OBJECTS AND METHODS. 35 



OBJECTS AND METHODS. 



Ill 18G8, before the publication of Ebermayer's results or those of any 

 other systematic series of co-operative observ^ations in forest meteor- 

 ology, the Congress of German Foresters and Farmers at Vienna, 

 strnck with the paucity of results from the much talkedof forest mete- 

 orological observations, put the subject in the hands of a special com- 

 mittee composed of the most eminent German students and authorities 

 on the subject. The committee met at Regensburg in November. Its 

 attention was chiefly directed to other aspects of the forestry question, 

 but it proposed a sort of programme or series of problems as the projier 

 object of forest meteorological observations. These are: 



(1) Determination of the temperature under woods and outside. 



(2) Investigation of the temperature of trees as compared Avith that of the soil and 

 air. 



(3) Investigation of the soil of forests, determination of its temperature at dif- 

 ferent depths, situations, exposure, and under differeut kinds of trees. 



(4) Influence of the covering of the soil on damage by frost. 



(5) Determination of rainfall under woods and outside. 



(6) Influence of the covering on the humidity of the soil and on the evaporation 

 from it. 



(7) Determination of the amount of evaporation in the forest and without. 



(8) Determination of the ground water at diflerent de])ths, under woods and out- 

 side^ with various aspects and under various kinds of trees. 



(9) Determination of the amount of carbonic acid and of the humidity of the for- 

 est during the season of vegetation, under a more or less compact cover of foliage, 

 under different trees and in varied situations. 



This is au extensive ])rogramme, and is of interest as the first which 

 had been formulated under such auspices. It will bo noticed, however, 

 that it does not include observations at any elevation, and especially 

 observations above the woods. It does not seem to have occurred to 

 the committee that meteorologically the forest is a sort of surface cov- 

 ering to be compared Avith that of sod or crops, sand or water, and that 

 in other cases observations are taken as well above the surface cover- 

 ing as in it or below it. Observations above woods w^ere, however, not 

 inchuled by the committee, and since this programme served to give 

 object and aim to tlie new services of that day, as well as to those 

 established later, these important observations have been almost 

 entirely neglect43<l. 



The Piiissian (afterward the German) forest meteorological service, 

 established six years later, adhered, in most points, to the Kogensburg 

 ])r(»graiimie. In its iiistru<;tioiis to its observers it dotincs their task 

 as that of furnishing observations on — 



(1) The temperature of the air in forests compared with that in open fields. 



(2) The temperature of the air at 5 feet elevation, compared witli that in the tree 

 crown. 



(3) The hygrometric condition of the air wiihin and wiMiont woods. 



(4) The same at a height of 5 feet compared with that in the tree crown. 



