482 



Garden and Forest. 



[Number 406. 



tion which will be of use in forestry and illustrate its 

 practical operation. There is no other place in the United 

 States at present where practical forest management can 

 be studied, and we are glad to know that Dr. Schenck, the 

 resident forester, is already collecting around him a small 

 body of American forest students. This is an appropriate 

 beginning for a real forest school, and if it develops into 

 the first fully equipped school of forestry in America it will 

 be a natural and normal growth. Biltmore would be an 

 ideal home for such an institution and for a forest experi- 

 ment station, and a result like this would be a happy cul- 

 mination of a broadly conceived and wisely conducted 

 enterprise. 



The Disappearance of Western Lakes. 



NOT long ago, the St. Paul Pioneer Press published 

 some reports from several counties in Minnesota 

 and Dakota, in reference to the reduction of the lake area 

 of that region. The map of Minnesota is dotted all over 

 with these sheets of water. There were some seven thou- 

 sand of them ten years ago, but probably one-third of 

 those that were shown in the surveys at that time have 

 disappeared, while the surface levels of those which 

 remain have fallen several feet. Flax and wheat and 

 grass are growing where fish were swimming a few years 

 ago ; lakes have degenerated into mud-holes, and the 

 larger ones have shrunk in area and decreased in depth 

 from four to eight feet. This remarkable change in the 

 surface of the country is one of which the people in the 

 east have heard comparatively little ; and in reply to 

 inquiries on the subject we have received interesting letters 

 from the experiment stations of North Dakota and Minne- 

 sota which verify the facts and give a few of the theories 

 which have been used to account for them. 



Professor Green, of the Minnesota station, writes, that 

 where for several years crops have been growing on these 

 former lake beds, the question as to the title to the land of 

 those \\A\o now till them, and who originally purchased 

 farms on their shores, is a question of much controversy. 

 The reason generally assigned for the phenomenon is that 

 since the contiguous prairie land has been broken up, a 

 great proportion of the rainfall soaks into the ground 

 instead of running off into the lake basins. Professor 

 Waldron, of North Dakota, after citing this theory, adds that 

 many lakes which are still surrounded by original prairie- 

 sod that has never been broken by the plow nor dis- 

 turbed by pasturage, have shrunk to the same extent as the 

 lakes in the tilled area. This, however, does not prove 

 the theory incorrect, from the fact that as the lakes in the 

 tilled area gradually dry up the natural water-table sinks 

 from year to year, and the effect of this is seen upon all 

 other lakes, including those surrounded by unbroken 

 prairie. Devil's Lake, which is fifly miles long, has fallen 

 eight feet in twelve years. Professor Waldron suggests 

 that there might be some geological causes for this 

 special case, but the fact that all the lakes over the eastern 

 part of North Dakota, some of them two hundred miles from 

 Devil's Lake and on different water-sheds, are passing 

 through the same change, and that the rivers are also much 

 smaller than they were ten years ago, would seem to indi- 

 cate some general cause which operates throughout the 

 whole area. 



Another explanation offered is that a series of wet 

 seasons tends to fill up the land depressions, while a series 

 of dry years has the opposite effect. But, so far as the 

 records for twenty years show, there is no such alternating 

 series of wet and dry seasons. If any three seasons taken 

 together are compared with any other three seasons, the 

 difference in the total rainfall for the two periods is less 

 than half an inch, while the rainfall of no single year has 

 fallen more than two inches below the average, or has ever 

 been more than two inches in excess of the average. The 

 distribution of the rainfall as to the seasons of the year has 

 a marked temporary influence on the amount of water in 



lakes and shallow sloughs. Five years ago a large slough 

 adjoining the city of Fargo was left entirely dry after a 

 dry spring and summer, and it remained dry until the 

 next year, when heavy autumn rains filled it to an average 

 depth of five or six feet, and the water thus accumulated 

 remained comparatively constant for three years, when the 

 slough was dried up liy draining. The rainfall during these 

 three years had not been perceptibly heavier than it was 

 during the three previous years, but larger quantities fell 

 during a short period in the spring and fall, and if the same 

 amount of precipitation had been distributed over longer 

 periods the adjoining lands would have absorbed more, 

 leaving the slough comparatively dry. This explanation, 

 however, will not account for the condition of lakes that 

 were ten years ago constantly full of water and have been 

 gradually becoming drier and drier, until crops are now 

 grown in their basins every year. 



There seems to be no doubt that there have been periods 

 in former times when the lakes were dry or the water in them 

 very low, after which they filled up again and remained so 

 for a long time. Whether this region is passing through 

 one of these periods of low levels now, which is to be fol- 

 lowed by a higher lake-level in a few years, no one knows, 

 but it is not improbable that the increased tillage of prairies 

 and the cutting away and the burning of the woods will 

 operate against a recurrence of the high-water level. The 

 subject is certainly one of great interest, and in the absence 

 of accurate meteorological data, which extend back for a 

 long period of years, it has been difficult, so far, to find any 

 solution of the question which is altogether satisfactory. 



Notes on some Arborescent Willows of North 

 America. ^V. 



Salix PipERi, n. sp. [§ Lanatje]. — Twigs stout, very 

 smooth, dark brown ; leaves elliptical-oblong, obovate or 

 oblanceolate, one and a half to two inches wide, four to 

 six inches long, acute, glabrous, dark green above, glau- 

 cous beneath, irregularly undulate-crenate or nearly entire ; 

 petioles slender, one-half to three-quarter inches long; 

 stipules none ; buds large, smooth, chestnut-brown ; male 

 aments sessile, thick, one to one and a half inches long-, 

 copiously silky with straight white hairs as long as the fila- 

 ments ; filaments united at base or free ; female aments 

 more slender, less silky, shortly peduncled ; scales obovate 

 or orbicular ; capsule ovate-lanceolate, smooth ; pedicel 

 three times the length of the gland ; style as long as the 

 pedicel ; stigmas bifid, entire. Seattle, Washington, Pro- 

 fessor Charles V. Piper, Nos. 558, 560. Named for the 

 discoverer, who has made a most thorough exploration of 

 the rich Willow flora of Puget Sound. Professor Piper 

 sends the following field-note : 



During the several seasons that I was especially interested 

 in tiie collection of Willows, I found, near Seattle, only three 

 plants, with one or two at other points. Two of these, staml- 

 nate, grew, one in a swamp near Lake Union, the other not far 

 distant in a Sphagnum-bog on high ground. Both had several 

 stems rising from the same root eighteen to twenty feet high, 

 not much branched till near the top ; branclilets dark-colored 

 and smooth. The one pistillate plant grew at the edge of Lake 

 Washington, three miles from the sfaminate mentioned above, 

 in the old gravel beach of the lake. This also had several 

 stems, three to four inclies in diameter, with a smooth dark 

 grayish bark, sparingly branched ; branches erect. Owing to 

 its extreme isolation the aments were very imperfectly fer- 

 tilized — perhaps by the pollen of Salix Scouleriana, which grew 

 in the vicinity and flowered at the same time. 



A most notable contribution to the known Willows of 

 North America was made in the Flora Boreali- Americajia 

 when three new species of the Lanata; group were de- 

 scribed, a full-plate illustration being accorded to each. Of 

 these Salix Richardsonii, of high northern distribution, is a 

 close geographical equivalent of S. lanata, which, Wahlen- 

 berg says, is " easily the most beautiful Willow in Sweden, 

 if not of the whole world.'' The other two^ — S. Barrattiana, 

 occurring rarely in the Rocky Mountains just north of the 



