Featured image: Lupine flowers, an invasive species, growing near a farm site near Qassiarsuk, South Greenland.

Introduced species

Q: There are many examples of introduced plants expanding beyond first planting areas. How is Greenland tree planting any different?

  • Our aim is to only plant native species. Which species are native, however, is debatable. We consult experts to investigate the matter.
  • On disruption
    • sheep farming, widespread in south Greenland, while highly disruptive, the area where we plant trees has designated by UNESCO as a World Heritage site defined by Norse and Inuit farming.
    • Planting trees is a counter-measure for Anthropogenic climate change, itself very disruptive.
  • We plant in fenced, protected, and isolated areas.
  • Tree growth is slow, so introducing trees presents no immediate out-of-control problem.
  • We are planting in the sub-Arctic, at an equivalent latitude as Norway or Labrador where trees thrive today.
  • The low amount of tree species compared to North America today is due to lack of natural immigration (from birds, sea drift) because of Greenland’s isolation. Ocean currents flow from the Arctic, clockwise around the island.

Q: Were there trees in south Greenland in the past that humans cut down?

  • The saga of the Greenlanders mentions ‘felling trees’, but in north America, not Greenland. Nevertheless, the woodlands and shrubs were undoubtedly cut down and the browsing especially from sheep grazing, destroyed tree regeneration. Land areas were also cleared of stones and vegetation by the Norse for farming and hay production. It was probably the same pattern as on Iceland, where the forest coverage at the Landnám (Settlement) was around 20% but was reduced to below 1%. Pollen diagrams indicate the presence of birch woodlands in south Greenland before AD 1000, when Norse settlement began.

Slow growth/sequestration rate

Q: Why not plant in an environment where tree growth (CO2 sequestration) is faster? Isn’t afforestation more effective in the tropics?

While the trees grow more slowly in southern Greenland…

  • We work in Greenland already.
  • We engage local people with an emphasis on youth to take part, reducing the CO2 footprint from flights to Greenland for forest management.
  • The sites have protection status in scientific research and sustainability.
  • Forest permanence in Greenland is likely.

I’ve offset, now I can keep on flying and using hydrocarbon fuels a lot!

  • We all should aim to decrease our CO2 emissions in the first place. However, our plantations reduce the amount of CO2 already in the atmosphere.
  • It would take more than the available arable land to reverse the hundreds of gigatons of CO2 already in the atmosphere. So, what we offer is a way to reduce CO2 impacts while engaging in various other benefits (youth education, sustainable forestry).

How to guarantee the forest will remain?

  • We secure the plantations for the indefinite future by working with Greenland communities and authorities to create plantations that have protection status through long term (century) area allotment leases.

Albedo effects

  • When planting trees in seasonally snow-covered areas, the radiative forcing from albedo reduction by trees overcompensates the cooling forcing from carbon storage (Bala et al 2007, Pitman et al 2009, Pongratz et al 2009, McGrath et al 2015). When snow-covered, forest area in general has ~0.3 lower albedo than non-forest area (Bonan, 2008 (DOI: 10.1126/science.1155121)). Despite evaporational cooling, the overall biophysical effect (evapotranspiration + albedo) of boreal forests (generally North of 45°N) is warming (Li et al., 2015 (DOI: 10.1038/ncomms7603)), especially in wintertime. However:
    • Wintertime solar irradiance is low.
    • For snow-free soil in summer, the albedo difference between background treeless tundra is low, especially for Siberian Larch. Since we are planting in areas where native willow and birch thrive, we estimate that our trees darken the surface by 10%. Thus, the darkening effect from our plantations is not offsetting the carbon benefit.

Humidity effects

Q: Isn’t it so that increased carbon dioxide levels cause plants to retain water that otherwise would have evaporated from their leaves, entered the atmosphere and helped cool the planet?

  • Yes, but atmospheric moisture content globally and in the Arctic has been increasing in past decades. South Greenland has been receiving more moisture, anyway.

Counter-balancing negative impacts

  • No environmental intervention is without issues. Yet, the positive effect of carbon capture, youth engagement, and symbolism of giving to nature and not only taking, means that Greenland Trees’ work is net-positive.