Application of semiochemicals to assess the biodiversity of subcortical insects following an ecosystem disturbance in a sub-boreal forest.

From 2000 through 2003 we used semiochemical-baited traps in northeastern Minnesota, USA, to assess changes in assemblages of subcortical forest insects after a catastrophic wind storm in 1999 and subsequent (1999-2000) fuel-reduction activities (salvage-logging and prescribed-burning). We determined the regional efficacy of fifteen semiochemical blends (pheromones and kairomones) as attractants for target and non-target subcortical insect species (Coleoptera: Anthribidae, Buprestidae, Cerambycidae, Cleridae, Cucujidae, Curculionidae, Histeridae, Nemonychidae, Salpingidae, Scolytidae, Tenebrionidae, and Hymenoptera: Siricidae). During the four summers, we trapped 86,471 subcortical insects (143 species) in baited and unbaited Lindgren funnel traps, and 500 beetles (44 species) in baited and unbaited pitfall traps. We report 23 new state collection records of subcortical insects from Minnesota. Trap catches of subcortical insects were greatest in the wind-disturbed areas 2 years after the event, and declined thereafter. Similar trends were observed for subcortical insects in the burned areas. Both wind-disturbance and burning increased the subcortical insect species richness and diversity on the landscape. The subcortical insect species compositions of the salvaged and burned forest areas differed from those of the undisturbed and wind-disturbed areas. Trap catches of subcortical insects in response to semiochemical treatments also varied with year of sampling and land-area treatment. The greatest diversity of subcortical beetle species was in traps baited with attractants for the scolytids, Dendroctonus valens [(+)-α-pinene and (−)-ß-pinene] and Dryocoetes spp. [exo-brevicomin and (−)-α-pinene], perhaps reflecting the generic nature of the baits. The most distinct species compositions were collected in response to the woodborer and Dendroctonus simplex baits, whereas the species compositions in traps with the D. valens and Dryocoetes spp. baits, and the unbaited funnel trap were the most similar. The variation in trap catch with time and across landscapes suggests that the responses of subcortical insects to semiochemicals are more complex than previously appreciated.

Hybrid poplar and forest soil response to municipal and industrial by-products: a greenhouse study.

Little research has been conducted in the Lake States (Minnesota, Wisconsin, and Michigan) to evaluate the effects of municipal and industrial by-product applications on the early growth of short rotation woody crops such as hybrid poplar. Anticipated shortages of harvestable-age aspen in the next decade can be alleviated and rural development can be enhanced through the application of by-products to forest soils. This study was conducted to evaluate the effects of inorganic fertilizer, boiler ash, biosolids, and the co-application of ash and biosolids application on tree growth and soil properties by measuring hybrid poplar clone NM-6 (Populus nigra L. x P. maximowiczii A. Henry) yield, nutrient uptake, and select post-harvest soil properties after 15 wk of greenhouse growth. Treatments included a control of no amendment; agricultural lime; inorganic N, P, and K; three types of boiler ash; biosolids application rates equivalent to 70, 140, 210, and 280 kg available N ha(-1); and boiler ash co-applied with biosolids. All of the by-products treatments showed biomass production that was equal to or greater than inorganic fertilizer and lime treatments. A trend of increased biomass with increasing rates of biosolids was observed. Soil P concentration increased with increasing rates of biosolids application. None of the by-products treatments resulted in plant tissue metal concentrations greater than metal concentrations of plant tissue amended with inorganic amendments. Biosolids, boiler ash, and the co-application of biosolids and boiler ash together on forest soils were as beneficial to plant growth as inorganic fertilizers.