Mr. Lin said that from their relation to stream flow and soil n, one could readily see the relation of forests to floods. 0 all denticled mountains, a heavy rain is generally followed by the for-motion of a system of gullies. These gullies begin a short distance below the divide and then form liner of least resistance to the passage of water. As these gullies or furrows extend down the slope, they neighbouring furrows and become rapidly wider and deeper unfit large gullies of many feet deep are formed, Where hills are thoroughly drained by " system of gullies, the water from a storm will sweep down through them in a fraction of the time that would be requi it had to trickle down in a thin sheet or amidst. vegetable obstacles, Now. if the main channel is unable ge the influx of water as rushes, down, the result from denuded hills and mountains, enables: them to.carry an enormous amount of silt and boulders of extraordinary size, The transporting power of water varies as the sixth power of its velocity, so that if the Welocity of a stream is increased ten times for instance, its transporting power is increased a million times. This. is why, in the case of CChibli rivers, they speak of stones and boulders) of large sizes carried down to the foot of mountains, and fof the enormous quantity brought down to raise the beds that have already' been silted up.
the problem of flood in Chihli, therefore, is fundamentally a forest problem; continued Mr. Lin. "A Systematic programme of reforestafion will have to be eried out before the problem of Silt, the problem of unrestrained run-off of infall, and the problem of reser-vairs, of dikes and: outlets can be permanently solved.
Me. Lin then quoted what several authoilties had to say in reference to forests and floods. Mr. J. Taylor, in his attempt to arouse the people in Chibli to the necessity of inaugurating s permanent, Conservancy Board, suggested among other things that reforestation was the most important remedial measure that should be taken in the control of Chihli floods, and he' emphasized the point by saying: "Iz is absolutely essential to ameliorate the rivers, especially the Hun Ho, -in the mountainous collecting basin, by reforestation and by the erection of barrages. The first effect of this is to delay the waters during heavy: and 80 reduce the freshets and the liability to floods. But these improvements have a much more important effect, namely the keeping back of the silt which is so injurious to rivers. Forests act as a sponge. retaining: moisture and furnishing s protective coating that prevents erosion." study of river system in Chihli, wrote: "There are three ways of solving the flood problem in Chihli, na: ly: (1) reforestation: (2) erection of barrages: and (3) construction. of reservoirs. But the erection of barrages and the construction of Yeservoirs require such an enormous expenditure of money, and besides they do not have a permanent effect. So we may safely say that reform estation is the best and the most important measure to be considered in the control of floods in Chihli provin Dr. PO. Licent and Mr, T. Pineione had the same thing to say, namely that the best way to crat: fate the flood menace was to pay. attention to reforestation, Mr. H, Vander Veen, C.E., who has been for many years consulting engineer to the Natural Conservancy Darvas ta, Pebing, re. the slope of the water level is such that a current can be maintained strong enough to carry all the matter held in' suspension along, no, harm is done. But....the natural slope of the plain is, for rivers, insufficient, In' such a case the river is therefore forced to get vid of the soil, held in suspension, along its way, consequently its bed gets raised and on the long run the river has to find another course, which it does by bursting its dykes to find in the lower lying Iand the place where it can deposit ite bu den, which it could carry no longer and for which no more room could be found in the old bed. the ease more or less with every iver running through the plain of Undergrowth as Barrier, "The reasons why the forest is fable to check surface ran-off and save portions of it to the soil are, Mr. Lin," first, the trunks and the underbrush in the forest offer mechanical obstruction: second, the litter of the forest floor checks rapid surface drainage of the water and also acts as a sponge; and ed third, the network of deeply penetrated rocks, living and decayed, make the forest soil more porous and permeable; hence the water sinks into it more readily. It is evident that the ability of the fo est to check surface run-off is grey est when the forest is dense and when the ground beneath it covered with an unbroken leaf litter.
"Purthermore, it must be borne in mind that when water is precipitated from the clouds, a portion of it is prevented from reaching the ground through interception by the Teaves, branches and trunks of intercepted portion varies according to the tree species and the density of the woods. According to Bavarian investigations, it averages 23 per cent. of the total rainfall. So after a rain, we often find that water continues to drop irom the leaves and twigs for hours.
"It is impossible to lay too much stress upon the enormous importance of reafforestation."
Text read from the printed page and cleaned; old type leaves the occasional error.