Forest Mensuration II

1. Forest Mensuration II Lecture 1 Introduction to Forest and Natural Resource Measurements Avery and Burkhart, Chapters 1, 18

2. Objectives • What are forest measurements? • Why measure forest resources? • Types and scales of measurements • Introduction to natural resource measurements

3. What are forest measurements? • “How-to-do-it” for tree overstory, i.e.,timber volume, tree form, growth, cull factors, mortality, etc. • Deals with direct measurements, sampling, and prediction There are still many measurement problems for which no perfect solutions exist

4. Why measure forest resources? • Forest management requires knowledge of the location and their current features • The role of measurements is to supply the numerical data required to make management decisions • Accurate measurements allow scientifically sound management decisions being made

5. Types of measurements • Direct measurements • Tree height • Tree diameter • Sampling • A portion of the entire resource - expand to characterize entire resource • Prediction • Those resources, such as tree volumes, not easily measured

6. Scales of measurements • Nominal scale • Numbering objects for field identification, e.g., tree number, plot number • Ordinal scale • Expressing rank or position in a series, where rank has meaning, e.g., tree crown classes, lumber grades, site quality classes • Interval scale • A series of graduations marked off at uniform intervals from an arbitrary origin, e.g., temperature • Ratio scale • A series of graduations marked off at uniform intervals from an origin of absolute zero, e.g., tree height, volume, length of trail, amount of habitat

7. Standard practices • Abbreviations and symbols (page 4) • Significant digits and rounding off • Don’t record more significant digits than were observed • Ignore the 5 when the digit preceding is an even number. Conversely, if the digit preceding is an odd number? • Rounding off should be carried at least two places beyond that of the final rounded figures • Conversions between metric and English units (Page 6 of the textbook)

8. Natural resource measurements

9. Forestland • Features measured: trees • Sampling units: fixed-radius plots, variable radius plots, strips • Sampling schemes: systematic sampling, stratified random sampling • Measures: timber volume, wildlife habitat, forest density

10. Rangeland • Features measured: grasses, forbs, shrubs • Sampling units: small square plots • Sampling schemes: systematic sampling, stratified random sampling • Measures: weight of herbage, grazing capacity, range condition and trend

11. Wildlife • Features measured: animals, habitat • Sampling units: plots, strips, areas • Sampling schemes: direct census, indirect census, mark-recapture techniques • Measures: animal presence, animal species richness, animal populations, wildlife habitat suitability

12. Water resources • Features measured: water • Sampling units: weirs, flumes, current meters • Sampling schemes: watersheds, stream reaches • Measures: water quantity, water quality

13. Recreation • Features measured: people • Sampling units: visitor days, vehicles, water usage • Sampling schemes: complete registration, self registration, surveys • Measures: recreation quality, recreation opportunity, visitor satisfaction