Measurement

Learning What's Out There and Predicting What Will Be

Researchers collecting data from numbered trees.Before we can manage natural resources, we need to know what is in the environment and observe how it has changed from past records. From ground observations to radio telemetry to aerial photography to satellite imagery, natural resource professionals and scientists gather data and use statistical methods to evaluate its precision and accuracy. These data are then used to draw out information for application to the broader landscape.

But it's not enough to know what's there now—managers also need the ability to look into the future to predict how the environment is likely to change. Early University of Minnesota researchers were world leaders in forest measurements and projections. The premier, early efforts in growth modeling and yield table development by University foresters in the '20s and '30s were used as the standard for all commercial tree species in the Midwest—these "Volume Yield and Stand Tables" are still of interest today. Computers enabled foresters to make better use of forest management data, and U of M researchers developed numerous forest growth, yield, and ecosystem dynamics models. Research at the U of M pioneered the application of statistical methods for model development and testing, and the incorporation of physiological processes in models.

U of M faculty back from World War II led the use of aerial photos to make efficient estimates of forest conditions and land use. Minnesota researchers were among the first to develop aerial photo volume tables—a cheaper, easier way to measure a large area quickly. The technology evolved in the '70s to include use of satellite imagery, but aerial photos remain important for many details.

In 1988, the University received a major NASA-funded natural resource project: a half-million-dollar grant to use satellite data to inventory Minnesota forests. Later, developments under the ForNet project kept Minnesota in the technological lead, and ongoing advances in high-resolution imagery make satellite images even more useful in areas such as lake water quality assessment.

Back on the ground, University scientists lead the world in "Bio Mathematics," with large-scale measures of game theory mathematically applied to animal populations. For example, researchers at Isle Royale modeled the effect of moose on boreal forest. Broader application ecosystem modeling predicts future landscape conditions with consideration of variables such as moisture, light, and possible climate changes.

Researchers using radio tracking on grouse.Radio Tracking of Birds

Radio tracking of birds was a University of Minnesota breakthrough. The long-term ruffed grouse research at Cloquet adopted radio telemetry in 1961, greatly enhancing the study of behavior, territoriality, and dispersal. The technology was soon applied to woodcock, bald eagles, and Canada geese, making it possible to identify and study nesting and migration habits and the establishment of territories. U of M faculty also wrote a widely circulated handbook, Techniques in Telemetry, and observers here were the first to use telemetry to track wolves and moose.

Experimental Forests

The first experimental forests at the Cloquet Forestry Center were planted in 1910. Wood towers were used for precise measurements of week-by-week tree growth in specific stands, taking into account soil, moisture, temperature, and species.

Fish ear stone.Determining Fish Age and Environment

This half-inch otolith, a fish ear stone, is from a 22-year-old freshwater drum caught in Red Lake. University fisheries biologists developed a "temporal signature" technique to accurately date the age of fish using the microscopic rings, and then match or calibrate it to the environment and climate in which the fish lived. Otoliths are frequently found in trash near places humans lived, and can help anthropologists accurately date sites and activities. After an overall chronology is developed, instead of knowing only how old a fish was, experts can determine what year the fish was hatched and which years were more or less productive.

Researcher working with aerial photography equipment.Aerial Photos Provide Forest Details

Following World War II, researchers adapted wartime techniques to use aerial photos to gather data over large regions, and tested specialized cameras and photo paper to improve the process. Later, U of M scientists developed techniques to use readily available 35mm cameras at low altitudes. Aerial photos can measure tree heights with stereo-photographs taken from slightly different perspectives, or help identify the ages and species of trees by their heights and crown sizes.

MapServer Software Provides Data-Rich Overview

Remote sensing lab.The University is a world leader in making information available and usable for agencies and the public, from developing the pioneering timber stand tables in the '20s to the MapServer software widely used today. Developed by College of Natural Resources researchers at the advent of the Internet, MapServer merges information from satellite images and existing ground sources into a data-rich picture of an area. It helps agencies and individuals quickly and accurately assess terrain characteristics for many uses, from predicting fire danger to planning forest regeneration. Enhancements to the software have extended its application to agriculture, environmental assessment, and urban development. Recently it was used to display where residue from a damaged oil tanker would flow in ocean waters.

Hands-On Techniques Provide Data for Computer Age

Conventional measurements of timber stands such as this plot of red pine at the North Central Research and Outreach Center, Grand Rapids, help scientists calibrate and evaluate computer models of forest growth.

Sharing Remote Sensing Lab Data

Throughout its history, the college has led the world in developing new techniques to assess our natural resources. The University's Remote Sensing Lab accesses satellite data, which researchers make user-friendly through innovations in computer software.

Related Websites

Remote Sensing and Geospatial Analysis Laboratory

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