Periodical Literature. 335 



stands of type i, the volumes lie between those for pure stands of 

 the two species ; in type 2 the admixture of spruce adds 15 to 20% 

 to the volume of pure pine in most cases. In type 3, no influence 

 of the spruce admixture or volume is noticeable. 



The three plots of larch-pine-spruce, originating from sowings 

 made over 100 years ago, correspond as regards volume and 

 height growth to the ideals which are usually ascribed to mixed 

 stands, their volumes being in excess of yield tables for pure pine 

 or spruce (by 15 to 50%). But the larch, for which yield tables 

 are lacking, is, to be sure, the ideal tree for a mixture, since under 

 its light shade the other species can still thrive. Stands like these 

 are a rarity in Germany. Failure to produce similar stands on the 

 same sites in later plantations in which only few larches have 

 maintained themselves and from which a nearly pure pine stand 

 with spruce underwood resulted, are ascribed to improper amounts 

 of seed used, and perhaps to game damage. 



The investigations into relative heightgrowth give valuable hints 

 for the establishment of mixed stands. Even-aged mixtures seem 

 to be appropriate only on the sites of type 1 ; on the other types 

 the introduction of the spruce is indicated only as underwood when 

 the pines have reached an age of 40 years. 



As regards the volume per cent., the interesting fact is brought 

 out, that while in earlier ages the pine shows mostly a higher per 

 cent, than the spruce, the per cent, for the latter after the 100 year 

 is approximately double that of the pine. While the data of tree 

 analyses are insufficient to make deductions for the whole stand 

 it may be concluded that in the mixed stand the current increment 

 shows a higher rate in old age than that of pure pine stands, and 

 that in such stands of pine and spruce mixed the index per cent, 

 sinks more slowly than in pure stands. 



The data so far gathered permit preliminary conclusions which, 

 however, may need further verification or correction. 



1. Mixed stands, in which the more fastidious species partici- 

 pate in considerable degree, say over 20% of the total volume of 

 the mature (over 100 year) stand are possible only on the better 

 sites which are favorable to that species ; otherwise this species 

 can only be underwood or soil cover. 



2. Site class I for pine corresponds to site class II to III for 

 spruce (and beech), site class II for pine to site class III to IV 

 for spruce (and beech). 



