How to Use DecAID: A Tutorial
This is a brief overview of how to use the DecAID Advisor to help you get started.
Quick-start: Explore DecAID on your own. You only need to specify the habitat and structural condition (collectively called "vegetation condition"), and from there all information is available through simple links. If you get lost, use the "back" button or click on the wood DecAID logo at the top of any screen to return to the home page to begin again.
WHAT IS DecAID?DecAID is an advisory tool to help managers evaluate effects,of forest conditions and existing or proposed management activities on organisms that use snags, down wood, and other wood decay elements. DecAID also can help managers decide on snag and down wood sizes and levels needed to help meet wildlife management objectives. It can help managers articulate those objectives in specific, quantitative terms that could be tested in the field.
In this way, the name “DecAID” can be read as decayed wood advisor and management aid (“decay-aid” or "decision-aid"). The advisor also can help long-term planning, as over "decades" of time.
DecAID mostly is a statistical summary of published research data on wildlife and forest inventory data, and of professional knowledge on fungi, insects, and pathogens. It is not a "model" in the sense of mathematically extrapolating or simulating wildlife use of wood decay elements. We built DecAID on actual field data, summarized by using conventional statistical methods.
It is important to note that DecAID is not a stand dynamics simulator. It does not predict numbers of snags, down wood, and other wood decay elements, over time, in a forest stand. However, DecAID can be used to help identify snag dbh and density (numbers of snags per hectare or acre), and down wood diameter and percent cover, that pertain to wildlife usage … and then you can run stand growth and harvest simulators, such as the Forest Vegetation Simulator (FVS), of USDA Forest Service, to provide such snag and down wood numbers or to determine what numbers would be provided under management scenarios, and relate those outcomes to levels of wildlife use.
The DecAID Advisor mostly addresses snag and down wood size and amount, but other wood decay elements and characteristics can be important to some species; these are listed in the ancillary data in the DecAID Advisor. Also see the discussion in Rose et al. (2001).
For more information on what DecAID is, go here.
For the statistical basis to DecAID, go here.
For caveats and cautions in its use, go here.
For information on snag dynamics, go here.
HOW CURRENT IS DecAID?
Data:The data and publications used in DecAID are current as of January 2012.
Version:For a current version history of the programming, go here.
Vegetation types:Note that as of June 2012 only 6 of the 10 forested wildlife-habitat types listed in the Wildlife-Habitat Relationships Project (Johnson and O'Neil 2001), which we used as the basis for the DecAID vegetation types, are provided in DecAID.
Simple to use but information- rich:DecAID is simple to use but has a vast amount of underlying biological and inventory data. DecAID is designed to first give you summary information in a text narrative, and from there you can follow linked references to see increasingly detailed, underlying data, all the way down to the original literature citations of the wildlife information, statistical summaries by vegetation condition of the inventory data, and narrative descriptions of fungi and insect and pathogen species.
RUNNING A DecAID QUERYHere is a step-by-step tutorial on running DecAID. You can follow along here as you actually run a query in DecAID, or just explore on your own and use this section to clarify questions or to help discover new functions. We will offer Tips to describe selected buttons, links, or information on each page.
OK, let's get started.
To run DecAID from the home page (http://apps.fs.fed.us/r6_decaid/legacy/decaid/):
1. Click on the "Run DecAID" button.
- Tip: Note that the home page has a set of links on the left side of the page. These should be self-explanatory. Know, though, that some of these links take you to selected sections of, or the home page for, a parallel Web site called the DecAID Repository. The DecAID Repository is like a vault with valuable background information you view only so often. The main Repository Web pages have a green (blue on some screens) background to distinguish them from the main DecAID advisor. Feel free to explore the Repository at your leisure.
2. Next, select from the pull-down menus the Habitat and the Structural Condition for which you want information. If you are uncertain as to which wildlife habitat type to select, you can select a map of forest inventory plot locations from the pull-down menu and view plot locations to see if they occur in your geographic location of interest.
- Tip: You can read about the habitats and structural conditions in the links "Habitat Descriptions" and "Structural Condition Descriptions." Note that we have further split two of the habitats (Eastside Mixed Conifer Forest, and Westside Lowland Conifer-Hardwood Forest) into several geographic subdivisions, because the wildlife and inventory data suggested significant differences in these subdivisions.
Click on the "Query" button to run the query. This will display the first results page, the Narrative page, which begins “Table of Contents.”
- Tip: Note that the buttons in the button bar on the top of each page may change depending on where you are. Some buttons are context-specific. Other buttons go to general information such as Data Caveats, Scientific Names, Back to Query Page, Glossary, and Literature Cited. "If in doubt, try it out!"
- Tip: If data are not available on species or habitats of interest, we suggest that the user might explore another similar vegetation condition (wildlife habitats and structural conditions) and their species data. We leave it up to the user to determine which these would be. Also, we offer in the Narrative page (see below) a way to list all data summarized in DecAID for all species that occur in a given vegetation condition (according to the species lists in the Species-Habitat Project database). In this way, the user can view a broad set of information even if specific wildlife data are not available for a given vegetation condition.
3. The Narrative page. This is the highest-level summary and synthesis of all the DecAID data and information for the habitat and structural condition (collectively "vegetation condition") you specified.
Yes, it is a lot of information here, but don't get daunted -- it is well organized into introduction, methods, results, and summary sections. Each of these sections is described next.
- Tip: If you need the bottom line fast, just page down to the first section "Synthesis and Recommendations." Other information in the narrative, and all the links from the Narrative to other screens, build upon this.
- Tip: On the top of the Narrative page, on the top row of the button bar are yellow buttons that provide information on wildlife and inventory data on snags and down wood, as well as insect and disease ("I&D") species and inventory data. You can also get to much of this information through links in the text narrative on this page.
a. Table of Contents -- for the entire page. Click on any entry to quickly skip to that section.
b. Synthesis and Management Implications – all the sections summarized into numbers and guideposts on wildlife use of snags and down wood, inventory summaries of snag and down wood levels, and other information. We encourage you to consider this synthesis but we also invite you to "drill down" deeper into the text narrative and the underlying data and draw your own conclusions and recommendations from the base information. We don't want this to be a black box; we want you to be able to see and evaluate for yourself as much of the information and data underlying our synthesis and management implications as possible.
c. Introduction to Vegetation Condition, Introduction to Available Data - text describing the habitat type and structural condition you selected for the query, and background methods and the extent of available wildlife and inventory data.
d. Integrated Summary of the Wildlife Data and Inventory Data From Unharvested Plots – summarizes the data on wildlife use of snags and down wood at three tolerance levels (more on this below), and discusses how to interpret the inventory data on snags and down wood from unharvested plots in terms of “natural conditions.” Links go to figures and tables showing the data underlying the summaries.
e. Ancillary Information on Wildlife Species Use of Decayed Wood Elements -- presents summaries of any available information from the literature on wildlife use of tree height, tree species, tree morality condition, hollow live trees and snags, snag decay, tree top condition, down wood length, down wood species, hollow down wood, down wood decay, and other factors.
f. General Wildlife-Habitat Relations with Wood Decay Elements -- information was taken from general wildlife-habitat relationships databases and not necessarily from field studies per se. This is provided because the actual field studies, used above, often do not provide field data on all possible wildlife species found associated with wood decay elements in a given vegetation condition. We wanted some way to provide you with fuller lists of wildlife species that might be found for the vegetation condition you queried.
g. Landscape-level Distribution of Decayed Wood Elements – comparisons of currrent and "natural" (unharvested) conditions from the forest inventory data. This information may be useful for describing current (including harvested) conditions and "reference" or “natural” (including unharvested) conditions. Links here drill down into more details of the inventory data, discussed further below.
h. Relationships of Fungi to Decayed Wood Elements – a summary of what is known about fungi and decayed wood. A link in this section takes you to a more detailed narrative on this topic but one that generally pertains to all forest habitats, as habitat-specific data on fungi and wood decay relations were lacking.
i. Considerations for Stand Dynamics -- a discussion of stand change dynamics and effects of insects, pathogens, and fire on stand structure. Links provide further, detailed information on insect and pathogen species. Also is a summary of the role of fire in this vegetation condition.
j. Ecological Functions and Processes of Decayed Wood Elements – links to lists of wildlife species associated with decayed wood elements and associated key ecological functions, and a summary of ecosystem processes related to wood decay with a link to a longer narrative. The aim of this section is to broaden thinking and discussion about wood decay to recognize the important ways that it provides for wide variety of ecological roles of wildlife and for other dynamics of ecosystems.
Tip: Most pages have a "Print" button. This brings up a separate browser screen with the same information and the printer menu. Note in this version of DecAID the new web software does not allow for formating the pages for printing. When printing tables and figures it would be best to copy them from the web site and paste them in a document to print copies of the tables and figures.
Next, let's explore the graphs and tables on wildlife, forest inventory, and insects and diseases, that underlie the Narrative.
4. From the Narrative page, now it gets fun. There are lots of ways to explore information about wildlife use of snags, down wood, and other wood decay elements, and about forest inventory data, insects and pathogens, fungi, ecological roles of wildlife associated with wood decay elements, and other topics. Yes, each combination of Habitat and Structural Condition you specified for the query has its own Narrative Page and links therein.
- Tip: The "Back to Narratives" button takes you back to the top of the Narrative page. If you want to return to the narrative in the same location where you left it, then hit the browser's Back button.
Let's look first at the underlying wildlife data on use of snags and down wood. At the top of the Narrative page within the button bar are 4 yellow buttons that provide this:
- - "Snag DBH" (wildlife use of snag diameter),
- "Down Wood Diameter" (wildlife use of down wood by diameter),
- "Snag Density" (wildlife use of numbers of snags per unit area, e.g., snags/acre), and
- "Down Wood % Cover" (wildlife use of down wood by percent of the forest floor covered by down wood).
- Tip: Open two or more browser windows to view different information simultaneously, such as the Summary Narrative, graphs, and species codes.
Note that, whereas the inventory data and the summary narrative are specific to a subregion for Westside Lowland Conifer-Hardwood Forest and Eastside Mixed Conifer Wildlife Habitat Types, the wildlife data are not specific to subregion. Thus, the "cumulative species curve" graphs may include data from all subregions within the wildlife habitat type. Also, for some graphs the data for Small/Medium Trees and Larger Trees structural condition classes are identical if data were collected in both structural condition classes; these figures and the underlying data tables are labeled with "S/L".
The wildlife line graphs are "cumulative species curves." Here is how to interpret these graphs.
The cumulative wildlife species curves display the synthesized data from wildlife studies for individual species, or groups of species if the data were presented that way by the researchers. The x axis is the size or amount of the particular decayed wood element (snag dbh, down wood diameter, snag density, or down wood percent cover). The y axis is the number of species for which there are data, and the data points are arranged from lowest x axis value to highest x axis value as number of species on the y axis increases. Each point is the value from one or more studies for the 30%, 50% (mean) and 80% tolerance levels, linked together in curves.
If there were data from more than one study for a given species, we weighted the values by sample size before plotting them on the graph. If a variability estimate for the data was not available, or the sample size was less than 5, then we displayed only the means (50% tolerance levels) for that species. When this happened, there are more data points on the 50% curve than the 30% and 80% curves.
In the example snag density graph below, the 50% tolerance level, or the mean, curve contains 5 species, whereas the 30% tolerance level and 80% tolerance level curves each contain only 4 species. This is because, in this example, data on Brown Creeper (BRCR) were reported only as a mean value and no variation (such as standard deviation) value was presented from which we could calculate 30% and 80% tolerance levels.
- Tip: Each point on the cumulative wildlife species curves is labeled with the species code. You can click on the yellow "Species Codes" button on the button bar at the top of the page to get a list of species names and their codes.
In the wildlife species snag density graphs, the lower curve pertains to 30% of the population, the middle curve 50%, and the top curve 80%. For example, in the snag density graph above (for illustration only), the points labeled DOSQ refers to Douglas' squirrel. On the 30% tolerance level curve, the DOSQ point is interpreted as follows: 30% of DOSQ (at least in the population studied) use areas which contain densities of snags up to 10 snags/ha; 50% of DOSQ use areas which contain densities of snags up to 25 snags/ha; 80% of DOSQ use areas which contain densities of snags up to 48 snags/ha. Conversely, the higher the snag density, the greater the percentage of a given species' population would provided for; only 30% of the DOSQ population would be provided for in areas with less than 10 snags/ha, but 80% of the population would be provided for in areas with 48 snags/ha. In this way, the three curves can be interpreted as different proportions of populations. Occasionally, the 80% tolerance level may exceed the maximum observation because the 80% level is statistically extrapolated from data on the small, sampled portion of the population to the entire population. See What is a Tolerance Level? for more details.
To see the actual data underlying the cumulative species curves in these graphs, click on the "Underlying Wildlife or Inventory Data" buttons above the graph. To properly interpret the graphs, read the interpretation of the data in the Narratives; any limitations of the data are discussed there. In general, however, the graphs can be interpreted as follows. For a given curve (tolerance level), the range of the wildlife-use data among species is from the bottom point on the curve to the top point on the curve. Note that the low point of the curve provides dead wood habitat for just one species. Manage areas with the complete range of dead wood values to provide for all species on the curve.
- Tip: A generalized assumption underlying the cumulative wildlife species curves, and our synthesis and management implications of the wildlife data, is that "bigger or more is just as good" -- that is, if some wildlife species, for example, is shown by research to use snags up to, say, 30 cm dbh, then we assumed it would also use larger diameter snags as well. The same holds for down wood diameter, snag density, and down wood percent cover. There are major exceptions so it is best to manage for the range of values displayed in the curves.
The inventory “box and whisker” graphs -- shown as blue horizontal bars along the bottom of the screens for Snag Density or Down Wood % Cover -- display vegetation inventory data statistics for 30%, 50%, and 80% tolerance levels and for Minimum and Maximum measured values. The inventory "box and whisker" graphs appear below the cumulative species curves on these pages. Notice that the “box and whisker” graphs are aligned with the x axis of the cumulative species curves so that they can give a visual comparison of the two data sets.
Here's how to read these inventory "box and whisker" graphs (and see the labeled figures below):
- · The colored boxes depict the tolerance interval of 30 to 80%, with the calculated values displayed in boxes below each end of the colored box.
· The vertical line through the box depicts the 50% tolerance level, with the calculated value above the line.
· The horizontal line depicts the range of the data (minimum to maximum), with the measured values displayed at the appropriate end of the range line.
Often there are two sets of inventory “box and whisker” graphs displayed under each cumulative species curve. The upper set of graphs displays the statistics for just those plots that actually contained a measurable piece of dead wood (snags or down wood). These are the graphs that are most appropriate to compare with the cumulative wildlife species curves, assuming that dead wood dependent species will only occur on plots with some dead wood.
Because of the uneven, often clumped, distribution of wood decay elements some inventory plots contain no measurable pieces of dead wood. When these inventory plots with no dead wood constitute a large portion of the inventory data in a particular vegetation condition, the 30% and 50% tolerance levels are zero. Although these inventory plots are important for determining the general distribution of dead wood (that is, the proportion of all inventory plot-size areas with no measurable dead wood), areas with no dead wood are unlikely to be used by wildlife species dependent on wood decay elements.
Below are several general examples of “box and whisker” graphs and how to interpret them.
The standard inventory "box and whisker" graph depicts the inventory statistics scaled horizontally the same as the cumulative wildlife species curves (which appear above these graphs on the same page), and with the minimum value less than the 30% tolerance level and the maximum value larger than the 80% tolerance level, as follows:
If the maximum value exceeds the maximum value on the x axis of the cumulative species curves, the solid line is shown as an arrow, as follows:
If the 80% tolerance level exceeds the maximum value on the x axis of the cumulative species curves, the tolerance interval box also has a pointed end, as follows:
If the maximum measured value is less than the calculated 80% tolerance level, or the minimum value is larger than the 30% tolerance level, then the range line is inside the tolerance level box, as follows:
- Tip: Remember to visually compare these inventory "box and whisker" graphs to the cumulative wildlife species curves appearing on the same page. They are scaled the same horizontally so you can quickly determine how the inventory values match wildlife use patterns.
6. Inventory distribution histograms appear by clicking on the yellow "Inventory Distribution" buttons in the button bar at the top of the Snag Density or the Down Wood % Cover pages.
The inventory distribution histograms display the percent of the plot-sized areas of a given vegetation condition that have various amounts of dead wood (density of snags or percent cover of down wood). The x axis is the density of snags or percent cover of down wood and the y axis is the corresponding percent of the area. Actual percentage values are shown at the top of each vertical bar.
In the example histogram below, the x axis displays snag density classes for snags > 50 cm (19.7 in) dbh. In this example, 4% of the area within the vegetation condition contained no measurable snags > 50 cm dbh. The second bar from the left indicates that 9% of the area within this vegetation condition contains snags up to 5 snags/ha (2 snags/acre). And so on.
7. From the pages showing the cumulative wildlife species curves and inventory data, you can follow links to view the underlying data that went into these curves. Click on the buttons "Underlying Wildlife Data" or "Underlying Inventory Data."
Several more levels of wildlife data are available from the underlying data. One can go all the way to the original piece of data and its reference citation. In this way, the user can see the origin of each data item to determine the appropriateness of considering it for local use. On the button bar at the top of most screens is a yellow button “Literature Cited,” which provides a complete bibliography of all the literature cited and used in DecAID.
8. Several lists of species are available in DecAID. Don't confuse them; they represent different things:
- From the Narrative pages, the yellow button "Scientific Names" on the top button bar gives a list of common and scientific names of species that are mentioned within the narrative for all vegetation conditions.
- From the pages on Snag DBH, Down Wood Diameter, Snag Density, and Down Wood % Cover, the button "Species Codes" on the top button bar gives a list of the 4-letter species code along with common and scientific names of species, for wildlife species shown in the cumulative wildlife species curves. As with all of the wildlife data presented in DecAID, the user may need to decide if specific wildlife species actually occur in their area of interest, and include or exclude those points accordingly.
- Also from the pages on Snag DBH, Down Wood Diameter, Snag Density, and Down Wood % Cover, the button "All Wildlife Species" on the top button bar gives a list of all wildlife species associated with each wood decay element in the selected vegetation condition. This list is taken dynamically from the Wildlife-Habitat Relationships database of O'Neil et al. 2001. Usually these lists are longer than the lists of wildlife species included on the cumulative species curves, because research has not been done on each and every species. These lists provide a way for the user to known which additional species might occur in a particular vegetation condition even if field research on snag and down wood use has not been done on the species. These lists did not influence the cumulative wildlife species curves, which were based on the published studies, not the wildlife-habitat relationships database.
SOME FINAL MISCELLANEOUS INFORMATIONThe DecAID Advisor Web site was constructed to strictly adhere to the regulations for accessibility listed in Section 508 of the American With Disabilities Act. This helps ensure that sight-impaired individuals can access all information on the Web site including text, tables, figures, and all other data. Constructing pages to meet these directives means that the Web pages are very simple in structure, format, and design. We have received suggestions for more complicated ways to access and display the information, but many of these designs would violate Section 508.
D.H. and T. A. O'Neil, ed. 2001. Wildlife-habitat
relationships in Oregon and Washington. Oregon State University Press, Corvallis
OR. 736 pp.
O'Neil, T. A., D. H. Johnson, C. Barrett, M. Trevithick, K. A., Bettinger, C. Kiilsgaard, M. Vander Heyden, E. L. Greda, D. Stinson, B.G. Marcot, P. J. Doran, S. Tank, and L. Wunder. 2001. Matrixes for wildlife-habitat relationships in Oregon and Washington. CD-ROM. in: D. H. Johnson and T. A. O'Neil, ed. Wildlife-habitat relationships in Oregon and Washington. Oregon State University Press, Corvallis OR.
Rose, C. L., B. G. Marcot, T. K. Mellen, J. L. Ohmann, K. L. Waddell, D.L. Lindley, and B. Schreiber. 2001. Decaying wood in Pacific Northwest forests: concepts and tools for habitat management. Pp. 580-623 in: D.H. Johnson and T. A. O'Neil, ed. Wildlife-habitat relationships in Oregon and Washington. Oregon State University Press, Corvallis OR. Rose et al. 2001
Spies, T.A., J.F. Franklin, and T.B. Thomas. 1988. Coarse woody debris in Douglas-fir forests of western Oregon and Washington. Ecology 69:1689-1702.
Bruce G. Marcot
10 December 2002
Updated January 2009
Updated December 2013