FORESTRY. 



351 



diminished supply of fuel if dependence was to 

 be placed upon the yearly growth of wood, 

 and if not, then the utter extinction of the 

 forests was threatened. It was found also that 

 the removal of the forests from the slopes of 

 the mountains gave rise to torrents, which car- 

 ried rocks and stones into the fields and plains, 

 and so covered them as to make them, in many 

 cases, no longer capable of cultivation, and to 

 oblige the inhabitants to remove. Floods and 

 droughts were also found to be increasing. 



Measures were then taken for the protection 

 of forests, and in some of the European coun- 

 tries the authority and care of the government 

 have been exercised in their behalf for several 

 hundred years. It is more than two hundred 

 years since the great Colbert, minister of Louis 

 XIV, called the attention of that monarch to 

 the dangers threatening France on account of 

 the destruction of her forests. From the royal 

 ordinance then issued, embodying severe laws 

 against trespassers, dates the system of forest 

 management and protection, which, with some 

 changes, has continued in operation in France 

 to the present time. 



The system of forest protection in Germany 

 dates further back, but has been much devel- 

 oped and improved within the past hundred 

 years. Indeed, we may say that forestry has 

 taken the position of a science and an art only 

 within the present century. Inquiries and ex- 

 periments, reaching through many years, have 

 been made by most competent observers ; laws 

 of vegetable growth have been diligently in- 

 vestigated ; the effects of climate, soil, and situ- 

 ation in other respects upon the growth of trees 

 have been traced, and the effects in turn of trees 

 upon the soil and climate, upon rain-fall and 

 moisture. The mechanical effect of forests as 

 barriers against harmful winds and as a protec- 

 tion to crops has been inquired into. These 

 and many other things connected with tree-life 

 and tree-growth have been made the subject of 

 patient and scientific study. 



It required but little examination to make 

 manifest the connection of forests with rain-fall 

 and water-supply as well as with floods and 

 droughts. It had been noticed that, as the for- 

 ests diminished, the volume of many streams, 

 such as the Volga, the ?o, the Rhine, and the 

 Seine, were lessened, while also floods and 

 droughts had become more frequent and tor- 

 rents more destructive. Investigation showed 

 that the leaves falling, from year to year, in the 

 forests, and sheltered from the winds so that 

 they are not dispersed, accumulate to a consid- 

 erable depth, and, slowly decaying, form a cov- 

 ering of light, spongy soil, or humus, which is 

 capable of absorbing the rains and snows. This 

 spongy soil, in woods long undisturbed, is some- 

 times two or three feet in thickness. It is easy 

 to see that such a mass would be able to hold a 

 vast amount of water, and that the rains, instead 

 of flowing off at once into the streams, would 

 be detained for a time, trickling away gradu- 

 ally, as from a sponge, into the water- courses, 



or, sinking slowly into the ground and follow- 

 ing the seams and channels in the rocks, would 

 come out as springs and rivulets in the distant 

 meadows. So the streams and rivers do not 

 rise and fall with every shower, but maintain 

 an equable flow most serviceable to man. 



The removal of the forests produces a great 

 change in the water-flow. The first effect is 

 to dry up the accumulated leafy soil by the in- 

 fluence of both sun and wind, which are now 

 let in upon it. Thus, as the leaves dry, they 

 are waited away by the winds or washed away 

 by the rains. The spongy soil being thus re- 

 moved, the rains or snows have nothing to de- 

 tain them, but flow at once down the hill-sides 

 into the water-courses, filling them often be- 

 yond their capacity, overflowing their banks, 

 and carrying destruction in their course. 



For the same reason that the rains pour so 

 quickly into the streams and cause sudden and 

 destructive floods, in those seasons when the 

 rains are not abundant, as in summer, there 

 being no longer a great spongy surface upon 

 the hill-sides, the streams are diminished, and 

 many of them disappear for a time. The fields 

 become parched, the cattle faint, the mills stand 

 idle, and great loss and suffering are the re- 

 sult. 



It is to be observed that the removal of the 

 forests affects the water-supply of streams in 

 another way. When ground which has pre- 

 viously been shaded by trees is opened to the 

 sun and wind by their removal, the evapora- 

 tion of moisture from the earth is greatly in- 

 creased. Hence, much of the water which 

 would otherwise sink into the ground and sup- 

 ply distant springs, or find its way into the 

 streams, is now carried into the air as vapor. 

 The streams, therefore, have a less average 

 depth than they would have if the forests were 

 not removed. The Rhine, the Elbe, and the 

 Oder, it was stated at a Forestry Congress 

 held in Vienna in 1873, are all shallower now 

 than in the past. It was asserted that the Elbe 

 at Altenbrucke, in Hanover, in 1787, was 48 

 feet in depth at low water. In 1812 it had de- 

 creased to 46 feet 6 inches ; and in 1837 a fur- 

 ther reduction to 38 feet was indicated, mak- 

 ing a diminution of 10 feet in half a century. 

 The Elbe rises in Bohemia, where, until re- 

 cently, the forests were under no control, and 

 so were destroyed in the most reckless manner. 

 The Rhine, also, has much less water than for- 

 merly. Its sources are in Switzerland, where, 

 more than in any other country of Europe, the 

 forests have been considered common prop- 

 erty, and their destruction has been most unre- 

 strained. A similar lessening of such streams 

 as the Connecticut, the Ohio, and the Hudson 

 is noticeable in this country. .These and many 

 other streams no longer afford such facilities 

 for commerce as formerly. Traffic upon them 

 has to be carried on in smaller vessels than 

 such as were formerly employed. The lesser 

 streams, which were used extensively for manu- 

 facturing purposes, have also become so dimin- 



