172 CLEARANCES AND UNDERPLANTING 



that underplanting and partial clearances should never be 

 attempted on poor soils lacking in moisture. For in such 

 soils the overcrop would probably be injured and the under- 

 crop would not thrive ; for all trees are less tolerant of shade 

 on dry soils or where the conditions are not suitable for their 

 growth. On such soils a short rotation of even-aged high 

 forest will generally be indicated. 



But on the other hand, whenever the soil is deep and good 

 and has a sufficiency of moisture, it is undeniable that crops 

 consisting of only thinly foliaged trees, such as Oak, Ash, and 

 Larch, will yield better returns if partially cleared and under- 

 planted ; whereas crops consisting of only thickly foliaged 

 trees may have slight partial clearances made if large girthed 

 timber is required, but not to such an extent as to cause the 

 growth of grass and weeds ; and they should not be under- 

 planted. 



NOTES AND TABLES FOR PARTIAL CLEARANCES. 



Oak. The first heavy thinning or partial clearance may 

 be made at about 60 years of age, though on stiff clay lands 

 it may be delayed till about 80 years. 



From the 5Oth to 8oth years, the clearances should be 

 repeated every 10 years; after that every 15 years. The 

 early thinnings must not be too severe, or epicormic branches 

 will appear, though this danger is lessened as the bark 

 becomes thicker. 



Underplanting should take place before any rank growth 

 appears. On most soils a mixture of Beech and Spanish 

 Chestnut will probably be most suitable ; or Spanish Chestnut 

 alone. On stiff clays, Hornbeam will probably succeed the 

 best, and, in places where there is much light, a few r Norway 

 Maple and Sycamore. Alder will also often be advisable, 

 especially if the land is wet ; it should, however, be periodi- 

 cally coppiced. 



The fast-growing conifers should not generally be used, 

 unless the underplanting is long delayed, for otherwise the 

 Oak will be overtaken. 



