Treesearch

An increase in the severity of drought events on Mediterranean climates highlights the need of using plant material adapted to drought during restoration efforts. Thus, we investigated between-population morpho-physiological differences in Cryptocarya alba and Persea lingue, two native species from Mediterranean central Chile, for traits that could effectively discriminate population performance in response to water restriction (WR) testing. Three populations from each species were subjected to WR treatment and physiological, morphological, and growth parameters were assessed at the...

Anthropogenic activity has caused persistent and prominent losses of forest cover in dry tropical forests. Natural regeneration of forest trees in grazed areas often fails due to lack of seed sources and consumption by ungulates. To address this, the effective restoration of such sites often requires fencing and outplanting nursery‐grown seedlings. In the degraded, dry forests of tropical Hawaii, USA, an additional challenge to restoration of native forest trees is the introduced kikuyu grass (Cenchrus clandestinus). This invasive, rapidly growing rhizomatous plant forms deep, dense mats....

The mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Scolytinae), is an economically important bark beetle species with a wide geographic range spanning from the southwestern United States into northern Canada. This beetle causes extensive tree mortality to 13 pine species. Mites (Acari) are common and abundant symbionts of mountain beetles that may influence their fitness through positive and negative interactions. We present a unique assessment of the mite associates of mountain pine beetles using measures of alpha and beta diversity. We sampled phoretic mites from five beetle...

This interim report represents the culmination of 9 months of exploration into the complex system by which seeds of native plants are produced and used in the United States. This system plays an essential but under-recognized role in the maintenance and restoration of the nation’s natural and semi-natural areas, including national parks and forests, rangelands, roadsides, lands recovered after energy development, and many, many others. Our assessment committee - a group of diverse professionals from the public and private sector - is now at the end of this initial phase in its assessment...

Woodpeckers are often focal species for informing management of recently burned forests. Snags generated by wildfire provide key nesting and foraging resources for woodpeckers, and nest cavities excavated by woodpeckers are subsequently used by many other species. Habitat suitability models applicable in newly burned forest are important management tools for identifying areas likely to be used by nesting woodpeckers. Here we present and test predictive models for mapping woodpecker nest-site habitat across wildfire locations that can be used to inform post-fire planning and salvage logging...

Climate change-driven increases in drought frequency and severity could compromise forest ecosystems and the terrestrial carbon sink. While the impacts of single droughts on forests have been widely studied, understanding whether forests acclimate to or become more vulnerable to sequential droughts remains largely unknown and is crucial for predicting future forest health. We combine cross-biome datasets of tree growth, tree mortality and ecosystem water content to quantify the effects of multiple droughts at a range of scales from individual trees to the globe from 1900 to 2018. We find...

Neleaf biscuitroot is most common in the northwestern US states of Washington, Oregon, and Idaho (USDA FS 1937; Soltis et al. 1997) and also occurs in the southern portions of British Columbia and Alberta, Canada. The species range covers both sides of the Cascade Range and Sierra Nevada Mountains, all but the northernmost and easternmost parts of Montana, all but the California, northern Nevada, eastern Utah, western Colorado, and northwestern New Mexico (BONAP 2017).

Large-scale wildfires have become more frequent in Greece and coupled with the country’s limited economic resources, investments in both pre-fire planning and post-fire rehabilitation for most affected areas are not feasible. From the perspective of forest and fire management agencies, the severity and importance of fire effects are evaluated based only on total area burned, while from a societal standpoint, by the number of fatalities and destroyed houses. A holistic approach to rank wildfires with an inclusive assessment of all their effects is missing. We developed a new evaluation and...

The process of identifying tangible actions to conserve important resources in the face of climate change is challenged because of uncertainties regarding future conditions. There is also a lack of existing methods for evaluating the effectiveness of proposed management actions for mitigating negative impacts. For piñon-juniper (PJ) ecosystems within the Southwest U.S., efforts are further hampered by a lack of information on the direction and drivers of changing population trends. PJ ecosystems, while ecologically important, have been the focus of eradication efforts due to perceptions...

Forests in the Northwest region (Washington, Oregon, and Idaho) represent a complex array of composition and structure. These complexities indicate the diverse range of soils and the physical environment which affect soil and plant interactions. In this region the textural classes range from gravel to heavy clay, many are skeletal (> 35% rocks), and many are derived from volcanic materials (Isaac and Hopkins 1937). Today, these forests and soils are being impacted by warmer, drier years often associated with El Niño or the Pacific Decadal Oscillation (or both), below-average snowpack and...