Practical Forestry in the Pacific Northwest / Protecting Existing Forests and Growing New Ones, from the Standpoint of the Public and That of the Lumberman, with an Outline of Technical Methods

by E. T. Allen

PROFITABLE THINNINGS

In addition to the yield of saw timber to be expected when the second crop reaches manufacturing size, there will be a market in many cases for material obtained by thinning. It is perfectly fair to compound for the remainder of the rotation any net profit so obtained and to set it against the carrying charges. In many cases it will go far to turn an apparently losing investment into a very profitable one. Moreover, the proper thinning of growing stands not only utilizes material which would otherwise die and be lost before the main harvest, but actually improves the quality of the first yield.

In obtaining the figures previously quoted the Forest Service found that the average Douglas fir stand at 40 years contains 410 living trees, most of them between 6 and 15 inches in diameter. At 60 years there are but 265 trees, 145 having died and decayed in the 20-year interval which were suitable for ties or other small timber products. The remaining trees would have been improved by thinning to prevent this loss, for the greatest diameter growth is made when the stand is open, and the ideal is to have just the density which will get the greatest wood production and still result in proper pruning and clearing of the trees.

Commenting along this line Mr. T. T. Munger, who conducted the investigation, says:

"That thinnings are silviculturally practicable and financially profitable in the Pacific Northwest has been demonstrated. In the vicinity of Cottage Grove, Oregon, many fully stocked even-aged Douglas fir stands now about 50 years old, most of them forming a part of ranches. Many of these stands have been cut over in the last 10 years and all the material then large enough for piling or mine timber cut out. This removed about 20 per cent of the stand. At the present time many of these same stands now contain much material valuable for small piles, ties and mine timber, yet the crown canopy is as dense and the trees as close and fine quality as though no cutting had ever been done in the stand. In fact, some of the 50-year old stands have already been cut over a second time, and each time with decided profit to the owner and no damage to the forest. From one 10-acre block of second growth now 50 years old, situated 7 miles from the railroad, already 32,000 feet of mining timber and about 100 50-foot piles have been taken out, yet the stand is now in good condition, and in a few years more of the smaller trees can be removed without infringing on the yield of the final crop. The material from these thinnings was worth at the railroad about $80 per acre."