EEPORT ON LARCH FOHESTS. 399 



value of the trees is three-fourths less than where they had been 

 thinned when about twenty years old. Not only is the present 

 difference in value in favour of tiraeous thinning, but the older 

 the trees grow the difference becomes still greater. At fifty-two 

 years old the thinned part is worth 8s. per tree on an average, 

 while the unthinned part is worth only 2s. per tree. Allowing 

 the plantation to stand till eighty years old, the difference in 

 value, as indicated by the present proportional growth, will then 

 be — the thinned trees 35s. each, and those unthinned 5s. each. 

 In other words, the unthinned trees at fifty-two years old are 

 worth one-fourth that of the thinned ones, while their prospective 

 value at eighty years old will be only one-seventh. 



Though the individual trees differ in value seven-fold, the 

 value per acre does not so differ. The unthinned parts, 6 feet 

 distant, contains 1200 trees per acre, at 5s. per tree = L.300 ; 

 and the parts thinned out to double that distance, contains only 

 302 trees per acre, at 30s. each = L.472, thus making the true 

 value of an acre thinned out to half the number planted at 6 feet, 

 between one-fourth and one-fifth more value than the part left 

 standing at the distance planted. At the end of eighty years 

 there is a balance in favour of thinning to the amount of L.l 72 

 per acre. 



The above calculations show the proportional rather than the 

 true increase and value of the wood. In consequence of the 

 want of thinning till the lower branches had withered and died, 

 the trees thus lost the means by which their growth is promoted, 

 and which under the best future management could never again 

 be restored, or attain the above estimate. 



On examining the concentric rings or layers of wood of a 

 number of trees in various parts of the forest where they were 

 cut and laid in heaps upon the road sides, it was quite observ- 

 able where the proper period of thinning had been exceeded. 

 Most of the trees planted at from five feet to six feet apart had 

 made annual layers of wood from one-sixth to one-fourth of 

 an inch thick, till about twenty years old, about which time the 

 branches met each other, and thus excluding light and air, speedily 

 destroyed their vitality. After this occurred, the growths annually 

 decreased, and by the thirtieth growth, in many cases, instead 

 of making annual layers of one-sixth to one-fourth of an inch 

 in one year, one-fourth of an inch was only made in four or 

 five years. With these facts before us, the urgency of thinning 

 at the proper time, in order to keep vital the lower branches, 

 must appear natural and reasonable to any one acquainted with 

 the laws of vegetation. The important function of the lower 

 branches to trees of any age (but especially young ones) are too 

 little regarded. By the lower branches the roots are nourished 

 and fed, by the latter the sap is absorbed and conveyed to all 



