Treesearch

The invasive emerald ash borer (Agrilus planipennis Fairmaire, EAB) has destroyed ash tree (Fraxinus spp.) populations across the US, but remnant populations including many small trees and, more rarely, larger trees remain after EAB had its first major impact across the landscape. The future survival of these remnant trees is critical to the viability of the ash species. Several different management options, including biocontrol, EAB-tolerant or resistant ash trees, and silvicultural strategies exist or are under development. Here we model changes that could occur in a preserve’s remnant...

Conflicting evidence exists supporting linear and nonlinear density‐dependent population growth when species have slow life histories. The Ricker (linear) and θ‐logistic (nonlinear) models are commonly used to analyze survey data for these species, but no evaluation has examined whether these hypotheses can be differentiated with field data. We conducted a simulation exploring effects from shape of density dependence and variation in vital rates on the fit of these models. When vital rates had moderate to high variation, the models had similar fit. The θ‐logistic model differed from the...

Population and land management relies on understanding population regulation and growth, which may be impacted by variation in population growth parameters within and among populations. We explored the interactions between variation in carrying capacity (K), intrinsic population growth rate (r), and strength of density dependence (β) within and among elk (Cervus elaphus) herds in a small part of the geographic range of the species. We also estimated stochastic fluctuations in abundance around K for each herd. We fit linear Ricker growth models using Bayesian statistics to seven time series...

The non-indigenous colonial tunicate Didemnum vexillumplagues many shellfish aquaculture operations around the world by smothering crop and gear and displacing juvenile bivalves. There are two populations of D. vexillumin Oregon, but little is known regarding their spatial extent, seasonal dynamics, annual variability, reproductive biology, or ecology. SCUBA divers monitored the seasonal variation and spatial extent of the nascent D. vexillumpopulation in its current foothold at Umpqua Aquaculture, a longline oyster farm adjacent to Winchester Bay, Oregon. From May 2011 to November 2016,...

The early detection of plant pathogens at the landscape scale holds great promise for better managing forest ecosystem threats. In Hawai‘i, two recently described fungal species are responsible for increasingly widespread mortality in ‘ōhi‘a Metrosideros polymorpha, a foundational tree species in Hawaiian native forests. In this study, we share work from repeat laboratory and field measurements to determine if visible near-infrared and optical remote sensing can detect pre-symptomatic trees infected with these pathogens. After generating a dense time series of laboratory spectral reflectanc...

Developing an efficient deconstruction step of woody biomass for biorefinery has been drawing considerable attention since its xylem cell walls display highly recalcitrance nature. Here, we explored transcriptional factors (TFs) that reduce wood recalcitrance and improve saccharifcation efficiency in Populus species. First, 33 TF genes up-regulated during poplar wood formation were selected as potential regulators of xylem cell wall structure.The transgenic hybrid aspens (Populus tremula ×Populus tremuloides) overexpressing each selected TF gene were screened for in vitro enzymatic...

As actors of global carbon cycle, Agaricomycetes (Basidiomycota) have developed complex enzymatic machineries that allow them to decompose all plant polymers, including lignin. Among them, saprotrophic Agaricales are characterized by an unparalleled diversity of habitats and lifestyles. Comparative analysis of 52 Agaricomycetes genomes (14 of them sequenced de novo) reveals that Agaricales possess a large diversity of hydrolytic and oxidative enzymes for lignocellulose decay. Based on the gene families with the predicted highest evolutionary rates—namely cellulose-binding CBM1, glycoside...

The immediate effects of wildfire on a community can be disastrous, as was evident with the Camp Fire in 2018 that burned over 95% of the structures in Paradise and Concow, California, and resulted in 85 casualties [one person is still missing to date (15 March 2020)]. But, the secondary effects of wildfire can also have substantial consequences. This was the case in 2017 when the Thomas Fire raged in Santa Barbara and Ventura Counties in Southern California, eventually burning 1,141 km2 of landscape. Before the wildfire was 100% contained, a storm system moved over the mountainous terrain...

There are several new and imminent space-based sensors intended to support mapping of forest structure and biomass. These instruments, along with advancing cloud-based mapping platforms, will soon contribute to a proliferation of biomass maps. One means of differentiating the quality of different maps and estimation strategies will be comparison of results against independent field-based estimates at various scales. The Forest Inventory and Analysis Program of the US Forest Service (FIA) maintains a designed sample of uniformly measured field plots across the conterminous United States....

A sequence of catastrophic wildfires that occurred during the past decades in Greece point to the need to re-examine the established wildfire risk governance policies. The most important regulations for fire suppression and fuel/forest management were established four decades ago (Law 998/1979). Wildfire suppression is now led by the Greek Fire Service, while pre-suppression vegetation management is supervised by the Greek Forest Service. The limited available budget is clearly distributed in favor of fire suppression (about $410 million annually), with minor funding remaining for fuel...