142 Forestry Quarterly. 



ful application. The over-mature, defective and decadent trees 

 are removed (selection) and the vacancies planted or left to re- 

 seed naturally, or else small circular patches are cut clear and 

 planted up, here and there as the stand requires ; these groups are 

 then enlarged until they merge into each other — the "oil spot 

 method." Sometimes a group of natural reproduction forms the 

 necessary nucleus "oil spot". 



The understory of hardwoods is almost always regenerated 

 naturally; not only do birch and beech seed abundantly, but they 

 can come in under the shade of the pine stand just as the pine can 

 well endure their shade — if not too heavy — in its youth. Some- 

 times, to encourage hardwood regeneration, and especially oak 

 and beech, the ground under seed-bearing trees of the desired 

 species is broken up — i. e., the mineral soil exposed — as by the 

 use of potato hoes. 



Only occasionally are acorns or beech nuts dibbled in or seed- 

 ling hardwoods planted. The expense is too great for extensive 

 planting aside from the planting of birch (often our Betula lutea 

 — yellow birch) on the fire breaks- 



As the stand approaches maturity the number of stems per 

 acre naturally diminishes so that on an average site there are : 

 3,200 trees per acre at 25 years, 800 trees per acre at 50 years, 200 

 trees per acre at 100 years, and only 140 trees per acre at 120 

 years. Established sowings or plantations are not "patched up" 

 after the first or second year, but any small gaps which may occur 

 are left to close up naturally. The patching process has not 

 proven successful since the newcomers seldom thrive. 



The diminution in number is encouraged by thinnings which be- 

 ginning at about tiie 20th year of the stand with "Cleanings" — 

 i. e. removal of only the over-grown, poorly shaped, suppressed 

 trees, become moderate between the fortieth and eightieth years 

 of the stand, removing not only the dead, dying, diseased, mal- 

 formed trees and the "wolf" trees, but also those of the inter- 

 mediate class, which crowd the crowns of the dominant trees, and 

 after the eightieth year till the hundredth year, become "heavy", 

 removing even co-dominant trees which are retarding the develop- 

 ment of the chosen individuals for the final stand. At present 

 thinnings are made every 5 or 10 years ; the tendency is toward 

 greater frequency — "thin early and often" — since otherwise the 

 light thinnings exert too temporary a benefit, the heavy thinnings. 



