Treesearch

Large trees are important to a wide variety of wildlife, including many species of conservation concern, such as the California spotted owl (Strix occidentalis occidentalis). Light detection and ranging (LiDAR) has been successfully utilized to identify the density of large-diameter trees, either by segmenting the LiDAR point cloud into individual trees, or by building regression models between variables extracted from the LiDAR point cloud and field data. Neither of these methods is easily accessible for most land managers due to the reliance on specialized software, and much available...

Treatments to reduce forest fuels are often performed in forests to enhance forest health, regulate stand density, and reduce the risk of wildfires. Although commonly employed, there are concerns that these forest fuel treatments (FTs) may have negative impacts on certain wildlife species. Often FTs are planned across large landscapes, but the actual treatment extents can differ from the planned extents due to operational constraints and protection of resources (e.g. perennial streams, cultural resources, wildlife habitats). Identifying the actual extent of the treated areas is of primary...

Pests or pathogens that affect trees have the potential to fundamentally alter forest composition, structure and function. Throughout the last six years, large areas of otherwise healthy ‘ōhi‘a (Metrosideros polymorpha) trees have been dying rapidly (typically within weeks) in lowland tropical wet forest on Hawai‘i Island, USA. This mortality is quite distinct from previous well-documented ‘ōhi‘a dieback episodes driven by cohort senescence. Ceratocystis fimbiata was identified and routinely found associated with rapidly dying individuals of ‘ōhi‘a, Hawai‘i’s most widespread native tree....

In arid systems, phreatophytes are often among the most effective invaders because of their capacity to access and exploit groundwater resources otherwise unavailable to native vegetation. On Hawai'i Island, a non‐native phreatophyte, Prosopis pallida (kiawe), has invaded extensive dry lowland areas following its introduction in the 19th century. To better understand the influence of this invader on the host ecosystem, and vice versa, we determined transpiration characteristics of P. pallida by monitoring sap flux of mature individuals over an 18‐month period on the arid leeward coast of...

Background: Spatially explicit forest carbon (C) monitoring aids conservation and climate change mitigation eforts, yet few approaches have been developed specifcally for the highly heterogeneous landscapes of oceanic island chains that continue to undergo rapid and extensive forest C change. We developed an approach for rapid mapping of aboveground C density (ACD; units = Mg or metric tons C ha−1) on islands at a spatial resolution of 30 m (0.09 ha) using a combination of cost-efective airborne LiDAR data and full-coverage satellite data. We used the approach to map forest ACD across the...

Monitoring studies often use marked animals to estimate population abundance at small spatial scales. However, at smaller scales, occupancy sampling, which uses detection/nondetection data, may be useful where sites are approximately territories, and occupancy dynamics should be strongly correlated with population dynamics. Occupancy monitoring has advantages in that it is less expensive and invasive, and marked animals are not needed. Here, we used empirical data to determine whether and when change in occupancy is a good proxy for population change for a territorial species. As part of...

The use of spring prescribed fires to reduce accumulated fuel loads in western forests and facilitate the return of natural fire regimes is a controversial topic. While spring burns can be effective at reducing fuel loads and restoring heterogeneous landscapes, concerns exist over the potential impacts of unnaturally-timed fires to native species. To protect native wildlife from disturbance during critical periods, limited operating periods (LOPs) are often implemented. However when LOPs for multiple species are combined into an integrated management plan, very few time windows for...

California supported a great diversity of plants with edible underground storage organs available to Indian tribes. Together, plant foods, fish and meat made up an indigenous diet that was well-rounded, diverse, and relatively secure. The edible underground parts possessed by these plants are classified as bulbs, corms, taproots, tubers and rhizomes, and when conditions turn unfavorable (too cold or too dry), the above-ground stems die back and the underground organs remain alive. Botanists and ecologists call the plants that employ this strategy geophytes. Indians often call them Indian...

Oil extraction and development activities in the Athabasca Oil Sands Region of northern Alberta, Canada, release NOx, SOx, and NHy to the atmosphere, ultimately resulting in increasing N and S inputs to surrounding ecosystems through atmospheric deposition. Peatlands are a major feature of the northern Alberta landscape, with bogs covering 6-10% of the land area, and fens covering 21-53%. Bulk deposition of NH4+ -N, NO3- -N, dissolved inorganic N (DIN), and SO42- -S, was quantified using ion-exchange resin collectors deployed at 23 locations, over 1-6 years. The results reveal maximum N...

Forest pathogens have strong potential to shape ecosystem function by altering litterfall, microclimate, and changing community structure. We quantified changes in litter decomposition from a set of distinct diseases caused by Phytophthora ramorum, an exotic generalist pathogen. Phytophthora ramorum causes leaf blight and increased litterfall %N, but no mortality on California bay laurel (Umbellularia californica), a common overstory tree that accumulates high levels of infection. Lethal twig and bole cankers on tanoak (Notholithocarpus densiflorus) lead to the disease sudden oak death...