Old-growth Acer macrophyllum trees host a unique suite of arbuscular mycorrhizal fungi and other root-associated fungal taxa in their canopy soil environment.

Canopy soils occur on tree branches throughout the temperate rainforests of the Pacific Northwest Coast and are recognized as a defining characteristic of these ecosystems. Certain tree species extend adventitious roots into these canopy soil environments. Yet, research on adventitious root-associated fungi remains limited. Our study used microscopy to compare fungal colonization intensity between canopy and forest floor roots of old-growth bigleaf maple (Acer macrophyllum) trees. Subsequently, two high-throughput sequencing platforms were used to explore the spatial and seasonal variation of root-associated fungi between the two soil environments over one year. We found that canopy and forest floor roots had similar colonization intensity and were associating with a diversity of arbuscular mycorrhizal fungi and other potential symbionts, many of which were resolved to species level. Soil environment and seasonality affected root-associated fungal community composition, and several fungal species were indicative of the canopy soil environment. In Washington State's (USA) temperate old-growth rainforests, these canopy soil environments host a unique suite of root-associated fungi. The presence of arbuscular mycorrhizae provides further evidence that adventitious roots form fungal associations to exploit canopy soils for resources, and there may be novel relationships forming with other fungi. These soils may be providing a redundancy compartment (i.e., "nutrient reserve"), imparting a resiliency to disturbances for certain old-growth trees.

Methodology to calculate forest stand level maximum potential productivity, potential achievable productivity and ecosystem fit.

A modified Loomis-William model was originally developed to estimate the theoretical maximum yields of crops. That model was adapted in this paper to measure how much of the theoretical maximum potential productivity (tNpptmax) is reached in any forest due to edaphic and climatic limits to growth, i.e., its "Ecosystem fit" (eFit). The procedure to calculate eFit has not been published except as a concept. Our goal is to describe the methodology in sufficient detail to facilitate its use by the scientific community and forest managers. To calculate eFit you need: 1) to convert all photosynthetically active radiation to a photosynthetic product for each forest plot or stand to calculate its tNpptmax, and 2) use field-collected data of total observed net primary productivity (tNppobs). Theoretical maximum potential tNpp is calculated with a simple light-use efficiency model as the product of the efficiency at which forest canopies absorb solar radiation, the photosynthetic conversion efficiency into biomass, and remotely sensed solar radiation with temperature data extracted to the geographic coordinates for the site. Ecosystem fit represents a forest's realized percent productive capacity and is the ratio of field-collected tNpp (i.e., tNppobs) to the theoretical maximum potential tNpp (i.e., tNpptmax).•Available indices to assess forest productivity and adaptive capacity to land-use disturbance and climate change are sensitive at the small-to-meso spatio-ecophysiological scales.•A more holistic index (such as eFit) will provide an informative picture of forest conditions where management practices are undertaken and the ecosystem's capacity to adapt to environmental change.•A comparison of eFit across similar forests within a climatic zone is an indication of the stressors or constraints that are being imposed locally and that limit tNppobs.

A rapid approach to profiling diverse fungal communities using the MinION™ nanopore sequencer.

The Oxford Nanopore Technologies MinION™ sequencer holds the capability to generate long amplicon reads; however, only a small amount of information is available regarding methodological approaches and the ability to identify a broad diversity of fungal taxa. To assess capabilities, three fungal mock communities were sequenced, each of which had varying ratios of 16 taxa. The data were processed through our selected pipeline. The MinION recovered all mock community members, when mixed at equal ratios. When a taxon was represented at a lower ratio, it was not recovered or decreased in relative abundance. Despite high error rates, highly accurate consensus sequences can be derived. This methodological approach identified all mock community taxa, demonstrating the MinION can be used as a practical alternative to profile fungal communities.

Indigenous knowledge informing management of tropical forests: the link between rhythms in plant secondary chemistry and lunar cycles.

This research used knowledge of the indigenous practice of timing nontimber forest product harvest with the full moon to demonstrate that chemicals controlling the decomposition rate of foliage fluctuate with the lunar cycle and may have developed as a result of plant-herbivore interactions. Indigenous knowledge suggests that leaves harvested during the full moon are more durable. Palm leaves harvested during the full moon had higher total C, hemicellulose, complex C and lower Ca concentrations. These chemical changes should make palm leaves less susceptible to herbivory and more durable when harvested during the full moon. This study proposes a mechanism by which plants in the tropics minimize foliage herbivory and influence the decomposition rates of senesced leaves and their durability, especially during the full moon. This research supports the need to use natural life cycles in managing forests and provides a scientific basis for an indigenous community's harvesting practice.