FORESTRY. 



It takes 30 years to grow a tree and 30 

 FORESTS AND STREAMS. 



Hardly a woodsman or old hunter can be 

 found who does not know of some puny, 

 spring stream which, before the forest was 

 removed from its source and drainage ba- 

 sin, was a large, vigorous stream all the 

 year round. Lumbermen will tell you that 

 when the timber in such and such a valley 

 was first cut off the drainage river was large 

 and sure enough to safely carry all the 

 winter's cut in the spring drives, but that 

 in handling the second cutting it was nec- 

 essary to build dams to store the spring 

 freshets, in order to get water enough for 

 the drive ; and that now, in order to drive 

 the third or fourth operation it will be 

 necessary to get the logs in and rush them 

 down to the main river during the few 

 days of the spring freshets. 



Almost every angler has noticed that dur- 

 ing a heavy all day rainstorm, one stream 

 will rise rapidly every half hour and will 

 reach its highest pitch within 2 hours after 

 the rain has stopped, and then the water 

 will fall rapidly, until in perhaps 10 hours 

 it stands where it did before the storm ; 

 while another stream will hardly show any 

 difference during a day's rain, but will rise 

 gradually for 24 hours after the storm, and 

 then will hold its head a day or 2, when it 

 will gradually fall off to its original depth. 

 If the angler be observant, he will know 

 that invariably the second stream rises in 

 and flows through a heavily wooded coun- 

 try, while the first stream flows through a 

 country where the ground is not protected 

 by a good tree cover. "In the first instance 

 the water does not sink into the ground at 

 all, but runs off immediately into the drain- 

 age, while in the last instance the soil, 

 thanks to decaying vegetable matter, leaves, 

 etc., is*covered with a thick layer of humus, 

 which serves as a sponge and absorbs the 

 water, holding it and gradually letting it 

 drain into the stream. In this case the soil 

 never becomes wholly dry, and the stream 

 has a constant and steady source until the 

 next rain. The canopy of tree cover, of 

 course, prevents the loss .of rainfall through 

 evaporation by wind and sun, which in a 

 country of small rainfall is a matter of the 

 greatest importance. It is the quantity of 

 water that passes into the soil, not the 

 quantity of rainfall, that makes a region 

 garden or desert. Authorities have debated 

 and disagreed for years on the influence of 

 forest growth on the rainfall of a region. 

 Because rainfall is most abundant where 

 forests grow, many reputable scientists have 

 contended that forests exert an important 

 influence on the actual quantity and fre- 



401 



minutes to cut it down and destroy it. 



quency of precipitation ; but, as Professor 

 J. W. Tourney says, in his admirable tract 

 on "The 'Relation of Forests to Stream 

 Flow," "A more reasonable inference is that 

 rainfall is the great factor in controlling the 

 distribution and density of forests." 



Precipitation occurs whenever the air is 

 suddenly cooled below the dew-point. The 

 most effective cause of this is the expansion 

 of air 00 ascending, and this upward move- 

 ment is caused largely by cyclonic storms. 

 Whether forests have any appreciable effect 

 in cooling the air to below the dew-point is 

 uncertain. From the known effect of for- 

 ests on the temperature and relative humid- 

 ity of the air, it is only reasonable to infer 

 that they may have some such effect, at 

 least to a small degree, and consequently 

 that they may have some influence in in- 

 creasing precipitation. The extent of this 

 influence, however, no well grounded for- 

 ester will attempt to define. In nearly every 

 one of the hysterical magazine articles on 

 forestry by the new school of professional 

 nature and forest lovers, we find some defi- 

 nite statement that if the forests are cut 

 off the rainfall will be cut off with them. 

 Fortunately, however, the reading public 

 has begun to be sceptical of these yarns, and 

 to tire of the self-advertised authors of 

 them. 



A determined effort is being made by the 

 Geological Survey and by the Bureau of 

 Forestry to find out definitely just what 

 and how great the influence of forest growth 

 is on both rainfall and stream flow. 



The State of New York recently appro- 

 priated $1,500 for co-operative hydrographic 

 work with the U. S. Geological Survey in 

 maintaining authentic records of the rise 

 and fall, the ordinary outflow, floods and 

 drouths of the streams in New York. The 

 division of Hydrography in the Survey has 

 been conducting similar experiments in 

 nearly every prominent river basin in 

 the United States for several years. The 

 final results will prove of great importance 

 to the progress of the forestry movement 

 in the country. 



LOUISIANA FOREST LAW. r 

 The last session of the Louisiana Legis- 

 lature passed an act to establish a depart- 

 ment of forestry to provide for the preser- 

 vation of the forests, to prevent and sup- 

 press forest fires, and to restore denuded 

 lands. 



It provides that the register of the State 

 land office shall be commissioner of fores- 

 try, with an addition of $500 in salary. 

 With him 4 other citizens, serving without 



