User Tools

Site Tools



This shows you the differences between two versions of the page.

Link to this comparison view

Next revision
Previous revision
field_methods:cover_board_method [2008/12/30 12:58]
kcolson created
field_methods:cover_board_method [2012/03/08 15:40]
Line 1: Line 1:
 +<​sup>​[[:​bug_reporting|Report a bug, broken link, or incorrect content]]</​sup>​[[http://​|{{ field_methods:​methodsguide3.png?​220x120|}}]]
 ====== Cover Board Method ====== ====== Cover Board Method ======
 +written by Jason Karl and Karen Colson
 ===== Description and Uses ===== ===== Description and Uses =====
-The Grazed Class Method ​uses photo guides of key species ​to make utilization estimates. These estimates reflect herbage removed but also show biomass remaining.  ​Using this technique ​the observer compares the sample plant(s) with the photo guides for that species and classifies the species according to one of six grazed-classes (0, 10, 30, 50, 70, or 90 percent use).  ​The utilization estimates are based on growth form of the plant.  ​Because variations ​in height ​are automatically adjusted for by the eye, variations in height growth due to site characteristics and seasonal precipitation are disregarded.+The Cover Board Method ​is used to evaluate vertical cover and vegetation structure over time.  ​It requires a profile board or density board to estimate ​the vertical area of a board covered by vegetation from a specified distance away.  ​Many different types of boards have been developed.  ​While they vary in dimensions they are generally narrow boards with bands of alternating colors that define vertical bands
-This method is best adapted for use on perennial grass, perennial grass-forb ​and grass-shrub rangelands where the key species are either bunch or rhizomatous/​sod-forming grass or grass-like species. It is designed ​for use after the plants have achieved full seasonal growth. +This method is applicable to a wide variety of vegetation types and is particularly useful when used with those vegetation types that show potential ​for changessuch as woody riparian vegetation.
- +
-Errors can be encountered because of variations in plant growth between sites and ecoregionstherefore photo guides should be compared with growth curves of local plants. New guides need to be prepared if the existing photo guides do not correspond to the growth curves. ​ In addition, it may be necessary to develop several guides for each key species in order to capture year-to-year or site-to-site variations in growth form+
 ===== Advantages and Limitations ===== ===== Advantages and Limitations =====
-This method ​is rapid and easy to learn and use with proper training The guides serve as standards of comparison that promote consistency in estimates. ​ This method also tends to reduce errors caused by variability in height growth, one of the major sources of error in height-weight methods. ​  +The Cover Board technique ​is a fast and easily duplicated procedure. The size of the board can be modified ​to meet the purpose ​of the study.
- +
-Another advantage is that, while the estimate of utilization is based on forage removed, each grazed-class shows both the degree of use and the amount of herbage remaining. ​  +
- +
-A disadvantage however is that in poor growth years when plants do not mature, the guides will not +
-distinguish between use and no-growth. +
- +
-It can also be difficult ​to develop photo guides if they are not available and it is hard to take good photos ​of “average” plants. ​ However, a guide that is properly developed for a given species and a typical site, can usually be appled to all sites over a fairly broad area in good and bad production years without serious error.  +
- +
-Minimal training of observers is needed to use this method. It is important that observers are able to identify the plant species. Error and bias will decrease dramatically with the more on-the-ground experience the observer has.  The biggest difference between experienced and inexperienced observers is that inexperienced observers tend to underestimate ​the use on more heavily grazed plants.+
 ===== Manuals ===== ===== Manuals =====
Line 29: Line 20:
 ===== Technical and Application References ===== ===== Technical and Application References =====
-  *SchmutzErvin M1971Estimation ​of range use with grazed-class photo guidesCoop. Extension Service and Agr. Exp. Sta., Univ. of Ariz., Tucson, AZ, Bull. A-73. 16 p.+  *NuddsThomas D1977Quantifying the vegetative structure ​of wildlife coverWildlife Society Bulletin 5:113-117
-  *Schmutz, E.M., G.A. Holt, and C.C. Michaels. 1963. Grazed class method of estimating forage utilization. Journal of Range Management. 16:54-60. 
-**The following are sources of existing photo guides:** 
-  *University of Arizona, Cooperative Extension Service and Agricultural 
-Experiment Station, Tucson Arizona 85721. Bulletin A-73. 
-  *University of Idaho, College of Forestry, Wildlife and Range Science, 
-Moscow, Idaho 83843. Station bulletin 54. 
-  *Montana State University. Forage Use - A Tool for Planning Range 
-Management. Extension Service. July 1988. 
-  *Kinney and Clary. 1994. A Photographic Utilization Guide for Key Riparian 
-Graminoids. USFS GTR-308. ​ 
 ===== Similar Approaches ===== ===== Similar Approaches =====
 +[[:​field_methods:​vegetation_structure_-_cover_pole_method]],​ [[:​field_methods:​visual_obstruction_method]],​ Line-point intercept with height
 ===== Additional Information ===== ===== Additional Information =====
 +===== Web Search Results =====
 +<script src="​http://​​jsapi"></​script>​
 +    <script language="​Javascript"​ type="​text/​javascript">//<​![CDATA[
 +      google.load('​search',​ '​1.0'​);​
 +      ​
 +      function OnLoad() {
 +        var searchString = '"​cover board vegetation structure"';​
 +        // create a tabbed mode search control
 +        var searchControl = new;​
 +        options = new;​
 +        options.setExpandMode(;​
 +        options.setRoot(document.getElementById("​web_results"​));​
 +        searchControl.addSearcher(new,​ options);
 +        var drawOptions = new;​
 +        options2 = new;​
 +        options2.setExpandMode(;​
 +        searchControl.addSearcher(new,​ options2);
 +        searchControl.draw(document.getElementById("​book_results"​),​ drawOptions);​
 +        // execute searches
 +        searchControl.execute(searchString);​
 +      }
 +      google.setOnLoadCallback(OnLoad,​ true);
 +    //]]>
 +    </​script>​
 +    <table border="​0">​
 +       <​tr><​td width="​50%">​ <div class="​search-control"​ id="​book_results">​Loading...</​div>​
 +           </​td>​
 +           <​td width="​50%">​ <div class="​search-control"​ id="​web_results">​Loading...</​div>​
 +           </​td>​
 +       </​tr>​
 +    </​table>​
 +===== Discussion/​Comments =====
 +<​sub>​**You must have an account and be logged in to post or reply to the discussion topics below. [[http://​​doku.php/​Home?​do=login&​sectok=db3676cff5bcd873b609b4e582432d73|Click here]] to login or register for the site.**</​sub>​
field_methods/cover_board_method.txt · Last modified: 2012/03/08 15:40 by jgillan