"2. Securing a second cut within thirty years.
"All cutting should be done under the 'selection system,' which requires a careful choice of the individual trees to be removed. Fixed diameter limits and the leaving of any specified number of seed trees per acre can be very largely disregarded.
"The condition of every sugar and yellow pine on the sale area should be studied closely to determine whether that tree will be merchantable thirty years hence, by which time a second cut is probable. As a rule the trees which will remain merchantable for another thirty years should be left. Suppressed and crowded trees which cannot develop should be removed. Under this system of marking, ordinarily about one-half of the present stand of merchantable pine would be left uncut. Will it pay?
"On areas where practically all of the pine is over-matured and would be cut under the rule given above, a sufficient stand must be left to reseed thoroughly the cut-over land. This requires not less than four full seed-bearing trees, at least 25 inches in diameter, per acre. The strongest and thriftiest trees available should be selected for this purpose, but not less than the number specified must be left even if every tree will be a total loss before a second cut is possible.
"Extensive areas of pine timber which are not yet fully mature should be excluded from the sale. On patches or small areas of immature pine, which it is not practicable to exclude from the sale, cutting should be very light, limited to one-third or less of the largest trees, or omitted altogether.
"No attempt to discriminate sharply between sugar and yellow pine should be made, as both trees are almost equally desirable. Where a choice is necessary, sugar pine should be favored on moist situations, as in canyons, moist pockets, or benches and on northerly exposures. Yellow pine should be favored on dry situations, including exposed ridges and southern exposures.
"Fir and incense cedar should be marked, as a rule, to as low a diameter as these trees are merchantable in order to reduce the proportion of these species in coming reproduction. It is essential, however, that no large openings be made in the present stand since the exposed ground is in danger of reverting to chaparral or of becoming so dry from evaporation that no reproduction will follow cutting. Where the stand of pine is insufficient to reseed thoroughly and protect the cut-over area, enough sound, thrifty fir and cedar should be left to form a fairly even cover with openings less than a quarter of an acre in size.'"
The under current of all opinion upon sugar pine up to date is that reproduction will not be very successful unless enough growth to shelter the seedlings remains after logging. Where the fire risk permits, the same end may be furthered by leaving the tops scattered on the ground.
Little experimenting has been done in planting sugar pine, but there are many indications that except where conditions strongly favor natural reproduction it will be resorted to eventually if any particular attempt is made to get this species. Leaving large seed trees is not only expensive, but rather uncertain, because heavy seed years are several years apart and squirrels consume a large portion of an ordinary crop. Transplants which have received nursery shelter until past the greatest danger of drying out should prove most successful on heavily-cut south slopes.