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When planting trees threatens the forest:
Campaigns to plant huge numbers of trees could backfire, according to a new study that is the first to rigorously analyze the potential effects of subsidies in such schemes.
The analysis, published on June 22 in Nature Sustainability, reveals how efforts such as the global Trillion Trees campaign and a related initiative (H. R. 5859) under consideration by the U.S. Congress could lead to more biodiversity loss and little, if any, climate change upside. The researchers emphasize, however, that these efforts could have significant benefits if they include strong subsidy restrictions, such as prohibitions against replacing native forests with tree plantations.
"If policies to incentivize 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 study co-author Eric Lambin, the George and Setsuko Ishiyama Provostial Professor in Stanford's School of Earth, Energy & Environmental Sciences. "That's the exact opposite of what these policies are aiming for."
[...] The researchers set out to quantify the full impact of the afforestation subsidies and calculate their effects on net carbon and biodiversity changes across the entire country. They compared the area of Chilean forests under three scenarios: actual observed subsidy patterns, no subsidies and subsidies combined with fully enforced restrictions on the conversion of native forests to plantations. They found that, relative to a scenario of no subsidies, afforestation payments expanded the area covered by trees, but decreased the area of native forests. Since Chile's native forests are more carbon dense and biodiverse than plantations, the subsidies failed to increase carbon storage, and accelerated biodiversity losses.
"Nations should design and enforce their forest subsidy policies to avoid the undesirable ecological impacts that resulted from Chile's program," said study coauthor Cristian Echeverría, a professor at the University of Concepción in Chile. "Future subsidies should seek to promote the recovery of the many carbon- and biodiversity-rich natural ecosystems that have been lost."
Journal Reference:
Robert Heilmayr, Cristian Echeverría, Eric F. Lambin. Impacts of Chilean forest subsidies on forest cover, carbon and biodiversity, Nature Sustainability (DOI: 10.1038/s41893-020-0547-0)
(Score: 2) by looorg on Tuesday June 23 2020, @02:40PM (11 children)
How about water consumption, or ground water levels for that matter? More trees sucking up more water means less water somewhere down the line, or?
(Score: 5, Informative) by JoeMerchant on Tuesday June 23 2020, @03:03PM (5 children)
When they plant pine plantations near pecans, the pecans wither due to all the water sucked up by the pines.
Varies by soil layer type, apparently shale bedrock provides a better water profile than sandstone - and a thousand other variables. Contact your local Ag extension office for their soil profile maps - in the US at least they know pretty well what grows well everywhere, and why.
🌻🌻 [google.com]
(Score: 2) by PartTimeZombie on Tuesday June 23 2020, @10:00PM (3 children)
That might also be because pine needles are toxic. This is an evolutionary advantage to prevent competition.
(Score: 2) by JoeMerchant on Tuesday June 23 2020, @11:34PM (2 children)
The folks that grow 'em blame the water. Pine needles aren't killing toxic to pecans, as near as I can tell, they just starve them for water so they don't grow or produce nuts - eventually they shade them out.
Black walnut and I think black cherry have some really impressive toxins that kill anything that tries to grow near them.
🌻🌻 [google.com]
(Score: 2) by PartTimeZombie on Tuesday June 23 2020, @11:41PM (1 child)
Pine needles are toxic to almost everything that might compete for sunlight and nutrients.
They might not kill the other plant, but they don't need to. They just need to prevent it from growing taller than the pine tree, and taking the sunlight.
To be fair, the pine trees may well be taking a lot of the water too, but if they want to prevent that, they should plant a willow. Willows can literally stop a creek from flowing.
It might not help their pecans I suppose.
(Score: 3, Informative) by JoeMerchant on Tuesday June 23 2020, @11:49PM
What was happening on the land we were looking at was people were planting pine plantations in what used to be pecan country, so you'd see these pecan trees on the edge of the pines, sometimes inside. The old timer who told me about the water was pointing to a ~25' tall skinny pecan tree that had been left in the middle of a now ~13 year old pine plantation, the pines were getting up around 30' or so, not quite completely shading it... yet. Folks around there preferred the pines because they are easier to manage.
🌻🌻 [google.com]
(Score: 2) by Reziac on Wednesday June 24 2020, @02:32AM
Indeed... sometimes trees don't grow somewhere, or are naturally widely spaced, because that's what the water profile can support. Suppress wildfire (and don't log out surplus) and pretty soon you have too many trees starving for water, and California-grade fires.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 4, Insightful) by Anonymous Coward on Tuesday June 23 2020, @03:56PM
Generally, the benefits of having the ground covered year-round by vegetation would offset any loss due to plant use. Trees are known to seed clouds with their respiration, and decreased loss of soil moisture and better absorption of rainwater mean they will help the water levels. There are tons of landscaping tricks that can help replenish aquifers as well.
(Score: 1, Touché) by Anonymous Coward on Tuesday June 23 2020, @04:32PM (2 children)
By that measure, Sahara should be the best place for water in the world. No trees to speak of!
(Score: 1) by fustakrakich on Tuesday June 23 2020, @05:08PM (1 child)
It does have some of the world's largest aquifers. In fact, big wars are being fought over it right now. It ain't the oil people are after.
La politica e i criminali sono la stessa cosa..
(Score: 0) by Anonymous Coward on Tuesday June 23 2020, @05:41PM
But they are acquifers that haven't seen significant new water in thousands of years. You start draining that at scale, and you are just "using it up." I've heard it called "fossil water."
(Score: 2) by DannyB on Tuesday June 23 2020, @05:47PM
Modern irrigation: bring in many truckloads of bottled water to be poured around the trees for growth.
The water comes from somewhere else. So it's not a concern of anyone. The trees won't drain the aquifers.
Dispose of bottles wherever convenient.
* Drop anywhere convenient?
* Grind up into small plastic bits and mix into soil.
* Bury?
* Burn?
* Throw in river in hopes they'll safely reach the ocean where they are no longer anyone's concern.
When trying to solve a problem don't ask who suffers from the problem, ask who profits from the problem.