Timberland Management
INVENTORY TECHNIQUES
A fundamental component of forest management is the determination of timber volume and growth potential for individual timber stands on a property. By definition, a stand is a group of trees growing under similar conditions with homogenous production potential and characteristics. Prior to any acquisition, TIR conducts thorough inventories of each stand on the property. After acquisition, the initial inventory is updated every three years. The timber inventory contains vital information at the stand level, such as site productivity, number of trees per acre, and timber product by category (i.e., pulpwood, chip-n-saw, and sawtimber). Active forest management techniques such as fertilization and control of competing vegetation can have a significant effect on timber growth and the future value of the forest. These timber stands grow rapidly in volume and value, and regular inventories provide foresters with better information for making management decisions to improve investment performance. Combining the timber stand management history with the current timber inventory allows us to project future timber growth and prescribe the best forest management plan for the individual timber stand and the entire forest.
TIR uses a variety of sampling designs for achieving a cost-effective and statistically accurate inventory of each forest stand. Traditionally, simple random sampling has been used for timber inventories. However, lower cost for the same statistical precision of simple random sampling can be achieved by employing double point sampling whereby basal area is quickly and inexpensively measured on all plots, and volume estimates are obtained on a smaller sub-sample. In addition, TIR employs the use of Global Positioning System (GPS) units to aid in the unbiased and accurate location of plot centers, as well as decrease the time needed to navigate from plot to plot, and permanently mark plot location for improved inventory audits.