What, Exactly, Causes Trees To Die During Drought?

How trees respond to drought is important for models used to predict climate change. Plants take up a large portion of the carbon dioxide (CO2) in the atmosphere — fewer trees means more CO2. Sudden large-scale changes in plant populations, such as the tree die-offs observed worldwide in recent decades, could affect the rate at which climate changes. Current global vegetation models have faced challenges in producing consistent estimates of plant CO2 uptake, scientists say. The predictions vary widely depending on assumptions about how plants respond to climate. One idea for improving the models is to base forest responses to climate change on how trees die in response to heat, drought and other stresses. (CLick on title for full story.)

That Pristine Jungle? Humans Have Been Altering It For 45,000 Years

The first review of the global impact of humans on tropical forests in the ancient past shows that humans have been altering these environments for at least 45,000 years. This counters the view that tropical forests were pristine natural environments prior to modern agriculture and industrialization. The study found that humans have in fact been having a dramatic impact on such forest ecologies for tens of thousands of years, through techniques ranging from controlled burning of sections of forest to plant and animal management to clear-cutting. (Click on title for full story.)

North America’s Song Birds At Greatest Risk From Central America’s Deforestation

The resulting analysis found that 21 species of eastern-flyway forest birds well known to U.S. birders—including Least Flycatchers, Tennessee Warblers, and Indigo Buntings—spend up to 200 days per year, on average, at their wintering grounds in Central America. And they really crammed into those southern forests: The migrants occurred in densities three times higher than at their summertime nesting areas. The researchers then modeled how changes in land-use (like converting forest to farmland or homes) and climate (like changes in temperature and rainfall) might affect both breeding and wintering areas by 2050. The computer models showed that, within 40 years, deforestation on wintering grounds will pose the greatest threat to these migratory species—even more so than habitat loss where they breed. (Click on title for full story.)

First Plant To Use Cockroach For Seed Dispersal Discovered

In forest ecosystems, cockroaches are known as important decomposers that consume dead and decaying plants. Quite unexpectedly, however, researchers have found that they also provide seed dispersal “services” for the plant Monotropastrum humile, a forest-floor herb belonging to the azalea family (Ericaceae). This entirely new mode of plant–insect interaction (Click on title for full story).

Remnant Prairies Survive In Forgotten Cemetaries

Illinois once had 22 million acres of tall-grass prairie. Today, only 2,300 acres remain. But of those acres, many of the finest examples of untouched, pre-settlement prairie sit on 29 tenuous pioneer cemetery plots, fragile islands of untamed land in what is now an ocean of agricultural conformity. Together these cemeteries, often left undisturbed because they are burial grounds, make up about 50 acres. It is as if the pioneers, in their deaths, left us a few seeds of life. (Click on title for full story.)

New Technologies Could Turn Ancient Herbal Remedies Into Effective Drugs

We highlight several plant natural products that are either in the clinic or currently under active research and clinical development, with particular emphasis on their mechanisms of action. Recent efforts in developing modern multi-herb prescriptions through rigorous molecular-level investigations and standardized clinical trials are also discussed. Emerging technologies, such as genomics and synthetic biology, are enabling new ways for discovering and utilizing the medicinal properties of plants. We are entering an exciting era where the ancient wisdom distilled into the world’s traditional herbal medicines can be reinterpreted and exploited through the lens of modern science. (Click on title for full story.)

Mangroves Cleanse Polluted Soil And Water Of Heavy Metals

Grey mangrove trees, Avicennia marina, filter heavy metals out of the surrounding soil and water. A new study from Indonesia has found that their leaf litter accumulates the most copper, followed by leaves and then roots. (Click on title for full story.)

Urban Forests Save Energy By Taming Urban Winds

To study the effect of trees on wind, the researchers built an incredibly detailed model of a Vancouver neighborhood by scanning every building, street, and tree using LIDAR technology and combining that with wind data that’s accurate down to a 1.6 feet from a University of British Columbia research tower. Using the data and an algorithm they developed to model wind speed, the scientists were able to create a virtual model using supercomputers in Switzerland. They found that when running the model without any trees, the wind speed increased by a factor of two. (Click on title for full story.)

Night Pollinators Turned Off When Lights Turned On

When the sun goes down, moths, beetles and other nocturnal insects that spread pollen between plants go to work. But the latest research reveals that these creatures might be at risk from artificial lighting. (Click on title for full story.)

Is This What The Earliest Flower Looked Like?

Though the team’s reconstructed ancestral flower doesn’t look radically different than many modern flowers, it does have a combination of traits not found today. Like many of today’s flowers, the putative ancestor contained both male and female parts on the same blossom. And the arrangement and numbers of its petals and its organs that shed and receive pollen all fall within the range of its modern descendants—no one trait stands out as obviously ancient. But no one current flower matches its form exactly, either. One discovery that will surprise some researchers is that its petals and other organs were organized in concentric circles in groups of three, rather than in spirals, (Click on title for full story.)