March 28, 1889] 



NA TURE 



515 



The cortex of course contains most ash, and the quan- 

 tity of total ash increases with age and with height ; these 

 facts have been shown for other trees also. 



In the wood proper, the quantity of ash as a whole 

 increases from the periphery to the centre, but as we 

 shall see that the distribution of the various constituents 

 is very different in different parts, this generalization 

 will have to be cut up into a series of less general state- 

 ments. In the same period of growth the total ash 

 increases with the height. 



It is somewhat striking that the inner zones of the 

 inner alburnum yield most ash, and thus the central 

 part of the highest transverse section of the stem will 

 contain most ash. 



As regards the changes due to age, the ash per cent, 

 decreases till the tree is about 60 years old, and then it 

 increases rapidly for twenty years or so, gradually 

 diminishing again with increasing age. These periods 

 show such close relation to certain facts in the culture of 

 the trees, that they are evidently explained somewhat as 

 follows. During the first 60 years in the plantation, the 

 young beeches crowd one another more and more, and the 

 competing roots restrict one another, and the percentage 

 amount of salts absorbed diminishes year by year : at 

 or about the age of 60 years the trees are thinned by 

 systematic felling, and so more space is given to those 

 which remain, as well as more soil and ingredients from 

 the decomposition of the roots, &:c., of the felled trees. 

 The consequence is the increase of ash to a first maximum. 

 At the period about 80 to 90 years the beech has attained 

 the seed-bearing age, and the probability that the diminu- 

 tion of ash henceforth is due to the drain to supply the 

 seeds is too great to be overlooked. 



It is interesting to note that shaded beeches, at all 

 periods and in all parts, show a higher percentage of 

 total ash than fully exposed trees, and the same is true 

 of the silver fir (another tree which bears much shading) : 

 the trees store up mineral substan es, which must be an 

 advantage to them under the circumstances of growth. 



If, instead of regarding the total ash, we now look at 

 the constituents, it results that the enormous excess of 

 ash in the cortex consists chiefly of calcium carbonate, 

 from the calcium oxalate (which may form 70 to 90 per 

 cent, of the whole). Much potash, magnesia, and phos- 

 phoric acid also occur. 



In the wood, the quantity of potassium salts increases 

 from the periphery to the centre ; whereas the reverse is 

 the case with the phosphoric acid, sulphur, and magnesia, 

 a fact the more remarkable because the potash usually 

 accompanies the phosphoric acid in other parts of plants 

 — e.g. in leaves, &c. It is no accident, however, and the 

 fact comes out that the beech forms large reserve stores 

 of potash (this being the chief cause of the large increase 

 of total ash in the interior of the stem), whereas the 

 phosphoric acid and sulphur travel outwards with the 

 proteids, being repeatedly used in -metabolism in the 

 cambium, &c. 



We must pass over a number of other peculiarities 

 of the distribution of the ash-constituents, to notice the 

 effect of the age of the tree on the chief salts. The dis- 

 tribution of the potash, lime, and magnesia is little in- 

 fluenced by age, but an extraordinary effect comes out in 

 the case of the phosphoric acid. The young tree starts 

 with a relatively large quantity of this constituent, but the 

 amount sinks year by year till the fiftieth or sixtieth year, 

 and then rises again to about the ninetieth year, to fall 

 afterwards : in fact, the behaviour is similar to what 

 occurs with the total ash, and is doubtless to be referred 

 to the same causes. 



Another curious result comes out in studying shaded 

 trees : whereas they take up as much potash and lime as 

 exposed trees, their magnesia and phosphoric acid fall far 

 below those of exposed trees. But the most astonishing 

 discovery is that shaded trees take up four times as much 



sulphur as exposed ones. The analyst himself notes 

 how astounding this is, but he insists that a second series 

 of analyses gave confirmatory results. 



Another queer fact is that the kind of soil exerts little 

 influence on the analyses ; though a similar conclusion has 

 been come to with other plants. 



The study of the absolute quantities of individual ash- 

 constituents in 1000 parts of the dry substance brings out 

 some interesting and important generalizations, which are 

 expressed in the form of curves, and fully bear out in 

 detail what has already been stated. 



The quantity of ash and of each ash-constitutent in 

 I cubic metre of beech-wood at various ages, as com- 

 pared with the wood of other trees, is next investigated. 

 The results show that the beech takes more potash than 

 most trees except the Robinia—iox instance, at 40 years 

 it contains more than four times as much as the spruce fir. 

 As regards phosphoric acid, the beech and oak need 

 more than other trees, beech-wood at 40 years old 

 having seven times as much as spruce at the same age. 

 With lime the facts are similar : beech needs much more 

 than conifers. 



From the whole of the preceding, it is possible to put 

 together some ideas on the quantity of ash-constituents 

 per acre needed for beech forests, and some interesting 

 tables and curves are given in this connection ; the return 

 of minerals to the soil in the leaf-fall, &c., is also con- 

 sidered. Perhaps the most important conclusion come to 

 here is that the increment in dry weight of the tree is 

 nearly proportional to the up-take of potash, whereas the 

 up-take of lime is the same — gradually increasing to old 

 age — whether the wood is good or bad, and whatever the 

 nature of the soil. The nitrogenous substance in beech- 

 wood behaves very like the phosphoric acid, in that it 

 diminishes from the tenth to the sixtieth year, and then 

 ascends to a second maximum as the tree reaches 80 

 years old ; and again, the cause is to be found in the 

 influence of the thinning, and in the demands on the 

 reserves when the tree begins to bear seed. 



.As in all trees, there is of course most nitrogen in the 

 twigs and buds, and in the finer roots. Beech and oak 

 need more nitrogen than other trees, and (so far as the 

 wood goes) the conifers need much less. The total 

 quantity of nitrogen taken up by the beech at 6 years 

 old, in fully stocked plantations, is calculated to be 39"43 

 kilogrammes per hectare, and this rises to 389'63 at 60 

 years, and 896 50 at 1 30 years. 



Calculations as to the quantity of nitrogen needed 

 annually per hectare to produce the known yield of wood 

 are then given, and again we meet with the rapid loss 

 after about 90 years, due to seed-production. To these 

 are added estimates of the nitrogen removed in the 

 thinnings, and of that restored in the fallen leaves. All 

 things considered, the quantity of nitrogen concerned 

 annually varies with the age, but at the critical period 

 of 50 to 100 years it amounts to something like 60 

 kilogrammes per hectare per annum. 



It is unnecessary to point out further the extreme 

 importance of such investigations as these : it is only 

 in proportion as a nation is armed with statistics based 

 on careful researches like these that it can form any 

 conclusions worth having as to the future value of its 

 forests and the technical merits of those administering 

 them. As to their "practical" bearings, the results 

 speak for themselves : if this is not allowed to be practical 

 science, we may indeed ignore the cry. 



H. Marshall Ward. 



SPECTROSCOPIC RESEARCHES A T THE 



NORWEGIAN POLAR STATION. 



TDART II. of the Report on the results obtained at the 



connection 



Norwegian Polar Station at Bossekop in Alten (in 

 ;ction with the International Polar Investigation, 



