July 23, 1891] 



NA TURE 



267 



necessarily be carried on in some instances on a large 

 scale, yet every effort ought to be made to develop good 

 systems of natural regeneration in the different provinces. 



On pp. 132-64 the author gives a clear account of 

 the different systems which have in course of time been 

 devised, in order to effect the natural regeneration of 

 woods by seed. Under the more favourable climate of 

 France the desired object is generally effected by a 

 simple and to some extent uniform system of successive 

 cuttings. In Germany, on the other hand, where droughts 

 are frequent, frosts severe, and where good seed years 

 generally are of rare occurrence, the system of regular 

 successive cuttings, which originated in Germany, in 

 many cases was found to fail, and accordingly, some sixty 

 or seventy years ago, the tide set in in favour of artificial 

 reproduction. A reaction, however, has for good reasons 

 taken place in many parts of the country, and during the 

 last thirty years German foresters have been busy in 

 adapting the system of natural regeneration to the 

 peculiar conditions of each forest district. Indian forest 

 students should go to France, in order to become im- 

 pressed with the fact that under favourable circumstances 

 natural regeneration of high forests may be effected by 

 a simple and easy system of treatment. In German 

 forests, on the other hand, they should learn how the 

 difficulties of a climate frequently unfavourable have 

 been successfully overcome by devising systems of 

 treatment suitable to the requirements of each locality, 

 and the knowledge here acquired will be most useful, nay, 

 necessary, to them in India, where the conditions of 

 climate by no means always favour the natural regenera- 

 tion of the more valuable forest trees. 



Space forbids a full discussion of this most important 

 and interesting subject. This portion of Dr. SchHch's 

 book, if supplemented by the study of forests on a large 

 scale, particularly in Germany, will be most useful to 

 foresters who may be called upon to devise methods of 

 forest treatment in other parts of the globe, be it India, 

 Australia, South Africa, or North America. 



Closely allied to the subject just adverted to is what the 

 author says in the fourth section of the same chapter 

 regarding the formation of mixed woods. Pure woods, 

 consisting of one species only, are exposed to various 

 risks, from which mixed woods are exempt. Hence, in 

 most Continental forests, there has of late years been a 

 strong tendency in the direction of favouring the growth 

 of mixed woods, such as oak and beech; oak and horn- 

 beam, oak and silver fir, Scotch pine and beech, and 

 the like. It goes without saying, that operations in this 

 direction, in order to be successful, must be guided by 

 careful study of the mode of growth and of the peculiar 

 requirements of the different species in different places 

 and under different conditions. Something has been said 

 above regarding the treatment of mixed woods of oak 

 and beech in the Spessart. But it does not follow that 

 oak and beech behave in the same manner everywhere. 

 On certain kinds of shale, belonging to the Devonian 

 formation, for instance, the oak rather than the beech 

 has the tendency to take the lead, and here mixed woods 

 of oak and beech can be produced from self-sown seed- 

 lings much more easily than would be possible on the 

 sandstone of the Spessart. Again, along the foot of the 

 Western Schwarzwald, where, as already stated, the 

 NO. I 134, VOL. 44] 



silver fir is associated with the oak, this tree, though a 

 shade-bearer like the beech, renders it much easier for 

 the oak to hold its own in an even-aged mixed wood, 

 because in its early youth it grows very slowly, thus 

 giving the oak a good start in life. 



Chapter iii. teaches how woods should be tended during 

 early youth and afterwards. Passing over what the author 

 says regarding cleaning of young woods and pruning, we 

 come to thinning operations. On p. 209 an interesting 

 statement is given showing the number of trees per acre 

 in certain mixed woods of the Schwarzwald. The figures 

 are as follows : — 



Age of wood 

 in years. 

 20 

 40 

 60 

 80 

 100 



Number of trees 

 per acre. 

 3960 

 IOI3 

 449 

 346 

 262 



Thus, during the life of a wood, and this holds good in 

 all cases, the number of trees per acre decreases gradually 

 from several thousand to a compiratively small number 

 at maturity. When, as usual, the object is to produce 

 high class limber, with clean well-shapen stems, the rule 

 is, as the author correctly states it : " The wood should be 

 thinned lightly until towards the end of the principal 

 height growth ; then the thinnings should gradually 

 become heavier, so as to assist a selected number of 

 trees by the gradual removal of all those which are 

 inferior and diseased." In its youth the wood is crowded, 

 the young trees maintaining a severe struggle for 

 existence. The weaker trees are suppressed and some 

 are actually killed, while the rest are either dominant 

 trees, with their head well above the others, or dominated, 

 though not suppressed. Formerly thinnings were generally 

 done by rule of thumb, the dead, oppressed, and a portion 

 of the dominated trees being removed. But it is obvious 

 that, when the object is to produce valuable timber,^ 

 thinnings must so be managed, that the trees which are 

 destined to attain the term of rotation, and which will 

 form the final crop to be cut down, in the example here 

 given, 262 trees per acre 100 years old, shall be sound 

 and regularly shaped. It is obvious that to attain this 

 object dominant trees also may occasionally have to be 

 removed, if unsound, spreading, or irregular shaped, and 

 this is properly recognized by the author. He justly adds 

 that in such cases dominated and even suppressed trees 

 may have to be spared in order to keep the ground well 

 under cover. Such would be the practice in the case of 

 woods consisting of one species only, or of several species 

 of equal value. Where one species, such as oak or teak, 

 is of much greater value than the others, all thinnings 

 must, as a matter of course, be so arranged as to favour 

 this species at the expense of the rest. 



So far concerning the thinning of crowded woods. The 

 last section of the same chapter deals with the tending of 

 open woods for the production of large timber. Into this 

 subject, which is one of some difficulty, though of great 

 importance, it would lead too far to enter on the present 

 occasion. 



Chapter iv. contains sylvicultural notes on British 

 forest trees, with notes (by Prof. H. Marshall Ward) on 

 botanical characters serving to distinguish the principal 

 British forest trees. The two species of oak dealt with in 



