June i, 1885.] 



THE TROPICAL AGRICULTURIST. 



•J'l 



clay on surface, unless thorough cultivation in the way of 

 stirring up soil by ploughing or scarifying can be afforded 

 every year. ( >f nil the acacias to which this report has 

 reference, the hark of the one under review contains the 

 iMgest percentage of tannic acid. According to experi- 

 ments instituted by Baron Sir Ferd. von Mueller, the 

 Government Botanist of Victoria, it yielded, when arti- 

 'ficially dried, from 30 to 45 per cent of tanning matter. 

 During the last year some interesting analyses have been 

 made- by Mr. George Goyder, jun., of the Survey J > 

 ment laboratory. As the result of the analyses [given 

 in detail in the report], Mr. Goyder makes the following 

 remarks:— "The thickness of the bark appears to have 

 little or no effect on the proportion of tannin. The age 

 of a tree at which the percentage of tannin in the bark 

 begins to fall off varies according to the soil, climate, &c. 

 As long as a tree looks healthy and strong, and has a 

 general appearance of sturdy growth, the percentage of 

 tannin in the bark does not appear to diminish with age. 

 Thus, although the tree at the Semaphore was about 

 thirty years old, the percentage of tannin it yielded was 

 only slightly below the average, the average for the 

 twenty samples of truuk hark examined being 2G17 per 

 cent, the lowest 174, and the highest 34'0 per cent of tan- 

 nin. In unhealthy trees, on the contrary, even though 

 young, the percentage of tannin falls off at once, as is 

 shown by those of Hundred of Bright and the Bay-road. 

 In both of these cases the trees were described as un- 

 healthy and apparently dying. Some of the trees on 

 Torrens Island were also unhealthy, and showed the same 

 results. The tannin in the bark in two-year-old twigs is on 

 an average 4 per cent lower than that of the truuk 

 bark from the same trees. The bark from the one-year- 

 old twigs, in the only case tried, contained 3 per cent 

 less tannin than the trunk bark. The leaves contained 

 on an average 4'3 per cent of tannin, but as their total 

 extractive matter averaged between seven and eight times 

 this amount, they could probably only be employed as a 

 weak solution for tanning, and even then the presence 

 of the large amount of gum and other extractive matter 

 might be prejudical to their use.'' A special feature of Mr. 

 Goyder's ananysis is that the bark unon the branches 

 and twigs of this wattle contains a very high percentage of 

 tannic acid. This fact points to the necessity of shipping 

 all available bark from the trees. During the summer 

 months this wattle exudes a very considerable quantity 

 of gum, which is used for the same purposes as the well- 

 known gum-arabic. With the conservation and cultivation 

 of the trees such as is now advocated, an opportunity 

 will again arise for the revival of this industry amongst 

 us. Acacia decurrens, or Black Wattle. — This tree is iu- 

 digneous chiefly to Victoria and New South Wales, and 

 it only appears in the South-Eastern district of this colony 

 where it is of frequent occurrence, and attains to a com- 

 paratively large size. This species of our wattle delights 

 in sandy soils with a clay subsoil ; hut it attains its 

 largest dimensions upon a black alluvial soil of great 

 depth, and where there is plenty of percolating moisture. 

 It will thrive "ell and make' very considerable progress 

 in very poor situations where the soil is almost pure 

 sand. It does remarkably well about Adelaide, as instance 

 some fan- specimens in the Botanic Gardens and Park. 

 From my experience of the tree I am of opinion that 

 while it will do well in almost any kind of soil, it will 

 net grow satisfactorily and as a payable crop on exposed 

 situations, or where the rainfall is below 15 inches 

 annually. I can therefore only recommend its cultiv- 

 ation in the moisture and more temperate portions of the 

 colony. It is recommended by Baron Mueller for plant- 

 ing upon worn-out lands overgrown with sorrel. Its 

 cultivation upon our South farms in the neighbourhood 

 of Strathalbyn, and in the older-settled districts among 

 the hills, would therefore be advisable. The climate 

 and soil of these districts are suited to its cultivation. 

 According to analysis made under the direction of the 

 Victorian Wattle Board, the bark of A. decurrens yields 

 from 29 to 34 per cent of tannic acid. Upon the bark 

 of a tree twelve years of age, grown near Mount Gambler, 

 Mr. fleorge Goyder's observations are as follows: — "Thiek- 

 ness of bark, (1-34 in.; per cent of tannin, 27 '5 ; and 

 per cent of extractive matter, 447. This species 

 cuu bo cultivated as readily as A. pyeuautha. Aftre 



bushfires run over any district composing its habitat, it 

 springs up in abundance. The tree is somewhat branchy 

 in its habit, and requires close planting in order to check 

 this and make it throw its woodmaking vitality into 

 the stem. One pound of seed is said to contain as 

 many as 40,000 grains. These can be germinated with 

 less heat and earlier than those of the broad-leaf species. " 

 Acacia salijma, or the Western Australian Wattle. — 

 This tree is now under experiment at the Wirrabara 

 Forest Nursery, but nothing can yet be said as to its 

 adaptability or otherwise to our conditions of soil and 

 climate. Acacia dealbata, or Silver Wattle. — In this colony 

 the silver wattle is confined to the South-Bastern district, 

 but unfortunately its bark is comparatively thin and 

 weak in tannic acid. 



THE SYSTEMATIC MANAGEMENT Or INDIGNEOUS AND PLANTED 

 WATTLE ENCLOSURES. 



Under this heading I shall make some general remarks 

 in regard to the best methods to pursue in the treat- 

 ment of natural-grown wattles, and of putticg land under 

 a crop of the tree by artificial means, so that the profits 

 may be realized which 1 maintain can be procured from 

 their cultivation. Unless where the name of a species is 

 specially referred to, the term ''wattles" will apply to 

 both A. pyenantha and A. decurrens in a general way. 

 First in importance to the wattle farmer is the subject 

 of how best to treat the seed so that it may germinate 

 in a reasonable time after being put in the ground. Tho 

 outer covering of the wattle seed is of great hardness, 

 and requires the adoption of extreme measures before it 

 will burst and permit the embryo to expand and start 

 the young plant. With this seed nature's method of 

 germination appears to be a very slow one, as it is 

 known that it will remain in the ground for many years 

 before sprouting takes place. The application of one 

 winter's rains to it does not have the usual effect pro- 

 duced ou most kinds of seeds, and it appears to require 

 several years of saturation before the hard covering be- 

 comes soft enough to permit germination. One of the 

 most effectual natural means of hastening their germin- 

 ation are bush fires ; after one such, over ground upon 

 which the wattles have grown naturally, thousands of 

 young plants spring up. This fact is well known to all 

 colonists. There are two methods of treatment adopted 

 in the preparation of the seed before sowing. Both of 

 these are effectual and have their respective advantages. 

 The first is to subject it to the softening influence of 

 hot or boiling water. Hitherto, in referring to this pro- 

 cess, I have recommended that the seed be placed in a 

 vessel and almost boiling water only poured upon it and 

 left to soak for one or two days ; after this the seed 

 to be taken out and kept damp in a bag until signs of 

 swelling takes place. From experiments lately made 

 bowi i it, by Professor Tate, of the Adelaide University, 

 of treating the seed to various degrees of hot water 

 the fact has been conclusively demonstrated that it will 

 stand partial boiling without injuring its vitality. As 

 these experiments are of vital importance to the "wattle 

 industry they have been handed to me for publication. 

 They are therefore given in full as follows:— Experiment 

 1. Acacia pyenantha— Equal parcels of seeds saturated 

 with water at the following decrees of temparature — 

 150% 170°, 190 , 200', and 212°. The seeds germinated 

 iu ubout equal proportions at end of three weeks. Ex- 

 periment 2. Acacia decurrens— Seed saturated nritfi 

 boiling water, and kept in wet sand in a warm place ; 

 germinated at end of two weeks. Experiment 3. Acaeia 

 saligna — Seed saturated with water at 212 of heat, .Tidy '-'2 ; 

 seeds began to burst July 29. Experiment 4. Acacia 

 pyenantha — July 22— Boiled for one minute, three minutes, 

 five minutes, and sevenmiuutfs respectively. All the seeds 

 germinated August 9. The second method of treating the 

 seeds is that of subjecting it to a slow (ire to such an ex- 

 tent that the outer covering only is slightly cracked with- 

 out injury to the embryo. The advantage claimed for this 

 method of preparation is that the seed can be sown either 

 broadcast upon the ground without covering or dibbled 

 in the soil iu the ordinary way at any season of the year, 

 and especially before the winter's rains set in, and then 

 lie dormant until such time as sufficient moisture falls to 

 geiminate and nourish the ynuig plant successfully through 



