Climate change in the forests of northern Germany

Read the full story from the University of Göttingen.

More and more trees are suffering the consequences of decades of human-made climate change. The growth of the European beech has so far suffered decline mainly in southern Europe. European beech is Germany’s most important native forest tree species and it is most commonly found in Central Europe.

A research team has now been able to show that the European beech is suffering from increasing drought stress in summer in northern Germany as well. This climate stress is particularly pronounced at warmer sites, when there is a higher density of these trees together, and on very sandy soils.

Searching the Texas brushland for a rare, temperamental plant

The author hovers near a Zapata bladderpod specimen. Photo courtesy Sara Johnson

Read the full story from the University of Illinois.

Deep South Texas is unique. It feels vast and nomadic, sprawling in all directions with hundreds of thousands of acres of ranchland and – if you don’t count the cows or the main thruways along the Rio Grande – sparsely populated. It’s a diverse region, thanks to the confluence of semi-arid and subtropical climates that meet in central South Texas to form a mixture of grasslands and extremely dry uplands.

The Zapata bladderpod is aptly named. It inhabits the Tamaulipan thornscrub, also known as mezquital, a dry ecoregion defined by shrubs and desertlike conditions, with seasonal marshlands and intermittent streams. As we search the dense thickets of shrubs and enormous prickly pear, Opuntia lindheimeri, I begin to think these plants don’t want to be found.

The education system makes us “disconnected from the botanical world”

Read the full story at Open Access Government.

At a time when plants could help solve global environmental problems, scientists warn we must become more in touch with botanical education

The lack of botanical education and knowledge has become a problem, exacerbated by schools and universities in the UK reducing their teaching of basic plant science, including plant identification and ecology.

Researchers describe the lack of public knowledge as a self-accelerating cycle which risks “…the extinction of botanical education,” where biology is taught predominantly by people with research interests in animal science.

The paper Botanical education extinction and the fall of plant awareness demonstrates the shortage of basic botany skills, which is hampering environmental improvements – such as the inappropriate planting of trees on peatbogs which can result in increased CO2 emissions by damaging these delicate habitats, or the various incidents of valuable wildflower meadows being threatened by careless tree planting or management.

How to save an ancient, giant tree from a wildfire

Read the full story in the New York Times.

California’s giant sequoias have faced particularly fierce wildfires since 2015, the result of climate change and a lack of frequent fire over the prior century, according to the National Park Service. The imminent threat — which has now reached some of the state’s most exalted trees — has prompted scientists and firefighters to take exceptional steps to save them.

Those lights aren’t just messing with your sleep. They’re bothering the trees.

Read the full story at Anthropocene.

Like humans, trees have circadian clocks. A new study finds urban light pollution changes those clocks, causing trees to leaf out earlier and change color later.

New map of ancient trees an opportunity for conservation

Read the full story from the BBC.

A new map shows there could be around two million trees with exceptional environmental and cultural value previously unrecorded in England.

Light pollution is disrupting the seasonal rhythms of plants and trees, lengthening pollen season in US cities

Some cities never sleep. Noam Cohen/EyeEm via Getty Images

by Yuyu Zhou, Iowa State University

The Research Brief is a short take about interesting academic work.

The big idea

City lights that blaze all night are profoundly disrupting urban plants’ phenology – shifting when their buds open in the spring and when their leaves change colors and drop in the fall. New research I coauthored shows how nighttime lights are lengthening the growing season in cities, which can affect everything from allergies to local economies.

In our study, my colleagues and I analyzed trees and shrubs at about 3,000 sites in U.S. cities to see how they responded under different lighting conditions over a five-year period. Plants use the natural day-night cycle as a signal of seasonal change along with temperature.

We found that artificial light alone advanced the date that leaf buds broke in the spring by an average of about nine days compared to sites without nighttime lights. The timing of the fall color change in leaves was more complex, but the leaf change was still delayed on average by nearly six days across the lower 48 states. In general, we found that the more intense the light was, the greater the difference.

We also projected the future influence of nighttime lights for five U.S. cities – Minneapolis, Chicago, Washington, Atlanta and Houston – based on different scenarios for future global warming and up to a 1% annual increase in nighttime light intensity. We found that increasing nighttime light would likely continue to shift the start of the season earlier, though its influence on the fall color change timing was more complex.

Why it matters

This kind of shift in plants’ biological clocks has important implications for the economic, climate, health and ecological services that urban plants provide.

On the positive side, longer growing seasons could allow urban farms to be active over longer periods of time. Plants could also provide shade to cool neighborhoods earlier in spring and later in fall as global temperatures rise.

But changes to the growing season could also increase plants’ vulnerability to spring frost damage. And it can create a mismatch with the timing of other organisms, such as pollinators, that some urban plants rely on.

Charts show the intensity of urban light in seven representative cities
Urban light intensity varies among cities, and among neighborhoods within cities. Yuyu Zhou, CC BY-ND

A longer active season for urban plants also suggests an earlier and longer pollen season, which can exacerbate asthma and other breathing problems. A study in Maryland found a 17% increase in hospitalizations for asthma in years when plants bloomed very early.

What still isn’t known

How the fall color timing will change going forward as night lighting increases and temperatures rise is less clear. Temperature and artificial light together influence the fall color in a complex way, and our projections suggested that the delay of coloring date due to climate warming might stop midcentury and possibly reverse because of artificial light. This will require more research.

How urban artificial light will change in the future also remains to be seen.

One study found that urban light at night had increased by about 1.8% per year worldwide from 2012-2016. However, many cities and states are trying to reduce light pollution, including requiring shields to control where the light goes and shifting to LED street lights, which use less energy and have less of an effect on plants than traditional streetlights with longer wavelengths.

Cars are parked on an old brick residential street at dusk with street lights and trees lining the sidewalks.
Baltimore has been converting its streetlights to LED to save money on energy. LEDs also have less of an impact on plants. Cyndi Monaghan via Getty Images

Urban plants’ phenology may also be influenced by other factors, such as carbon dioxide and soil moisture. Additionally, the faster increase of temperature at night compared to the daytime could lead to different day-night temperature patterns, which might affect plant phenology in complex ways.

Understanding these interactions between plants and artificial light and temperature will help scientists predict changes in plant processes under a changing climate. Cities are already serving as natural laboratories.

Yuyu Zhou, Associate Professor of Environmental Science, Iowa State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.