Treesearch

As the sole habitat for terrestrial life, the Earth's critical zone (CZ) refers to the upper, porous layer of the continental crust that is interacting with the circulating meteoric waters. Conceptually, water is central to the intriguing co‐evolution of both the hydrologic behaviour and the structure of the CZ. On one hand, the path and rate of water circulating through the CZ are shaped by the CZ physical structure itself, such as the distribution of material porosity and permeability. On the other hand, and at longer time scales, the circulating water shapes the CZ structure through...

Fish passage out of reservoirs is a critical issue for downstream movement of juvenile salmonids and other migratory species. Reservoirs can delay downstream migrations by juvenile salmon for months or years. Here, we examine whether a novel management activity implementing annual short‐term draining of a reservoir to streambed improves timely downstream migration of juvenile salmonids. We analyse 12 years of fish capture data from a screw trap located downstream of Fall Creek Reservoir (Oregon, USA) to examine changes in timing of passage out of the reservoir and to compare fish species...

We measured whole-tree transpiration of mature Fagus sylvatica and Picea abies trees exposed to ambient and twice-ambient O3 regimes (1xO3 and 2xO3 free-air fumigation). After eight years, mean daily total transpiration did not vary with the O3 regime over the 31 days of our study, even though individual daily values increased with increasing daily O3 peaks in both species. Although the environmental parameters were similar at 1xO3 and 2xO3, the main factors affecting daily transpiration were vapour pressure deficit in 2xO3 spruce and O3 peaks in beech. For a mechanistic explanation, we...

Scotch broom (Cytisus scoparius (L.) Link) is an invasive, N-fixing shrub in recently harvested Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) forests in the Pacific Northwest. The ability of Scotch broom to dominate a site and displace Douglas-fir in this region may be mediated by site quality and site resource supply. Individual seedlings of Scotch broom (n = 46) and Douglas-fir (n = 46) were planted in a controlled nursery 'Cities and the Environment (CATE). 14: Article 4. ​​​38 p.​​​'setting and monitored over two years to test the effects of irrigation and fertilizat...

Data describing aircraft position and attitude are essential to computing return positions from ranging data collected during airborne laser scanning (ALS) campaigns. However, these data are often excluded from the products delivered to the client and their recovery after the contract is complete can require negotiations with the data provider, may involve additional costs, or even be infeasible. This paper presents a rigorous, fully automated, novel method for recovering aircraft positions using only the point cloud. The study used ALS data from five acquisitions in the US Pacific...

We document the 1st record in 93 y of Umpqua Chub (Oregonichthys kalawatseti) in the North Umpqua River. Although the North Umpqua River has been surveyed for Umpqua Chub over the past 3 decades without success, we captured 34 Umpqua Chub on 14 May 2019, using baited minnow traps, 5.8 km downstream from Winchester Dam on the North Umpqua River. We vouchered 1 specimen for confirmation of field identification at the Oregon State University Ichthyology Collection (OSUIC). Our unexpected capture of Umpqua Chub in the North Umpqua River supports an almost century-old record of the species...

The United States national inventory program measures a subset of tree heights in each plot in the Pacific Northwest. Unmeasured tree heights are predicted by adding the difference between modeled tree heights at two measurements to the height observed at the first measurement. This study compared different approaches for directly modeling 10-year height increment of red alder (RA) and ponderosa pine (PP) in Washington and Oregon using national inventory data from 2001–2015. In addition to the current approach, five models were implemented: nonlinear exponential, log-transformed linear,...

A Bayesian probabilistic modeling platform was used and evaluated for application in a relatively complex individual-tree growth and yield model for coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco), which was expressed as a mixed discrete and continuous Bayesian Network for annual projections. The modeling platform used a common and open-source Bayesian analysis program (JAGS v3.3.0), and was sufficiently flexible to handle a relatively complex model structure; namely, a differential form, highly dynamic, recursive, hierarchical, non-linear system of equations with...

Forest land managers rely on predictions of tree mortality generated from fire behavior models to identify stands for post-fire salvage and to design fuel reduction treatments that reduce mortality. A key challenge in improving the accuracy of these predictions is selecting appropriate wind and fuel moisture inputs. Our objective was to evaluate post-fire mortality predictions using the Forest Vegetation Simulator Fire and Fuels Extension (FVS-FFE) to determine if using representative fire-weather data would improve prediction accuracy over two default weather scenarios. We used pre- and...

Understanding change in forest carbon (C) is important for devising strategies to reduce emissions of greenhouse gases. National forest inventories (NFIs) are important to meet international accounting goals, but data are often incomplete going back in time, and the amount of time between remeasurements can make attribution of C flux to specific events difficult. The long time series of Landsat imagery provides spatially comprehensive, consistent information that can be used to fill the gaps in ground measurements with predictive models. To evaluate such models, we relate Landsat spectral...