Automated planning technologies show great promise of reducing operations costs by automating the spacecraft mission planning process. However, one of the bottlenecks is acquiring spacecraft operations knowledge from operations personnel and expressing it in a plan model. One of the primary design goals of the ASPEN planning language is to eliminate the knowledge acquisition bottleneck by makin...

Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and wi...

• Extension • Research • Consulting • PHOTO 1. Boreal mixedwood stand where both aspen and white spruce are within the dominant and co-dominant crown classes. Mixed species stands provide options for creating a wide variety of future stand conditions. Forest managers are increasingly being asked to consider and apply a diversity of silviculture systems to address the variety of social, economic...

Effects of temperature, storage time and their combination on germination of aspen (Populus tomentosa) seeds were investigated. Aspen seeds were germinated at 5 to 30°C at 5°C intervals after storage for a period of time under 28°C and 75% relative humidity. The effect of temperature on aspen seed germination could not be effectively described by the thermal time (TT) model, which underestimate...

Owing to their long life span and ecological dominance in many communities, forest trees are subject to attack from a diverse array of herbivores throughout their range, and have therefore developed a large number of both constitutive and inducible defenses. We used molecular population genetics methods to examine the evolution of eight genes in European aspen, Populus tremula, that are all ass...

BACKGROUND White-rot basidiomycete fungi are potent degraders of plant biomass, with the ability to mineralize all lignocellulose components. Recent comparative genomics studies showed that these fungi use a wide diversity of enzymes for wood degradation. Deeper functional analyses are however necessary to understand the enzymatic mechanisms leading to lignocellulose breakdown. The Polyporale f...

Human activities are increasing the concentrations of atmospheric carbon dioxide ([CO2]) and tropospheric ozone ([O3]), potentially leading to changes in the quantity and chemical quality of leaf litter inputs to forest soils. Because the quality and quantity of labile and recalcitrant carbon (C) compounds influence forest productivity through changes in soil organic matter content, characteriz...

To broaden our understanding of gibberellin (GA) biosynthesis and the mechanism whereby GA homeostasis is maintained in plants, we have investigated the degree to which the enzyme GA 3-oxidase (GA3ox) limits the formation of bioactive GAs in elongating shoots of hybrid aspen (Populus tremula x Populus tremuloides). We describe the cloning of a hybrid aspen GA3ox and its functional characterizat...

Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO(2)]) and elevated ozone concentration ([O(3)]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work ...