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The distribution and effects on soil chemistry of shrub alders (Alnus spp.) occurring in the understory of the boreal forest of Alaska were examined. Understory alder ramet distribution was mapped on three sites; ramet density ranged from 150 to 5280 ramets/ha. Allometric biomass models were developed for alder ramets; maps of the spatial distribution of ramets and of estimated aboveground alder biomass are presented. Biomass of alders in the understory ranged from 20 to 690 g•m−2. The total nitrogen of soils collected beneath alder and from areas without alder differed among the three sites and between two sampling episodes. In undisturbed forest, alder soils tended to have more nitrogen than nonalder soils. On the two sites where background soil fertility was low, a greenhouse bioassay matched these results: alder soils had greater nutrient-supplying capacity than nonalder soils. In soil collected after the sites were harvested, however, results varied. Areas that had supported dense alder before harvesting had more soil nitrogen than areas with no alder at only one site, and at another site, alder soils had significantly less total nitrogen. This study suggests that the effect of understory alders on the boreal forest soil mosaic is a function of site characteristics such as canopy openness and soil background fertility.

The spread of invasive species in riparian forests has the potential to affect both terrestrial and aquatic organisms linked through cross-ecosystem resource subsidies. However, this potential had not been explored in regards to terrestrial prey subsidies for stream fishes. To address this, we examined the effects of an invasive riparian tree, European bird cherry (EBC, Prunus padus), spreading along urban Alaskan salmon streams, by collecting terrestrial invertebrates present on the foliage of riparian trees, their subsidies to streams, and their consumption by juvenile coho salmon (Oncorhynchus kisutch). Riparian EBC supported four to six times less terrestrial invertebrate biomass on its foliage and contributed two to three times lower subsidies relative to native deciduous trees. This reduction in terrestrial invertebrate biomass was consistent between two watersheds over 2 years. In spite of this reduction in terrestrial prey resource input, juvenile coho salmon consumed similar levels of terrestrial invertebrates in stream reaches bordered by EBC. Although we did not see ecological effects extending to stream salmonids, reduced terrestrial prey subsidies to streams are likely to have negative consequences as EBC continues to spread.

Vertebrate herbivores can be effective agents of biological weed control in certain applications. I compared the use of domestic geese for weed control in an agricultural field with the herbicide hexazinone and with hand control. Newly planted spruce seedlings acted as a prototype crop that would be unpalatable to the geese. Trampling by geese led to as much as 47% tree seedling mortality during the 1st yr; this was reduced significantly by either limiting the amount of time the geese spent in the plots or surrounding seedlings with small wire fences. When compared with plots with no weed control, weed control by geese improved the diameter growth of the surviving seedlings by over 100% during the 1st yr of the study, but had no effect in the 2nd yr. The geese controlled a variety of weed species, but were most effective against quackgrass (Agropyron repens). However, grazing effectively selected for unpalatable weed species (including pineapple weed, Matricaria matricarioides, prostrate knotweed, Polygonum aviculare, and wild chamomile, Tripleurospermum phaeocephalum) so that by the end of the 2nd yr plots weeded only by geese had 25 times as much cover of unpalatable species as plots with no weed control. In contrast, the herbicide was ineffective against grass and effective against the unpalatable weed species. A successful integrated weed management strategy would thus require combining geese with another method of weed control, and would include measures to prevent crop trampling.

Morels are edible, choice wild mushrooms that sometimes fruit prolifically in the years immediately after an area has been burned by wildfire. Wildfires are common in interior Alaska; an average of 708,700 acres burned each year in interior Alaska between 1961 and 2000, and in major fire years, over 2 million acres burned. We discuss Alaska's boreal forest environment, describe what is known about the ecology of morels that fruit after fire, and report the morel productivity of three recently burned areas in Alaska. In addition, we describe the results of a series of indepth interviews on the commercial harvest of morels in the Pacific Northwest, western Canada, and Alaska, including information on current harvests, the potential for and constraints to development of an Alaskan morel industry, and potential resource management and business development implications.