Synopsis of Inventory Procedures for Private Lands

Equipment

100 foot logger’s tape graduated in feet and tenths of feet with diameter in inches on the back side clinometer graduated in percent and topo hand , such as a Silva Ranger Type II , 16 inches or longer hand lens 20 & 40 BAF wedge prisms (optional) Log Scaling and Timber Cruising by John R. Dilworth

General Concepts

Before we make decisions on how to manage a forested property we need information about the forest. Generally it is too time consuming and costly to collect information on every tree and other forest component for an entire property so we usually sample a small portion of the property in a systematic manner. This procedure is known as an inventory. Information from an inventory is then expanded to give a picture of the whole property.

Types of Inventories

Inventories are conducted for various purposes and are known by names specific to those purposes. The following are some common types of inventories:  timber cruise - to determine the volume and value of merchantable trees on a property for timber sale purposes  - to assess the characteristics of the forest, including tree species, size and density of trees, growth rates and growing potential, forest health and resource problems for purposes of managing the forest  wildlife habitat inventory - to assess habitat characteristics for purposes of wildlife management  wildlife species inventory - to determine whether particular species are found in an area  survival exam - to assess the survival of seedlings following planting to determine post planting treatments  non-timber forest products inventory - to assess the presence, abundance, condition, accessibility, and marketability of forest products, other than logs, for purposes of management  archeological inventory - to determine whether there are historic or prehistoric sites or artifacts in an area  carbon cruise – to determine the amount of carbon stored in trees for sale as carbon credits 2

Inventory Intensities

The intensity of an inventory depends upon various factors, including the purposes of the inventory, the money and time available, the size of the property, and the characteristics of the forest, including variability and value. In fixed plot inventories intensities generally range from 2-10% and in variable plot inventories they include enough plots to result in an acceptable statistical accuracy [commonly ranging from ≤20% at a 68.3% confidence level to ≤20% at a 90% confidence level, which means that 68.3% (or 90%) of the time the information developed from the inventory is within 20% of an average].

Inventory Methods

There are four commonly used inventory methods, fixed plot inventories, variable plot inventories, a combination of the two, and walk through inventories. Fixed plot inventories are generally used for gathering information on seedling, sapling, and pole size trees. Variable plot inventories are used to gather information on sawtimber size trees. The combination method is used where these tree sizes are mixed within the forest. Walk through inventories are used for general assessment of the forest resource and for discovery of archeological sites or wildlife species. The general methods for conducting these inventories are as follow:

Fixed Plot Forest Inventory:  On an aerial photo delineate the boundaries of the forest stands. A stand is a distinct grouping of trees of similar species, size, and density. Transfer these boundaries to a .  Determine the area of each stand using a dot matrix, graph paper, or computer (GIS).  Determine the cruise intensity and multiply by the area of each stand to determine the area to be sampled. Divide this area by the size of plot (typically 1/100, 1/10, or 1/5 ac