122 



NA TURE 



{Dec. 12, 1889 



haustively treated, and in regard to the climatic influence 

 of forests the author gives a most useful summary of the 

 researches which have been made to determine the effect 

 of forest growth upon the temperature of air and soil, 

 rainfall, humidity, and evaporation, in Germany, Switzer- 

 land, and France, mainly by the establishment of parallel 

 stations, one being situated inside a fully stocked forest 

 and the other at some distance in the adjoining open 

 country. 



Part II. sets forth the fundamental principles of sylvi- 

 culture. The author maintains, with justice, that the 

 principles of sylviculture hold good all over the world, 

 but adds that the illustration of these principles must be 

 taken from a limited area. For this purpose he has 

 chosen the timber trees of Western Europe on the 

 50th degree of north latitude, and the countries im- 

 mediately to the north and south of it— in other words, 

 the forest trees of England, Northern France, and the 

 greater part of Germany. These species the author does 

 not attempt to describe ; he assumes that his readers are 

 familiar with them. The first chapter dwells upon the ex- 

 ternal conditions which influence the development of 

 forests. He says : — 



" Soil, including subsoil, and atmosphere are the media 

 which act upon forest vegetation, and they together are in 

 sylviculture called the ' locality.' The active agencies, or 

 factors, of the locality depend on the nature of the soil 

 and the climate, the latter being governed by the situation. 

 The sum total of these factors represents the quality or 

 yield-capacity of the locality. The forester requires to 

 be well acquainted with the manner in which soil and 

 climate act on forest vegetation, in order to decide in 

 each case which species and method of treatment are best 

 adapted, under a given set of conditions, to yield the 

 most favourable results." 



Every forester knows that on good soil, and under 

 conditions otherwise favourable, a timber crop is heavier 

 than one of equal age grown under less favourable con- 

 ditions. In the concluding section of this chapter the 

 author shows how one may use this fact in order to 

 assess the quality of a locality. Numerous measurements 

 of woods of different species and ages, grown under dif- 

 ferent conditions, have been made in Germany on a syste- 

 matic plan, and from the data thus obtained yield tables 

 have been calculated, showing the volume of timber pro- 

 duced at different ages on a given area by the principal 

 species on localities of different quality classes. Using 

 the yield tables published for the Scotch pine by Wilhelm 

 Weise, now Professor at the Forest School of Karlsruhe, 

 the authar shows that at.the ages of 50 and 120 years the 

 volume per acre of timber only, not including faggots, in 

 localities, which according to their yield-capacity are 

 classed as first, second, and third class, is as follows : — 



The figures of these yield tables Dr. Schlich has 

 found to a certain extent to be applicable to Scotch pine 

 forests in England. They can therefore be used in order to 

 assess the yield-capacity of any locality stocked with 

 Scotch pine. Eventually, similar yield tables will doubt- 

 less be prepared for the Scotch pine and other forest trees 

 in Great Britain, and it will then be possible with 



certainty to say what yield of timber may be expected 

 from plantations made in a certain locality. 



The second chapter deals with the shape and develop- 

 ment of forest trees, but we can refer only to what the 

 author says regarding height-growth. Building again 

 chiefly upon researches made in Germany, Dr. Schlich 

 explains how the different species have a different mode 

 of height-growth. On p. 163 an instructive diagram will 

 be found exhibiting the relative height-growth of spruce, 

 silver fir, beech, and Scotch pine, in a locality of the first 

 quality. At the age of 50 years the mean height attained 

 by each species is as follows : — 



Scotch pine 

 Beech 

 Spruce 

 Silver fir 



64 feet 

 60 „ 

 55 „ 

 40 ,, 



At a later age spruce and silver fir take the lead, while 

 beech and Scotch pine remain behind in the race ; and 

 when 120 years old the order of the species stands as 

 follows : — 



Spruce 

 Silver fir 

 Beech 

 Scotch pine 



118 feet 



108 „ 



102 ,, 



97 » 



Scotch pine and beech therefore make the principal 

 height-growth during the first period of their life, whereas 

 spruce and silver fir continue to grow vigorously in height 

 to a much greater age, spruce more so than silver fir. 

 The progress of height-growth of the different species is 

 much affected by the character of the soil, by elevation, 

 the more or less crowded state of the wood, and other 

 circumstances, but under otherwise similar conditions it 

 will always be found that deep, fresh fertile soil produces 

 much taller trees than shallow, dry, or rocky soil. 



In the third chapter, which deals with the character 

 and composition of woods, the author points out that the 

 object of sylviculture is not to rear isolated trees, but con- 

 siderable masses of trees, forming more or less crowded 

 woods. Pure woods consist of one species only, or of one 

 species with a slight admixture of others, whereas mixed 

 woods contain a mixture of two or more species. The 

 advantages of mixed woods are clearly set forth, and th e 

 author's remarks on this subject may be specially recom- 

 mended to the attention of proprietors and managers of 

 woodlands in Great Britain. 



The last and most important chapter deals with the 

 sylvicultural systems — that is, the different methods under 

 which the creation, regeneration, tending, and utilization 

 of woods are effected. The three well-known classes 

 are : first, high forest, originating in seedlings, either 

 self-sown or artificially raised ; second, coppice, which 

 regenerates itself from coppice shoots ; and third, coppice 

 with standards, a combination of seedling and coppice 

 forest. The modifications of these three main systems are 

 numerous, and particularly the treatment of high forest 

 has developed in a great variety of ways. On this subject 

 wa must refer the reader to the manual. These are 

 matters which can hardly be fully understood without 

 opportunities for obtaining practical experience of forests 

 treated under the various systems described. Such 

 opportunities may, to some extent, be found in Great 

 Britain. The high forests of larch and Scotch pine in 

 Scotland, raised by planting, are excellent, and in some 



