Sam L Davis

• Environmental Sciences Ph.D.
• Staff Scientist at PFPI

Alliaria petiolata is a European biennial herb that invades North American forests and has direct negative effects on associated flora and fauna. In some places, A. petiolata has invaded the habitat of Pieris virginiensis, a rare, univoltine butterfly that normally uses native spring ephemeral crucifer hosts. There are occasional observations of P....

Specialized metabolites in plants influence their interactions with other species, including herbivorous insects, which may adapt to tolerate defensive phytochemicals. The chemical arsenal of Alliaria petiolata (garlic mustard, Brassicaceae) includes the glucosinolate sinigrin and alliarinoside, a hydroxynitrile glucoside with defensive properties...

The Natura 2000 network is comprised of a) “Special Protection Areas” under the Birds Directive (2009/147/EC) designated for the protection of the 197 threatened bird species and sub-species that are listed in Annex 1 to the Directive, and b) “Special Areas of Conservation” under the Habitats Directive (92/43/EC) designated for the protection of pl...

Your community needs leaders who care about the environment. As climate change, pollution, and loss of biodiversity threaten our planet's health, we can't afford to wait for governments or corporations to solve these problems. We need individuals who are willing to take action, inspire others, and make a difference. And those differences need to ha...

Industrial logging activities are making North Carolina more susceptible to the effects of climate change. The logging and wood products sector in North Carolina is very carbon intensive and is likely the third largest source of greenhouse gas emissions despite being excluded in the state’s official greenhouse gas inventory. This sector is also mak...

Old-growth forests are some of the largest terrestrial carbon stores on the planet, and harbor extraordinary amounts of biodiversity, including rare and endemic species. The World Resources Institute estimates only 21% of the world's forests are in an old-growth condition. We review the importance of old-growth forests and evaluate threats and pote...

Investor reports say that the wood pellets are profitable. But, behind record profits is a habit of getting subsidies just to stay open. Here is the truth: • European subsidies drive wood pellet exports from the US South • Drax, the UK’s largest bioenergy producer, received nearly $1 billion dollars in 2019 to purchase US wood pellets. • Enviva, th...

Wood pellets are being heralded by producers as the savior to our fossil fuel and climate change crises. However, the reality is that wood pellets are very damaging to our forests, our climate, and the communities where they are produced and used. Here’s the truth of the matter: • Wood pellets are not carbon neutral; their production and combustion...

Forests clean our water and air, provide habitat for wildlife, suck carbon out of the atmosphere, and can even prevent or mitigate flooding during natural disasters. That is why some believe that carbon credits and markets may be a way to mitigate climate change. However, there are some serious concerns being raised around carbon markets, including...

Economic development can be difficult in rural communities, especially in the South. Community members and elected officials want to be sure that the companies not only provide well paying jobs for decades to come but also serve as “good actors” in the community. Unfortunately, many companies mislead politicians about their impacts on health and po...

A common misconception in land use and forestry is the saying, “healthy markets keep forests healthy.” Versions of this statement imply, paradoxically, that cutting trees down somehow keeps forests on the landscape. However, the metrics used by the forest products industry do not assess forest health, but instead only the ability of forests to prov...

Recently, initiatives to plant trees as a way to offset climate change have gained steam in the public sphere. Although planting trees can be helpful in urban settings, large scale plantings must be done with the intent to restore complex native ecosystems in perpetuity. Focusing heavily on planting trees can take the world further away from more i...

Garlic mustard is an invasive Eurasian biennial that has spread throughout the eastern United States and southern Canada. Populations of this plant vary in their susceptibility to Erysiphe cruciferarum, a causal agent of powdery mildew disease in Brassicaceous plants. We examined whether there were biogeographic patterns in the distribution of resi...

Each year, roughly 201,000 acres of forestland in North Carolina are clearcut to feed global markets for wood pellets, lumber, and other industrial forest products. Roughly 2.5 billion board feet of softwood and hardwood sawtimber are extracted annually, an amount equivalent to over 500,000 log truckloads.1 The climate impacts of this intensive ac...

Defining and modeling wetland forests in the US Southeast

Understanding the necessity of climate action.

The impacts of the forest products industry on forests in the US Southeast.

The history of forests in the US Southeast

As efforts to decarbonize the electric sector take on increased urgency, governments are turning to wood pellets as a potential renewable energy resource. However, the production of pellets from woody biomass has immediate community-wide impacts on air and water quality. This article investigates the siting of wood pellet production facilities in t...

Stretching from the historic Chesapeake Bay, along the coastline of the Atlantic, across the Gulf into the mysterious bayou swamps of Louisiana, to eastern Texas, and up the Mississippi, wetland forests are a valuable, yet vulnerable, national treasure. Before colonization, wetland forests stretched across the US South. Current estimates suggest th...

Standing forests are the only proven system that can remove and store vast amounts of carbon dioxide from the atmosphere at the scale necessary to keep global temperature rise below 1.5 degrees Celsius this century. It is therefore essential to not only prevent further emissions from fossil fuels, deforestation, forest degradation, and bioenergy, b...

Pieris virginiensis, the West Virginia White butterfly, faces severe potential habitat loss and degradation of existing suitable habitat in the near future from climate change and plant invasion. Increasing isolation and local extinction events resulting from deforestation and climate change have a chance to significantly impact the future of this...

Pieris rapae L., an invasive crop pest, may have recently begun using Alliaria petiolata Bieb. (Cavara & Grande), a European invasive biennial. We investigated how P. rapae uses forest habitats for nectar and oviposition and examined larval performance on A. petiolata in the field and laboratory. Being known primarily to occupy open habitats, we fo...

As it pertains to insect herbivores, the preference-performance hypothesis posits that females will choose oviposition sites that maximize their offspring's fitness. However, both genetic and environmental cues contribute to oviposition preference, and occasionally "oviposition mistakes" occur, where insects oviposit on hosts unsuitable for larval...

Pieris virginiensis is a rare, univoltine butterfly that inhabits Eastern deciduous forests and normally uses Cardamine diphylla (Brassicaceae) as its larval host plant. In areas invaded by the European biennial garlic mustard (Alliaria petiolata; Brassicaceae), P. virginiensis females prefer to oviposit on the novel host. When P. virginiensis eggs...

Background/Question/Methods While apparently benefiting from enemy escape for several decades in North America, the invasive plant Alliaria petiolata has increasingly shown evidence of being attacked by several pathogenic fungi and bacteria. A fungal pathogen has been identified through morphological and molecular analyses as a strain of Erysiphe...

Background/Question/Methods Pieris virginiensis Edwards, the West Virginia White butterfly, is a rare, univoltine butterfly that resides in mature riparian forests in the eastern United States. This butterfly uses Brassicaceae family members Cardamine diphylla, C. concatenata, and Arabis laevigata as its primary host plants, and nectars on a wide...

Background/Question/Methods Pieris virginiensis, the West Virginia White butterfly, is a rare, native, univoltine butterfly that occupies mature woodlands, completing its lifecycle on native mustard hosts. Since the introduction of Alliaria petiolata (garlic mustard), a biennial invasive forest mustard, there has been concern that P. virginiensis...

Background/Question/Methods Rare organisms are often strongly affected by chance, disease, invasive species, and other factors. Pieris virginiensis (Pieridae), a rare woodland butterfly, flies only in April and May, in often unsuitable weather, and uses the native mustards Cardamine diphylla, C. laciniata, and Arabis laevigata as its primary larv...