﻿36 BULLETIN 24, IT. S. DEPARTMENT OP AGRICULTURE. 



of ash and gum are heavier than that of cottonwood, and therefore 

 more seed trees are required per acre to insure dense restocking. 

 Acorns can not be scattered for any distance by the wind, and there- 

 fore natural reproduction of oak can not readily be secured under a 

 clear cutting system with seed trees. The best way to encourage 

 oak in a cottonwood stand is to preserve young, thrifty immature 

 trees wherever they occur. In swamping, or in cutting or deadening 

 inferior species, the aim should be to save the oaks and free them 

 from crowding. Besides forming part of the next cut, they will 

 reproduce to some extent. 



One cottonwood seed tree per acre will usually be adequate for 

 seed purposes. Where either ash or gum are present the total number 

 of seed trees per acre of all species should be from three to four. 

 On cut-over areas completely in possession of weed trees it is useless 

 to leave cottonwood to reproduce beneath thin shade. Here ash will 

 sometimes meet the demand, since it will reproduce under moderate 

 shade, but in its absence little can be done to keep boxelder, syca- 

 more, hackberry, and other species of doubtful value from taking 

 complete possession of the ground. 



PREPARATION OF THE GROUND. 



Preparation of the ground in mixed stands should be about the 

 same as in pure stands. The shade in mixed stands is ordinarily 

 more dense than that in stands of pure cottonwood. Consequently, 

 there is likely to be less underbrush and vines, and slashing of under- 

 growth is correspondingly less troublesome. 



In mixed stands, however, the problem is usually somewhat com- 

 plicated by the presence of many inferior trees which have no mer- 

 chantable value. Proper ground preparation in these stands will 

 entail an outlay for removing or deadening these undesirable asso- 

 ciates. Where conditions are favorable to cottonwood reproduction, 

 it would hardly seem justifiable to leave scattered inferior species 

 merely in the hope that within a few years they may acquire com- 

 mercial importance. An expenditure of $2 or $3 at most per acre 

 in deadening these trees should result in the establishment of a valu- 

 able young cottonwood stand, which otherwise might be indefinitely 

 delayed. 



Where, however, the unmerchantable species are very numerous the 

 cost of deadening will often be prohibitive and the reproduction of 

 cottonwood impracticable. 



Deadening is often a questionable course, in that numerous dead 

 trees scattered over an area afford breeding places for insects which 

 might later prove injurious to sound trees. Moreover, there is no 

 positive assurrance that satisfactory reproduction will follow. It 



