CHAP. XL] Effects of Underplanting 239 



close canopy, and is already partially forcing its way into the 

 lower portions of the crowns of the standards. The Oaks were 

 rather short-stemmed ; for not only was the soil somewhat 

 inferior, but the trees had also been allowed to develop without 

 forming close canopy. Records showed that the soil had 

 formerly been overgrown with whortleberries, though at the 

 time of the investigations it had a thick layer of dead foliage 

 and humus. The underwood was formed by sowing during 

 1843 to 1847, immediately after a thinning took place, which 

 was followed by a clearance of all diseased stems during 

 1853-1856. 



The measurements made on the stems, when felled, showed 

 that (i) about eight years after the formation of the undergrowth 

 the rate of increment had sunk considerably, after having in- 

 creased at the time of its formation owing to the thinning; (2) 

 the effects of these two thinnings or partial clearances continued 

 for about two decades to induce tapering growth with larger 

 annual rings near the base than the upper part of the bole ; 



(3) during the third and fourth decades after the formation of 

 the underwood the basal increment was lower in No. i and the 

 same in No. 2 as previously, whilst in both cases the increment 

 in the upper portions of the trees was somewhat enhanced; and 



(4) finally, during the fourth decade, the superficial increment of 

 the various sections, and the total increment in cubic contents, 

 were practically about twice as great as they were throughout the 

 decade previous to underplanting. This last result completely 

 disposes of the argument that the growth of the standards is 

 prejudiced by the underwood consuming a large share of the 

 nutrients in the soil. At the same time it is hardly open to 

 reasonable doubt that the gradual improvement in the shape 

 of the bole is due to the underwood growing up into the 

 crown, and interfering more or less with the activity of the 

 foliage of its lower portion. 



The third series of investigations was carried out in an Oak 

 wood eighty-eight years old, whose past history was accurately 



