Woody vines strangle trees and takeover forests as temperatures get hotter

In the face of Earth’s hottest year on record, has unveiled a disturbing trend: woody vines, known as lianas, are aggressively overtaking forests worldwide.

This phenomenon, discovered in a pivotal global study spearheaded by the University of the Sunshine Coast (UniSC), poses a significant threat to these ecosystems’ ability to mitigate climate change by storing carbon.

Tipping point: Climate and disturbance

This research encompasses a remarkable scope, spanning 44 countries across five continents. The team’s comprehensive analysis has pinpointed the forests most at risk, revealing a particular vulnerability in tropical, low-elevation forests.

Notable examples include regions in East Africa, Vietnam, Colombia, and Australia’s Wet Tropics, among numerous others worldwide.

Professor Andy Marshall, from UniSC’s Forest Research Institute, emphasizes the study’s discovery of a “tipping point” – a critical juncture where the dominance of lianas becomes pronounced.

This point is reached when the mean annual temperature exceeds 27.8° Celsius, coupled with rainfall less than 1,614 mm, particularly in forests already disturbed by human activities like logging and clearing.

Implications of woody vine dominance

Lianas, by their very nature, choke trees and impede their growth as they climb towards the forest canopy.

“Woody vines are increasingly taking over the world’s forests,” said Marshall. “For the first time, we have a global assessment that confirms that forest disturbance and climatic factors are major drivers of liana dominance.”

These findings are crucial for the restoration of the world’s forests. “They allow us to know where to concentrate our efforts for restoration and identify future areas of concern in a changing climate,” explains Marshall.

He further highlights that environmental conditions fostering liana vines could out-compete trees and stall recovery in disturbed native forests globally.

Professor Marshall draws particular attention to Australia, where the coastal and low-elevation forests of north Queensland are most vulnerable.

“In Australia, the coastal and low-elevation forests of north Queensland are the most vulnerable—
adding to the ongoing threat of deforestation which, in Queensland, is already greater than any other developed country,” he said.

“With warmer temperatures and ongoing disturbances from logging and clearing, those forests areas under threat from liana around the world are only going to increase.”

Woody vines are thriving in climate change

Tracing back to his first rainforest expedition in East Africa in 1998, Professor Marshall recalls his intrigue with the vines blanketing the trees.

Since then, research has escalated in scale, predominantly with local or regional focuses, leading to this global study.

This research is grounded in an “unprecedented dataset” from 651 vegetation samples representing 26,538 lianas and 82,802 trees, from 556 unique locations worldwide, derived from 83 research publications.

The collaborative effort involved 20 co-authors from diverse research institutions across continents including Australia, South Africa, the UK, Singapore, Panama, Brazil, the USA, and China.

The study reveals that lianas are better adapted to climate change conditions, such as warmer temperatures, lower rainfall, and disturbances like fire, logging, and clearing.

Their dominance over trees hampers the latter’s recovery from disturbances, a situation that can persist for decades.

Carbon sink dilemma

Forests, alongside oceans and soil, are the world’s largest carbon sinks. The encroachment of lianas not only contributes to forest loss and degradation but also exacerbates the threat to this vital carbon sink.

The urgency now lies in developing sensitive, effective solutions to help trees recover from vine domination and to restore the global carbon sink.

However, Professor Marshall cautions against the full-scale clearing of lianas. He underscores the role of lianas in forest ecosystems and biodiversity — from boosting soil fertility and carbon cycling to benefiting other plants, animals, soils, and overall ecosystem function, in both intact and disturbed forests.

“We certainly wouldn’t want this work to lead to forest managers going and cutting out all these vines out of their forests,” he said. “Liana plays its part in the forest ecosystem and biodiversity by boosting soil fertility and carbon cycling, and can benefit other plants, animals, soils and overall ecosystem function, in both intact and disturbed forests.”

The challenge is to manage their growth, which, under human impact, has become excessively high and unnatural.

“It is just that human impact is so great in some areas, that they are growing in very high numbers, they are not growing in a natural way,” Marshall concluded.

More about woody vines

As discussed above, woody vines, known scientifically as lianas, are becoming increasingly significant in our ecosystems.

These climbing plants, often found in tropical and subtropical forests, have shown a remarkable ability to adapt and thrive in changing environmental conditions.

Adaptability of woody vines

Woody vines possess unique characteristics that enable them to flourish in diverse environments.

They typically use trees or other vertical structures for support, allowing them to reach sunlight more efficiently than their non-climbing counterparts.

This ability gives them a competitive edge, especially in dense forests where light is a precious resource.

The growth of woody vines has profound implications for forest ecosystems. By climbing and enveloping trees, they often hinder the trees’ ability to grow and reproduce.

This interaction can lead to reduced forest density and diversity, impacting the overall health of the ecosystem.

Moreover, the aggressive nature of these vines often makes them a dominant species in disturbed habitats, such as areas affected by logging or deforestation.

Woody vines and climate change

Climate change plays a significant role in the proliferation of woody vines. These plants have shown a remarkable resilience to changes in temperature and precipitation patterns, often outcompeting other species in altered environments.

As such, they are becoming more prevalent in regions experiencing the effects of climate change, reshaping forest landscapes and biodiversity.

Forests act as carbon sinks, absorbing and storing carbon dioxide from the atmosphere. However, the increasing dominance of woody vines poses a challenge to this vital function.

By inhibiting tree growth and survival, they can potentially reduce the capacity of forests to sequester carbon, thus exacerbating the impact of climate change.

Need for balanced ecosystem management

In summary, woody vines are an intriguing yet challenging component of our natural world. As discussed here in depth, the rise of woody vines underscores the need for effective ecosystem management.

While these plants are a natural part of forest ecosystems and contribute to biodiversity, their uncontrolled growth can lead to ecological imbalances.

As the world grapples with climate change, understanding and addressing the rise of lianas in forests becomes an essential part of our global environmental strategy.

The balance between forest conservation and management is delicate, yet critical, for the health of our planet.

The full study was published in the journal Global Change Biology.

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