REPRODUCTION OF WESTERN YELLOW PINE. 



65 



BTTION ZONES. 



The above test applies to areas either well within the zone of 

 maximum root activity or entirely beyond the reach of tree roots, 

 that is. within a radius of 30 to 40 feet from living trees on one 

 hand and the same distance from the stomps of felled trees on the 

 other. Obviously there are transition zones intermediate between 

 these extremes. In order to secure some idea in regard to the effect 

 of cutting in different conditions of root activity, samples were 

 taken in 1919 at various points in transects extending from groups 

 of freshly cut stumps, across openings, and into groups of living 

 trees. Two such transects were made, one on a light limestone- 

 sandstone soil and another on a heavy clay loam derived from 

 basalt. In both instances from 75 to SO per cent of the timber had 

 been logged off within a few months or a year previous to the soil 

 sampling. Wilting coefficients were not determined, and therefore 

 the results are expressed in terms of total rather than net available 

 moisture content. In view of this fact, care was exercised to secure 

 samples of apparently uniform texture, especially v:ith reference 

 to clay content. This necessitated omitting a few of the selected 

 sampling points. 



Taele IS. — SoU r various zones of root act' 



Llml 1919. 



Distance o: 



: <oiI moisture, per cent. 



June 13. 



June 2- . 



Froc: Prom rumps. 



6 inches . 



12 inches. 



6 inches. 



12 inches. 





10.1 



8L4 



6.5 



7.0 

 4.6 

 4.3 

 3.7 



6.2 



90 feet west .r 





4.9 







5.6 



4.1 





4-9 



3.2 



Under trees 120 fe^t past 



7.0 



3.0 









::c Clay loam soil, 1919. 



Distance of sar::r.Ii::g | 



Total soil moisture, 

 per cent. 



From trees. 



From stumps. 



June 14, 



depth 

 6 inches. 



July 1, 



depth 

 6 inches. 



west 



B0 fert east 



19.8 



20.7 

 15.0 



ia.7 



21.0 



14.2 



20 feet west just outside of crowns 



9(1 feet east 



14.6 



Under tre«^ 







20 feet east, just outside of crowns 





11.3 



•50 feet east 







t 60 fed 



12.9 



SO feet east 



30 feet west 



18.0 



110 feet east 



Tn prnnp nf stumps 



19.7 









Note. — In both soils the moisture content is higher directly under the trees than at a distance. This 

 isevider. hade. 



—23- 



