Title: Ring profiler: a new method for estimating tree-ring density for improved estimates of carbon storage
Author: Vahey, David W.; Scott, C. Tim; Zhu, J.Y.; Skog, Kenneth E.
Source: In: Morin, Randall S.; Liknes, Greg C., comps. Moving from status to trends: Forest Inventory and Analysis (FIA) symposium 2012; 2012 December 4-6; Baltimore, MD. Gen. Tech. Rep. NRS-P-105. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. [CD-ROM]: 386-390.
Description: Methods for estimating present and future carbon storage in trees and forests rely on measurements or estimates of tree volume or volume growth multiplied by specific gravity. Wood density can vary by tree ring and height in a tree. If data on density by tree ring could be obtained and linked to tree size and stand characteristics, it would be possible to more accurately predict changes in density and weight of tree biomass with projected changes in tree size and stand characteristics. Ring Profiler is a patented method for characterizing the structure of softwood tracheids and their changes from one tree ring to another over time. Measurements can be converted to density and can be multiplied by volume to estimate total weight and weight of carbon by ring. A sample displaying pith-to-bark ring structure is prepared from a radial core and scanned beneath a microscope as images are taken. Despite the sample’s thickness (up to 6mm) it is possible to image it with light transmitted from below using a single light-emitting diode (LED) for illumination. Near-infrared radiation (NIR) from the LED is captured by tracheid walls and travels efficiently to the viewing surface, much as light travels through an optical fiber. NIR captured by lumens tends to be absorbed by particulate matter introduced during sample preparation. The result is a high-contrast image in which tracheid walls are bright, lumens are dark and the interface is sharp. Images containing approximately 400 tracheids each are processed by ImageJ, public software available from the National Institutes of Health (NIH). Measurements include the distribution of radial and tangential diameters and wall thicknesses, from which local density can be estimated and applied to improved estimates of carbon storage. Over time, measurements from Ring Profiler can increase our understanding of tree response to stress.
Keywords: statistics, estimation, sampling, modeling, remote sensing, forest health, data integrity, environmental monitoring, cover estimation, international forest monitoring
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Vahey, David W.; Scott, C. Tim; Zhu, J.Y.; Skog, Kenneth E. 2012. Ring profiler: A new method for estimating tree-ring density for improved estimates of carbon storage. In: Morin, Randall S.; Liknes, Greg C., comps. Moving from status to trends: Forest Inventory and Analysis (FIA) symposium 2012; 2012 December 4-6; Baltimore, MD. Gen. Tech. Rep. NRS-P-105. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. [CD-ROM]: 386-390.
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