8
of Chrome and Firefox (for Android phones and tablets), Safari (for iPhones and iPads),
and to a lesser extent, Internet Explorer 9 and 10 (for Windows phones and tablets). IE is
limited by its ability to cache data ofine—users must remain “connected” while collecting
eld data. For this reason, if you are using IE, you should be prepared to transfer your
data from your mobile device to the server frequently and recognize that a lost data
connection means all data since last submission will be lost.
For a running list of compatible devices, see the i-Tree forum at forum.itreetools.org or the
system requirements document at www.itreetools.org/resources/manuals.php.
In addition to the mobile webform, Eco v.5.0 continues to support the use of a PDA for
data collection, which works seamlessly with the desktop application. It is customizable
for your project needs, easy to use, and results in a database that is properly formatted
for Eco and can be uploaded with a single click. The PDA application works with a variety
of handheld devices, including PDAs, smart phones, Trimble dataloggers, etc. running
Windows Mobile 5.0–6.5 operating system.
If your community lacks funding to support the use of PDAs or mobile devices or you
simply prefer to use an alternate method, that’s no problem. Inventories can be conducted
using paper forms, proprietary inventory tools, spreadsheets, etc. An inventory form is
included to make inventorying simpler, and the desktop Eco application includes a user-
friendly input form to simplify the data entry process. You should review the section Phase
III: Out in the Field: Collecting Data to help with planning.
Creating a Sample
If you are conducting a sample inventory of a large-scale study area, the most important
step in planning is to create the random sample of the plots. There are several decisions
to be made before you begin. The following sections are provided to help you understand
elements of designing a sample such as stratication options, the number of plots needed
and a method of randomly distributing plots. As Eco projects can differ greatly, these are
only guidelines and may not always be applicable to your project. Users are advised to
consult with a statistician regarding their project sample design if they have very specic
needs or concerns.
Your sample design decisions should be based on your desired project goals (i.e., the
questions you are trying to answer), the available resources to manage and complete
the project, and the desired precision of the model estimates. For example, a stratied
sample design with many plots may allow for comparison between land use types or
neighborhoods and for greater precision of the model estimates. However, there will be
associated project considerations such as the additional resources that will be needed to
create maps, obtain permission to access properties, travel to plots, and collect eld data.
Conversely, a simple unstratied random sample will not allow for comparison of subunits
but may provide sufcient information to achieve the project objectives.