Chapter Ii. the Habitat

CONCEPT AND ANALYSIS

27. Definition of the habitat 18 28. Factors 18 Classification of Factors 29. The nature of factors 19 30. The influence of factors 19 Determination of Factors 31. The need of exact measurement 20 32. The value of meteorological methods 20 33. Habitat determination 21 34. Determinable and efficient differences 21 Instrumentation 35. Methods 22 36. Method of simple instruments 22 37. Method of automatic instruments 23 38. Combined methods 23

CONSTRUCTION AND USE OF INSTRUMENTS

39. The selection of instruments 24 Water-content 40. Value of different instruments 25 Geotome methods 41. The geotome 25 42. Soil borers 26 43. Taking samples of soil 26 44. Weighing 27 45. Computation 28 46. Time and location of readings 28 47. Location of readings 29 48. Depth of samples 30 49. Check and control instruments 30 Physical and Physiological Water 50. The availability of soil water 30 51. Terms 31 52. Chresard determination under control 32 53. Chresard readings in the field 33 54. Chresard values of different soils 34 Records and Results 55. The field record 35 56. The permanent record 36 57. Sums and means 36 58. Curves 37 Humidity 59. Instruments 37 Psychrometers 60. Kinds 37 61. The sling psychrometer 38 62. Readings 39 63. Cog psychrometer 39 64. Construction and use 40 65. Hygrometers 40 Psychrographs 66. The Draper psychrograph 41 67. Placing the instrument 42 68. Regulating and operating the instrument 43 69. The weekly visit 44 Humidity Readings and Records 70. The time of readings 44 71. Place and height 45 72. Check instruments 45 73. Humidity tables 46 74. Sums, means, and curves 47 Conversion scale for temperatures 75. Records 48 Light 76. Methods 48 The Photometer 77. Construction 49 78. Filling the photometer 50 79. Making readings 50 80. The Dawson-Lander sun recorder 51 81. The selagraph 52 Standards 82. Use 53 83. Making a standard 53 84. Kinds of standards 54 Readings 85. Time 55 Chart for determining sun’s altitude 57 86. Table for determining apparent noon 58 87. Place 59 Table of intensity at various angles 60 Reflected and Absorbed Light 88. The fate of incident light 60 89. Methods of determination 61 90. Leaf and epidermis prints 62 Expression of Results 91. Light records 63 92. Light sums, means and curves 63 Temperature 93. 64 Thermometers 94. Air thermometers 64 95. Soil thermometers 64 96. Maximum-minimum thermometers 65 97. Radiation thermometers 67 98. Thermographs 67 Readings 99. Time 69 100. Place and height 70 Expression of Results 101. Temperature records 70 102. Temperature sums and means 70 103. Temperature curves 71 104. Plant temperatures 71 Precipitation 105. General relations 72 106. The rain gauge 73 107. Precipitation records 74 Wind 108. Value of readings 74 109. The anemometer 75 110. Records 76 Soil 111. Soil as a factor 76 112. The value of soil surveys 77 113. The origin of soils 77 114. The structure of soils 78 115. Mechanical analysis 79 116. Kinds of soils 79 117. The chemical nature of soils 80 Physiography 118. Factors 80 Altitude 119. Analysis into factors 81 120. The barometer 82 Slope 121. Concept 83 122. The clinometer 83 123. The trechometer 84 Exposure 124. Exposure 85 125. Surface 85 126. Record of physiographic factors 86 127. Topography 86 Biotic Factors 128. Influence and importance 86 129. Animals 87 130. Plants 87

METHODS OF HABITAT INVESTIGATION

131. 88 Method of Simple Instruments 132. Choice of stations 88 133. Time of readings 89 134. Details of the method 89 135. Records 91 Method of Ecograph Batteries 136. 92 Expression of Physical Factor Results 137. The form of results 94 Factor Records 138. 94 Factor Curves 139. Plotting 95 140. Kinds of curves 96 141. Combinations of curves 96 142. The amplitude of curves 98 Factor Means and Sums 143. 98