PROPAGATION OF WHITE PINE J5 



mained until the following May. They were then transplanted to an opening 

 in the College forest. They had made no top growth up to tJiat time (see Figure 1) 

 and their average growth was less than one-half inch during the first growing 

 season after they were set outdoors. It is possible that they would have resumed 

 growth more promptly, come out of their apparent dormancy more quickly, had 

 they been subjected to lower temperatures than those of the greenhouse that 

 first M^inter after they rooted, a factor yet to be investigated. 



But in the following year, their second growing season outdoors, these rooted 

 cuttings of white pine made good growth, an average of five inches. And as is 

 shown in Figure 2, the new growth was in the desired or vertical direction. Their 

 present form or habit (see Figure 3) is at least as good as that of trees of compar- 

 able age grown from seeds, and the indications are that these rooted cuttings of 

 white pine are growing into well-formed, normal trees. 



Summary 



Some individual white pines are more desirable from the viewpoint of forestry 

 than others. But certain abnormal forms, although useless as timber, are useful 

 in ornamental horticulture. 



White pines with certain individual characteristics may be worth perpetuating. 

 Propagation by means of cuttings from such trees may be expected to produce 

 trees identical in form and behavior with the parent tree. Many white pines 

 can be thus propagated, although cuttings from different trees differ markedly in 

 their ability to root. 



Cuttings should be taken as early in the life of a tree as its desirable qualities 

 become evident, for they root better if taken from young trees. 



Late winter is a good time of year to take cuttings. Those taken in midsummer 

 require longer to root. 



Cuttings should be taken from wood of the last growing season and should 

 consist of small twigs from lateral branches of lower limbs, with no needles 

 removed. 



Cuttings from some white pines are more responsive to treatments with root- 

 mducing substances than are others. But a short immersion in a relatively con- 

 centrated solution of indolebutyric acid often improves rooting, and such treat- 

 ment is recommended. 



Cuttings rooted equally well in freshly prepared and in previously used sand- 

 peat. Sterilizing the medium by steaming did not affect rooting. The presence 

 or absence of mycorhizal or other soil fungi did not appear to be important. A 

 sand-sedge peat, if not too wet, gave good results. 



High relative humidity, as maintained by an automatic humidifying unit is 

 important. ' 



Rooted cuttings of white pine are developing into normal, well-formed trees. 



Literature Cited 



1. Dallimore, W., and Jackson, A. Bruce. A Handbook of Coniferae. London. 



2. Delisle, A. L. Histological and anatomical changes induced by indole- 



acetic acid in rooting cuttings of Finns Sirobus L. Va. Tour Sci 3 -5 -IIS 

 124. 1942. ■ ■ ■ ■ 



3. Deuber, Carl G. Vegetative propagation of conifers. Trans. Conn Acad 



Arts and Sci. 34:1-83. 1940. 



^ — - -- T^he vejretative propagation of eastern white pine and 



other five-needled pines. Jour. Arnold Arboretum 23:198-215. 1942. 



