Incorporating GIS topographic information in forest inventory estimates

A raster-based geographic information system (GIS), in which a 100% inventory of certain measurements can be stored and manipulated, can provide inexpensive, low variance timber stand volume estimates. Timber volume can be correlated to such topographic variables as slope, aspect, slope position, slope shape, and elevation which can be produced through the manipulation of a digital elevation model. More precise estimates can be achieved through a procedure which utilizes the 100% sample of this information as opposed to the more traditional method of random sampling. Through the use of such a procedure, the potential for more cost effective estimations is available. The use of this same procedure for periodic re-inventory estimations could also provide a more precise estimate. The model-based approach, which utilizes all the information provided by the GIS, produced a more precise estimate of stand volume than did simple random sampling. Statification of the area into two basic cover types, mixed pine/hardwood and upland hardwood, did not provide a more precise estimate of the total stand volume. However, the model-based approach did provide better individual group estimates than random sampling; relative efficiency was 1.380 for mixed pine/hardwood and 1.121 for upland hardwood. In terms of 'cost effectiveness, the percent reduction of the initial sample plots placed in the field to achieve the lower variance would be 29.7 % for mixed pine/hardwood and 14.8 % for upland hardwoods. For reinventory, a more precise estimate was achieved through the use of the model-based approach as opposed to an estimate derived from probability proportional to the volume estimates computed from the previously derived volume equations. The relative efficiency of the model-based estimate as compared to the probability proportional to size sample, was 1.097.

Name thesis:degree_name

M.S.

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Forestry

Department dc:contributor.department

Forestry

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1988

Author dc:creator

• Sieg, Gregory Edwin

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10919/109905

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/109905