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

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

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

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

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 Types of measurements

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

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)

Natural resource measurements

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

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

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

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

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