Koelera-Andropogon-psilium
April 25, 1901. Clear. South wind.
| TEMPERATURE | LIGHT | HUMIDITY | WATER-CONTENT | WIND | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TIME P.M. | 3:20 | 3:24 | 3:30 | 3:35 | 3:40 | 3:45 | 3:55 | % | 2:40 | 3:05 | ||||
| STATION | 1½ m. | Surf. | 5 | 10 | 15 | 1½ m. | Surf. | 1½ m. | Surf. | 5 | 10 | 15 | 1½ m. | Surf. |
| 1. | 27.8 | 29.6 | 17.8 | 15.8 | 10.9 | 57 | 59 | 17.7 | 14.6 | 17.4 | 740 | 280 | ||
| 2. | 26.5 | 31.3 | 18.3 | 16.6 | 12.8 | 59 | 59 | 17.9 | 12.2 | 14.3 | 1100 | 510 | ||
| 3. | 26.9 | 28.5 | 18.2 | 14.2 | 13.5 | 58 | 59 | 16.5 | 16.9 | 19 | 980 | 520 | ||
| 4. | 26.2 | 30 | 16.8 | 13.2 | 11.6 | 63 | 66 | 24.4 | 21.3 | 24.8 | 920 | 460 | ||
| 5. | 28 | 32.4 | 18.6 | 14.6 | 14.2 | 59 | 60 | 10.7 | 17 | 17.2 | 1080 | 490 | ||
| 6. | 28 | 40.8 | 23.8 | 16 | 15 | 51 | 51 | 5 | 8.3 | 10.3 | 1010 | 410 | ||
| 7. | 26.4 | 30.8 | 16 | 13 | 11 | 68 | 70 | 27 | 24.3 | 21.4 | 680 | 52 | ||
Quercus-Hicoria-hylium
April 20, 1901. Clear. Southeast wind.
| TEMPERATURE | LIGHT | HUMIDITY | WATER-CONTENT | WIND | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TIME A.M. | 10:40 | 10:46 | 10:50 | 10:55 | 11:00 | 12:00 | 12:05 | 11:10 | 11:20 | % | 11:30 | 11:45 | ||
| STATION | 1½ m. | Surf. | 5 | 10 | 15 | 1½ m. | Surf. | 1½ m. | Surf. | 5 | 10 | 15 | 1½ m. | Surf. |
| 1. | 16 | 25 | 9.6 | 8.4 | 7.8 | .08 | .06 | 73 | 81 | 24.2 | 19.2 | 19.5 | 298 | 0 |
| 2. | 16.2 | 30.5 | 8.5 | 8.4 | 7.8 | .11 | .09 | 73 | 86 | 22 | 22.5 | 19.4 | 375 | 2 |
| 3. | 16.2 | 17.8 | 7.6 | 7.8 | 8 | .08 | .06 | 73 | 95 | 22.1 | 20.4 | 21.6 | 640 | 6 |
| 4. | 15.6 | 26.2 | 10.6 | 8.4 | 8.2 | .06 | .03 | 81 | 95 | 25.4 | 23.1 | 22.4 | 275 | 12 |
| 5. | 17.6 | 25.4 | 7.6 | 7.4 | 7.2 | .03 | .02 | 90 | 95 | 27.2 | 19.8 | 18.8 | 178 | 2 |
| 6. | 16.2 | 20.2 | 8.4 | 7 | 6.2 | .02 | .01 | 82 | 90 | 27.6 | 20.8 | 18.8 | 115 | 4 |
| 7. | 15.8 | 17.2 | 6.4 | 6.4 | 6.1 | .05 | .04 | 82 | 90 | 23.8 | 19 | 19.3 | 60 | 0 |
METHOD OF ECOGRAPH BATTERIES
136. A battery of recording instruments consists of a selagraph, a psychrograph, and a thermograph, to which an anemograph is added when possible. As stated before, the determination of water-content by the geotome method is more satisfactory than by any automatic instrument yet devised. When the base station is located where the sunlight is unobstructed, which should be the case whenever possible, it is unnecessary to include a selagraph in those batteries placed in similarly exposed stations, since the light values will be the same. As a rule, batteries are established within different zones or different habitats, except where a highly diversified habitat is made the subject of special inquiry. Such a restriction arises from the fact that expense, care of operation, etc., place a limit upon the number of batteries, and, in such case, the task of primary importance is to establish the physical character of representative habitats. For these reasons, the first series of thermographs established in 1903 was located with respect to altitude, the instruments being placed at Manitou 2,000 m., Minnehaha, 2,600 m., and Mount Garfield 3,800 m. In 1904, the stations established for the record of temperature and humidity were situated with respect to habitats representing the four formations: gravel slide, half gravel slide, spruce forest, and brook bank.
The batteries are located and set up according to the directions already given. A 2–meter quadrat with the battery as the middle is staked and mapped. Within this, all readings of water-content, soil temperature, and physiographic factors are made. Altitude, slope, exposure, and cover are recorded when each battery is located, and a soil sample is taken for mechanical analysis. When the position of the batteries permits it, water-content readings should be made frequently, once or twice a week at least. In addition, a complete series of samples should be taken daily for a period sufficient to indicate the ordinary extremes of water-content.
The ecograph battery of each habitat constitutes a standard to which the results obtained by simple instruments may be referred with accuracy. It not only does this, but it also serves as a basis for interpreting the readings of simple instruments in distant habitats of the same character. In this way a few batteries judiciously placed make possible the exact physical investigation of a large number of habitats, covering a considerable area. The only limit, indeed, upon this method is that placed by time. The proportionate use of batteries and of simple instruments must be largely determined by the conditions which confront the investigator. It is obvious that, where expense is not a decisive factor, the gain in time and in completeness of results is enormously in favor of the battery. There is an additional value in the automatic and continuous record which can not be overlooked. When the use of instruments in the study of habitat and formation becomes universal, the importance of the ecograph will be immeasurably enhanced. It will be possible to secure duplicate records of batteries located in the most remote and diverse regions, from the equator to the poles, and comparative phytogeography upon a scientific basis will for the first time be possible. This opens an alluring vista of the future when ecologists the world over will cooperate in such a way that the results obtained by ecograph batteries anywhere on the globe will permit of exact comparison.