Vol. IX. No. 207. 



THE AGRICULTURAL NEWS. 



99 



It is too early to indicate \vry definitely the 

 practical application of the facts that have been 

 demonstrated. The following general, tentative con- 

 clusions, however, affect directly the work of the 

 planter: (1) that the growth of young plants may 

 be stimulated by means of freshly applied ammo- 

 nium sulphate; (2) that, unless the land is verj' poor 

 in nitrogen, there is little need for an interval to 

 elapse between the application of ammonium salts to 

 the soil and the growing of the crop, for they are immed- 

 iately available, to a fair extent: (3) that ammonium 

 salts applied after the plant is well established will 

 do immediate good to a certain degree: (4) that where 

 plants are required to assimilate a large amount of 

 nitrogen, it seems likely that applications of ammonium 

 salts, together with nitrates, would bo beneficial. 



METHODS OF MEASURING TREES. 



Tlie following discussion on the methods of 

 measuring trees appeared in the Indian Forester, 

 Vol. XXXV, No. 11 (November 1909). It is of more 

 particular interest in view of the increasing attention 

 that is being given, in the West Indies, to matters 

 coniieeted witli forestry and rubber production : — 



There are two .systems ordinarily in vogue [in India and 

 liurina] for the classification of trees; one by giith classes, 

 and the other by diameter classes. For the former, classes 

 of 18-inch periods are usually adopted, and for the latter, 

 classes of 6-inch periods. Thus for girth classes, it is usual 

 to speak of trees measuring less than \h feet in girth, at 

 breast height, as V class trees; those above 1 i feet and up to 

 3 feet as IV class: those above .3 feet and up to ih feet as 

 III class; those above li feet and up to 6 feet as II class, 

 and those above 6 feet in girth as I class. It is equally 

 common, when reference is made to trees classified by 

 diameter measurements, to speak of trees up to 6 inches in 

 diameter, at breast height, as V class trees; trees above 6 

 inches and up to 1 foot in diameter as IV class; trees above 

 1 foot and up to IJ, feet as 111 class; trees above \l feet and 

 up to 2 feet in diameter as 11 class; and trees above 2 feet in 

 diameter as 1 cla.ss. 



It thus comes about, that 1 class trees are loosely refer- 

 red to as being either above 6 feet in girth or above 2 feet in 

 diameter, as if these measurements were synonymous. 



Again, the classes mentioned above have practically 

 become, throughout India, standard classes of measurement, 

 and it only remains for it to be decided whether girth classes 

 or diameter classes are to be adoiited for the future. 



It is therefore, we consider, most advisable that definite 

 standard classes should be fixed so that it will always be 

 known what is meant by a I class tree, II class, and so on. 

 In our opinion, girth classes are the most suitable, for the 

 sections of trees are seldom circular, and it is a matter of 

 some difficulty to ascertain the e.xact average diameter of 

 a tree, whereas the exact girth can ahvays be easily ascer- 

 tained. l!y this we do not mean that all measurements of trees 

 for marking, etc., should be done by tape. It is easy to have 

 callipers graduated to correspond to the diameters of the 18- 

 inchcs girth classes, and it is usual in practice, whpn using 



callipers, to measure each tree in two directions at right angles. 

 We have found it quite accurate, if it is shown that a tree, 

 measured in both directions, falls to the sVaine, to record it as 

 belonging to that class; but when the measurement in one 

 direction locates a tree in one class, and in the other direc- 

 tion in another cla.ss; we found that the simplest way to decide 

 the right class was by girth measurement with a tape. We 

 recommend that the girth classes given above be now otiicially 

 adopted as standard classes, so that in future, there will be no 

 doubt as to wliat is meant by a I class tree, 11 class, and so 

 on; and as these classes are already generally known and used, 

 it would be sinqjier to adopt them than to lay down a revised 

 scale of classes altogether. 



Of course, we recognize the fact that, for many working- 

 plans and other purposes, the standard classes would not be 

 sufficient, as it is often necessary to discriminate between the 

 sizes of trees above 6 feet in girth, and to differentiate in more 

 detail between smaller trees. For the latter, subdivisons of 

 the standard classes will generally suffice, but for all other 

 divisions from the standard classes, we recommend the 

 adoption of letters to indicate that the class referred to is 

 a special one. Thus, in cases where a minimum exploitable 

 size of above 7\ girth is adopted, the class above 7i feet in 

 girth might conveniently be termed M class, meaning 

 mature, or by any other appropriate letter. Any officer 

 coming across the mention of an M class tree for the first 

 time, would at once enquire what it meant, and no confusion 

 would arise. 



The question as to the height at which the girth 

 measurements should be taken is more complicated, for on 

 account of some species developing large buttresses, they 

 cannot be measured at the usual breast height, which is 

 generally taken to be 4^, feet above the ground. For 

 practical purposes, it will probably be sufficient for the 

 girths to be taken as they are now at breast height, where 

 there are no buttre.sses, and as near above that as the 

 buttresses will allow, if there are no buttres.ses, except when 

 the buttressed portion is utilized, in which case a correcting 

 factor might possibly be adopted. This matter is one on 

 which some enquiry is necessary before standard rules can be 

 decided on. 



The Cause of the Germination of Seeds. 



It is a matter of conunon observation that a stage exists, 

 in all vegetable life, when the vital activities seem to be 

 suspended. In most of the plants with which thera is 

 a common familiarity, this stage belongs to the seed. There 

 is a period of dormancy, followed by what is called 

 germination. 



This period probably had its origin in the necessity for 

 the provision of a form of protection during a time when the 

 plant was surrounded by untoward conditions, as in winter, 

 or in the dry season. The end of the resting period, as it 

 may be called, came when those conditions were succeeded 

 by others which were favourable. There is the additional 

 consideration that time and opportunity had also been 

 aftbrded for the wide separation of the embrj-o plant from its 

 parent, or parents; provision was made for the distribution 

 of the species. 



These matters naturally lead to the question which asks 

 what it is within the seed that causes an awakening of life to 

 take a,dvantage of the favourable conditions that occur once 

 again. The answer given by the most careful investigations 

 that have been undertaken up to the present is, that the 

 cause is provided by the ability of the protoplasm in the 

 seed to respond to its surrounduigs. 



