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