SAMPLING VEGETATION ATTRIBUTES - New Mexico NRCS - US ...

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102 METHODS—Double Weight Sampling J. Double-Weight Sampling 1. General Description This technique has been referred to by some as the Calibrated Weight Estimate method. The objective of this method is to determine the amount of current-year above-ground vegetation production on a defined area. The following vegetation attributes are monitored: • Peak standing crop, which is the above-ground annual production of each plant species • Species composition by weight It is important to establish a photo plot (see Section V.A) and take both close-up and general view photographs. This allows the portrayal of resource values and conditions and furnishes visual evidence of vegetation and soil changes over time. 2. Areas of Use This method can be used in a wide variety of vegetation types. It is best suited to grasslands and desert shrubs. It can also be used in large shrub and tree communities, but the difficulties increase. 3. Advantages and Limitations a Double-weight sampling measures the attribute historically used to determine capabilities of an ecosystem. b It provides the basic data currently used for determining ecological status. c Seasonal and annual fluctuations in climate can influence plant biomass. d Measurements can be time-consuming. e Current year’s growth can be hard to separate from previous years’ growth. f Accurate measurements require collecting production data at peak production periods, which are usually short, or using utilization and phenology adjustment factors. g Green weights require conversion to air-dry weights. h In most areas, the variability in production between quadrats and the accuracy of estimating production within individual quadrats requires the sampling of large numbers of quadrats in order to detect reasonable levels of change. 4. Equipment The following equipment is needed (see also the equipment listed in Section V.A, page 31, for the establishment of the photo plot): • Study Location and Documentation Data form (see Appendix A) • Production form (Illustration 22) • Sampling frames or hoops • One stake: 3/4- or 1-inch angle iron not less than 16 inches long
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SAMPLING VEGETATION ATTRIBUTES INTE
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TABLE OF CONTENTS SAMPLING VEGETATI
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TABLE OF CONTENTS TABLE OF CONTENTS
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I. PREFACE PREFACE The intent of th
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2 INTRODUCTION values when individu
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4 INTRODUCTION represent the “pul
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6 INTRODUCTION G. Coordination Moni
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8 STUDY DESIGN AND ANALYSIS A. Plan
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10 STUDY DESIGN AND ANALYSIS Macrop
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12 STUDY DESIGN AND ANALYSIS Becaus
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14 STUDY DESIGN AND ANALYSIS d From
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16 STUDY DESIGN AND ANALYSIS b Cove
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18 STUDY DESIGN AND ANALYSIS sideoa
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4 3.5 3 2.5 20 5 STUDY DESIGN AND A
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22 STUDY DESIGN AND ANALYSIS C. Oth
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24 ATTRIBUTES Frequency is the numb
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26 ATTRIBUTES 2. Advantages and Lim
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28 ATTRIBUTES b Standing crop and p
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30 ATTRIBUTES
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32 METHODS—Photographs c Angle ir
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METHODS—Photographs Hinge Rod sta
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METHODS—Photographs angle iron st
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38 METHODS—Frequency • One tran
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40 METHODS—Frequency transected,
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42 METHODS—Frequency (3) Total fr
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Page of Frequency 44 Study Number D
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METHODS—Frequency The frame is ma
Page 57 and 58: 50 METHODS—Dry Weight Rank C. Dry
Page 59 and 60: 52 METHODS—Dry Weight Rank After
Page 62 and 63: D. Daubenmire Method METHODS—Daub
Page 64 and 65: METHODS—Daubenmire b Ten Cover Cl
Page 66: Page of Daubenmire Study Number Dat
Page 70 and 71: 50 cm Six Cover Class Frame 20 cm R
Page 72 and 73: METHODS—Line Intercept b Pilot St
Page 74 and 75: METHODS—Line Intercept Hanley, Th
Page 77 and 78: 70 METHODS—Step Point F. Step-Poi
Page 79 and 80: 72 METHODS—Step Point the boot an
Page 81 and 82: 74 METHODS—Step Point measures AN
Page 85 and 86: 78 METHODS—Point Intercept G. Poi
Page 87 and 88: 80 METHODS—Point Intercept 8. Sam
Page 89 and 90: 82 METHODS—Point Intercept b Tran
Page 91 and 92: METHODS—Point Intercept Examples
Page 93 and 94: 86 METHODS—Cover Board H. Cover B
Page 95 and 96: 88 METHODS—Cover Board g Study Do
Page 98: Page of Cover Board Method Profile
Page 101 and 102: 94 METHODS—Density I. Density Met
Page 103 and 104: 96 METHODS—Density (often very mu
Page 105 and 106: 98 METHODS—Density able to make s
Page 107: Page of Density Study Number Date E
Page 111 and 112: 104 METHODS—Double Weight Samplin
Page 118 and 119: Record weights of all plants within
Page 120 and 121: • Clippers • Paper bags • Kil
Page 122 and 123: Use the following table to convert
Page 124 and 125: METHODS—Comparative Yield a Site
Page 126 and 127: METHODS—Comparative Yield each qu
Page 128: Study Location Notes Illustration 2
Page 131 and 132: METHODS—Visual Obstruction—Robe
Page 133 and 134: METHODS—Visual Obstruction—Robe
Page 136 and 137: 48" 1 1/8" 15 13 11 9 7 5 3 1 1. 2.
Page 138 and 139: VI. GLOSSARY OF TERMS A GLOSSARY ac
Page 140 and 141: GLOSSARY evaluation: (1) an examina
Page 142 and 143: N GLOSSARY native pasture: land on
Page 144 and 145: GLOSSARY resource value ratings. Tr
Page 146 and 147: VII. REFERENCES REFERENCES Barrett,
Page 148 and 149: REFERENCES Floyd, D.A. and J.E. And
Page 150 and 151: REFERENCES Mack, R. and D.A. Pyke.
Page 152 and 153: REFERENCES Robel, R.J., J.N. Briggs
Page 154 and 155: REFERENCES ———. 1981. Arid la
Page 156 and 157: APPENDIX A APPENDIX A Study Locatio
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152 APPENDIX A
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154 APPENDIX B b The next character
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156 APPENDIX B
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DATE 158 APPENDIX C NO. R.A. ALLOT.
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APPENDIX D APPENDIX D— SELECTING
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Table of Random Digits (Zar 1984) A
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