68 



TIMBER RESOURCES FOR AMERICAS FUTURE 



there are several developments which indicate 

 that reductions can also be expected in the growth 

 impact from destructive agents other than fire. 

 One of these is the action being taken xmder the 

 Forest Pest Control Act of 1947 to detect and 

 control attacks by insects and disease. New 

 insecticides and improved methods of application 

 are increasing the effectiveness of insect control. 

 Greater accessibility, more efficient equipment, 

 and rising timber values will favor continuation of 

 the current trend toward increasing salvage of 

 dead and dying timber. 



Timber owners are gradually becoming aware 

 of the basic principle that many kinds of losses 

 can be reduced by indirect methods such as better 

 forest management practices. Timber stand im- 

 provement operations and other management 

 measures that improve the thrift and vigor of 

 forests help to control losses. Forest tree improve- 

 ment progi'ams aimed at development of resistant 

 strains of trees are increasing and hold promise for 

 the future although they may not add significantly 

 to supply dm-ing the century. 



Because many forms of insect damage can be 

 reduced by direct attack on the insects, the reduc- 

 tion in growth impact from this cause may reach 

 or closely approach the percentage reduction 

 expected from advances in fire control. However, 

 with diseases, weather, animals, and miscellaneous 

 causes of loss where indirect methods of control 

 must play a larger part, percentage reductions will 

 probably be smaller than those for fire and insects. 



Catastrophic 



Losses Take 

 Toll 



Additional 



In addition to the losses from destructive agents 

 considered in the mortality and growth impact 

 estimate, there are losses from unpredictable 

 events characterized by extraordinary severity 

 and concentrated loss which are termed "cata- 

 strophic" timber destruction. Since 1900, 14 such 

 events have been recognized and are enumerated 

 in the section on Forest Protection. Examples 

 include the Tillamook burn of 1933 in Oregon, 

 the New England hurricane of 1938, the more 

 recent destructive outbreak of the Engelmann 

 spruce beetle in Colorado, and the chestnut blight 

 in the East. Total estimated losses from these 

 14 events exceed 122 billion board-feet, of which 

 approximately 16 billion have been salvaged. 

 Insects were responsible for 52 billion board-feet, 

 fire 32 billion, wind over 19 billion, and disease 18 

 billion. These total losses prorated over the 

 first half of the century average 2.3 billion board- 

 feet a year, but they are unpredictable as to 

 locality or time. However, 72 percent of the loss 

 occurred in the West. An effort is made to 

 account for such catastrophic losses by providing 

 a margin when estimating needed growth. 



Forest Tree Planting 



Because so much of the commercial forest land 

 of the United States (114 million acres) is poorly 

 stocked, or nonstocked, and because planting 

 offers an effective way to restore some nonstocked 

 lands to productivity, to improve stocking of some 

 poorly stocked land, and to shorten the lapse of 

 time waiting for natural regeneration, an appraisal 

 of the status of forest planting and planting possi- 

 bilities was made in connection with the Tunber 

 ResoiU'ce Review. 



The planting estimates summarized hereafter 

 are conservative because they do not include (1) 

 planting in lieu of natural regeneration after 

 cutting, (2) interplanting to improve stocking on 

 medium-stocked and some poorly stocked lands, 

 or (3) conversion of agricultural land to forest 

 by tree planting under the Soil Bank program of 

 1956.'^ It is believed that planting for these 

 purposes will become more common as the in- 

 tensity of forestry increases in the United States. 

 Therefore, total planting possibilities and needs 

 may ultimately be significantly larger than the 

 estimates in the current appraisal. 



Estimates of plantable area and acceptable 

 plantations have been developed. Briefiy, plant- 

 able area includes lands (1) on which the planting 

 of forest trees is practical from a physical or 

 biological standpoint and gives reasonable promise 

 of economic feasibility, and (2) which need to be 

 planted if they are to be restored to producti^^ty 

 within a reasonable time. 



Acceptable plantations are defined as those 

 which have, at the end of the fifth year after 

 planting, at least 400 trees per acre for all eastern 

 species, 200 trees per acre for all western species 

 except Engelmann spruce and lodgepole pine for 

 which the standard is 300. These standards 

 ordinarily will provide satisfactory stocking at 

 maturity. 



The significance of planting possibilities is em- 

 phasized b}^ the estimate that the plantable acre- 

 age which was included could be expected to yield 

 an annual growth of 8 billion board-feet after the 

 trees reach merchantable sawtimber size. If this 

 were achieved, the output from the plantable area 

 would equal 17 percent of 1952 net growth of 

 sawtimber. Such an addition to net growth would 

 help substantially in raising growth to the levels 

 needed to meet projected timber demand. 



'5 Under the Conservation Reserve part of the Soil Bank 

 program, it is estimated that possibly 5 million acres of 

 farmland may be planted to trees. The land to be planted 

 is from land regularly used in the production of crops 

 (including crops such as tame hay, alfalfa, and clovers, 

 which do not require annual tillage). The Soil Bank 

 program was authorized by the .\gricultural Act of 1956, 

 several years after completion of the Timber Resource 

 Review estimates. 



