In interior Alaska, increased use of mechanical fuel reduction treatments, increased interests in the use of wood energy systems as alternatives to fossil fuels, and elevated populations of northern spruce engraver, Ips perturbatus (Eichhoff), have raised concerns regarding the impact of this bark beetle to forest resources. We conducted a large-scale field study in 2009-2011 (Study 1) to determine the effects of slash scoring (mechanical by chainsaw versus none), slash distribution (scattered versus decked), and cutting date (spring versus fall) on I. perturbatus colonization of and reproductive performance in white spruce, Picea glauca (Moench) Voss, slash, and to determine the effects of resulting treatments on adjacent levels of tree mortality caused by I. perturbatus. Unfortunately, attack densities were lower than expected, and did not provide for a very robust examination of the effects of these treatments. As a result, we reproduced several aspects of Study 1 in a second study (2011) using a baited design. Higher levels of I. perturbatus attack and emergence occurred on dispersed logs. Attack densities were highest in the dispersed, unscored treatment, and similar to 70% higher than observed in the decked, scored treatment. The scoring of dispersed logs significantly reduced attack densities by similar to 28%, but had no effect in decked treatments or on levels of emergence in either treatment. Higher levels of attack and emergence were observed on the tops of logs as compared to the bottoms of logs. Brood production (i.e., defined here as emergence/attacks) was also greater on the tops of logs compared to the bottoms of logs, suggesting the tops of logs are not only more attractive to I. perturbatus, but confer some advantage to brood development. Lower levels of attack and emergence occurred on small diameter logs. Higher levels of attack and emergence were observed on logs in a shaded fuelbreak (i.e., a more open condition of lower tree density) compared to the adjacent forest. Overall, our research suggests that unlike other works on Ips spp. in the western USA that promote the desiccation of slash to minimize colonization and brood production, I. perturbatus appears regulated by the apparency and accessibility of host material. This finding highlights the importance of developing management guidelines based on local science. A third study found two semiochemicals, trans-conophthorin and verbenone, reduced colonization of slash by I. perturbatus, and therefore holds promise as a tool for managing I. perturbatus populations. The implications of these and other results to the management of I. perturbatus in interior Alaska are discussed.

Spruce aphid, Elatobium abietinum (Walker) (Homoptera: Aphididae), causes chlorosis, defoliation and mortality of spruce, Picea spp., but has also been recorded infesting pine, Pinus spp., and Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Furniss and Carolin 1977, U.S. Dept. of Agric. For. Serv. Misc. Pub[. 1339). This species, an exotic invasive in North America, was first reported in British Columbia in 1916 presumably originating from native populations in Europe (Carter and Halldórsson 1998, Scot. For. Comm. Tech. Pap. 24) and has since spread throughout coastal areas of the Pacific Northwest where maritime climates moderate temperatures and increase E. abietinum survivability (Bejer-Petersen 1962, Oikos 13: 155-168). Little has been published on E. abietinum in North America. Sitka spruce, Picea sitchensis (Bong.) Carr., is a preferred host and grows in a narrow band along the Pacific coast from a latitude of about 61°N in south-central Alaska to 39°N in northern California. Extensive amounts of P. sitchensis mortality has been attributed to E. abietinum infestations in British Columbia (Koot 1991, Can. For. Serv. For. Pest Leafl. 16), but appears to be a rare occurrence elsewhere. Since 1998, large-scale outbreaks have occurred in Southeast Alaska resulting in defoliation of P. sitchensis over extensive areas (Wittwer 2003, U.S. Dept. of Agric. For. Serv. Tech. Rept. R10-TP-113) and some tree mortality. Elatobium abietinum overwinters as wingless, parthenogenetic females, which allows populations to rapidly increase following mild winters. There are usually several generations per year. Feeding is restricted to 1-yr-old and older needles as settling on younger needles is deterred by volatiles present in the epicuticular wax (Jackson and Dixon 1996, Ecol. Entomol. 21: 358-364). Needles that are fed upon quickly turn

Coniferous stands that regenerate following clearcutting in southeast Alaska can be characterized by the amount of soil disturbance during logging. There are indications that red alder in mixed stands mitigates some of the negative effects of clearcutting. We compared invmebrate biomass in four stands each of (1) young conifers, (2) young mixed alder and conifer, and (3) old conifers to dctcrtmnc if aldcr was hcncfic~al to invcrtchratcs. Collcmhola, thcn Aranac taxa wcrc nlow ahundant hut Cdcnptcra had thc . greatest invertebrate biomass on boles of red alder, Sitka spruce, or westem hemlock. Diptera taxa were the most abundant in flight traps in young mixcd aldcr and wnifcr stands. Pmcnptea taxa WMC thc most ahundant invcrtchratcs collcctcd from any foliage. Some rarer invertebrate families were unique to one or another of the tree species. Crawling invertebrate species richness was greatest on red alder and in young mixed alder and conifer stands. The greatest biomass of crawling invertebrates occurred on Sitka spruce boles. Old stands had about the same invertebrate biomass as mixed alder or conifer young stands. Hying invertebrate biomass and species richness was greatest in young stands of mixed alder and conifer. mice as many invertebrate species were found on westean hemlock or Sitka spruce foliage as on red alder foliage but invertebrate species richness was greatest on red alder. fnvertebrate biomass on red alda foliage was 20-100 times greater than on the equivalent weight of Sitka spluce or WcStm hcmlock foliagc. Rcd aldcr significantly contrihutcs invcrtchratc spccics richncss and hiomass to young forcst stan& of southeast Alaska.

Forest clearcutting has been the primary timber management practice in forests of southeastern Alaska since commercial timber harvesting began in the 1950s, and the dense, even-aged conifer stands that subsequently developed have broad and undesirable consequences for some nontimber resources-most notably, fish and wildlife. Because a few earlier reports suggested that red alder (Alnus rubra Bong.) helps mitigate some negative effects of timber harvesting (Deal 1997, Wipfli 1997, Hanley and Barnard 1998), we studied the influence of red alder on a broad set of nontimber resources in young conifer forests (40-year-old; equivalent to early third stage of Appendix 1, Chapter 1) in southeastern Alaska (Figure 1). It is unclear what the ecological functions of red alder are in young forested ecosystems in southeastern Alaska. Key questions include: Does red alder affect forest understory development, tree growth, and timber production? How does red alder influence food and habitat for fish and wildlife? How does red alder function in stream and riparian habitats? Does red alder influence forest ecosystem diversity and productivity?

Red alder (Alnus rubra Bong.) appears to influence the productivity of young-growth conifer forests and affect the major resources (timber, wildlife, and fisheries) of forested ecosystems in southeast Alaska.We propose an integrated approach to understanding how alder influences trophic links and processes in young-growth ecosystems.The presence of red alder is expected to increase understory biomass, and aquatic, riparian, and terrestrial invertebrate abundance, providing more food for herbivores, fish, and birds.We predict that most red alder trees will die standing, and woody debris will be small and mobile in streams.Nitrogen fixation by red alder in mixed stands may result in larger, more commercially valuable conifers.Inclusion of red alder in the regenerating stand may therefore mitigate some negative impacts of clearcutting, and may increase total wood production from the landscape.

A spruce beetle (Dendroctonus rufipennis Kby.) epidemic that began in the mid-1970s and persisted to the 1990s caused significant Sitka spruce (Picea sitchensis (Bong.) Carr.) mortality in the Beardslee Islands and in a few neighboring mainland areas of lower Glacier Bay. Entomologists of the U.S. Forest Service installed vegetation plots in 1982 and have followed the progression of the outbreak and its influence on forest structure and plant succession for 20 years. Stagnant tree growth from low nutrient availability probably contributed to the spruce beetle epidemic. Tree death was heavy in some sites resulting in a large volume of dead wood and the formation of forest gaps, which are now occupied by tree seedlings, shrubs, and herbaceous plants. This secondary disturbance by spruce beetle appears to have accelerated succession in the direction of an old-growth forest condition as these forests now have a more complex structure than forests with a similar age structure unaffected by spruce beetle.