Treesearch

Many of the plants and fungi that are harvested for nontimber products (e.g., foods, medicines, crafts) are critical to healthy forest ecosystems. These products also are essential to rural societies, contributing to the material and nonmaterial composition of communities and cultures. Product sales make important contributions at all economic scales, from household to national economies. Nontimber forest products (NTFPs) have been harvested for generations, sometimes centuries, yet they are seldom integrated into forest management. Few methods exist for inventory and assessment, and there...

In this paper; we propose a new estimator for creating expansion factors for survey plots in the US Forest Service (USFS) Forest Inventory and Analysis program. This estimator was previously used in the GIS literature; where it was called Penalized Maximum Entropy Dasymetric Modeling. We show here that the method is a regularized version of the raking estimator widely used in sample surveys. The regularized raking method differs from other predictive modeling methods for integrating survey and ancillary data; in that it produces a single set of expansion factors that can have a general...

Climate change is altering the conditions for tree recruitment, growth, and survival, and impacting forest community composition. Across southeast Alaska, USA, and British Columbia, Canada, Callitropsis nootkatensis (Alaska yellow‐cedar) is experiencing extensive climate change‐induced canopy mortality due to fine‐root death during soil freezing events following warmer winters and the loss of insulating snowpack. Here, we examine the effects of ongoing, climate‐driven canopy mortality on forest community composition and identify potential shifts in stand trajectories due to the loss of a...

Disturbance is an integral component of forest ecosystems. Therefore, contemporary changes to the frequency and severity of disturbances in forests may have lasting ecological consequences. In recent decades, widespread mountain pine beetle (MPB; Dendroctonus ponderosae) outbreaks have contributed more to total tree mortality than other disturbances such as wildfire. Past studies have used a broad range of measurements to evaluate the local effects of beetle outbreaks on birds (e.g., dead trees per acre versus percent mortality) and this has led to some challenges and inconsistencies in...

We tested 3-methyl-2-cyclohexen-1-one (MCH) and novel semiochemicals as potential spruce beetle (Dendroctonus rufipennis Kirby) (Coleoptera: Curculionidae, Scolytinae) repellents over multiple years in Utah and Colorado trapping bioassays. MCH is a known spruce beetle repellent and our testing revealed Acer kairomone blend (AKB) and isophorone plus sulcatone as repellents. We subsequently tested these semiochemicals for area and single tree protection to prevent spruce beetle attacks at locations in Utah, Colorado, Wyoming, New Mexico, and Alaska. Individual tree protection trials found...

DNA analysis of predator faeces using high‐throughput amplicon sequencing (HTS) enhances our understanding of predator–prey interactions. However, conclusions drawn from this technique are constrained by biases that occur in multiple steps of the HTS workflow. To better characterize insectivorous animal diets, we used DNA from a diverse set of arthropods to assess PCR biases of commonly used and novel primer pairs for the mitochondrial gene, cytochrome oxidase C subunit 1 (COI). We compared diversity recovered from HTS of bat guano samples using a commonly used primer pair "ZBJ" to results...

Forest headwater catchments are critical sources of water, but climate change and disturbance may threaten their ability to produce reliable and abundant water supplies. Quantifying how climate change and forest disturbances individually and interactively alter streamflow provides important insights into the stability and availability of water derived from headwater catchments that are particularly sensitive to change. We used long-term water balance data, forest inventory measurements, and a multiple-methods approach using Budyko decomposition and paired catchment models to assess how...

The dynamics of fire propagation through forest fuels are best characterized as a coupled fuel – fire – atmosphere system, where key interactions among processes at each scale become the basis for interpreting overall fire behavior across scales. While wildfires dominate the combustion of forest fuels in the western USA, prescribed fires are of greater significance in the eastern USA, where they are conducted primarily to reduce hazardous fuel loads and maintain desired ecological structure and functioning in forests (Agee and Skinner 2005, NIFC 2018). Much of our understanding of combustio...

We develop a spatial-dynamic optimization model of landscape scale, jointly produced ecosystem services on a forest at-risk of catastrophic wildfire. We show optimal fuel management strategies vary over time in response to biomass growth dynamics, how biomass contributes to ecosystem services, the implied tradeoffs and complementarities between ecosystem service values, and the spatial dynamics of fire spread. Fuel reduction strategies increase expected ecosystem service values in the future by lowering the probability ecosystem services will be lost to catastrophic fire. However, fuel...

The vast majority of measurements in the field of plant hydraulics have been on small‐diameter branches from woody species. These measurements have provided considerable insight into plant functioning, but our understanding of plant physiology and ecology would benefit from a broader view, because branch hydraulic properties are influenced by many factors. Here, we discuss the influence that other components of the hydraulic network have on branch vulnerability to embolism propagation. We also modelled the impact of changes in the ratio of root‐to‐leaf areas and soil texture on vulnerabilit...