By Adrian Higgins
A pear seedling selection named Bradford was cloned by the gazillion to become the ubiquitous street tree of America’s postwar suburban expansion. Then it turned invasive.
Carole Bergmann pulls her small parks department SUV into an aging 1980s subdivision in Germantown, Md., and takes me to the edge of an expansive meadow. A dense screen of charcoal-gray trees stands between the open ground and the backyards of several houses. The trees are callery pears, the escaped offspring of landscape specimens and street trees from the neighborhood. With no gardener to guide them, the spindly wildlings form an impenetrable thicket of dark twigs with three-inch thorns.
Bergmann, a field botanist for the Montgomery County Parks Department, extricates herself from the thicket and in the meadow shows me that what I take to be blades of grass are actually shoots of trees, mowed to a few inches high. There are countless thousands, hiding in plain sight in Great Seneca Stream Valley Park. If it were not cut back once a year, the meadow would become like the adjacent screen, wall upon wall, acre upon acre of black-limbed, armored trees worthy of Sleeping Beauty’s castle.
“You can’t mow this once and walk away,” said Bergmann, who began her 25-year career in the department as a forest ecologist but has been consumed by an ever-pressing need to address the escape of the Bradford pear and other variants of callery pear, a species that originated in China, along with other invasive exotics.
By Dr. Ranil Senanayake
What is known by science reveals the forest as an ecosystem of tremendous complexity. The trees, while providing the essential framework of a forest constitutes only a fraction of the total biodiversity. It contains a huge array of organisms, that continually change in form and function. Thus biodiversity is what gives a forest its identity. It should also be borne in mind that, from the small bushes of an area after a fire to the tall growth fifty years later, the species and architecture goes through many changes, and all these ecosystems are expressions of the growing, maturing forest.
The international response to the loss of natural forest ecosystems can be seen in the massive global investment in forestry. However, a great majority of these revegetation programs around the world do not seem to provide an environment that is hospitable for sustaining local forest biodiversity. A situation brought about by neglect of the ecological and biodiverse reality of a forest in project planning. There is no excuse to be found in the argument that there was no information. Forest Ecology has a long and distinguished history in the scientific literature. The result of this neglect was that institutional forestry activity was centered around the growing of even aged monocultures of fast growing trees with no requirement to attend to the rehabilitation of forests.
The discussions on the sustainable management of forests still lack clear definitions creating a sense of confusion in the identification of goals. For instance, the inability to distinguish between plantations and forests have allowed processes that have led to a massive reduction of forest biodiversity. A clear definition of ‘a Forest’ needs to be clarified and harmonized in statements transmitted from the CBD to the IPF or the CSD. As forests are biological entities, any criteria or indicator chosen to represent biodiversity status must be rooted in biological variables. The current practices of assessing physical cover alone will not adequately indicate forest quality and trends. In this context, socio-cultural values should also be incorporated into the setting of criteria and indicators. Further, for every acre of forest that stands today, hundreds of acres of forest have been lost in the surrounding countryside. Yet there has been no mention of the need for rehabilitation and recovery of the biodiversity status of such degraded lands. If these fundamental issues are not addressed, the loss of forests and biodiversity in these critical ecosystems cannot be contained.
By Brett French
If there’s a plant-based poster child for wildland fire in the subalpine forests of Yellowstone National Park, it would be the cone of the lodgepole pine tree.
“All of these forests evolved with fire after the last glacial retreat,” said Roy Renkin, a vegetation specialist for Yellowstone National Park. “Different species have evolved different mechanisms to deal with fire.”
The Douglas fir has thick bark meant to resist low-intensity fires. Fireweed spends a lot of time spreading its roots out so it can sprout after fires remove competition. And the lodgepole pine’s specially devised cones will open to release seeds only when heated to 104 to 122 degrees.
“This green forest over here looked like that black forest many times,” he explained.
Renkin is one of the few people still on staff at Yellowstone who was around when the 1988 fires swept across roughly one-third of the park, charring more than 793,000 acres. Since then, he’s been witness to the rebirth of the park’s vegetation following what many at the time thought would be a legacy of scorched earth and a slow rebound.
“You guys will be lucky to have a meadow there in 100 years,” let alone a forest, he remembers one group of “ologists” concluding after visiting a heavily burn site. Thirty years later some of the trees that repopulated the area are 25 feet tall. Elk sedge that took root has grown “as big as basketballs.”
New research suggests the removal of timber harvest residue during harvesting may be a boon for wild bees, an important step toward better understanding the planet’s top group of pollinators.
The findings are important because bees are the driving force behind $100 billion in global economic impact each year, with insect pollinators enhancing the reproduction of 90 percent of the Earth’s flowering plants, including many food crops.
Insect pollinators are also ecologically critical as promoters of biodiversity. Bees are the standard bearer because they’re usually present in the greatest numbers and because they’re the only pollinator group that feeds exclusively on nectar and pollen their entire life.
Researchers at Oregon State University spent two years studying 28 contiguous 1-acre clearcut sites. They assessed whether the abundance and diversity of wild bees was affected by the removal of timber harvest residue, also known as slash, and the soil compaction that goes along with it.
“Bees are important for biodiversity in managed forest landscapes but we just don’t have a very good handle on them in these areas,” said lead scientist Jim Rivers of the OSU College of Forestry.
The study plots occurred within a managed conifer forest in western Oregon. Each plot received one of five unique treatments, ranging from removing only the boles – tree trunks that are used to make lumber – without compacting the soil at all (no heavy equipment used on the plot) to removing all of the logging slash and compacting the entire plot.
The findings were surprising, Rivers said.
“The combination of the most intense timber residue removal and soil compaction treatment made for the greatest number and diversity of bees,” he said.
Things are looking up in a swath of forest in southern Germany, thanks to innovative funding from the European Union for a project that aims to help policymakers better understand how the forest’s ecosystems work.
The ECOPOTENTIAL project uses satellite images for ecosystem modelling in 25 Protected Areas in Europe (as well as Kenya, the Caribbean and Israel) to address climate change and other threats to ecosystems. In the Bavarian forest, the images and mathematical models of ecosystems, or “Earth Observation tools”, are helping to assess the impact of climate change and pollution, and shape national protection policies.
UN Environment is one of many partners supporting the 2015-2019 ECOPOTENTIAL project, funded by the European Union to the tune of 16 million euros.
Within the ECOPOTENTIAL project, Earth Observation tools and “remote sensing”, including by aircraft and drones, are being used to better understand how vegetation is evolving across the park and over time.
Satellite and drone pictures are detecting patterns of dominant plant species, linking habitat characteristics with terrain, and tracking animal movements. The park administration is also carrying out intensive research on tree regeneration, the role of dead wood, and the impact of global warming and extreme climatic events on the future development of these ecosystems.
By Jade Boyd
Widespread logging and hunting have endangered virtually all of Madagascar’s 100-plus species of iconic lemurs, and a new study by Rice University ecologists illustrates how saving the animals may also be key to saving the island’s largest trees.
“Forest loss is a huge problem in Madagascar right now, but our study suggests that just saving the trees is not enough,” said Amy Dunham, associate professor of biosciences at Rice and co-author of a paper appearing online today in a special issue of the International Journal of Primatology. “Not only are we facing the loss of these unique, charismatic animals, we’re also losing their role in the ecosystem. Without lemurs, the rainforests themselves will change because the lemurs alone disperse the seeds of many of the forests’ largest hardwoods.”
The study builds upon nearly a decade of collaborative work by Dunham and lead author Onja Razafindratsima at the island nation’s Ranomafana National Park.
Lemurs mostly eat fruit, and for many of the largest trees in Madagascar, lemurs are the only animals large enough to ingest the seeds of their fruit. By dispersing seeds throughout the forest in their scat, lemurs serve as the unwitting gardeners of these large canopy trees.
By Henry Fountain
The country lost most of its trees long ago. Despite years of replanting, it isn’t making much progress.
The country lost most of its trees more than a thousand years ago, when Viking settlers took their axes to the forests that covered one-quarter of the countryside. Now Icelanders would like to get some of those forests back, to improve and stabilize the country’s harsh soils, help agriculture and fight climate change.
But restoring even a portion of Iceland’s once-vast forests is a slow and seemingly endless task. Despite the planting of three million or more trees in recent years, the amount of land that is covered in forest — estimated at about 1 percent at the turn of the 20th century, when reforestation was made a priority — has barely increased.
A study of Front Range forests burned by wildfires between 1996 and 2003 shows they are not regenerating as well as expected and large portions may become grasslands or shrub lands in coming years.
The paper, published in the journal Ecosphere by former doctoral student Monica Rother and geography professor Thomas Veblen, examined the sites of six low-elevation ponderosa pine forest fires which collectively burned 162,000 acres along the Colorado Front Range between 1996 and 2003. Eight to 15 years after the fires, the researchers expected – based on historical patterns – to see young trees cropping up across the landscape. Instead, 59 percent of plots surveyed showed no conifer seedlings at all and 83 percent showed a very low density of seedlings. Although it is possible that more seedlings will appear in upcoming years, future warming and associated drought may hinder significant further recovery.
“It is alarming, but we were not surprised by the results given what you see when you hike through these areas,” said Rother, who earned her doctorate from CU Boulder in 2015 and works as a fire ecologist at Tall Timbers Research Station in Tallahassee, Florida.
By Mike Gaworecki
A study published in the journal Science Advances this month found that, between 2000 and 2013, the global area of intact forest landscape declined by 7.2 percent, a reduction of 919,000 square kilometers, or a little over 227 million acres.
Intact forest landscapes (IFLs) are areas of natural land cover that are large and undisturbed enough to retain all their native plant and animal communities — defined at 500 square kilometers. For an IFL to be considered “lost,” its vegetation needs to be degraded to an extent at which it can no longer support its original levels of biodiversity.
Among the study’s other findings, one in particular was quite surprising: Certification of logging concessions, which aims to ensure sustainable forest management practices, had a “negligible” impact on slowing the fragmentation of IFLs in the Congo Basin, home to the world’s second-largest rainforest as well as high levels of biodiversity, including more than 600 tree species and 10,000 animal species.