A NATIONAL PLAN FOE AMERICAN FORESTRY 707 



While in time the extract industry can very likely utilize a con- 

 siderable part of the killed southern chestnut, every effort should be 

 made to promote its immediate use for other purposes for which it is 

 suited. 



Reports from some New England pole-using companies indicate 

 that the average service life of untreated chestnut poles set in recent 

 years from local cuttings is materially shorter than that formerly 

 secured. Whether this is due to the use of blight-killed poles which 

 have been standing dead in the woods for some years before use, the 

 increased prevalence of chestnut heartwood decaying fungi or some 

 other factor is unknown. 



DETERIORATION OF FOREST PRODUCTS 



Fungi, microscopic plants which include in their number the 

 principal causes of disease in forest trees, are also the most important 

 causes of deterioration of forest products. 2 The fungi attacking 

 forest products belong to two distinct groups. The stain and mold 

 organisms consume the contents of the wood cells with relatively little 

 damage to their structure or strength, the losses they cause being due 

 to the discolorations that result. The decay fungi by attacking the 

 cell-wall material weaken and ultimately soften the wood, or may 

 even completely destroy it. Both groups are able to grow only in 

 wood that is moist but not water-logged. The less important 

 discoloring fungi will be considered first. 



STAIN AND MOLD 



The fungi that cause both of these defects are practically limited 

 to the sap wood. The slender filaments of the stain fungi that pene- 

 trate the wood give it a permanently darker color, commonly bluish 

 in cast, and therefore often referred to as blue stain. The mold 

 fungi are related organisms that happen to have colorless filaments 

 so that only their surface growth is visible, and all signs of their 

 presence disappear if the wood is planed. Therefore, while molds 

 interfere with sales of certain kinds of material, they are less important 

 than stain. Stain decreases the marketability of wood for most 

 purposes and in pine it throws lumber down into the lower grades 

 which bring a price less than the cost of production. Sap stain thus 

 aggravates the glut in the market for the very lowest grades of 

 lumber. It affects the drain on timber resources by increasing the 

 tendency to overcut the forest in meeting the demand for the higher 

 grades of lumber. This in turn results in a still further oversupply 

 of the lower grades, and a still greater difference in prices between 

 upper and lower grades. Pine and gum are most susceptible to 

 damage, and wood from second-growth stands is more affected 

 because of the higher proportion of sap wood. For both of these 

 reasons the sap-stain damage is greater in the East than in the 

 West. In pulpwood it is also something of a. factor, making neces- 

 sary stronger bleaching treatment in paper manufacture. The over- 

 cut to replace high-grade material that has been reduced in grade by 

 the staining fungi has never been estimated on a quantitative basis; 



3 Insects as agents in the deterioration of forest products are considered in the section entitled, " Progress 

 of Forest Entomology." 



