490 



Garden and Forest. 



[December 5, 1888. 



elusive for the same reason — lack of proper data. He arrives 

 at the opposite result from that of Mr. Gannet for the same 

 region by comparing the position of isohyetal lines constructed 

 for two different periods about thirty vears apart. 



The second class of wholesale methods, which compares 

 data simultaneously obtained from stations differently situated 

 as regards forest conditions, has been lately employed by the 

 eminent Russian climatologist, A. Woeikoff. He chooses an 

 area in northern India, which is partly a treeless region and 

 partly densely wooded, and is otherwise uniformly' situated 

 with reference to other climatic influences. He concludes 

 from his data that, at least for sub-tropic regions, a forest cover 

 has the effect of reducing temperature e.xtremes and increas- 

 ing precipitation. 



Woeikoff further investigates whether the influence of the 

 forest upon the climate of surrounding areas may also be 

 proved for latitudes of thirty-eight to fifty-two degrees north — 

 all the West European Continent — and he proceeds as follows: 



Taking the temperature of July as that of the warmest 

 month, and assuming that, on the whole, the temperature at 

 the Atlantic coast is lower and rises toward the interior of tlie 

 continent, he compares the temperature of a niunberof places 

 situated near the fiftieth degree, the observations being all 

 taken outside of the forest. To bring them upon a unitbrm 

 Ijasis for comparison, he assumes an increase of temperature 

 of 0.5 degrees, centigrade, for each degree of latitude to- 

 wards the south, and a decrease of 0.7 degrees for every hun- 

 dred metres of altitude. By an easy calculation he then ob- 

 tains the mean July temperatures for every station in this 

 line, reduced to e.\actly fifty degrees, north latitude, and 200 

 metres of altitude. 



The result is that in this series a rapid rise of temperature 

 appears from the Main River, eastward, then a considerable 

 reduction in the eastern and western Bohemian stations, 

 where large forest areas prevail, while in the Bohemian basin 

 the temperature is higher, as it is also in Silesia, and again 

 much lower in the well-wooded Carpathian Mountains of 

 Hungary. The apparent influence of these large wooded 

 areas is still noticeable in east Galicia as far as Kiew, where 

 the neighborhood of forest and morasses works in the same 

 direction, while in tlie Steppes the highest temperature is 

 reached. 



In the same manner a series of stations lying on or near 

 the forty-si.xth degree are treated, reducing their July temper- 

 atures to the theoretical temperatures for the forty-sixth de- 

 gree and 200 metres of altitude ; and another series'of stations 

 is worked out for the forty-fourth degree in Croatia, Bosnia, 

 Herzegovina, Dalmatia, and here the heavily wooded Bosnia 

 is found from twenty-five to forty-five degrees cooler. 



The results of these comparisons lead the author to con- 

 clude that in the western part of the continent large forest 

 areas influence the temperature of neighboring localities, 

 and interrupt the normal increase of temperature from the 

 Atlantic Ocean into the interior of the continent to such an 

 e.xtent that even regions far in the interior have a cooler sum- 

 mer than those nearer the sea. 



He concludes further, not only that there exists a climatic 

 influence of the forest, but that it exerts itself over considera- 

 ble distances according to the size, kind and position of the 

 forest areas ; that, therefore, forest-planting or deforestation 

 offers a means of changing a climate consideral.ily. 



Another modification of this method has been employed by 

 H. F. Blanford, and by Dr. Brandis, late Forest Inspector-Gen- 

 eral of British India, by comparing the records overa confined 

 area (61,000 square miles and 600,000 acres, respectively) dur- 

 ing a decade of forest destruction and a decade of' forest 

 protection under government regulations. In both cases a 

 progressive increase of rainfall is observed in the second 

 period, until the mean increase within ten years has been 

 twenty per cent, and twelve and one-half per cent., respec- 

 tively, for the two areas thus reforested. 



The latest interesting, instructive and quite novel applica- 

 tion of the wholesale method is that employed by Dr. F. J. 

 Studnicjka, Professor of Mathematics at the University of 

 Prague. It consists in comparing the rain records of stations 

 differently situated as regards forest conditions, after the rec- 

 ords have been reduced to a theoretical quantity which cor- 

 responds to the altitude of the station. To understand the 

 significance of these observations, the reader should refer to 

 a map of Bohemia, and note its peculiar geographical posi- 

 tion, being a basin shut in on all sides by liigh mountain 

 ranges, niclosing an area of about 20,000 square miles. 



This basin has been covered with a net of over 700 rain- 

 gauge stations, for the purpose of obtaining accurate data of 

 the ciuantity and distribution of precipitation over the king- 



dom. Uniform ombrometers (rain gauges) were used and 

 very carefully placed. As at present organized, there is one 

 station for every thirty sciuare miles. No other country, I be- 

 lieve, can boast of such a service. Although the time of ob- 

 servation at most stations has been short, and the averages 

 would have been more accurately represented by an extension 

 of observations for ten to twelve years, yet the last four years 

 of observation, for which all stations furnish data, according to 

 the author, represent two extreme and two average years, and 

 are therefore quite useful. 



The very large mass of material permitted a sifting out of 

 doubtful observations without impairing the number available 

 for the construction of a rain-map of Bohemia, showing by 

 isohyetal lines seven rain belts or zones, the lowest belt show- 

 ing an annual rainfall of less than twenty inches, the second a 

 rainfall of less than twenty-four inches, the third of twenty- 

 eight inches, and so on. 



Sufficient material was on hand from which to calcidate the 

 influence of altitude on the increase of precipitation, although 

 for altitudes above 1,600 feet the material is not considered 

 reliable. Yet the general law is well shown that with the alti- 

 tude the cjuantities of precipitation increase in a retarded pro- 

 gression. This progression is calculated by forming zones for 

 every hundred metres of altitude, grouping the stations in 

 each, calculating the mean elevation and also the mean pre- 

 cipitation as observed for each ; then by dividing the differ- 

 ence of precipitation in the neighboring two zones by the 

 dilTerence of altitude, the amount of precipitation which cor- 

 responds to each one metre of elevation within that zone is 

 found. With this figure the average amount of rainfall which, 

 tlieoretically, lielongs to each station, according to its absolute 

 elevation, can be approximated by adding to or subtracting 

 from the mean precipitations of the zone the proper correc- 

 tion for the number of metres between the actual altitude of 

 the station and the mean altitude of the zone. 



And now comes the application of this method to the ques- 

 tion in hand. The author argues that if the actually observed 

 differs considerably from the theoretically calculated rainfall, 

 this is an indication that special influences are at work. He 

 tinds now that of the 186 stations which he subjects to scrutmy 

 (these offering the longest and most trustworthy observation), 

 forty-eight show a considerable excess of the observed over 

 the theoretically expected rainfall, and he finds also that these 

 stations are situated in the most densely wooded portions of 

 the kingdom. The increased rainfall on the forty-eight sta- 

 tions is so considerable, that enough of it may be credited to 

 other local causes, as, for instance, to the height and form of 

 a mountain range on one side or the other, and still leave a 

 large balance to be accounted for. Besides, the greater 

 amounts of rainfall at these stations have been used in cal- 

 culating the averages for the altitude zones, magnifying, there- 

 fore, these averages, so that the difference between the calcu- 

 lated rainfall and the actuallyobserved rainfall appearssmaller 

 than it really is. 



I-^xpressed in percentages of the amount of precipitation a 

 large increase is shown for several localities — as much as 

 fifty-nine per cent. — and it would seem that so great an in- 

 crease would not lose its significance as bearing upon the 

 main proposition, even after every reduction for other influ- 

 ences is made. 



Especially important appears the comparison between two 

 stations near the rain minimum, for the influence of the forest 

 is here plainly shown. B. E. Fernow. 



Washington, D. C. 



Correspondence. 



Latinized Names of Garden Plants. 

 To the Editor of Garden and Forest : 



Sir. — I take the liberty of applying to you as an acknowledged 

 authority on botanical nomenclature, for information. I find 

 that there is in the formation of a certain class of botanical 

 names a great diversity of practice existing among the various 

 writers for horticultural papers and those who prepare cata- 

 logues of plants. Is there any reason why I should write Ains- 

 worthii.Warnerii, Forstermannn, Nilsonii, Parishii, Roebellenii, 

 Sallierii, Schlimii, and at the same time write Regnieri, Barteti, 

 Boxalli, Sedeni, doubling the final -i in the one case and not in 

 the other ? 



Linden, of Brussels, in his Lindenia uses the single i in all 

 such instances. Sometimes in the same catalogue I find the 

 same name formed at one time with a single -i and at another 

 with the double. If you can give in your valuable paper any 

 rule for the formation of these words you will greatly oblige 



Yours very truly, 



Short Hills, N. J. James R. Pitcher. 



