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• 1. [Article] A preliminary investigation into the use of the tarif system and three tree selection methods for obtaining Douglas-fir stand and stock tables from large-scale aerial photography

  As a preliminary step toward the establishment of a 70 mm. aerial photo timber inventory system capable of generating accurate stand tables, stock tables, and gross volume estimates, this project focuses ...

  Citation × Citation Citation Abstract Copy Title: A preliminary investigation into the use of the tarif system and three tree selection methods for obtaining Douglas-fir stand and stock tables from large-scale aerial photography Author: McCadden, Richard Jay As a preliminary step toward the establishment of a 70 mm. aerial photo timber inventory system capable of generating accurate stand tables, stock tables, and gross volume estimates, this project focuses on the development of a system which (1) eliminates the need to measure tree height on the photos through use of the tarif system and, (2) incorporates the use of three distinct tree selection methods-- fixed plot, variable plot, and line transect sampling. The methodology is developed and applied to a 346 acre parcel of Douglas-fir forestland. The accuracy of individual tree predictions for diameter at breast height, volume, tarif number, and tree height (which is derived without traditional photo measurement) are evaluated by ground subsampling a 206- tree validation set and comparing actual and predicted values. The results show that an average underprediction of ground-measured tarif number by about 5% occurs, which in turn results in similar underpredictions of tree volume and height. The accuracy of the stand tables, stock tables, and gross volume estimates are examined by comparison to independently derived ground measurements. The photo estimates of mean gross volume per acre, using each of the three photo tree selection methods, are all within 5% of the ground-derived estimates; in all cases the 68% confidence intervals of the ground and photo estimates overlap. Graphic comparisons of the photo and ground-derived stand and stock tables are presented; they are similar, except for the inability of the photo method to accurately predict the stocking of trees less than twelve inches in stem diameter. The aerial photo system, using each of the three tree selection methods, demonstrates an ability to produce results comparable to those derived from conventional ground inventory techniques. Future research is recommended, and specific needs for this research are identified. Title: A preliminary investigation into the use of the tarif system and three tree selection methods for obtaining Douglas-fir stand and stock tables from large-scale aerial photography Author: McCadden, Richard Jay As a preliminary step toward the establishment of a 70 mm. aerial photo timber inventory system capable of generating accurate stand tables, stock tables, and gross volume estimates, this project focuses on the development of a system which (1) eliminates the need to measure tree height on the photos through use of the tarif system and, (2) incorporates the use of three distinct tree selection methods-- fixed plot, variable plot, and line transect sampling. The methodology is developed and applied to a 346 acre parcel of Douglas-fir forestland. The accuracy of individual tree predictions for diameter at breast height, volume, tarif number, and tree height (which is derived without traditional photo measurement) are evaluated by ground subsampling a 206- tree validation set and comparing actual and predicted values. The results show that an average underprediction of ground-measured tarif number by about 5% occurs, which in turn results in similar underpredictions of tree volume and height. The accuracy of the stand tables, stock tables, and gross volume estimates are examined by comparison to independently derived ground measurements. The photo estimates of mean gross volume per acre, using each of the three photo tree selection methods, are all within 5% of the ground-derived estimates; in all cases the 68% confidence intervals of the ground and photo estimates overlap. Graphic comparisons of the photo and ground-derived stand and stock tables are presented; they are similar, except for the inability of the photo method to accurately predict the stocking of trees less than twelve inches in stem diameter. The aerial photo system, using each of the three tree selection methods, demonstrates an ability to produce results comparable to those derived from conventional ground inventory techniques. Future research is recommended, and specific needs for this research are identified. Close