The Application of Silviculture in Controlling the Specific Gravity of Wood

Abstract

Signl1!cance o! soeclflc gravity as a basis Investigations of coniferous species________12 of judging wood quality___._____________3Conc1usions_____________________________ 17 Mothods used In thejnvestJgotioDs________ 4 The appllcation of the results__________________ 18 InveStigations of breaU-leaved species_____5 Literature cltod_____________________________ 19Until recently it has been possible to sec.ure easily, whenever .needed,wood haying the properties desired for a special use.The extent of the progressive exhaustion of our virgin forests, however, now emphasizes ,our ultimate dependence upon the younger, second growth forest ,stands to J.I all of our needs for lumber and other wood.When the time of ;that dependence comes, the difficulty of securing materials well suited for the more exacting wood uses will become infinitely greater, because the supply must then come both , from fewer species and from trees of smaller size, that .eontain a lower :relative ,amount ;of ,clear lumber~ Learning what :growiih '!fac tors affect the quality of wood the most has consequently ;become ,a matter exceedingly important.'This 'bulletin gives the results of silvicultural studies which show that the specific gravity of the woods studied may ;be modified.by controlling localactors which .affect the growth either of forest .standsor of individual forest trees, so that it becomes possi ble, within .naturallimits, to regulate the .specificgravity of wood .according to the particular use in view. HISTORICALThe investigations upon whiCh this bulletin are based are the first of their kind to be condu;::ted on a .comprehensivescale .in the United States.