Treesearch

As wolf and grizzly bear populations recover across the American West, livestock producers face renewed challenges of coexistence, prompting increased interest in nonlethal conflict mitigation strategies. One such tool – range riding – uses human presence to prevent depredation and monitor livestock. While range riding is gaining traction among conservation practitioners and producers alike, empirical research on its implementation, effectiveness, and sustainability remains limited. This study examines range riding in the context of the “New West,” focusing on three long-standing programs...

Spruce beetle, Dendroctonus rufipennis(Kirby) (Coleoptera: Curculionidae), poses a significant threat to mature spruce (Piceaspp.) in western North America. We evaluated 3-methylcyclohex-2-en-1-one (MCH), the primary anti-aggregation pheromone of D. rufipennis, for tree protection at 3.5 and 7 g MCH/tree (SPLAT MCH, ISCA Inc., Riverside, CA) alone and in combination with acetophenone + (E)-2-hexen-1-ol + (Z)-2-hexen-1ol (PLUS) or with linalool + β-caryophyllene + (Z)-3-hexanol (AKB). Dendroctonus rufipenniscolonization and subsequent mortality of individually treated spruce and of untreated...

Rapid ‘ōhi‘a death (ROD), caused by Ceratocystis lukuohiaand C. huliohia, severely impacts ‘ōhi‘a lehua (Metrosideros polymorpha), a keystone tree species on the Hawaiian Islands. This study examined the ability of these pathogens to colonize ‘ōhi‘a fine roots in a series of root dip experiments under in vitro conditions, focusing on the potential roles of host genetics and root tissue condition in susceptibility. The results showed that both pathogens can colonize and form fruiting bodies on fine roots; however, C. lukuohiahad greater colonization rates and produced more perithecia than...

I compile information on five rare conifer species in the White Mountains: Pinus albicaulis, P. contorta, P. ponderosa, P. jeffreyi, and Juniperus grandis.

Wildfire is a topic that raises much controversy in the context of forests and forest management in Europe. Fire is often viewed as a natural disaster that is harmful, yet fire is also a natural process and an important component of the disturbance regime in some forest ecosystems. A long history of land use has made it difficult to unravel the natural role of fire in European forests. Land use changes and past forestry practices have also increased fuels and fire hazard in some areas. In recent times a warming and increasingly drought-prone climate are raising concerns that fires are...

Four undescribed species or subspecies of Reticulitermes Holmgren 1913 in northern California have been identified by chemotaxonomic and phylogenetic analyses of voucher specimens used for chemotaxonomy. To date, useful morphological keys do not exist. We present eight direct and 22 derived measures and indices of soldier head capsules of multiple colonies of each of five cuticular hydrocarbon (CHC) phenotypes. Our objective was to identify one or more morphological measurements of soldier head capsules that would unequivocally separate taxa previously identified by CHCs and phylogenetic...

It can be challenging to deploy and monitor biocontrol for invasive species, particularly in remote forest settings. One of the most abundant and disruptive invasive tree species in Hawai‘i and across the Pacific is Psidium cattleyanum Sabine (strawberry guava), which replaces native vegetation and negatively impacts forest structure and ecosystem services. A Brazilian leaf-galling insect named Tectococcus ovatus Hempel (Homoptera: Eriococcidae) is an approved biocontrol for strawberry guava, but its introduction to date has been restricted to areas with established road and trail networks...

Native dry forest habitat is one of the most threatened and rare ecosystems in the Hawaiian Islands. The Ka‘ūpūlehu Dry Forest Preserve, on the west coast of Hawai‘i Island, is one of the few remaining intact examples of this low elevation habitat. To aid restoration efforts, flowering phenology of nine native species was estimated monthly from 2001 to 2007. Some species flowered prolifically, others seldom. Two dioecious tree species are in the survey, one only has female flowering trees, the second has both male and female trees. Each gender is treated as a separate species, making ten...

Mangrove forests are the dominant ecosystems on tropical and subtropical coasts, subjected to widespread degradation and land conversion, such as aquaculture. To restore mangrove cover, mangrove seedlings were planted in coastal fringes and abandoned ponds. Most restoration reports were focused on seedling survival and growth rates. However, physiological conditions of mangrove seedlings, in terms of photosynthetic characteristics under field conditions has seldom been studied. Mangrove seedlings from restored “planted” (5 ,8, 15, and 30 yr old) and recolonized (5 and 20 yr old) stands...

Elevated soil temperatures resulting from reintroduction of prescribed fire into long unburnt stands have been associated with unintended tree mortality. Several models exist to predict soil temperatures resulting from soil heating by fire; however, data to develop and validate these models are limited. A model to predict soil temperature at depths up to 25 inches (0.63 m) was developed from a data set from 46 prescribed burns in coniferous forests in national forests and parks in Arizona and California. Soil temperature was less than 140 °F (60 °C) at depths greater than 6 inches (0.15 m)...