Spike-topped and broken spruce were recorded separately in the 10 transects 

 (table 2). All dead tops in small spruce apparently resulted from suppression, but in 

 larger trees 8 of 14 spike-tops originated at rust infections. Broken trunks were not 

 significantly correlated with rust in the samples, but trees broken at rust brooms are 

 commonly seen in Colorado (fig. 1). 



Table 2. — Occurrence of rust brooms in spike-topped and broken spruce in 10 transects 



in Colorado 



Tree size 





All Uve 



Spike -topped 



Broken 



; Total 



[ Broomed 



Total 



Broomed] 



Total 



' Broomed 







Number 



Percent 



Number 



Percent 



Number 



Percent 



Less than 6" 



d.b.h. 



241 



5 



7 







3 



33 



More than 6" 



d.b.h. 



900 



17 



14 



57 



10 



20 



All trees 





1,141 



15 



21 



38 



13 



23 



Figure 1 . --Engelmann spruce 

 in San Juan National Forest. 

 Rust infections in trunks 

 provide starting points for 

 decay that makes trees sus- 

 ceptible to wind breakage. 



