Cold-hardiness of adult and larval spruce beetles Dendroctonus rufipennis (Kirby) in interior Alaska

1987 ◽  
Vol 65 (12) ◽  
pp. 2927-2930 ◽  
Author(s):  
L. Keith Miller ◽  
Richard A. Werner

Dendroctonus rufipennis, a serious insect pest causing periodic widespread damage to mature white spruce (Picea glauca (Moench) Voss) stands in Alaska, was studied to determine if either larvae or adults were freezing-tolerant. Mean supercooling points in both larvae and adults dropped from −12 °C in summer to about −31 °C in winter. The decrease in supercooling points in larvae was closely associated with synthesis of glycerol, but the decline in adult supercooling points partially preceded the synthesis of glycerol in the fall. Winter glycerol levels reached 3 molal. Neither larvae nor adults were freezing-tolerant at any time of the year. Measurement of temperatures beneath the bark of standing spruce showed that only beetles hibernating below the snowline would be expected to survive a typical winter.

1999 ◽  
Vol 29 (7) ◽  
pp. 993-1001 ◽  
Author(s):  
E C Cole ◽  
M Newton ◽  
A Youngblood

The current spruce bark beetle (Dendroctonus rufipennis Kirby) epidemic in interior Alaska is leaving large expanses of dead spruce with little spruce regeneration. Many of these areas are habitat for moose (Alces alces). To establish spruce regeneration and improve browse production for moose, paper birch (Betula papyrifera Marsh), willow (Salix spp.), and three stocktypes (plug+1 bareroot, and 1+0 plugs from two nurseries) of white spruce (Picea glauca (Moench) Voss) were planted in freshly cutover areas on Fort Richardson, near Anchorage. Four vegetation-management treatments were compared: broadcast site preparation with herbicides, banded site preparation with herbicides, mechanical scarification, and untreated control. Spruce seedlings had the greatest growth in the broadcast site preparation treatment (p < 0.01). Stocktype was the most important factor in spruce growth, with bareroot transplant seedlings being the tallest and largest 5 years after planting (p < 0.001). In the first 3 years, relative stem volume growth was greater for plug seedlings than for bareroot seedlings (p < 0.001). By year 4, relative growth rates were similar among all stocktypes. Treatment effects for paper birch and willow were confounded by moose browsing. Results indicate spruce can be regenerated and moose browse enhanced simultaneously in forests in interior Alaska.


2017 ◽  
Vol 47 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Qing-Lai Dang

Conifer winter damage results primarily from loss of cold hardiness during unseasonably warm days in late winter and early spring, and such damage may increase in frequency and severity under a warming climate. In this study, the dehardening dynamics of lodgepole pine (Pinus contorta Dougl. ex. Loud), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) were examined in relation to thermal accumulation during artificial dehardening in winter (December) and spring (March) using relative electrolyte leakage and visual assessment of pine needles and spruce shoots. Results indicated that all four species dehardened at a similar rate and to a similar extent, despite considerably different thermal accumulation requirements. Spring dehardening was comparatively faster, with black spruce slightly hardier than the other conifers at the late stage of spring dehardening. The difference, however, was relatively small and did not afford black spruce significant protection during seedling freezing tests prior to budbreak in late March and early May. The dehardening curves and models developed in this study may serve as a tool to predict cold hardiness by temperature and to understand the potential risks of conifer cold injury during warming–freezing events prior to budbreak.


2012 ◽  
Vol 42 (3) ◽  
pp. 561-573 ◽  
Author(s):  
Glenn Patrick Juday ◽  
Claire Alix

This paper calibrates climate controls over radial growth of floodplain white spruce ( Picea glauca (Moench) Voss) and examines whether growth in these populations responds similarly to climate as upland trees in Interior Alaska. Floodplain white spruce trees hold previously unrecognized potential for long-term climate reconstruction because they are the source of driftwood that becomes frozen in coastal deposits, where archeological timbers and beach logs represent well-preserved datable material. We compared ring width chronologies for 135 trees in six stands on the Yukon Flats and Tanana River with temperature and precipitation at Fairbanks from 1912–2001. Our sample contains a stable common signal representing a strong negative relationship between summer temperature and tree growth. We developed a floodplain temperature index (FPTI), which explains half of the variability of the composite chronology, and a supplemental precipitation index (SPI) based on correlation of monthly precipitation with the residual of the temperature-based prediction of growth. We then combined FPTI and SPI into a climate favorability index (CFI) in which above-normal precipitation partially compensates for temperature-induced drought reduction of growth and vice versa. CFI and growth have been particularly low since 1969. Our results provide a basis for building longer chronologies based on archeological wood and for projecting future growth.


1972 ◽  
Vol 104 (12) ◽  
pp. 1977-1983 ◽  
Author(s):  
Roy C. Beckwith

AbstractWithin white spruce stands near Fairbanks, Alaska, and on the Kenai Peninsula, Alaska, Dendroctonus rufipennis, Ips spp., and Trypodendron lineatum disperse in late May and early June; other scolytids fly during June and July. Flight in interior Alaska precedes by about 2 weeks that on the Kenai Peninsula. Mean daily temperatures during spring and early summer are generally warmer in the interior than in coastal areas. There was a large increase in the total number of beetles in a thinned area, mostly of Dryocoetes affaber.


Botany ◽  
2016 ◽  
Vol 94 (2) ◽  
pp. 117-126 ◽  
Author(s):  
Rongzhou Man ◽  
Steve Colombo ◽  
Pengxin Lu ◽  
Qing-Lai Dang

Compared with the effects of spring frosts on opening buds or newly flushed tissues, winter freezing damage to conifers, owing to temperature fluctuations prior to budbreak, is rare and less known. In this study, changes in cold hardiness (measured based on electrolyte leakage and needle damage) and spring budbreak were assessed to examine the responses of four boreal conifer species — black spruce (Picea mariana (Mill.) B.S.P.), white spruce (Picea glauca) (Moench) Voss), jack pine (Pinus banksiana Lamb.), and lodgepole pine (Pinus contorta Dougl. ex. Loud.) — to different durations of experimental warming (16 °C day to –2 °C night with a 10 h photoperiod, except for night temperatures during November warming (+2 °C)). Seedlings showed increased responses to warming from November to March, while the capacity to regain the cold hardiness lost to warming decreased during the same period. This suggests an increasing vulnerability of conifers to temperature fluctuations and freezing damage with the progress of chilling and dormancy release from fall to spring. Both lodgepole pine and jack pine initiated spring growth earlier and had greater responses to experimental warming in bud phenology than black spruce and white spruce, suggesting a greater potential risk of frost/freezing damage to pine trees in the spring.


1999 ◽  
Vol 29 (4) ◽  
pp. 413-423 ◽  
Author(s):  
R V Densmore ◽  
G P Juday ◽  
J C Zasada

Site-preparation and regeneration methods for white spruce (Picea glauca (Moench) Voss) were tested near Fairbanks, Alaska, on two upland sites which had been burned in a wildfire and salvage logged. After 5 and 10 years, white spruce regeneration did not differ among the four scarification methods but tended to be lower without scarification. Survival of container-grown planted seedlings stabilized after 3 years at 93% with scarification and at 76% without scarification. Broadcast seeding was also successful, with one or more seedlings on 80% of the scarified 6-m2 subplots and on 60% of the unscarified subplots after 12 years. Natural regeneration after 12 years exceeded expectations, with seedlings on 50% of the 6-m2 subplots 150 m from a seed source and on 28% of the subplots 230 m from a seed source. After 5 years, 37% of the scarified unsheltered seed spots and 52% of the scarified seed spots with cone shelters had one or more seedlings, but only 16% of the unscarified seed spots had seedlings, with and without funnel shelters. Growth rates for all seedlings were higher than on similar unburned sites. The results show positive effects of burning in interior Alaska, and suggest planting seedlings, broadcast seeding, and natural seedfall, alone or in combination, as viable options for similar sites.


2013 ◽  
Vol 43 (4) ◽  
pp. 331-343 ◽  
Author(s):  
Andrea H. Lloyd ◽  
Paul A. Duffy ◽  
Daniel H. Mann

Ongoing warming at high latitudes is expected to lead to large changes in the structure and function of boreal forests. Our objective in this research is to determine the climatic controls over the growth of white spruce (Picea glauca (Moench) Voss) at the warmest driest margins of its range in interior Alaska. We then use those relationships to determine the climate variables most likely to limit future growth. We collected tree cores from white spruce trees growing on steep, south-facing river bluffs at five sites in interior Alaska, and analyzed the relationship between ring widths and climate using boosted regression trees. Precipitation and temperature of the previous growing season are important controls over growth at most sites: trees grow best in the coolest, wettest years. We identify clear thresholds in growth response to a number of variables, including both temperature and precipitation variables. General circulation model (GCM) projections of future climate in this region suggest that optimum climatic conditions for white spruce growth will become increasingly rare in the future. This is likely to cause short-term declines in productivity and, over the longer term, probably lead to a contraction of white spruce to the cooler, moister parts of its range in Alaska.


2010 ◽  
Vol 40 (7) ◽  
pp. 1197-1209 ◽  
Author(s):  
A. David McGuire ◽  
Roger W. Ruess ◽  
A. Lloyd ◽  
J. Yarie ◽  
Joy S. Clein ◽  
...  

This paper integrates dendrochronological, demographic, and experimental perspectives to improve understanding of the response of white spruce ( Picea glauca (Moench) Voss) tree growth to climatic variability in interior Alaska. The dendrochronological analyses indicate that climate warming has led to widespread declines in white spruce growth throughout interior Alaska that have become more prevalent during the 20th century. Similarly, demographic studies show that white spruce tree growth is substantially limited by soil moisture availability in both mid- and late-successional stands. Interannual variability in tree growth among stands within a landscape exhibits greater synchrony than does growth of trees that occupy different landscapes, which agrees with dendrochronological findings that the responses depend on landscape position and prevailing climate. In contrast, the results from 18 years of a summer moisture limitation experiment showed that growth in midsuccessional upland stands was unaffected by moisture limitation and that moisture limitation decreased white spruce growth in floodplain stands where it was expected that growth would be less vulnerable because of tree access to river water. Taken together, the evidence from the different perspectives analyzed in this study clearly indicates that white spruce tree growth in interior Alaska is vulnerable to the effects of warming on plant water balance.


1994 ◽  
Vol 72 (12) ◽  
pp. 2186-2192 ◽  
Author(s):  
R. Terry Bowyer ◽  
Victor Van Ballenberghe ◽  
Karen R. Rock

We studied scent marking (rubbing of trees) in Alaskan moose (Alces alces gigas) in interior Alaska during 1989. Pole-sized trees were stripped of bark and rubbed by adult female and adult male moose; marking by females occurred during the peak of rut (late September – early October) when most females were in estrus, whereas marking by males was in late rut (mid-October – November). Moose selected white spruce (Picea glauca) as well as trees with particular physical characteristics for marking. The tops of 18.5% of 54 trees marked by moose were dead, whereas only 0.5% of 201 trees available for marking had dead tops. The distribution of scent-marked trees on rutting grounds was not spatially clumped. We hypothesize that rubbing of trees by females advertises their estrus, and that rubbing by males late in rut serves to attract females not successfully bred early in rut and may help prime estrus in these females.


2002 ◽  
Vol 32 (7) ◽  
pp. 1137-1150 ◽  
Author(s):  
Kirsten E Haberkern ◽  
Barbara L Illman ◽  
Kenneth F Raffa

We examined the major bark beetles and associated fungi colonizing subcortical tissues of white spruce (Picea glauca (Moench) Voss) in the Great Lakes region. Trees were felled at one northwestern Wisconsin site in a preliminary study in 1997 and at 10 sites throughout northern Wisconsin, Minnesota, and Michigan in 1998. Fungal isolations were made from beetles colonizing felled trees, beetles that emerged from felled trees, tissue of colonized trees, and tissue of uncolonized trees. Dryocoetes affaber (Mannerheim) and Polygraphus rufipennis (Kirby) accounted for over 90% of the insects that emerged from logs. Time of colonization had a significant effect on abundance and composition of emerging insects. New records include Dendroctonus rufipennis (Kirby) in Wisconsin and two Michigan counties and Crypturgus borealis (Swaine) in Wisconsin and Minnesota and one Michigan county. Five fungal species from two genera were isolated both from beetles and colonized tree tissue. None were isolated from uncolonized trees. Ten new beetle–fungal associations were identified. The association of specific fungi with specific bark beetles, both as they colonize and emerge from hosts and the isolation of these fungi from subcortical tissues of colonized but not uncolonized trees, is consistent with vector relationships. We compare our results with bark beetle – fungal associations reported elsewhere in spruce and suggest possible mechanisms constraining population growth by Dendroctonus rufipennis in the Great Lakes region.


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