Comment | Where do plants grow best?

Lush, green rainforest teaming with life. Warm or preferably wet and warm is where we understand that plants grow best. 

What is often overlooked is how little of the earth’s land surface falls into this productive category. 

A map from research modelled the standard measure of plant growth, net primary production, showing lush parts of the earth in blue.

Map of mean Net Primary Production (NPP) in mg C ha−1y−1derived from the mean annual temperature and mean annual precipitation using the Miami model. Source: Abdalla, M., Hastings, A., Chadwick, D. R., Jones, D. L., Evans, C. D., Jones, M. B., … & Smith, P. (2018). Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands. Agriculture, Ecosystems & Environment, 253, 62-81.

African savanna dotted with a million wildebeest all munching away at the never-ending supply of grass is another caricature of plant growth. The Serengeti wildebeest population is a consequence of a unique combination of seasonal rain that forces migration that rests the grass from continuous grazing and the periodic eruptions of volcanoes that replenish nutrients.

These open woodland and grasslands comprise much larger areas than tropical forests. The global grassland area is 53 million km2, accounting for 40% of the global land area without permanent ice cover and are the light green to yellow areas on the map.

What is striking about the map is the proportion of the land area that is too dry or too cold or too high or a combination of the three to have much plant growth—the orange to brown shades.

The Sahara, middle east, central and northern Asia, much of Australia, the Andes and the Rockies through to Canada, Alaska, and Greenland have little primary production. Most of it is restricted to short seasonal pulses.

There is no more to say in this post. 

We want to remind everyone that at least half of the earth’s land surface is not great for plant growth, nor is it hospitable to humans.

Any talk about food security, rewilding, or habitat restoration requires this caveat. 

The proportion of the earth’s naturally lush surface that can grow food or support vegetation for abundant wildlife is finite.

Hero image from photo by Piotr Usewicz on Unsplash