scholarly journals Effect of contemporary infestation by the spruce aphid (Elatobium abietinum) on root growth in Sitka spruce transplants

1997 ◽  
Vol 70 (1) ◽  
pp. 1-5
Author(s):  
K. Day
Keyword(s):  
Root Growth ◽  
Sitka Spruce ◽  
Elatobium Abietinum

Root System Fibrosity of Sitka Spruce Transplants: Relationship with Root Growth Potential

1990 ◽  
Vol 63 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. D. DEANS ◽  
C. LUNDBERG ◽  
M. G. R. CANNELL ◽  
M. B. MURRAY ◽  
L. J. SHEPPARD
Keyword(s):  
Root Growth ◽  
Root System ◽  
Sitka Spruce ◽  
Growth Potential ◽  
Root Growth Potential

scholarly journals Defoliation and dieback of Sitka spruce in Reykjavík, Iceland

2021 ◽  
Vol 34 ◽  
pp. 15-28
Author(s):  
Juliane Kuckuk ◽  
Sibren van Manen ◽  
Ólafur Eggertsson ◽  
Edda Sigurdís Oddsdóttir ◽  
Jan Esper
Keyword(s):  
Heavy Traffic ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Urban Trees ◽  
Tree Ring Data ◽  
Winter Temperatures ◽  
Elatobium Abietinum ◽  
One Year ◽  
Spruce Needles ◽  
Aphid Populations

The green spruce aphid Elatobium abietinum is an important defoliating pest of Sitka spruce (Picea sitchensis) in Iceland. A comparison of two urban Sitka stands in Reykjavík, from 2013-2017, reveals a distinct defoliation difference between trees located near a main road (94% defoliated) and several hundred meters away from heavy traffic (47%). Chemical analyses of the spruce needles demonstrate substantially higher nitrogen ratios in trees near traffic. Furthermore, the recently warming winter temperatures promoted larger overwintering aphid populations since 2003, as well as a shift of mass outbreaks from autumn to spring, accompanied by distinct growth suppressions one year after an aphid population spike in the post-2003 tree-ring data. The results of this study indicate that the mechanisms triggering Sitka spruce dieback in Reykjavík include a combination of increasing winter temperatures, more frequent and severe green spruce aphid outbreaks, as well as elevated N values in the needles of urban trees.

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