Plants cool!

Inspired by Michal Kravčík’s work I have been using a thermal imaging camera to show the cooling impact of plants. It’s a Seek Compact XR lens that plugs into the usb port on my mobile phone.

This first image is from Coronation Reserve in Whāngarei. The bottom image is a thermal image of the same site, with a slightly different perspective, mainly caused by different camera lenses. The key information distilled from these images is the temperature differences. Note that the grass and the bush have similar heat signatures. Temperatures range from 29 to 37oC., while the dividing herbicide strip is up to 53 oC. Note also the vehicle tracks in the top image with roughly proximate higher temperature readings in the bottom image with an 8 oC. differential. Over time vehicles compact soil structure leading to reduced plant growth, especially when vehicles drive on wet soils.

Glyphosate was probably the herbicide used to create the bare strip. In addition to the heat generated, the well documented health and environmental impacts of glyphosate detract value.

This one image teaches so much and opens options for climate action.

The image on the right is a planted and mulched meridian strip. The thermal image reveals the ground cover coprosma are in the low 30s (OC.) while the dry wood mulch is up to 61 OC. Note that the larger pieces of wood have not heated to the same extent as the smaller chips of wood.

This side-by-side image of spinifex grass on sand dunes reveals a high temperature of 71oC. Spinifex has adapted to grow in very dry conditions and is designed to limit transpiration, but it is still cool in relation to the sand.

Plants cool by transpiring. A tree with a five-metre diameter canopy uses about 70 kWh of power. The first image suggests that pasture can achieve a similar impact. Planting every square metre possible with vegetation will help us to cool the planet.

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