514 L. ZUFA 



terminal shoots and grew as vertical as the terminals. Cuttings taken 

 from the basal part of the crown rooted better than those taken from the 

 apical part. 



Several authors have studied the influence of ortet age on rooting. 

 Thimann and Delisle (1939) found that cuttings taken from 1- to 3-year- 

 old P. strobus rooted easily, and that rooting ability of older trees 

 decreased. Cuttings taken from mature trees were difficult to root even 

 with auxin treatments. Snow (1940) found no significant decrease in the 

 rooting of cuttings taken from P. strobus trees 15 years of age or 

 younger. Doran, Holdsworth and Rhodes (1940) successfully rooted cuttings 

 taken from 30-year-old eastern white pines. Patton and Riker (1958a) 

 had far less success in rooting cuttings taken from trees over 10 years 

 of age. 



Large individual variation in rooting ability was reported by Snow 

 (1940) and Patton and Riker (1958b). They noticed, furthermore, a 

 fluctuation in rooting ability of the same clones in different years. 



Thomas and Riker (1950) found it difficult to lift and transplant 

 rooted cuttings of eastern white pine because of their unilateral and 

 unbalanced root system. However, once the rooted cuttings started to 

 grow, they developed normally. Patton and Riker (1954) found no signi- 

 ficant differences in the survival and growth of seedlings and rooted 

 cuttings after 12 years. 



Needle fascicles produce a large number of propagules. Thimann and 

 Delisle (1942) rooted needle fascicles of eastern white pine. Mergen and 

 Simpson (1964), experimenting with hard pine needle fascicles, found a 

 sharp decrease in rooting ability with ortet age and had difficulty in 

 obtaining rooted needle fascicles that would grow. However, once a rooted 

 fascicle started to grow, it developed into a normal tree. Recently, 

 Hoff and McDonald (1968) rooted western white pine {Pinus monticola 

 Dougl.) needle fascicles. Only the needles with fascicular buds produced 

 shoot growth. Bud formation can be induced in needle fascicles of P. 

 strobus by pruning the terminals in early summer (C. Heimburger, 

 unpublished data) . 



MATERIALS AND METHODS 



During the winter of 1967 and spring of 1968, a series of experiments 

 dealing with the vegetative propagation of white pines were initiated. 

 All trials were established with propagules taken from lateral branches 

 in the basal part of the crown. The propagules were dipped in 50% captan 

 powder 1 and planted in coarse acid sand (except in the experiment on media) 

 either in tubes or in rooting beas. 



Slit tubes, made of polystyrene, were 3/4 inch in diameter and 

 3 inches long (described by McLean, 1959) . These tubes were arranged in 

 16-x-8-inch wooden flats which were covered with transparent polyethylene 

 and kept shaded in a greenhouse. The greenhouse temperature varied from 

 50° to 100°F, and the humidity was not controlled. 



50% captan is orthocide 50, a N-trichloromethylmercapto - 4-cyclo- 



hexene - 1,2 - dicarbomixide compound 



