46 BULLETIN 13, U. S. DEPARTMENT OF AGRICULTURE. 
burning over of the surface prior to the seed fall is necessary. The 
areas dealt with are ordinarily so large that disengagement cuttings 
are out of the question. 
The seed-tree method has been employed in the white and Nor- 
way pine stands on the Minnesota National Forest (see Plate VII). 
Owing to the inadequacy of the law under which cuttings were made, 
however, it has not proved satisfactory except under accidental 
combinations of circumstances, such as the occurrence of severe 
ground fires before and not after a seed fall. The law provides 
that 10 per cent (originally 5 per cent), by volume, of the trees 
above 10 inches diameter breast high shall be left as seed trees. 
Since no adequate provision was made for the distribution of these, 
spaces left without seed trees were often too large, and very little 
reproduction resulted. The stand was cut not only during seed 
years, but also in years when there was absolutely no seed produc- 
tion. In the absence of cultural fires to free the ground from com- 
peting growth before the seed fall, the benefits of cutting during 
seed years are minimized, since most of the reproduction, even if 
abundant, is killed by the dense brush that rapidly springs up. On 
some areas which had been burned over during the spring or summer 
of a seed year and logged the following fall and winter, reproduction 
was excellent. On many of these, however, the young pine was killed 
by subsequent fires, and before the next seed year the ground was 
again covered with brush. 
In lumbering old stands by the shelterwood method the first cut- 
ting should be made during a seed year and should be heavy enough 
to provide sufficient light for the pine seedlings without unduly 
encouraging the growth of brush. If reproduction is satisfactory — 
that is, if it should average at least 2,000 well-distributed seedlings 
per acre — a second cutting should be made during the first heavy 
seed year after the young pines are 5 or 6 years old. The stand may 
be cut clear at this time if the fire risk is small and the expense of 
leaving seed trees prohibitive. If, however, too much brush has 
sprung up since the first cutting, the ground should be thoroughly 
burned over in the spring or summer of the seed year in which the 
second cutting is made and seed trees or even enough of the stand 
to warrant a later cutting left on the ground. 
Should the shelterwood method be thought too expensive, the 
seed-tree method may be used with good results if the cutting — 
made during a full seed year — is preceded by a thorough surface 
burning. The seed trees should be selected in advance from the 
most windfirm of the pines, and should be protected from surface fires 
by trenching or some other means. They should be well distributed 
at least 2 or 3 to the acre. Before each subsequent seed year, 
areas on which reproduction is poor should be carefully burned over. 
