42 PRACTICAL FORESTRY IN THE ADIRONDACKS. 
In most cases the increased growth began with the first season after 
the cutting. On the areas cut over in 1888 there were but a few trees 
which showed an accelerated growth beginning after that year. In 
these cases it was not possible to determine whether the new start had 
been delayed, or whether it was due to windfalls following the cutting. 
On the area cut over in 1891 a considerable number of trees showed a 
small increase in growth the first year, and a much more rapid increase 
the following years. In general,it may be said that the increased 
growth takes place, as a rule, the first year, and that it wiil in all prob. 
ability continue until the next cutting, for if the first cause (the rapid 
decomposition of the humus) ceases after a few years, the roots and 
crowns will have begun to spread, and the second cause will thus have 
come into operation. 
The average rate of growth in diameter on the stump of 1,593 trees is 
found in the table following. It was determined for all the trees 
together for the periods just before and after the previous cutting, and 
separately for those whose growth was accelerated. These trees 
occurred on eleven of the sample plots which were studied at Santa 
Clara. The other three plots were omitted because only a very few 
trees were taken at the first cut, and almost none of the remaining 
small trees showed accelerated growth. These measurements exhibit 
the rate of growth under various conditions of situation and soil. 
The figures of diameter growth given in the table were derived from 
measurements of the last ten rings. For example, the third column 
gives the average rate of growth of all trees just before the last cutting, 
and was found in each case by subtracting the increment for the period 
since lumbering from the increment for the last 10 years, and dividing 
by the number of years during which the growth thus ascertained was 
made. The fifth column gives the average rate of growth of all trees 
~ since the lumbering, whether they show an increased growth or not. 
The column which gives the current annual growth in diameter atter 
the values have been made regular by a curve also requires a word of 
explanation. When a series of averages are made out it often happens 
that the successive figures do not follow quite regularly. It will be 
noticed in the table that this is true of the lower part of the fourth col- 
umn, and that it is probably explained by the lack of enough trees of 
15 inches in diameter to get a fair average. In such cases the values 
are plotted on cross-section paper and a regular curve is drawnthrough 
or near the points which represent them. The points through which 
the curve actually passes are then taken as the true values. In this 
way accidental irregularities are avoided, and the results are brought 
much nearer the truth. 
