Treesearch

Butternut (Juglans cinerea), a native riparian forest tree, has suffered significant decline throughout most of its range due to a fatal fungal disease, butternut canker (caused by Sirococcus clavigignenti-juglandacearum). It has also been subject to natural hybridization pressures from Japanese walnut (J. ailantifolia), first introduced to North America ~1850. Butternut is now listed as a “species of concern” in Canada and similarly classified in several states of the United States. Previous experience indicates site-related shifts in fitness for Japanese walnut × butternut hybrids...

American chestnut (Castanea dentata) was once a foundational species in much of its native range, especially in the Appalachian Mountains of the eastern United States. Unfortunately, the species was driven to functional extinction by the accidental importation of an exotic fungal pathogen (Cryphonectria parasitica), the causal agent of chestnut blight disease. Efforts to restore the American chestnut have been ongoing since the early 20th century and include three primary techniques: classical plant breeding, genetic modification, and reduction of fungal virulence. While restoration of the...

Long term storage of seeds at freezing temperatures is one strategy for genetic conservation of tree species. It can be used to preserve species that produce seeds that remain viable after drying to a low seed moisture content. The U.S. Department of Agriculture Forest Service (USDA FS) National Seed Laboratory (NSL) began long term seed storage for genetic conservation in 2005. The program is mostly focused on five-needle pines (Pinus) and ash (Fraxinus) species. The genetic resources of both groups of species are eroding rapidly in the wild because of attack from invasive exotic pests...

Mexico is both an oak (Quercus) biodiversity hotspot (over 160 described species) and the western hemisphere's leader in magnolia (Magnolia) diversity (36 described species). In the face of myriad threats to these groups, including climate change, habitat loss/fragmentation, overharvesting, and plant pests/pathogens, the imperative to preserve the genetic diversity of these trees has become a high priority of the Vallarta Botanical Garden (VBG). In collaboration with researchers from the University of Guadalajara, the VBG has several new initiatives underway to acquire diverse and well-docu...

Resource managers in Hawaii face unique forest conservation challenges. Invasive species continue to inundate the remote island archipelago, directly threatening its forest resources. Hawaii has the largest number (> 400) of endangered plants in the United States, and managers use genetic approaches to preserve these small populations which are often island endemics. Many of the common forest tree species that grow throughout the islands face threats from pests and disease, but in most cases, little is known about their genetics and whether breeding resistance is a viable option. This...

Across the United States, forest communities are faced with the prospect of extirpation of Fraxinus (ash) species owing to mortality caused by invasion of the emerald ash borer (Agrilus planipennis). However, with the advancement of ex situ seed conservation practices, we have the opportunity to conserve the ecoregional-based genetic variability of Fraxinus species before they are lost from the wild. Genetic variability is critical to resistance research and to potential future reintroductions. Established in 2009 by the U.S. Department of Agriculture Forest Service (USDA FS), the Ash...

Genetic variation is the most powerful factor in ensuring the long term success of trees and forests in times of change. In order to protect against loss of genetic variation from threats, including pests and diseases and climate change, the Royal Botanic Gardens, Kew, is developing a national tree seed collection for the United Kingdom. This paper describes the authors methodologies and experiences of developing the national collection: firstly, forming species target lists using plant health risk and conservation assessments; then, developing national sampling strategies based on the...

In the face of ongoing environmental change, conservation and natural resource agencies are initiating or expanding ex situ seed collections from natural plant populations. Seed collections have many uses, including in provenance trials, breeding programs, seed orchards, gene banks for long-term conservation (live plants or seeds), restoration, reforestation, and scientific study of plant germination or other plant ecology studies. Well-known examples of ex situ collections include the Millennium Seed Bank Partnership, Australian Seed Bank Partnership, United Kingdom National Tree Seed...

Geological, climatological and ecological processes partially or entirely isolate evolutionary lineages within tree species. These lineages may develop adaptations to different local environmental conditions, and may eventually evolve into distinct forms or species. Isolation also can reduce adaptive genetic variation within populations of a species, potentially compromising their ability to respond to climate change. Dramatic climate changes during the Pleistocene, for example, caused species ranges to contract and fragment into isolated glacial refugia before expanding and reconnecting....

The U.S. Department of Agriculture Forest Service (USDA FS) began ash (Fraxinus) germplasm preservation in 2005, through seed collections for long term seed storage. The work was coordinated with the Agricultural Research Service (ARS). Collections have been accomplished through many cooperators. Various methods of outreach were deployed to solicit cooperators. No method stood out as better than another. However, the level of interest in genetic conservation held by the cooperator seemed much more important in determining if they chose to participate rather than how they were contacted....