1 WIMAS GROWTH 



The occurrence of lammas growth is a phenomenon quite com- 

 monl) observed in trees. Many hardwoods, notably species of beech 

 (Fagus I.) and oak (Quercus L.), develop vigorous secondary shoots 

 which often exceed the length of the spring shoots (10). Among 

 coniferous species European larch (Larix decidua Mill.) has been 

 reported (9) to form late shoots, and the author has observed them 

 on Scotch pine (Pinus sylvestris L.), red pine (Pinus resinosa Ait.) 

 and eastern white pine (Pinus strobus L.). Biisgen and Munch (10) 

 slate that lammas shoots occur more commonly on younger trees, 

 and cite the "green" Douglas-fir as an example. Lammas branches 

 arc associated with the formulation of a terminal bud in the middle 

 of the summer. These buds undergo a brief period of rest, a month 

 or slightly less in Douglas-fir. The part of the annual shoot formed 

 a fur the pause in such cases appears as new growth to which the 

 name "Lammas shoot" has been given in view of the approximate 

 date^ of its appearance. 



The relationship of lammas growth to the Rhabdocline needle 

 cast disease has been overlooked due to the supposedly short sporu- 

 lation period of the fungus. Liese (29) in a study on the biology 

 of R. pseudotsugae, considered lammas shoots but believed that they 

 developed too late to be infected. The overlapping of the period of 

 spore discharge with lammas shoot expansion suggested the probable 

 importance of this phenomenon in the development and spread of 

 the disease. 



Lammas shoots are usually very vigorous. In Douglas-fir they 

 sometimes equal or surpass the spring growth, but often fail to ripen 

 or harden-off. This may result in frost kill of the new terminals and 

 resultant poor form of the tree in succeeding years. Such damage 

 was common in the Camden area, and as a result many trees devel- 

 oped poor forms unsuited for Christmas trees even if the effects of 

 R. pseudotsugae were not considered. Another factor promoting the 

 disfigurement of trees which produce late shoots is the suscepti- 

 bility of such shoots to insect attack. 



All branches of a tree do not exhibit lammas growth. Certain 

 trees in a plantation, and certain plantations in an area, vary in 

 late shoot development. In the Cortland area a relatively few lammas 

 brandies developed in 1956, whereas in the Cheningo area, only 5 



(1) Lammas day was a bread festival celebrated in the past by Roman Catholics 

 on August 1. 



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