The lesson of deforestation in China is a lesson which mankind should have learned many times already from what has occurred in other places.  Denudation leaves naked soil; then gullying cuts down to the bare rock; and meanwhile the rock-waste buries the bottomlands.  When the soil is gone, men must go; and the process does not take long.

This ruthless destruction of the forests in northern China has brought about, or has aided in bringing about, desolation, just as the destruction of the forests in central Asia aid in bringing ruin to the once rich central Asian cities; just as the destruction of the forest in northern Africa helped towards the ruin of a region that was a fertile granary in Roman days.  Shortsighted man, whether barbaric, semi-civilized, or what he mistakenly regards as fully civilized, when he has destroyed the forests, has rendered certain the ultimate destruction of the land itself.  In northern China the mountains are now such as are shown by the accompanying photographs, absolutely barren peaks.  Not only have the forests been destroyed, but because of their destruction the soil has been washed off the naked rock.  The terrible consequence is that it is impossible now to undo the damage that has been done.  Many centuries would have to pass before soil would again collect, or could be made to collect, in sufficient quantity once more to support the old-time forest growth.  In consequence the Mongol Desert is practically extending eastward over northern China.  The climate has changed and is still changing.  It has changed even within the last half century, as the work of tree destruction has been consummated.  The great masses of arboreal vegetation on the mountains formerly absorbed the heat of the sun and sent up currents of cool air which brought the moisture-laden clouds lower and forced them to precipitate in rain a part of their burden of water.  Now that there is no vegetation, the barren mountains, scorched by the sun, send up currents of heated air which drive away instead of attracting the rain clouds, and cause their moisture to be disseminated.  In consequence, instead of the regular and plentiful rains which existed in these regions of China when the forests were still in evidence, the unfortunate inhabitants of the deforested lands now see their crops wither for lack of rainfall, while the seasons grow more and more irregular; and as the air becomes dryer certain crops refuse longer to grow at all.  That everything dries out faster than formerly is shown by the fact that the level of the wells all over the land has sunk perceptibly, many of them having become totally dry.  In addition to the resulting agricultural distress, the watercourses have changed.  Formerly they were narrow and deep, with an abundance of clear water the year around; for the roots and humus of the forests caught the rainwater and let it escape by slow, regular seepage.  They have now become broad, shallow stream beds, in which muddy water trickles