Governments have pledged to plant trees to cut carbon emissions, mitigate extreme heat, and meet climate commitments.
The Australian Government has committed to planting 1 billion additional trees by 2030.
However, a new study highlights a shortage of tree seedlings in the US, where a chronic lack of seedlings obstructs planting targets.
The research, which has implications for global reforestation efforts, is published in Bioscience and calls for greater species diversification.
For the study, 13 scientists scrutinised 605 plant nurseries across 20 northern states.
Only 56 of them – or less than 10% – grow and sell seedlings in the volumes required for conservation and reforestation.
The team, led by Peter Clark, a forest ecologist at the University of Vermont and the study’s lead author, discovered that forest nurseries often maintain a limited inventory of a select few species of trees, mainly focusing on trees valued for commercial timber production.
An overwhelming scarcity of seedlings.
This has resulted in nurseries suffering from an “overwhelming scarcity of seedlings” well-suited for climate plans.
Clark stated, “Despite the excitement and novelty of that idea in many policy and philanthropy circles – when push comes to shove, it’s very challenging to find either the species or the seed sources needed.”
According to the Guardian, the 2021 Infrastructure Investment and Jobs Act provided money for the US Forest Service to plant over 1 billion trees in the next nine years.
These ambitious planting targets, however, face considerable challenges due to seedling shortages and a need for more diversity.
The World Economic Forum aims to help plant 1 trillion trees worldwide by 2030.
Nevertheless, achieving these targets requires trees that can flourish in the context of regional biological and climatic conditions.
Many of the nurseries the researchers examined needed a stock of seedlings that had been acclimated to the region.
The researchers also found an absence of “future-climate-suitable” varieties, which will survive amid worsening heat and extreme weather conditions.
The study found that trees that play critical roles in local ecosystems were also scarce.
The red spruce, for instance, is highly carbon-sequestering and serves as a habitat for many species, but it has been threatened in recent decades by development and acid rain.
“Efforts are in the works to restore the species, [but] in our investigation, we found only two nurseries that sold the species,” said Clark.
Many factors led to the absence of crucial seedlings.
Among them is the decline of government nurseries.
Increased investment in regional tree nurseries.
The team argues that dramatic increases in seedling production and diversity at many regional nurseries will be central to any successful campaign to address climate change with tree planting.
“In recent years, many states have elected to close their publicly funded nurseries because of budgetary concerns,” Clark said.
“The economics haven’t supported maintaining it in the eyes of those writing the checks.”
The decline of nurseries has not only led to a decrease in seedling production but also resulted in a loss of knowledge about seeds.
Clark added that skilled seed collectors are also becoming rarer, meaning diverse seeds are becoming more challenging for nurseries to obtain.
The researchers argue that dramatic increases in seedling production and diversity at many regional nurseries will be central to any successful campaign to address the climate crisis with tree planting.
The research calls for expanded federal and state investment into government-owned and operated tree nurseries and public seed collection efforts.
“This strategy may stimulate production from private nurseries once a stable demand is apparent.”