9 2 



Garden and Forest. 



Number 419. 



inhabitants of even the most crowded city districts have an 

 absolute antipathy for the country. If this system can be 

 made to work in one or two cities, why should it not be 

 made to work in all, and why may we not hope that if this 

 practice is adopted generally and intelligently in different 

 cities that this will prove the beginning- in a small way of 

 the return from the city to the country? And if, under capa- 

 ble instruction, agriculture can be made profitable in city 

 lots, and if the good example of experiment stations is 

 visible in better farming all about them, why should not 

 actual instruction in agriculture be made a part of the cur- 

 riculum of rural common schools? It certainly is not too 

 much to hope that we can have advanced dairy schools in 

 the grazing districts and experimental instruction in fruit 

 culture, or in truck-farming, or in any other branches of 

 agriculture in the locations best adapted to each. 



We have only touched upon a few of the points which 

 are suggested by this instructive pamphlet, which is pub- 

 lishedin this city at 105 EastTwenty-secondStreet, andean be 

 bought for ten cents. No public-spirited man or woman can 

 read it without feeling that a new and promising outlet for 

 philanthropic activity is here presented, while any one 

 interested in the cultivation of the soil will find here sub- 

 ject-matter for reflection and a new and striking proof of 

 the value of intensive farming. The illustrations, from 

 photographs of natural scenes, are a most helpful addition 

 to the text, which, it may be added, is a clear, straightfor- 

 ward and forcible piece of work from a literary point of 

 view. 



Rate of Growth of Loblolly Pine. 



THE rate of growth of Loblolly Pine, Pinus Taeda, may 

 be fairly indicated by the analysis of 47 individual 

 trees, which were selected for the study in the Division of 

 Forestry on various sites within the geographical range of 

 the species. The comparison of the growth of Loblolly 

 Pine on sites of different descriptions also throws some 

 light upon the silvicultural requirements of this species, 

 and suggests forest conditions favorable or unfavorable to 

 its development. 



Height Growth. — The height growth of Loblolly Pine is 

 very vigorous. For the first 10 years it reaches a height 

 from 18 to 20 feet, thus producing from 22 to 23 inches 

 annually. The second decade seems to be the period of 

 most rapid height growth, during which period the annual 

 accretion gradually increases and reaches the maximum 

 between the 15th and 20th year, that maximum being 

 somewhat more than 24 inches. With the third decade the 

 annual accretion begins to lessen, though the height growth 

 is still vigorous, and gives an annual increase from 15 to 16 

 inches. A tree 30 years old is 50 feet high. From the 30th 

 year the decrease in the height accretion becomes more 

 noticeable ; for the next 20 years the stem lengthens only by 

 20 feet, or by an annual increase of only 12 inches. A tree 

 50 years old will be 70 feet high. From this age the annual 

 height growth decreases considerably, being nine inches for 

 the sixth and seventh decades, and six inches for eighth 

 and ninth decades. Thus a tree at the 90th year of its age 

 reaches a height of 95 feet. At this age the Loblolly Pine 

 actually reaches its full height growth, for the height accre- 

 tion after 90 years becomes in most situations insignificant, 

 and does not exceed more than from three or four inches 

 annually. 



Though such a rate of growth in height may be looked 

 upon as a rapid one, still we learn from the analysis of the 

 individuals taken from sites of better descriptions that the 

 capacity of this species is considerably greater than that 

 shown by the average of all the trees analyzed ; for which 

 the forest conditions, to be sure, were far from being favor- 

 able ones in all cases. We find among the trees measured 

 one 36 years old with a height of 77 instead of the 56 feet 

 average. The excess of 21 feet is due to the more favora- 

 ble conditions under which it grew. The tree was taken 

 from a grove of the same age and size, and dense enoug-h 



to keep the individuals constantly in a struggle for light, 

 forcing them to lengthen their boles and to lift their crowns 

 above the others. Another tree taken from young growth 

 of Long-leaf Pine mixed with Loblolly Pine reached in 44 

 years a height of 76 instead of 65 feet. We find also in the 

 tree records two individuals 100 years old, with a total 

 height of 1 1 3 instead of the average 98 feet. These in- 

 stances show that the height growth of Loblolly Pine could 

 be considerably increased by proper care. 



Diameter Growth. — The stage of most rapid diameter 

 growth of Loblolly Pine occurs in the first 10 years, during 

 which it forms a stem of two and a half inches at breast 

 height (bark excluded). The second decade shows a de- 

 crease to 2.3 inches, the third to 2.2 inches, the fourth to 

 two inches ; a tree 40 years old would, therefore, be about 

 10 inches in diameter at breast height, including the bark. 

 The diameter accretion continues to decrease with age, 

 being 1.8 inches for the fifth, 1.6 inches for the sixth and 

 1.5 inches for seventh decade. A tree 80 years old at breast 

 height is 17 inches in diameter, including bark. From the 

 80th to 100th year the diameter increases with two inches, 

 and the average accretion for the 10th decade becomes less 

 than one inch. The diameter growth of Loblolly Pine, 

 then, follows the same law which was observed for Long- 

 leaf Pine — that is, the diameter accretion invariably de- 

 creases with age, while the area accretion remains almost 

 the same. From the table of growth given below it is seen 

 that, with the exception of the first three decades, the areas 

 formed on the cross-sections for each of all the successive 

 decades are almost equal, while the width of the rings 

 changes gradually from two and a half millimeters, which is 

 the width of a ring for the fourth decade, to 1. 2 millimeters, 

 which is the width of a ring of the 10th decade. This law 

 has a biological significance. It shows that the mass in- 

 crement, allotted to each of the stages of growth into which 

 the tree development may be divided, is equally distributed 

 over the years constituting the period. The successive 

 layers being spread over a larger surface area are, therefore, 

 successively thinner. The value of this law will be more 

 appreciated if looked at from a practical forestry point of 

 view. It establishes a definite relation between the area 

 accretion and the number of years required for its forma- 

 tion ; it says that the ratio between them is a constant one. 

 This constant factor may be obtained from the analysis of 

 a large number of trees, and once determined, it may be 

 applied in anticipating the average diameter dimensions of 

 a tree at any given age, for then a simple multiplication of 

 the factor and age is required to establish the area, and 

 hence the diameter for that age. The knowledge of the 

 dimensions of a tree at any given age, and hence the 

 knowledge of the future yield and increment of the forest 

 at any given period of its life, is the corner-stone on which 

 forestry economy bases its financial calculations. 



Mass Accretion. — The rate of volume growth of Loblolly 

 Pine is subjected to the law observed to betrj-ie with regard 

 to all other species. It begins comparatively slow, in- 

 creases gradually with age until it reaches its maximum 

 point, remaining at that point for a few years, then enters 

 into a stage of growth where the volume accretion becomes 

 smaller again. From the table given below it is seen 

 that Loblolly Pine produces for the first 50 years 25 cubic 

 feet and grows with an average annual accretion of half a 

 cubic foot. For the next 25 years it produces as much as 

 for the first 50 years. A tree 70 years old has a volume of 

 49 cubic feet. From the 70th to the 100th year the volume 

 accretion equals 40 cubic feet, and the total volume of a 

 Loblolly at 100 years is S9 cubic feet. In the table is 

 shown the increase of volume for every 10 years. Exam- 

 ining the last two columns of the table it will be seen that 

 while the current accretion, passing its maximum point in 

 the ninth decade, begins to lessen, the average annual 

 accretion still increases, approaching its maximum between 

 100 and 1 10 years. By that time the average annual accre- 

 tion will become equal to the current accretion ; that sig- 

 nifies, as we already know, that here Loblolly Pine reaches 



