The work was carried on for three and one-half months by the writer and two student assistants, Messrs. J. D. Aiken and Miles Bur-ford, of the Faculty of Forestry, University of Toronto, whose efficient co-operation made possible the gathering and the organization of the data for the report.
The original plan was to run parallel compass lines one-half mile apart through the burns of various ages, and to measure all of the trees one inch and more in diameter. This plan was adhered to for the first month, when it was found that the composition of the various types was so constant that the running of the lines so near together appeared to be unnecessary. None of the lines, however, were more than a mile apart. At least one line was run through each type in its longest direction and the trees were counted and measured with calipers. Then paced reconnaissance lines were run parallel or perpendicular to the calipered lines and in this way the boundaries of the various types were determined. The strips, a chain (66 feet) wide, on which the trees were actually counted and measured, aggregated nearly 25 miles, while the reconnaissance lines aggregated over 80 miles.
In the field work, the following types were found
Basis of within the burns of various ages, and separately Classification
tallied: (1) Low amphibolite ridges; (2) low granite ridges; (3) low limestone ridges; (4) sand ridges; (5) depressions between ridges; and (6) sand plains. Upon compilation of the results, however, it was found that, while there were interesting differences botanically, there were not differences enough as regards the amount of second growth pine and poplar to justify such classification. Hence, the differences due to topography, soil, and attendant conditions have been neglected, and the areas have been classified alone according to the number of times burned.
In the field work, also, an area burned a certain number of times was sub-divided into several smaller areas, according to the amount of pine and poplar reproduction per acre, but, in the final tabulation, it seemed best for the purposes of this report, to group these areas and to strike the average in terms of the young pine and poplar for the entire area burned a stated number of times.
The number of times an area had been burned was determined in two ways: (1) By the age of the stands of poplar, and (2) by the number and age of the fire scars on the old trees. For example, it would be found that the great majority of the young trees on a certain area fell into three age classes, of 8, 16, and 25 years. In addition, the poplars 25 years old would show that they had been burned at the base 8 and 16 years ago, while the poplars 16 years old would have-