Treesearch

Invasive species, non-native plants, insects, and diseases can devastate forests. They outcompete native species, replace them in the ecosystem, and even drive keystone forest species to functional extinction. Invasives have negative effects on forest hydrology, carbon storage, and nutrient cycling. The damage caused by invasive species exacerbates the other forest stresses of the Anthropocene: increased human intrusion throughout natural landscapes, the fragmentation of forests, and a changing climate. Warming will open new areas for ecological invasion while the rising concentration of...

We provide an overview of the principal threats to land based protected areas and then discuss measures by which protected areas can continue to be effective at conserving biodiversity this century.

Wildfire in western U.S. federally managed forests has increased substantially in recent decades, with large (>1000 acre) fires in the decade through 2012 over five times as frequent (450 percent increase) and burned area over ten times as great (930 percent increase) as the 1970s and early 1980s. These changes are closely linked to increased temperatures and a greater frequency and intensity of drought. Projected additional future warming implies that wildfire activity may continue to increase in western forests. However, the interaction of changes in climate, fire and other disturbances,...

This paper will primarily focus on the management and restoration of forests adapted to frequent, low-moderate intensity fire regimes. These are the forest types that are most at risk from large, high-severity wildfires and in many regions their fire regimes are changing. Fire as a landscape process can exhibit self-limiting characteristics in some forests which can assist managers in mitigating large, severe wildfires. In mixed conifer forests in Yosemite National Park, when the amount of time between successive adjacent fires is under nine years, the probability of the latter fire...

Studies show that changes in climate may exceed plant adaptation and migration. The mismatch in rates between climate change and plant adaptation and migration will pose significant challenges for practitioners that select, grow, and outplant native tree species. Native tree species and populations that are planted today must meet the climatic challenges that they will face during this century. Anticipated shifts in climate call for the revision of ethical, legal, political, and economical paradigms, as well as changes in the guidelines for growing and outplanting trees to maximize...

Throughout Earth’s history, its climates have been changing, and biotic systems have mutated, migrated, and otherwise adapted as tectonic shifts have reconfigured the continents and polar ice caps have ebbed and flowed across the latitudes through glacial cycles. In our own era, there is growing evidence that changes in climate that in the past have taken place over the course of millennia are now taking place in a matter of decades. These accelerated changed in climate are challenge the ability of both human civilization and the natural systems on which it depends, to adapt quickly enough...

The Anthropocene epoch presents a mix of old and new challenges for the world’s forests. Climatic instability has typified most of the Cenozoic Era but today’s situation is unique due to the presence of billions of humans on the planet. The potential rate and magnitude of future warming driven by continued fossil fuel combustion could be unprecedented during the last 56 million years, and the recovery of atmospheric carbon dioxide concentrations to pre-industrial conditions is likely to last tens of thousands of years. Paleoecological records suggest that responses of forests to human-drive...

Forest conservation under climate change requires conserving species both in their present ranges and where they may exist in the future as climate changes. Several debates in the literature are pioneering this relatively novel ground. For instance, conservation planning using species distribution models is advocated because it uses information on both exposure to climate change and species’ sensitivities to climate change, while approaches focusing on land facets are advocated because there is uncertainty regarding both exposure and sensitivity. Other debates include assisted/managed...

What forestry needs in the Anthropogenic Era is what has been needed for the past 30 years. The proper methods, theory, and goals have been clear and are available; the failure has been, and continues to be, that our laws, policies, and actions are misdirected because we confuse a truly scientific base with nonscientific beliefs. The result is a confusion of folklore and science that is counterproductive, both for forests and for human needs and desires. Our love of forests gets confused with our attempts to understand them. In the practical world of incomplete knowledge, our management of...

We examined the germination response of 21 forb species collected from semiarid grasslands of central New Mexico. After-ripened seeds were subjected to 1 of 3 treatments: 1) no treatment; 2) a 3-wk stratification at 5 °C (cold-moist treatment); or 3) a 3-wk warm-moist treatment at 30 °C. All seeds were incubated under an alternating 10/20 °C temperature regime for 6 wk following treatment. Temperature regime had a significant effect on 13 of the 21 species. Twelve species responded positively to the warm-moist treatment, germinating during or following 3 wk at 30 °C. Six species were...