632 



TIMBER RESOURCES FOR AMERICA'S FUTURE 



regions were extended to all commercial forest 

 land. 



Growth deficiency. See Growth impact. 

 Growth impact. Mortality plus growth loss. 

 (See section on "Forest Protection," p. 185.) 



Mortality. The net board-foot volume re- 

 moved from live sawtimber, or the net cubic- 

 foot volume removed from growing stock, 

 during a specified year through death from 

 natural causes, exclusive of catastrophic losses. 

 Growth loss. Growth deficiency plus loss of 

 accumulated growth. 



Growth deficiency. Timber loss due to 

 (a) delay in restocking or deficiencies in 

 stocking resulting from damage by insects, 

 disease, animals, fire, or adverse weather, 

 and (b) the reduction in growth due to changes 

 in timber type, defoliation, reduction of tree 

 vigor, increase in cull percent, or deterioration 

 of site due to such destructive agents. 



Loss of accumulated growth. The efl'ect 

 on present and prospective yields of live saw- 

 timber or growing stock due to mortality 

 (caused by such agents as fire, insects, disease, 

 animals, and adverse weather) of poletimber 

 trees, saplings, and seedlings in the case of 

 sawtimber yields, and saplings and seedlings 

 in tlie case of growing-stock yields. 

 Hardwood limbs. The limbs of live sawtimber 

 hardwood trees and sawtimber-size cull hardwood 

 trees to a minimum diameter of 4.0 inches inside 

 bark. 



Hardwoods. In the United States and Coastal 

 Alaska, dicotyledonous (usually broad-leaved and 

 deciduous) trees of commjercial species. See 

 Species groups. 



Indian ownership. See Owner.'ihip. 

 Industrial wood (round wood basis). All wood 

 timber products, except that portion of the fuel- 

 wood output cut directly from trees or parts of 

 trees. Industrial-wood products in roundwood 

 form (as saw logs, veneer logs, and bolts) do con- 

 tain a certain wood volume eventually used foi- 

 fuel in the shape of mill residues. 



Input index. A statistical means for measuring 

 the relative quantities of any broad class of raw 

 materials consumed by the Nation's economy dur- 

 ing a series of years. Conventional units of meas- 

 ure (such as cubic feet of timber, tons of mineral 

 ore, bales of cotton, etc.) cannot be compared 

 one with another nor aggregated. In construct- 

 ing the input index, the consumption of each 

 material, in its conventional unit of measure, is 

 weighted by its national average price during a 

 specified base period. The common unit of meas- 

 ure is thus the quantity of a given material, or 

 mix of materials, that could have been purchased 

 for one dollar in the base period. Such an index 

 provides a rough approximation of quantity in- 

 put, weighted by values as of the base period. 

 Labor force. That section of the population 14 



years of age and older that is or could be expected 

 to be: (a) productively engaged in civilian eco- 

 nomic activity of all kinds, (b) serving in the 

 Nation's armed forces, and (c) out of employment 

 but available for and willing to accept employment. 

 Land area. Includes dry land and land tempo- 

 rarily or partially covered by water, such as marsh 

 lands, swamps, and river flood plains (omitting 

 tidal flats) ; streams, sloughs, estuaries, and canals 

 less than one-eighth of a statute mile in width; 

 and lakes, reservoirs, and ponds having less than 

 40 acres of area. 



Forest land. See Forest land area. 

 Cropland in farms. Includes cropland har- 

 vested and cropland not harvested and not pas- 

 tured, as defined in the 1950 Census of Agricul- 

 ture as follows: 



Cropland harvested. This includes land 

 fi'om which crops were harvested; land from 

 which hay (including wild hay) was cut; and 

 land in small fruits, orchards, vineyards, nurs- 

 eries, and greenhouses. 



Cropland not harvested and not pastured. 

 This includes idle cropland; land in soil-im- 

 provement crops only; land on which all crops 

 failed; land seeded in crops for harvest after 

 1949; and cultivated summer fallow. 

 Pasture and range in farms. Includes crop- 

 land used only for pasture and other pasture, 

 as defined in the 1950 Census of Agriculture as 

 follows: 



Cropland used only for pasture. Includes 

 rotation pasture and all other cropland that 

 was used for pasture. 



Other pasture. Includes rougli and brush- 

 land pastured and any other land pastured 

 excepting woodland and cropland. 

 Pasture and range not in farms. Grazed non- 

 forest land not in farm ownership. Confined 

 almost entirely to lands in public ownership. 



Other land. This item includes all house lots, 

 barn lots, lanes, roads, ditches, power lines, etc. 

 It includes all nonforest land that is not included 

 in any of the other specified land-use classes. 

 Log grades. Criteria for describing the rela- 

 tive quality of a log or for classifying a given 

 volume of sawtimber according to the quality of 

 its saw-log components. The log grades used in 

 this report are those developed for (1) eastern 

 hardwood saw logs suitable for standard lumber 

 and (2) southern pine saw logs suitable for yard 

 lumber. 



For eastern hardwoods three standard lumber log 

 grades are used: Grade 1 logs, studies have shown, 

 yield about 65 to 80 percent of their volume in No. 

 1 Common and Better grades of lumber. Grade 2 

 logs yield about 40 to 64 percent, and Grade 3 logs 

 yield only about 13 to 36 percent of No. 1 Common 

 and Better lumber. Included with tlie volume of 

 Grade 3 standard lumber logs is the volume of 

 hardwood logs which are not suitable for standard 



