“We have to be aware that climate change and biodiversity loss are stress factors for ecosystems, for humans, for animals, and for the microbiome. Our research shows that if the different axes of the disease pyramid are destabilized, new infectious diseases can be expected, including for humans.” Dirk Schmeller, Université de Toulouse

Forests, like the ocean, help keep our climate safe and stable by absorbing carbon dioxide through photosynthesis. The process shows how the forest uses solar energy from the sun and CO2 to feed themselves and to grow. The CO2 gets stored below the ground and above the ground like leaves and needles.

A healthy forest will absorb CO2 and release oxygen into the atmosphere. Terrestrial plants pull  30% of our fossil fuel emissions, according to Monga Bay. They note that “for forests to be good carbon-removal investments, they need to be relatively permanent, meaning that the plants and soil in a forest will absorb carbon and keep it locked away for decades or centuries. What climate change does is exacerbate many of the threats to forest permanence.”

Most of the earth's vast forests teeming with biodiversity are only fragmented now in many parts of the world. Reforestation is seen as a “low cost, high impact solution to climate change.” by many governments. As a result, many nations have begun massive tree-planting campaigns as a carbon drawdown.

According to the BBC, scientists have warned these same campaigns planting forests may be a bad idea by eliminating biodiversity and releasing more carbon.

While it was intended not to apply to existing forests, lax enforcement and budgetary limitations meant that some landowners simply replaced native forests with more profitable new tree plantations.

Their study found the subsidy scheme expanded the area covered by trees but decreased the area of native forest.

They point to the fact that in the Bonn Challenge nearly 80% of the commitments made to date involve planting monoculture plantations or a limited mix of trees that produce specific products such as fruit or rubber.

The authors of this new study have looked closely at the financial incentives given to private landowners to plant trees.

These payments are seen as a key element of increasing the number of trees significantly.

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In their article, they provide a case study from Chili.

The law subsidised 75% of the costs of planting new forests.

While it was intended not to apply to existing forests, lax enforcement and budgetary limitations meant that some landowners simply replaced native forests with more profitable new tree plantations.

Their study found the subsidy scheme expanded the area covered by trees, but decreased the area of native forest.

The authors point out that since Chile's native forests are rich in biodiversity and store large amounts of carbon, the subsidy scheme failed to increase the carbon stores and accelerated biodiversity loss.

“If policies to incentivise tree plantations are poorly designed or poorly enforced, there is a high risk of not only wasting public money but also releasing more carbon and losing biodiversity,” said co-author Prof Eric Lambin, from Stanford University.

NASA writes on the loss of groundwater in Europe. 

The maps on this page show shallow groundwater storage (above) and root zone soil moisture (below) in Europe as of June 22, 2020, as measured by the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) satellites. The colors depict the wetness percentile; that is, how the levels of groundwater and soil moisture compare to long-term records for the month. Blue areas have more abundant water than usual, and orange and red areas have less. The darkest reds represent dry conditions that should occur only 2 percent of the time (about once every 50 years).

Root Zone Wetness
Root Zone Wetness Percentile

Groundwater Wetness Percentile
Groundwater Wetness Percentile

Note the differences between the groundwater and root zone moisture maps. Monitoring root zone moisture is essential for managing agriculture because it is the water naturally available for growing crops. Soil moisture at Earth’ surface and in the root zone can fluctuate significantly over short periods of time; it can be quickly replenished by rainfall, but also can evaporate rapidly during heat waves and dry spells. In fact, recent rains in parts of Europe have significantly reduced surface moisture deficits.

Groundwater is a deeper resource for crop irrigation and drinking water, and it also sustains streams during dry periods. Unlike surface and root zone moisture, groundwater takes months to rebound, as it has to be slowly and steadily replenished by surface moisture that seeps down through soil and rock to the water table. Because much of Europe experienced drought in the summers of 2018 and 2019, and saw little snow in the winter of 2019-20, much of the continent began this year with a significant deficit.

“In recent years, Central Europe has experienced a series of droughts caused by exceptionally stable weather patterns and high temperatures that can both be linked to climate change,” said Wolfgang Wagner, a remote sensing scientist at Technische Universität Wien. “The fact that some regions have experienced drought conditions in several consecutive years has already caused significant damage to forests (due to bark beetle infestation) and declines in groundwater levels.”

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The University of Würzburg in a presser from the Julius-von-Sachs-Institute for Biosciences notes how climate extremes will force changes in forests.

“At such temperatures, our Central European vegetation reaches its limits,” says the JMU professor. Together with other researchers from Germany and Switzerland, the plant ecologist was able to confirm with physiological measurements: When it is too hot, the tree simply loses too much water via its surface. As a result, the negative tension in the wood's conducting tissue becomes too steep, which ultimately leads to hydraulic failure interrupting the water transport.

Already during the course of the summer, severe drought-related stress symptoms were observed in most ecologically and economically important tree species, including widespread leaf discoloration and premature lead shedding.

Moreover, unexpectedly strong drought-legacy effects were detected in 2019: many broad-leaved trees did not unfold their leaves – they had died. Others that survived the 2018 event where not able to withstand the following drought in 2019, or became increasingly susceptible to infestation with bark beetles or fungi.

“Spruce was most severely affected, mainly because this mountainous species has been planted outside its natural habitat in Central Europe,” explains Schuldt. “Unexpected was, however, the extent to which beech trees were affected. Here in Northern Bavaria, I have seen several stands with complete dieback, especially on sites with shallow soil”. Until this event, beech has been considered as “future tree species”, even though its drought tolerance has been controversially discussed since the hot drought in 2003.

This year’s climatic condition in spring again started too warm and too dry. “Now in June 2020 we have fortunately received high amounts of rainfall,” the Würzburg professor is pleased to report. This has mitigated the situation, but the water deficit in the deeper soil layers has certainly not been recharged. Therefore, he assumes that affected trees will continue to die-off in the coming years due to legacy effects.

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