Treesearch

Crop production as a function of water use or water applied, called the crop water production function (CWPF), is a useful tool for irrigation planning, design and management. However, these functions are not only crop and variety specific they also vary with soil types and climatic conditions (locations). Derivation of multi-year average CWPFs through field experiments for different locations and soils is time-consuming and expensive, as it requires careful long-term and multi-location field experiments to obtain them. Process based crop system models provide a useful tool for determining...

Flotation of seeds in solvents is a common means of separating unfilled and filled seeds. While a few protocols for processing red spruce (Picea rubens) seeds recommend ethanol flotation, delayed and reduced germination have been reported. We conducted an ethanol bioassay on seeds previously stored at -20°C to quantify the concentration required to separate red spruce seeds and the effects on germination. We used seeds from Canada (CAN) that had been exposed to ethanol during processing, and seeds from the United States (USA) that had not been exposed to ethanol during processing. Seeds...

We summarize the status of semiochemical-based management of the major bark beetle species in western North America. The conifer forests of this region have a long history of profound impacts by phloem-feeding bark beetles, and species such as the mountain pine beetle (Dendroctonus ponderosae) and the spruce beetle (D. rufipennis) have recently undergone epic outbreaks linked to changing climate. At the same time, great strides are being made in the application of semiochemicals to the integrated pest management of bark beetles. In this review, we synthesize and interpret these recent...

Collaborations between artists and scientists have a long history. In recent years, artists have joined with ecologists to showcase biodiversity, links between biodiversity and ecosystem function, and the effects of human activities on the broader environment. In many cases, artists also have provided “broader impacts” for ecological research activities, communicating scientific findings in creative and novel ways to audiences much broader than the readership of our technical journals.

The preference-performance hypothesis states that ovipositing phytophagous insects will select host plants that are well-suited for their offspring and avoid host plants that do not support offspring performance (survival, development and fitness). The mountain pine beetle (Dendroctonus ponderosae), a native insect herbivore in western North America, can successfully attack and reproduce in most species of Pinus throughout its native range. However, mountain pine beetles avoid attacking Great Basin bristlecone pine (Pinus longaeva), despite recent climate-driven increases in mountain pine...

Tropical forests are subject to seasonal hurricanes resulting in cycles of canopy opening and deposition of litter, followed by periods of recovery and canopy closure. Herein, we review two studies of litter-based communities in Puerto Rico; (i) a survey of bromeliad invertebrates in three montane forest types along an elevational gradient in 1993–1997, during a period of canopy recovery after two severe hurricanes, and the results compared with those from a resurvey in 2010, and (ii) a large scale canopy trimming experiment in the lower montane (Tabonuco) forest designed to simulate an...

Aim: Seasonally dry tropical forest (SDTF) of the Caribbean Islands (primarily West Indies) is floristically distinct from Neotropical SDTF in Central and South America. We evaluate whether tree species composition was associated with climatic gradients or geographical distance. Turnover (dissimilarity) in species composition of different islands or among more distant sites would suggest communities structured by speciation and dispersal limitations. A nested pattern would be consistent with a steep resource gradient. Correlation of species composition with climatic variation would suggest...

While the relationship between abiotic drivers of sap flux are well established, the role of biotic disturbances on sap flux remain understudied. The invasion of the emerald ash borer (Agrilus planipennis Fairmaire, EAB) into North America in the 1990s represents a significant threat to ash trees (Fraxinus spp.), which are a substantial component of temperate forests. Serpentine feeding galleries excavated by EAB larvae in the cambial and phloem tissue are linked to rapid tree mortality. To assess how varying levels of EAB infestation impact the plant water status and stress levels of...

High-throughput amplicon sequencing (HTAS) of conserved DNA regions is a powerful technique to characterize microbial communities. Recently, spike-in mock communities have been used to measure accuracy of sequencing platforms and data analysis pipelines. To assess the ability of sequencing platforms and data processing pipelines using fungal internal transcribed spacer (ITS) amplicons, we created two ITS spike-in control mock communities composed of cloned DNA in plasmids: a biological mock community, consisting of ITS sequences from fungal taxa, and a synthetic mock community (SynMock),...

The association between invasive plants and disturbance is well-documented. Most forest management regimes include disturbance (i.e., harvesting and fire) to improve regeneration of native plants, such as oaks. There is a need for land managers of northeastern forests to foster regeneration of native species without promoting invasive species establishment. We evaluated the germination, first-year survival, and growth of three exotic plants (Ailanthus altissima, Alliaria petiolata, and Microstegium vimineum) in 56 uninvaded forest stands located in five management regimes (control, single...