SawlogCalc is an Android® tool to estimate the weight and lumber yield of a sawlog, using the diameter of the small end of the log, and it's length. The Pro version can also keep lists of logs with running totals, and export the lists via email. Average weights for more than 100 North American tree species are included. You can enter your own species and weights in a custom list. Log rules include Doyle, Scribner Decimal C (formula), Scribner Decimal C (table) and International ¼ inch.
So, your tree is on the ground, bucked to length. How do you use SawlogCalc? Measure the diameter inside the bark, tap the D: button, and tap in the diameter (let's say 25 inches). Hit the =. button to finish the diameter. Enter the length by tapping the L: button and the length (8 feet), again finishing with =. Now tap the species button. If the species of tree you would like isn't shown, select FULL LIST. Scroll through the species list to find the correct one, tap it (check mark it) if you want it to appear in the short list from now on, and then long-press it. For our example, long-press "Ash, white". The Sawlog screen will now show white ash. At the top of the screen, the weight estimate shows 1700 pounds and the lumber yield is 221 board feet (Doyle log rule).
If you are keeping a tally, tap the T+ button to add the log to the active tally. (SawlogCalc calls a list of logs a 'tally', to avoid confusion with species lists, lists of lists, etc. The T+ is the Tally Add button.) The button text will change from 'new' to '1' to show one log in the list. If your next log is the same length and species, you only need to enter the diameter and tap T+ to add it to the tally. On a tablet, the Tally List is already showing and you can watch the running totals increase with every log added. On a one-pane device, press the list button (bottom right of screen) or use the menu to switch to the Tally List screen.
This is the starting screen, where it all begins. Pressing the 'home' icon or the 'calc' icon will bring this screen up (if it isn't already showing). The species, log rule, length and small diameter of a sawlog are entered here, to calculate an estimated weight and the number of board feet for the sawlog. A price per board foot can be entered here, or left blank. A note can be entered here, or left blank. The T+ button (Tally Add) will add the currently displayed sawlog to the active sawlog tally.
To change the length, diameter, log rule or species, tap the button where the current value is displayed, then enter the new value. For example, tap the length. It will turn orange (to show that numbers entered will go there) and the weight, yield (bd ft) and larger diameter will go blank because they depend on the length. Tap 8 (sp) 1 = to enter a length of 8 feet 1 inch. The L: button now displays 8’ 1” and the weight, yield and large diameter are updated.
To enter a fraction, tap the space button (sp) after the whole part. For example, nine and a half feet is entered as 9 (sp) 1 / 2 ft =
Since sawlogs are often cut to the same length but the diameter is always changing, entering a measurement without tapping anything first will change the small diameter.
Measurements can be entered in a variety of formats:
Note: 8 (sp) 1 can only be feet/inches, so the feet button and the inches button aren’t needed. Also, if no units are entered at all, a diameter will be taken as inches and a length (up through 24) will be taken as feet.
Pressing: ft (feet button) or in (inches button) when nothing is being changed will display the last measurement entered in feet or inches. This can be handy to convert between feet and inches. Try it twice for inches or three times for feet to see all the possibilities.
Tapping the species will bring up the short list. Initially this will be empty, except for the CUSTOM LIST and FULL LIST lines (which will always be at the bottom of the list). Tap this to see (amazingly enough) the custom list or full list of species. Tapping any species in a list will mark it checked, which adds it to the short list. Touching a species and holding (long press) will select that species as the current species without affecting whether it appears in the short list, and will return to the sawlog screen. As an example, tap Ash, White. It will now be checked, and will appear in the short list the next time the short list comes up. Long press Aspen, Bigtooth: the sawlog screen will be displayed with bigtooth aspen as the current species. Bigtooth aspen will not appear in the short list (it wasn't checked).
The T+ button
shows the number of logs currently in the active tally. Pressing
the button adds the currently showing log to the active tally. In
the tally, each log has a “serial number”. This comes from the # button, and can be
changed if desired. It will go up by one every time the T+ button is pressed.
For example, press #
1 0 0 = . The “serial number”
will change to 100. Press T+,
the log showing will be put in the active tally with a serial
number of 100, and the number in the # button will advance to
101. The next press of T+
will put a log in the active tally with a serial number of 101.
You can set the serial number to a any number you like. Any time a
new tally is created, all lists of logs will be scanned and the
serial number will be set to highest serial number found plus one,
to make sure there are no duplications.
A long press on the T+ button will change to the Tally screen, showing the active tally
The large diameter of the sawlog is estimated to increase by 15% for every eight feet of log length. This value (shown in the calced button on the Sawlog screen) is calculated whenever a new length or small diameter is entered. If a different large diameter will give a better estimate of weight, press the calced button and enter the new large diameter. The button will change to show D2: and the new value.
The weight given by the log weight calculator is a rough estimate. Like any estimate, it is wrong, possibly by a lot.The density of green wood can vary wildly from one tree to the next within the same species, or even within the same tree. The density values in the Master Species List are average for North America. Rot, disease, growing conditions, bark thickness, height of the wood above ground in the tree, time of year, geography and a host of other factors all change the density of the wood. For this reason, the result is rounded to make it clear that this is not an exact value:
The four flavors of board yield are Doyle, Scribner Decimal C
(formula), Scribner Decimal C (table), and International ¼ inch.
The Scribner formula will not always match the original Scribner
table: a log that is 16 feet long and 6 inches diameter small end
will come up as 10 board feet using the Scribner Decimal C formula
but will be 20 board feet from the Scribner Decimal C table. The
Scribner table will handle logs from 3 feet to 20 feet in length
and 3 inches to 40 inches in diameter. Anything outside this range
will show ERROR for board feet.
This screen shows a list of all the tallies. Pressing the 'list' icon in the action bar will bring this screen up if it isn't already showing. Each tally shows a tally name, the date the tally was created, number of logs, total yield (bd ft), total estimated weight and the sum of log costs if any log has a price set. Tapping a tally brings up a list of choices that apply only to that tally:
At the bottom of the screen is a row for buttons:
new tally will create a new tally, make it the active
tally (so that the T+ button on the Sawlog page adds logs to
it) and display the new tally in the One Tally screen if it is
showing. When the tally is created, the creation date is
stored with it. (Note that older tallies from the previous
version of SawlogCalc will show ??/??/???? for the date.)
If it is showing, undelete will recover a tally that was previously deleted. The button appears when a tally is deleted, and will show for one hour of app run time. Confusing as this sounds, it just means that no matter how many times you exit and restart SawlogCalc, the undelete button will show up on the tally list until the app has run for at least an hour. Example: delete a tally, button appears. After 15 minutes, quit app. Come back to it a week or two later, run it for another 30 minutes. Quit again. Some time later, start the app again. Use it for 15 minutes. The undelete button still shows, but if you quit the app, it will be gone the next time you start it up again, because the app has run for 15 + 30 + 15 minutes, one hour.
The details of one tally are shown here, with the totals for the tally shown in the header at the top, with a list of all the individual logs in the tally below. Tapping the header brings up the same choices as in the Tally List screen. Tapping an individual log brings up the following choices:
Reached by tapping a log from the One Tally screen and selecting Edit log, this screen can be used to change the values for a sawlog that has already been entered. If any changes are made, a Save button appears. When the Save button is pressed, the sawlog in the tally is changed. If Cancel is pressed, changes are thrown away; the sawlog in the list is untouched.
The tree species on the Sawlog screen is used to estimate the
green weight of the sawlog, and is useful if tallies are used for
record keeping. It would be clumsy to have to scroll through more
than a hundred species every time you wanted to change, so tapping
the species button will bring up a short list. You can add the
species you use most to the short list, and still get to the full
list or custom list to choose a less commonly found species with a
The full list is fixed and can't be changed. Each species density
is an average of North American values for the green weight,
pulled from several sources. The different sources usually agree,
but a few species (Black Walnut is an example) have significantly
different values from place to place. The highest density was
chosen when sources didn't agree, to err on the side of caution.
The custom list is yours. It will start out with Osage Orange in
it as an example. Delete it, change it, add to it, you can edit
this list to contain whatever species and densities you want.
When SawlogCalc first comes up, the species button will show
"Alder, Red" just because that is the first species in the full
list. A tap on the button will bring up the short list, which
shows "CUSTOM LIST" and "FULL LIST". To set up the short list, tap
"FULL LIST". You will get a long scrollable list of species. Tap
any that you want to appear in the short list, which will mark the
check box beside the name. You can also long-press a name, which
will bring you back to the calculator page with that species
selected. From the short list you can also tap "CUSTOM LIST" and
do the same set up or long press, though the list will only have
Osage Orange in it until you change it.
At the bottom of the Custom Species List is a button, Edit custom list.
Pressing this will bring up the list of custom species in a screen
where every name and density can be changed. Tap a name or density
to change it. Density is in pounds per cubic foot, and needs to be
entered as two digits. Note: there is no validity checking on the
value entered for density. If you wish to enter 0 1, it will be
accepted. Since one pound per cubic foot is roughly the density of
styrofoam, the weight of a log calculated using this custom
species is not likely to be a useful estimate. But it's up to you.
There will also be a blank line at the bottom of the list, with
the light gray text "new name" showing. You enter new species in a
blank line like this. The "new name" shows up any time the name of
the species is blank. The button add new to end at the
bottom of the list will add one new blank line per press. Don't
worry about extras: blank lines are trimmed off the end of the
list when you leave it. To set up the Custom Species List, press add new to end, tap the
new blank name, type in a name, tap 'next' or the density, and
type in the density. Repeat for all the custom species you want,
tap 'back' to see your new Custom List, tap to check mark those
that you want to appear in the short list. Custom species appear
at the top of the short list, above any species check marked in
the full list.
Preferences can be reached by tapping the 'settings' icon in the action bar (gear shape).
CSV example: to move the data to Excel,
- copy the CSV text from the email
- select a single cell in the Excel spreadsheet
- paste (which should put the text into one column)
- select the column if it isn't already
- in the Data Menu choose Text to Columns to bring up a wizard
- when the wizard asks for delimiters, select comma
- when the wizard asks for data format, use General
- when the wizard finishes, the Tally should be neatly spread out in the columns of the spreadsheet with headings above the columns
SawlogCalc comes in Personal (free) and Pro (paid) versions. There is no advertising in either version. Both share the same screens and almost the same functionality. The Personal version is limited: it will not export a tally, or keep Custom Species, and all tally information evaporates (and is lost) when you leave the application, rotate the device, are interrupted by a phone call, etc. If you only need to deal with one log at a time, or temporarily add up a tally of logs, the Personal version will work well. If you need to retain tallies or export them, the Pro version is required.