Treesearch

Carbonyl sulfide (OCS) has recently emerged as a tracer for terrestrial carbon uptake. While physiological studies relating OCS fluxes to leaf stomatal dynamics have been established at leaf and branch scales and incorporated into global carbon cycle models, the quantity of data from ecosystem-scale field studies remains limited. In this study, we employ established theoretical relationships to infer ecosystem-scale plant OCS uptake from mixing ratio measurements. OCS fluxes showed a pronounced diurnal cycle, with maximum uptake at midday. OCS uptake was found to scale with independent...

Forest densification, wildfires, and disease can reduce the growth and survival of hardwood trees that are important for biological and cultural diversity within the Pacific Northwest of USA. Large, full-crowned hardwoods that produce fruit and that form large cavities used by wildlife were sustained by frequent, low-severity fires prior to Euro-American colonization. Shifts in fire regimes and other threats could be causing declines in, large hardwood trees. To better understand whether and where such declines might be occurring, we evaluated recent trends in Forest Inventory and Analysis...

Reviewing: William J. Matthews and Edie Marsh-Matthews, Stream Fish Community Dynamics: A Critical Synthesis, 2017 Johns Hopkins University Press, 330 pp. Community dynamics are often difficult relationships to describe because they encompass multiple taxa involved in numerous types of interactions of varying strengths, all of which may shift over space and time. Gaining insights from a suite of several long-term projects is difficult logistically and can be difficult to sustain. However, in their book Stream Fish Community Dynamics: A Critical Synthesis, Matthews and Marsh-Matthews offer...

Future vegetation shifts under changing climate are uncertain for forests with infrequent stand-replacing disturbance regimes. These high-inertia forests may have long persistence even with climate change because disturbance-free periods can span centuries, broadscale regeneration opportunities are fewer relative to frequent-fire systems, and mature tree species are long-lived with relatively high tolerance for sub-optimal growing conditions. Here, we used a combination of empirical and process-based modeling approaches to examine vegetation projections across high-inertia forests of...

Background: Volume and taper equations are essential for obtaining estimates of total and merchantable stem volume. Taper functions provide advantages to merchantable volume equations because they estimate diameter inside or outside bark at specific heights on the stem, enabling the estimation of total and merchantable stem volume, volume of individual logs, and a height at a given diameter. Methods: Using data collected from 1218 trees (1093 Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) and 125 western hemlock (Tsuga heterophylla)), we evaluated the performance of one simple...

Background: Satellite-based aboveground forest biomass maps commonly form the basis of forest biomass and carbon stock mapping and monitoring, but biomass maps likely vary in performance by region and as a function of spatial scale of aggregation. Assessing such variability is not possible with spatially-sparse vegetation plot networks. In the current study, our objective was to determine whether high-resolution lidar-based and moderate-resolution Landsat-base aboveground live forest biomass maps converged on similar predictions at stand- to landscape-levels (10 s to 100 s ha) and whether...

1 Red turpentine beetle Dendroctonus valens LeConte is a non-aggressive bark beetle in North America that attacks weakened or recently dead pines, as well as their fresh logs or stumps. Fire-injured ponderosa pines releasing stress-induced ethanol are often attacked. The oleoresin from these trees frequently contains 3-carene as a major component mixed with 𝛼- or 𝛽-pinene. 3-Carene lures usually attract more D. valens than 𝛼- or 𝛽-pinene lures or 1 : 1 : 1 mixtures, whereas the attraction of ethanol+3-carene lures has never been tested.2 Funnel traps with ethanol, 3-carene or ethanol+3-care...

Many forest-dependent animals require complex branch and bole structural features as substrates for nesting, and these features may take decades or centuries to develop. In young forests, lack of suitable nest substrates may limit occurrence and abundance of arboreal rodents. To test this hypothesis, we measured the response of arboreal rodents to installation of 429 artificial nest platforms at 17 young forest sites in the Coast Range of Oregon, United States. We compared the percentage of 100-m2 plots at sites containing nests before and after installation of nest platforms, and examined...

Recently, Stewart et al. (2017) investigated the origins of contemporary fisher populations in the Cooking Lake Moraine (CLM) of east-central Alberta, Canada, where fishers (Pekania pennanti) from Ontario and Manitoba, Canada were reintroduced in the early 1990s. To address this objective, Stewart et al. (2017) compared microsatellite alleles from extant fisher populations in the CLM to those from Ontario, Manitoba, and other Alberta populations. They reported that the CLM population clustered with adjacent native Alberta populations, consistent with recolonization, but also that 2 of 109...

Subsistence harvesters in high latitudes rely on frozen rivers for winter access to local resources. During recent decades, interior Alaskan residents have observed changes in river ice regimes that are significant hindrances to travel and subsistence practices. We used remote sensing in combination with local observations to examine changes in seasonality of river breakup and freeze-up and to assess the implications on travel for subsistence harvesters. Spring and autumn air temperatures, respectively, were found to impact timing of breakup (-2.0 days °C-1) and freeze-up (+2.0 days °C-1)....