Forests ground us. They give us materials to build our homes, and the energy to heat them. They offer solitude, escape, and shade. They even filter the air we breathe.
But our forests are changing, in some cases almost overnight, and they face an uncertain future. Climate change, droughts, insect outbreaks, and invasive species are dramatically impacting forests worldwide and it has never been more imperative to precisely measure the condition of these ecosystems over time.
By combining a simple software workflow with multispectral sensors like Sequoia and the elevated perspective that drones give us, one is able to quickly assess the conditions of forest ecosystems and take action to ensure their longevity.
Enhancing our view of forestry
These opportunities to make more informed decisions require an innovative set of tools for scientists and land managers. While satellites used in remote sensing are highly informative, they can leave gaps in areas covered by clouds and deliver comparatively low-resolution data, while boots-on-the ground surveys are time consuming and costly.
Drones, however, have the potential to transform how forest ecosystems are measured and monitored, from the rainforests of the tropics to the boreal forests near the poles. New ultra-lightweight sensors such as the Sequoia camera by Parrot can be carried on drones to help study vegetation dynamics.
Sequoia is the smallest and lightest multispectral sensor in its class. In one flight it automatically captures images across four discrete visible and non-visible spectral bands, plus RGB imagery. This makes it easier than ever to collect forest data and calculate valuable vegetation indices, such as NDVI.
Forest monitoring plots near Gothic, Colorado, displaying the 4 different multispectral bands (red, green, red-edge, and near infra-red) of the Sequoia camera, along with a NDVI vegetation index and a digital surface model all collected on single flight in June of 2016.
Despite the fact that we have been hearing about deforestation for decades now, it is still a critical issue. Tropical areas such as the Amazon, Borneo, and Madagascar are being cleared at a phenomenal rate. In complex business and political environments, it can be difficult to measure ecological hotspots from the ground.
In North America, forests are being wracked by numerous invasive species, such as the hemlock woolly adelgid, a small, aphid-like insect that has brought ruin to eastern hemlock over the past decade. Sudden Oak Death has had devastating effects on oak forests on the Pacific coast. Invasive species will continue to be a major problem as they hitchhike on the raw materials and goods transported in support of our global economy.
Perhaps most important, the climate is changing. Rising temperatures are creating new challenges, such as more frequent fire return intervals and extreme weather events.
For example, the U.S. Forest Service estimates the record-breaking drought in California over the past few years has alone killed over 66 million trees in the Sierra Nevada mountains.
Aspen dieoff area near Almont Triangle, Colorado, July, 2016 (Video link)
Similarly, aspens in the Rocky Mountain West are dying out for a variety of reasons linked to climate change, such as beetles and disease.
Shoots of green
Scientists, landowners, conservationists and governments are starting to pay attention. So are tech companies: advances in small UAVs and sensors like Sequoia will allow us to understand more and more about how to detect, manage and eventually prevent adverse impacts in these fragile ecosystems.
Today, most consumer-level drones allow you to easily save flight plans for future missions. Having this level of simple repeatability means we can standardize survey protocols for data collection across research teams, locations, and over time. Such a high level of standardization is currently missing from global forest inventory assessments (Trumbore et al. 2015), but drones will enable repeatability with a previously unheard-of consistency.
Drones will also enable sustainable forestry management. Forestry companies and land managers can use the multispectral imagery captured by Sequoia to calculate precise estimates of re-plantings, rates of regeneration, risk assessments for fuel loading, and accurate inventories for selective cutting.
Harvesting in color and NDVI collected with the Parrot Sequoia camera near Seeley Lake, Montana (June 2016).
Because Sequoia is so small and light, you don’t need a large, expensive UAV to be able to use the technology. Put Sequoia on the drone you already have, plan your flight, and let it automatically capture and accurately tag all of the images during your flight.
While the complexities of managing forest ecosystems far outweigh the complexities of imaging from the air, the vast amount of data that will be collected from these new technologies will undoubtedly help us make better decisions in the future on how we manage our forests.