Allometric relationships between large and small scale tree spacing studies Mike Strub and Ralph Amateis

Topics Spacing studies Scaling – isomorphic versus allometric Comparison of small and large scale spacing studies Conclusions

Spacing Studies Full scale studies were planted at four locations with three replications in the spring of Treatments include 4’X4’, 6’X6’, 8’X8’, 12’X12’ and various rectangular spacings. A single replication of a 1/16th scale study was planted in the spring of 1989 and a second replication was planted in 1998.

Scaling Early work dates back to the development of geometry and notions about similar triangles, these ideas involve a single scaling factor and are termed isometric. Latter work came from using scale models of engineering projects and resulted in the development of dimensional analysis to address more complex allometric problems.

Scaling The dimensional analysis model is : Y=  *X^  These ideas have been applied to biological organisms in the last thirty years.

Scaling

Buckling Limit A tree will buckle under its own weight when: Which implies that to prevent buckling:

Buckling Limit from McMahon and Bonner (1983)

Buckling Limit from Horn (2000)

4’X4’ spacing

6’X6’ spacing

8’X8’ spacing

12’X12’ spacing

4’X4’ spacing

6’X6’ spacing

8’X8’ spacing

12’X12’ spacing

4’X4’ tree spacing

6’X6’ tree spacing

8’X8’ tree spacing

12’X12’ tree spacing

D=  *(H-4.5)^ 

full scale spacingalphabeta miniature scale spacingalphabeta

Results Both miniature and full scale studies approach the buckling line in a similar fashion. Miniature scale studies have relatively larger diameters than full scale studies, likely because they were measured at ground line rather than scaled breast height. The miniature scale studies tend to be more variable than the full scale studies, perhaps because they are the results of a few years of weather rather than decades.

4’X4’ tree spacing

6’X6’ tree spacing

8’X8’ tree spacing

12’X12’ tree spacing