Considering what forest inventory design to use for QC?
When considering a forest inventory, as foresters we often need to create a sample plot layout across of net stocked area. There is a range of options available to the user in selecting the type of sampling structure to be used for the plot layouts. Plots can be arranged in a systematic grid from a random start point, randomly located (with/without replacement), and distributed via a space-filling algorithm (“Quasi-random“). Most foresters will be familiar with a systematic sampling grid. It is the most commonly applied technique in selecting sample locations across a forest area and almost used exclusively for a couple of key reasons:
- Complete coverage of the entire stand is ensured.
- No risk plots will clump together into one area, often resulting in an unusually large sample error.
- And traditionally with compass and hip-chain navigation, they are less time-consuming and more cost-efficient to install as field crews simply walk in a straight line installing plots at a constant interval.
A more recent approach is the use of a quasi-random sampling grid, this uses a space-filling algorithm to allocate the plots across the stand. With the benefit of GPS, field crews no longer need to walk in straight lines, and actually it is far more efficient that they don’t so they can walk around obstacles and with the terrain in movement from plot to plot. Hence the evolution of the option for quasi-random sampling for forest inventory. Check out this article to learn more about these different options: Forest Inventory Sampling Designs for Plot/Sample Locations
How to Create QC Plots for a Planting Event
Before any plots can be generated you need to have a stand with planting event already logged or a new stand that needs to be planted.
NOTE: Data that is collected as part of an event (eg. Quality Assessment), should be entered in the assessment tab of that event, which in this case would be the Planting event.
Steps to do sample plots with a planting event:
- You need to open the Silviculture.mxd map or any mxd that has the Strata and Plot (QC) layers loaded
- Select the stand that needs to be planted
- in GeoMaster go to – Events – Planting
- Fill in the relevant information about the planting event under the Description Tab. Make sure you enter the correct dates. (Planned Date or Actual Date)
- Click on the Assessment Tab and fill out the following information:
- Click on Attributes and select SPH [sph] and type in the SPH
- Save the event (at the top of the window click on the red tick)
- Click on prepare assessment plots. This will open a new window in your Arcmap project where you will generate the plots.
- Save your plots and create your map or export the plot points as a GPX file.
Video Tutorial for Creating QC Plots in GeoMaster
Video Tutorial for Deleting QC Plots From GeoMaster