manage- 
ment of cattle on the range, management of sheep on the range, range reseed- 
ing, and timber protection. Very full lists of references are given. 
e ecological study of pastures has been taken up also in foreign lands. 
The work of Brews in South Africa has already been noted in these pages.* 
An interesting study of Scottish hill pastures has been made by SmitH5 A 
ill pasture is defined as an arca that is uninclosed and unploughed. Sixty 
per cent of the area of Scotland, or 18,000 square miles, comes under this 
category, although much of this is unsuitable for grazing. The different 
plant associations of these lands are mentioned and characterized, and it is 
clearly brought out that each association represents a particular combination 
of climate, soil, and grazing animals. The improvement of pasture land is 
based on the fundamental principle that the herbage changes as the growth 
conditions change. The foundation of hill pasturage is in the alluvial and 
flush grasslands, where the vegetation is rich and palatable; these areas may 
be extended by irrigation, diversion of surface water, and drainage. Bracken 
(Pieris aquilina) land is flush grassland with a luxuriant growth of the bracken. 
This land makes excellent pasturage if the bracken is removed by cutting 
or by spraying with 5 per cent sulphuric acid. Heather (Calluna) land is 
valuable for sheep grazing, but it should be burned over every few years, to 
stimulate the increased development of palatable green shoots. Peaty lands 
may be improved by drainage or burning. Considerable areas are charac- 
terized by rough grasses of low grazing value, notable among which are Nardus 
stricta and Molinia coerulea. It is desirable to replace these by finer herbage, 
by flushing, or by diverting surface water. 
Quite another sort of applied ecology is represented in a paper by CO KER® 
on pisciculture. Plants are the chief oxygenators in confined ponds, and are 
3 JarDINE, James T., and ANDERSON, Marx, Range ——— on the National 
Forests. Bull. 790, U.S. Dept. Agric. pp. 98. pls. 32. figs. 4. 1919. 
4 Bor. GAz. 672370. 1919 
5 Suiru, W. G., The Lect of hill pasture. Reprint from Scottish Jour. 
i pp. 8. tron 
-m. EK co, and problems of fish culture in Vaccaagt Scientific 
ween: 7: risibae ‘bese 19 
