Harvest Model Spatial Demo

This demonstration illustrates the spatial progression of harvesting activity within a simulated landscape unit that has first been roaded automatically. The harvest simulation attempts to achieve the specified targets while respecting various environmental, adjacency and accessibility constraints (see below for more information on simulation conditions).

The initial image shows the contours of the landscape unit in blue, and the center points and boundaries of the blocks in green.

When "Start" is pressed, the automatically-generated road tree is displayed as red lines in the order that the roads are created, starting at the access point for the region (lower center). The order of generation of the roads is indicated by their thickness, with those generated first being the thickest.

After a brief pause, the spatial progression of the harvesting for each time period is shown dynamically. For each time period, two stages are shown: before and after harvesting for that period.

Note: To run the demo you may first need to install a Java2 plug-in (Version 1.3.1_01 or higher) in your browser. A copy for Windows can be found here (the file size is 5MB).

The harvesting status of the cut blocks is denoted by color of the box representing the block. Reserve blocks (which cannot be cut) are indicated by hollow white boxes. Blocks that are available for harvesting are indicated by blue-green boxes. Blocks that have been cut but have not yet reached the minimum harvest age are shown as yellow boxes, while red boxes indicate those blocks that are adjacent to recently cut blocks which have not yet reached the green-up age. After the last time period of the simulation, those non-reserve blocks that have never been harvested are shown as solid white boxes. (Harvesting of these blocks has been prevented as a result of adjacency restrictions and/or environmental constraints.)

Note how the harvesting initially proceeds from the access point along the road tree, since roading costs are taken into account in determining the order in which blocks are considered for harvesting. Note also that, once the progression along the road tree is essentially complete, the regions harvested are then generally distributed throughout the overall landscape unit.

The conditions used in the simulation for the demo are:

• 50 time periods (years)
• 20x20 km simulated landscape unit
• 0-1000 m elevation range for simulated geomorphology
• 1,000 blocks, randomly distributed throughout the landscape unit
• 100 reserve blocks
• 100 deferred blocks, becoming available for harvest between years 10-50
• 20,000 stands (20 stands/block)
• 500 stands designated as wildlife tree reserves
• 100 environmental age-area constraints
• minimum harvest age: 40 years
• green-up age for prohibiting cutting of adjacent blocks: 10 years
• harvest targets: 30,000 cubic meters per year for years 1-10, declining linearly to 25,000 cubic meters per year at year 50, and remaining constant thereafter