TIMBER RESOURCES OF NORTH AMERICA AND THEI WORLD 



329 



8-9 inches. Reproduction is by layering and 

 seedling growth. Fii-es are intense; the density 

 and small size of the trees favor crown fires. 



Timber Volume Is Substantial and 

 Net Growth Is Good in Spite of 

 Fire 



The commercial forests of the Interior are not 

 stunted Arctic stands. They are in various stages 

 of recovery following fires. Some are just repro- 

 ducing, while others have been unbumed for more 

 than 100 years. Volumes of these older stands are 

 comparable to those of southern Ontario or 

 northern Maine. Occasional spruce stands of 15 

 thousand board-feet per acre are found. Trees 

 24 to 30 inches in diameter at not over 200 years 

 have been found north of the Arctic Circle. 

 Mortality due to fire, insects, disease, and climatic 

 damage is an unknown factor. Rates of growth, 

 yields at various ages, and location of the best 

 stands all await study. Cutting is pretty much 

 confined to the spruce type, although spruce-birch 

 has almost equally high volumes. Pure birch, or 

 birch with spruce in the understory, forms dense 

 stands over large areas and probably runs as high 

 as 8 thousand board-feet to the acre. Amount or 

 kind of defect taking the largest toll is unknown. 

 There is an immense resource in spite of great 

 losses from fire and other destructive agents. 



Thirty-Two Billion Cubic Feet 

 Await Use 



It is estimated that Interior stands average 

 about 800 cubic feet or 4,500 board-feet per acre. 

 Thus, the 40 million acres of commercial forest 

 land support an estimated total volume of 32 

 billion cubic feet and 180 billion board-feet. 

 Approximately 72 percent of the volume is esti- 

 mated to be softwoods (mostly spruce) and 28 

 percent hardwoods (mostly birch). 



Area 

 (thousand Sawtimber Growing slock 



acres) {thousand bd.-ft.) (thousand cu. ft.) 



Softwoods 28,932 130,194,000 23,145,600 



Hardwoods 1 1 , 068 49, 806, 000 8, 854, 400 



Total 40,000 180,000,000 32,000,000 



Net Growth Could Be Much Greater 



Growth could be greatly increased through 

 more adequate fire protection. Fires destroy not 

 only stands of commercial size, but immature 

 stands which may take as much as 10 years to 

 reproduce. Thus growth is being retarded over 

 large areas through failure of stands to reach 

 maturity or areas to restock, and stands generally 

 are kept more or less continuously in a poor 

 growing condition. 



It has been estimated that mature 160-year-old 

 stands on good sites wUl contain about 3,900 cubic 

 feet per acre of growing stock and 15,500 board-feet 

 of sawtimber. The mean annual net increment 

 indicated by such stands of 24 cubic feet and 97 

 board-feet per acre totals nearly 1 billion cubic 

 feet of growth annually including 3.9 billion board- 

 feet, as shown in the following tabulation : 



Total net growth 



Area Sawtimber Orowing stock 



(thousand (thousand (thousand 



acres) bd.-ft.) cu.ft.) 



Softwoods 28,932 2,806,404 694,368 



Hardwoods 11,068 1,073,596 265,362 



Total 40,000 3,880,000 959,730 



Mortality Losses Are High 



Sawtimber mortality caused by a combination 

 of fire, insects, disease, and climatic factors have 

 been ro uglily estimated at 2 billion board-feet per 

 year on commercial forest land. It is estimated 

 that about 50 percent of total mortality is due to 

 fire. What part is caused by insects and disease 

 separately cannot be estimated on a practical 

 basis. Since practically all of the Interior has 

 been burned at least once, stands are young and 

 subject to less damage by insects, disease, and 

 windthrow than would be the case if the stands 

 were- more mature. 



During the past 3 years, rough surveys of exist- 

 ing forest insects and diseases have been made 

 annually. Before that, only occasional trips into 

 the Interior were made by forest entomologists 

 and pathologists. Of the insects, Dendroctinus 

 borealis has been very destructive of white spruce, 

 and during 1949 and 1950 much of the timber be- 

 tween Anchorage and Palmer, 40 miles north, was 

 badly damaged. Many insects have been identi- 

 fied as common to the tree species of Interioi- 

 Alaska and many diseases also have been found. 

 Losses due to wind and animals also doubtless 

 occur. However, no quantitative data exist upon 

 which to base individual estimates of the mortality 

 and growth losses due to these destructive agencies. 



Protection Is Difficult in a Frontier 

 Country 



In the more inhabited areas, fire control is at- 

 tempted. In remote areas little can be done as 

 yet. Fire protection began in 1939 with the 

 organization of the Alaskan Fire Control Service, 

 under tlie General Land Office. Prior to that 

 from 5 to 8 million acres were burned each year. 

 With very limited funds this agency succeeded in 

 reducing the annual burn from 4.5 million acres in 

 1940 to 117 thousand acres in 1945, but this was 

 partly due to cessation of normal pursuits such as 

 mining and trapping during the war years. With 

 a resumption of these activities following 1945 



