# Forestry from 'Landsat Imagery: A Unique Resource'

## Science Center Objects

Landsat satellites provide high-quality, multi-spectral imagery of the surface of the Earth. These moderate-resolution, remotely sensed images are not just pictures, but contain many layers of data collected at different points along the visible and invisible light spectrum.

A dense forest. USFWS photo.

SilviaTerra: Landsat Use by a Forestry Start-up

SilviaTerra is a four-year-old start-up company with five full-time employees that is contributing to the change in the way forests are managed in the United States. The company provides next-generation, highly accurate forest inventory data to fifteen users of various sizes. The customer base includes national and international timber companies. SilviaTerra is profitable and continues to grow.

The launch and success of this company are in no small part due to the free availability of Landsat imagery. Other technologies are utilized in the development of the final product, although this work could not be accomplished without Landsat’s free availability of red, green, blue and infrared bands. Potentially, SPOT imagery could be used as an alternative. However, the cost of using SPOT for a nation-wide inventory would be prohibitively high for the company. “With a full-retail price of $3,666 per scene and the need for an estimated 6,000 scenes to cover the U.S., the total cost without annual updates could amount to$22 million,” says Max Nova, founder and Lead Engineer at SilviaTerra. Even with potential bulk discounts, the cost of alternative imagery would create roadblocks for this start-up. Additionally, SPOT has higher spectral resolution, which Nova notes would impose more processing and analysis time. Thus, Landsat imagery, due to its spectral resolution and free and open data policy, remains the most preferred option for this start-up.

Flood mapping in 2002 in the Barmah-Millewa forests, north-central Victoria and south-central New South Wales, Australia. Courtesy of the Victoria Department of Environment and Primary Industries.

Flood Extent Monitoring in Riparian Forests, Australia

Landsat imagery is also used by the Department of Environment and Primary Industries in Victoria, Australia, to map flood extent in some of the major riparian forests along the Murray River (New South Wales and Victorian border). The results of flood mapping are used as an input to hydrological models in some instances, and in other cases as an independent source used for the calibration of model outcomes. Hydrological models are actively used as management tools. The cost of satellite images has a direct bearing on how often flood mapping is carried out to support forest management. In the absence of Landsat data, alternative sources (for example, SPOT-5) cost about $3,853 ($4,000 in Australian dollars) for the Barmah-Millewa forests (fig. 1), and the same amount for the Gunbower and Koondrook-Perricoota forests within the Murray Valley riparian systems. The current frequency of monitoring and flood mapping would not be possible without Landsat imagery availability (Kathryn Sheffield and Mohammad Abuzar, Department of Environment and Primary Industries , written commun., 2013).