How Do You Rate This Publication?       

Title:	Using crown condition variables as indicators of forest health
Author(s):	Zarnoch, Stanley J.; Bechtold, William A.; Stolte, K.W.
Date:	2004
Source:	Can. J. For. Res. 34: 1057-1070
Description:	Indicators of forest health used in previous studies have focused on crown variables analyzed individually at the tree level by summarizing over all species. This approach has the virtue of simplicity but does not account for the three-dimensional attributes of a tree crown, the multivariate nature of the crown variables, or variability among species. To alleviate these difficulties, we define composite crown indicators based on geometric principles to better quantify the entire tree crown. These include crown volume, crown surface area, and crown production efficiency. These indicators were then standardized to a mean of 0 and variance of 1 to enable direct comparison among species. Residualized indicators, which can also be standardized, were defined as the deviation from a regression model that adjusted for tree and plot conditions. Distributional properties were examined for the three composite crown indicators and their standardized-residualized counterparts for 6167 trees from 250 permanent plots distributed across Virginia, Georgia, and Alabama. Comparisons between the composite crown indicators and their associated standardized residual indicators revealed that only two or three plots were jointly classified as poor by both when thresholds were set at the lower 5 percentiles of statistical distributions. In contrast, 19-21 other plots were classified differently, emphasizing that different aspects of crown condition are being summarized when the raw values are adjusted and standardized. Generally, crown volume and crown surface area behaved similarly, while crown production efficiency was substantially different.
	View and Print this Publication (569 KB)
Pristine Version:	An uncaptured or "pristine" version of this publication is available. It has not been subjected to OCR (Optical Character Recognition) and therefore does not have any errors in the text. However it is a larger file size and some people may experience long download times. The "pristine" version of this publication is available here: View and Print the PRISTINE copy of this Publication (2.2 MB)
Publication Notes:	We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information. This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain. Our on-line publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS Webmaster, srswebmaster@fs.fed.us if you notice any errors which make this publication unuseable.
	Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility