Treesearch

Call surveys used to monitor breeding choruses of anuran amphibians generate index values that are frequently used to represent the number of male frogs present, but few studies have quantified this relationship. We compared abundance of male Boreal Chorus Frogs (Pseudacris maculata), estimated using capture-recapture methods in two populations in Colorado, to call index values derived from automated recordings. Single index values, such as might result from large monitoring efforts, were unrelated to population size. A synthetic call saturation index (CSI), the daily proportion of the...

This study presents an alternative assessment of the MODIS LAI product for a 58,000 ha evergreen needleleaf forest located in the western Rocky Mountain range in northern Idaho by using lidar data to model (R2=0.86, RMSE=0.76) and map LAI at higher resolution across a large number of MODIS pixels in their entirety. Moderate resolution (30 m) lidar-based LAI estimates were aggregated to the resolution of the 1-km MODIS LAI product and compared to temporally-coincident MODIS retrievals. Differences in the MODIS and lidar-derived values of LAI were grouped and analyzed by several different...

Escape from specialist natural enemies is frequently invoked to explain exotic plant invasions, but little attention has been paid to how generalist consumers in the recipient range may influence invasion. We examined how seed preferences of the widespread generalist granivore Peromyscus maniculatus related to recruitment of the strongly invasive exotic Centaurea stoebe and several weakly invasive exotics and natives by conducting laboratory feeding trials and seed addition experiments in the field. Laboratory feeding trials showed that P. maniculatus avoided consuming seeds of C. stoebe...

We developed an integrated system for photographing a wolverine's (Gulo gulo) ventral pattern while concurrently collecting hair for microsatellite DNA genotyping. Our objectives were to 1) test the system on a wild population of wolverines using an array of camera and hair-snag (C&H) stations in forested habitat where wolverines were known to occur, 2) validate our ability to determine identity (ID) and sex from photographs by comparing photographic data with that from DNA, and 3) encourage researchers and managers to test the system in different wolverine populations and habitats and...

Extreme weather often contributes to crown fires, where the fire spreads from one tree crown to the next as a series of piloted ignitions. An important aspect in predicting crown fires is understanding the ignition of fuel particles. The ignition criterion considered in this work is the critical mass flux criterion - that a sufficient amount of pyrolysis gases must be generated for a diffusion flame to be established above the surface. An apparatus was built to measure the critical mass flux for sustained flaming ignition of woody materials for varying environmental conditions (heat flux...

Phenology is the annual cycle of plant development as influenced by seasonal variations. Dormancy and cold hardiness are two aspects of the annual cycle. In temperate plants, the development of cold hardiness results in the ability to withstand subfreezing winter temperatures. Cold hardiness is also a reflection of overall stress resistance. In addition to describing cold hardiness and its use as a tool for understanding seedling quality and making management decisions in the nursery and in the field, this paper describes four tests used to determine cold hardiness: the whole-plant freeze...

Nursery cultural practices are used to help growers achieve pre-determined size and physiological targets for seedlings. In that regard, irrigation is used to accelerate or slow growth and as a trigger for changing growth phase. In a case study highlighting the effects of irrigation on seedling development, western larch (Larix occidentalis Nutt.) seedlings were grown under three irrigation regimes to study seedling irrigation frequency, growth, and instantaneous water use efficiency (WUEI). Seedlings were irrigated when daily container weights were reduced to 65% of saturated weight (SW),...

Liverwort and moss are economically significant weeds across a range of US container production sites, including forest seedling greenhouse culture in the Pacific Northwest. We have demonstrated the effectiveness of essential oils, or distilled plant extracts, in controlling liverwort and moss container weeds over three seasons of trials. When applied at the appropriate concentration and volumes, essential oils act as an effective contact herbicide. There is little or no residual, and under heavy pressure, liverwort and moss can re-establish within 2 weeks of knockdown. The applicator must...

Operational vegetative propagation systems provide a means of bringing new genetic material into forestry programs through the capture of a greater proportion of the genetic gain inherent within a selected tree species. Vegetative propagation systems also provide a method for multiplying superior varieties and/or families identified in tree improvement programs. Twenty years ago, a program at the Forest Biotechnology Centre, BC Research Incorporated (Vancouver, British Columbia, Canada), was initiated to apply somatic embryogenesis technology to conifer species with the intent of creating...

The challenge for a silviculturist is the creation of a seedling microsite that is favorable enough for the seedling to not only survive, but thrive. The silviculturist must do this without irrigation, heat, glass, plastic, or daily monitoring and management. The silviculturist does this by understanding the needs of the forest seedlings and the shortcomings of the reforestation site and by using management techniques to bring them closer together.