COMPARATIVE LENGTH OF GROWING SEASON OF 

 RING-POROUS AND DIFFUSE-POROUS WOODS 



FERDINAND W. HAASIS 



Jenkins, Kentucky 



The object of these studies was to answer the question: does 

 the growth of so-called diffuse-porous woods continue after that 

 of ring-porous woods has largely ceased; in other words, is the 

 growth of the former distributed over a longer period than that 

 of the latter? 



The work was done during the 1916 growing season at Jen- 

 kins, Kentucky. A small number of trees of various species were 

 selected growing under essentially identical conditions of site, 

 and of these the growth in length of specific branches was meas- 

 ured, it being assumed that this would be a reasonable indicator 

 of the diameter growth. The specimens were located on a 30 

 degree southeast slope, with rather rocky thin soil, the bed- 

 rock being a gray conglomerate: litter light, ground cover mod- 

 erate, and including Epigcea repens, Smilax rotundifolia, grasses, 

 moss, lichen, etc. The area was logged in 1911 leaving few 

 older trees, and the specimens were practically in the open. 



Measurements were made of the following trees with ring- 

 porous wood: Sassafras Sassafras, Quercus Prinus: of the follow- 

 ing with diffuse-porous wood: Nyssa sylvatica, Kalmia latifolia, 

 Acer ruhrum; and of the conifer: Pinus rigida. Two chestnut 

 oaks were used, one situated almost directly on outcrop. Its 

 total height was 43 cm., and it was branched all the way up, 

 but with one distinct niain stem. Measurements were made 

 on a 7-cm. twig at the top. The other was an upright shoot 

 of a semi-prostrate sprout 1.5 m. high and from the same stump 

 as another 4 m. high. The growth was measured of a twig 

 near the top, and 61 cm. in length. The sassafras was one of 

 two seedling sprouts from the same root, and was 15 cm. high. 



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