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Remote Sensing for Diagnosing Nutritional Status of Forest Plantations

This image shows the leaf area index in loblolly pine plantations in Florida that were calculated using Landsat Imagery.

Over the years, on-site computations of Leaf Area Index (LAI) have been demonstrated to be the best indicators of the nutritional status of pine forest plantations and of whether they will require fertilization to achieve maximum productivity and value. Researchers at the Center for Advanced Forest Studies (CAFS) have developed techniques that use LANDSAT imagery to remotely estimate the leaf area index.

Prior to the development of this LANDSAT methodology, the only reliable way to determine leaf area index was to send field crews to visit plantations and make on-site field measurements. This was and remains very time-consuming and costly to do. That plus an obvious limitation of on-site LAI measurements has been that it can only examine small samples of the forestry stands of interest. 

Satellite imagery provides a total, 100% examination of entire plantation/forest stands. One CAFS member company now collects satellite data on every one of its plantations (approximately 1.8 million acres). It calculates LAI on every plantation that is greater than 3 years old. They use it to more accurately determine the plantations that will require fertilization. This helps the firm reduce costly and wasteful fertilization of stands that will not respond to fertilization. 

Too often, below average plantation responders to fertilizer applications are in stands that had good Leaf Area Indexes (LAIs). Taking advantage of this satellite-based LANDSAT-enhanced breakthrough, LAI technology can enable users to minimize or eliminate unnecessary fertilizing. The breakthrough has demonstrated that by using satellite enhanced LAI, average response to plantation fertilization can be maximized. With the addition of satellite-based Leaf Area Index (LAI) technology, this CAFS member company has become more capable of identifying and treating nutrient deficient stands and of better tracking the impact of fertilization applications on stands.

Economic Impact:

This CAFS research will help develop higher, more productive forest plantations that yield wood for eventual use in building materials, paper and bioenergy. Annual LAI assessments yield data that allows this firm to delay additional fertilizations and still maximize response; thus saving substantial amounts of unwarranted expenditures. Stands with low satellite LAI measurements are the ones then targeted in order to maximize responses to fertilizer applications. Fertilization is an expensive treatment ($75-$100 per acre) so postponing fertilization on stands until they will be responsive works out well economically and maximizes the response when dollars are spent. It is estimated that this CAFS sponsor alone has realized over $1,000,000 in annual savings from reduced fertilization expenses. IF LAI becomes adopted nationwide, there is potential for an estimated $18,000,000 in annual savings throughout the large pine forest plantation industry.

For more information, contact Tom Fox at Virginia Tech’s Department of Forest Resources and Environmental Conservation,, Bio, 504.231.8862.

PDF icon CAFS-2016.pdf