870 



SCIENCE 



[N. S. Vol. XXVIII. No. 729 



some other family or some other com- 

 munity. In the total absence of regulation 

 of the matter in the interest of the whole 

 people, each small group is inevitably 

 pushed into a policy of destruction which 

 can not afford to take thought for the mor- 

 row. This is just one of those matters 

 which it is fatal to leave to unsupervised 

 individual control. The forests can only 

 be protected by the state, by the nation; 

 and the liberty of action of individuals 

 must be conditioned upon what the state 

 or nation determines to be necessary for 

 the common safety. 



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 bottom lands. 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 iq bringing ruin to the 

 once rich central Asian cities; just as the 

 destruction of the forests in northern 

 Africa helped toward the ruin of a region 

 that was a fertile granary in Roman days. 

 Short-sighted 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 ter- 

 rible 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 practi- 

 cally 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 moun- 

 tains, 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 conse- 

 quence, instead of the regular and plentiful 

 rains which existed in these regions of 

 China when the forests were still in evi- 

 dence, 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 aU. 



That everything dries out faster than 

 formerly is shown by the fact that the level 

 of the wells all over the land has sunk per- 

 ceptibly, many of them having become to- 

 tally 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 rain-water and let it 

 escape by slow, regular seepage. They 

 have now become broad, shallow stream 

 beds, in which muddy water trickles in 

 slender currents during the dry seasons, 

 while when it rains there are freshets, and 



