68 SEEDING AND PLANTING 



takes more or less of the group character. In this manner of 

 planting, where the principal crop tree is a tender species, it may 

 be advisable to plant three or four rows of the tender species and 

 then a row of the more hardy one, whose chief function is to pro- 

 tect and assist in the development of the former. 



In most instances the formation of even-aged mixtures should 

 be by groups, care being taken, however, that the groups are not 

 sufficiently large to partake of the characteristics of small patches 

 of pure woods. Mixing by groups is most closely related to the 

 method of natural reproduction in mixed stands. In such stands, 

 as a rule, as a tree dies or is removed a single species is dominant 

 in seeding the open spot. In cases where several species start, 

 one of them soon becomes dominant and crowds out the others, 

 so that natural reproduction is usually more or less in the form 

 of small patches of single species. 



Seeding or planting in groups is the safest method of forming 

 an even-aged mixture and the only one in which the varying 

 character of the site can be utilized to the fullest extent. The 

 size of the groups should vary with the site and the species. 

 The larger the groups, however, the more nearly the mixture 

 partakes of the characteristics of a pure wood. It is usually de- 

 sirable that the groups be more or less variable in size and form 

 as it makes possible a better utilization of the site. 



The permanent preservation of an even-aged mixture in suit- 

 able proportion becomes more difficult as the species differ in tol- 

 erance, height growth, suitability for the site, and the shape of 

 the trees. Mixtures of tolerant species, such as sugar maple and 

 beech, sugar maple and spruce, beech and hemlock, maple and 

 white pine, are usually acceptable. Mixtures of tolerant with 

 intolerant species permit of great variety when suitable species 

 are selected. 



10. Uneven-aged Mixtures 



When the maximum number of intolerant trees, such as larch, 

 white oak, walnut, tulip, cherry, or ash, is desired they should 

 be grown in uneven-aged mixtures, in the form of an overwood 

 with tolerant species beneath. As a rule, but two age classes 

 should be represented, the older being the intolerant species which 

 should be seeded or planted some years in advance of the tol- 

 erant species. The time between the regeneration of the two 



