Treesearch

Black walnut (Juglans nigra L.) is a shade-intolerant hardwood tree common in riparian forests across the Central United States. Commercial values for top-quality black walnut logs are the highest for any tree in North America. Production of juglone from walnuts may have phytotoxic effects on neighboring plant communities. Genetic diversity of this species is high due to seed dispersal and pollen flow characteristics, while population structure is low. Common garden studies revealed relatively weak clines for growth traits but strong latitudinal gradients for cold tolerance. Seed transfer...

Peatlands contain enormous carbon stocks, but the stability of this carbon is variable. Peatlands can vary in tree cover from completely open to forested with associated differences in peat quality. Peat quality, or potential for mineralization, is a contributing factor affecting how the carbon balance of peatland ecosystems could change with climate or land use changes. We compared the peat quality of open peatlands dominated by Sphagnum mosses to forested, or silvic, peatlands dominated by black spruce and tamarack or northern white cedar to quantify the effects of different carbon...

Nature-based Climate Solutions (NbCS) are managed alterations to ecosystems designed to increase carbon sequestration or reduce greenhouse gas emissions. While they have growing public and private support, the realizable benefits and unintended consequences of NbCS are not well understood. At regional scales where policy decisions are often made, NbCS benefits are estimated from soil and tree survey data that can miss important carbon sources and sinks within an ecosystem, and do not reveal the biophysical impacts of NbCS for local water and energy cycles. The only direct observations of...

We compared the interannual variability of stand-level biomass growth (estimated from annual tree-level measurements) to carbon uptake (measured from towers monitoring gas exchange over forest canopies) to identify temporal mismatches between the two processes. We used data from multiple forested sites with long-term measurements of carbon uptake to ask the question: is there a consistent temporal offset between the uptake of carbon and the allocation to plant biomass? We found that the relationship between growth and carbon uptake varies among sites, and there was no consistent temporal...

In spite of overall improvements in air and water quality, biological stress from low pH and high concentrations of inorganic aluminum continue to impact fish and fish habitat in northeastern North America, with independent and interactive effects on individuals, populations and communities. Integrative indicators can therefore be useful in monitoring both impact and recovery across multiple scales. Using coupled water chemistry (pH, conductivity, and base cation and inorganic aluminum concentration), geographic (site elevation and watershed area) and biological (fish diversity, fish...

The Central Appalachian Spruce Restoration Initiative was formed to promote restoration of red spruce Picea rubens forests in Central Appalachia. One goal of the initiative is to increase availability and enhance quality of habitat for wildlife, including the threatened Cheat Mountain salamander Plethodon nettingi. The purpose of this research was to compare microhabitat characteristics between an occupied Cheat Mountain salamander site and early-stage spruce restoration sites, and between four occupied sites and proximal nondetection sites. We found that soil pH was higher and soil...

An analysis of United States national forest inventory observations in the Laurentian Mixed Forest reveals a marked increase in forest disturbance between 1999 and 2015. The Laurentian Mixed Forest Province ecological subregion spans the northern sections of Michigan, Minnesota, and Wisconsin and includes forest area of between 16.7 and 17.5 million hectares depending on the year. Forest disturbance ranges from a low of 0.13 million hectares (0.8% of forest area) in 2000 to a high of 2.09 million hectares (11.9% of forest area) in 2014. The year 2015 is notable for being the first year...

The proliferation of energy rights-of-way (pipelines and powerlines; ROWs) in the central Appalachian region has prompted wildlife management agencies to consider ways to use these features to manage and conserve at-risk songbird species. However, little empirical evidence exists regarding best management strategies to enhance habitat surrounding ROWs for the songbird community during stop over or breeding periods. We used a before–after–control–impact design to study cut-back border (linear tree cuttings along abrupt forest edges) harvest width (15, 30, and 45 m wide into the forest), and...

When conducting urban forest inventories, complete or partial inaccessibility of sample plots results in non-response for a portion of the selected sample. Unfortunately, the non-response is rarely random and thus a potential bias may be imparted in the sample and associated data analyses. In this study, results from an alternative estimation method that employs response homogeneity groups (RHGs) appeared to be more robust to non-random non-response when compared to those of a standard estimation method. Across the six cities studied, the total non-response rates varied from 8.0 to 20.4%....

Survey practitioners commonly encounter various types of nonresponse and strive to implement methods that mitigate any resulting bias when reporting results. In national forest inventories (NFI), complete or partial nonresponse usually results from hazardous conditions or lack of plot access permission. While many factors may be related to nonresponse, the two primary factors in the NFI of the USA are public/private land ownership and office/field plot status. To ameliorate potential nonresponse bias, these factors should be accounted for in the estimation process. An estimation method is...