temperate

Forest-based agroforestry

July 30, 2025 By EarthWise Leave a Comment

Tree plantings have become a go-to climate solution for governments and conservation groups due to the carbon-storing potential of trees. While planting new trees on open farmland would help capture additional carbon, a new study led by scientists from Yale School of the Environment suggests a powerful alternative: forest-based agroforestry.

Instead of clearing land for crops or starting fresh with new trees, forest-based agroforestry (or FAF) brings agriculture into existing forests. Think fruits, nuts, and medicinal plants, for example, grown sustainably under a forest canopy – all while maintaining biodiversity and storing carbon.

According to the researchers, human activity in forests is often seen as harmful. But for thousands of years, Indigenous and local communities have managed forests in ways that actually strengthen them.

The study, which was recently published in the journal Nature Climate Change, found that FAF not only rivals tree planting in terms of climate benefits, but it can also generate income and support cultural practices tied to the land.

Despite these benefits, forest-based agroforestry receives far less funding and policy support due to two key misconceptions. It’s frequently confused with industrial systems focused on global commodity crops, and results from tropical regions are wrongly assumed to apply to temperate and boreal forests.

The researchers recommend including FAF in agroforestry policies, clearly distinguishing it from harmful industrial practices, and expanding research on FAF in temperate and boreal regions to guide better land management.

Forest-based agroforestry appears to be a natural climate solution hiding in plain sight.

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Agriculture in Forests Can Provide Climate and Economic Dividends

Photo, posted May 8, 2023, courtesy of Preston Keres / USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wrong trees in the wrong places

January 20, 2025 By EarthWise Leave a Comment

Temperatures in cities are rising around the world and urban heat stress is already a major problem. Extensive surfaces of man-made materials absorb the sun’s energy, and lead to temperatures well above those in the surrounding countryside. This is known as the urban heat island effect, and it can lead to greater energy use, higher air pollution levels, and a greater risk of heat-related illnesses, as well as death.

Some cities have already started implementing mitigation strategies, with tree planting prominent among them. Planting trees can cool the climate by absorbing carbon dioxide, providing shade, and releasing water vapor, which lowers air and surface temperatures.

However, while trees can cool cities significantly during the day, new research from the University of Cambridge in the U.K. shows that tree canopies can also trap heat and raise temperatures at night.

According to the study, which was recently published in the journal Communications Earth & Environment, planting the wrong species or the wrong combination of trees in suboptimal locations or arrangements can limit their benefits.

The researchers found that in temperate climates, trees can cool cities by up to 6°C during the day but can increase nighttime temperatures by 1.5°C. Cities with open layouts in temperate and tropical climates benefit from a mix of evergreen and deciduous trees, enhancing cooling by 0.5°C more than in cities with only deciduous or evergreen trees.

The researchers hope their findings will help urban planners choose the best combinations of trees and planting locations to combat urban heat stress.

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Wrong trees in the wrong place can make cities hotter at night, study reveals

Photo, posted October 29, 2017, courtesy of Lars Plougmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and fish migration

May 17, 2024 By EarthWise Leave a Comment

The warming climate is changing the distribution of fish species. Researchers at the University of Adelaide in Australia have observed that tropical fish species are moving into temperate Australian waters.

The Eastern Australian Current is strengthening as the climate warms and larvae of tropical fish are getting caught in the current and moving into more temperate regions. These larvae would not normally survive in the cooler Australian ocean water, but the warming current keeps the baby fish warm and increases their chances for survival. The fish migration observed in the study is an ongoing process that has strengthened in the last few decades due to ocean warming.

The novel populations of tropical fish in these temperate ecosystems are not having much impact at the present time, but they may do so in the future. The water is still cooler than the fishes’ natural environment and therefore they do not grow to their maximum size. As a result, they don’t represent stiff competition for the native species – at least not yet.

As the ocean temperatures continue to rise, these tropical species will eventually grow to their full size and their diets will overlap more and more with those of temperate fish species. Tropical herbivores tend to overgraze temperate kelp while the impact of tropical fish that eat invertebrates is less well understood. Tropical fish with varied diets are the most successful invaders. The ultimate effects on temperate ecosystems remain to be seen but survival may become difficult for the native fish in rapidly warming temperate ocean environments.

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Tropical fish are invading Australian ocean water

Photo, posted March 28, 2017, courtesy of Ryan McMinds via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate Change And Crops | Earth Wise

December 22, 2021 By EarthWise Leave a Comment

A new NASA study published in the journal Nature Food looks at the impact of global climate change on food crops. According to the study, declines in global crop yields are likely to become apparent by 2030 if high greenhouse gas emissions continue.

The study used advanced climate and agriculture models to predict the effects of projected increases in temperature, shifts in rainfall patterns, and elevated surface carbon dioxide concentrations from human-caused greenhouse gas emissions.

These climate changes would make it more difficult to grow corn in the tropics but would actually expand wheat’s growing range. The reduction in corn yields could be as much as 24% by late in the century. Corn Is grown all over the world and large quantities are produced in countries nearer to the equator. As temperatures rise in countries such as the US, Brazil, and China, yields are likely to decline because of the increased stress on the plants.

Wheat, which grows best in temperate climates may see a broader area where it can be grown as temperatures rise, but these gains are likely to level off by mid-century.

Rising temperature is not the only factor influencing crop yields. Rising carbon dioxide levels have a positive effect on photosynthesis and therefore on crop yields, especially for wheat. But changing rainfall patterns and rising temperatures can affect the length of growing seasons and accelerate crop maturity. This can result in the production of less grain than in a longer development period.

The changing climate has complicated effects on the growth of breadbasket crops and will be felt worldwide.

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Global Climate Change Impact on Crops Expected Within 10 Years, NASA Study Finds

Photo, posted September 8, 2004, courtesy of Lynn Ketchum/Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.