Tree Farmer - May/June 2011 - (Page 30)

Forestry 101 : Conduct a Simple Timber Inventory Timber inventories are the main tool used to determine the volume and value of standing trees on a forested tract. A timber inventory, like any inventory, involves taking stock of how much material is available. While timber inventories have traditionally been performed to place a value on a stand before sale, they are also useful for providing information for the development of management strategies, estate planning, tax basis, or litigation. A timber inventory will establish two key pieces of information: 1) the number of trees per acre (tpa) on a forested tract, and 2) the volume per acre of wood that could be extracted from those trees. The two most common products of a timber harvest are saw timber and pulpwood. Saw timber is generally more valuable than pulpwood. The volumes of standing trees designated as saw timber are typically estimated in board feet (bf). The volumes of standing trees designated as pulpwood are often estimated in cubic feet (cu. ft.), cords, or tons. To estimate volume, a professional forester will normally use a diameter tape (d-tape) or Biltmore stick to measure diameter at breast height (DBH). Merchantable height is also measured and is the number of logs that a tree will be sawn into when harvested. Professional foresters will generally us a clinometer or Merritt hypsometer to measure merchantable heights. Merchantable heights are measured to a minimum top tree diameter. The minimum top diameter depends on whether the tree represents pulpwood or saw timber. Minimum top diameters can differ by market, so check with local mills for limits in your area. Once you have measured the DBH and height of a tree, you are ready to determine the tree’s volume. Saw timber volumes for each combination of height and diameter can be found in a volume table. There are a number of available volume tables each differing in how they estimate the volume that could be extracted from a standing tree. There are different types of inventory. This is too involving to discuss in detail here, but the types are: 1) 100 percent tally; 2) fixed radius plot sampling; and 3) variable radius plot sampling. The sampling methods have some error because the entire tract is not being measured. Before undertaking an inventory, you should be comfortable finding your way around the forest. Foresters rely on a hand-held compass for direction determination and on pacing for distance determination. The use of a compass and pacing are necessary for determining the location of plots. One way to help ensure a successful timber inventory is to plan properly before you start measuring trees. It is important that you understand how to measure tree DBH and merchantable height, as well as how to navigate in the forest using a compass and pacing before you begin an inventory. The boundaries of your forested tract should be clearly marked before undertaking any sampling to avoid accidentally sampling outside the tract of interest. In many cases boundaries are obvious, but in cases where there might be some confusion, flagging or paint can be applied to boundary trees. Often there will be considerable variation in the size, distribution, and species of trees across a forested tract. These By Mercker & david C. Jason g. henning variations can result from previous land use, soil conditions, slope, etc. To maximize the accuracy and utility of your inventory results, it is best to map your tract into stands that are similar in the size and species of trees present prior to collecting field data. For instance, a forest stand that originated following abandonment of row cropping would have different attributes than a stand that had been continuously forested. By mapping the forest into different stands — and collecting and summarizing data for each of those stands — you can gain valuable insight into which stands would be best to harvest and what treatments may be necessary to increase the value of other stands. This article is a very brief introduction to the terminology and methodology of timber inventory. Timber inventory can be a very complex and subjective process. Even trained professional foresters and experienced loggers often arrive at differing volumes and values when inventorying timber. Because most private forest landowners are not comfortable with inventorying their own timber, professional assistance is highly recommended. This is particularly the case when decisions related to timber value have lasting consequences. For more information, refer to our guide, Conducting a Simple Timber Inventory (Henning, Jason, and David Mercker. 2009; PB 1780), through the University of Tennessee Extension, . David C. Mercker is an Extension specialist and Jason G. Henning is an assistant professor with the Department of Forestry, Wildlife and Fisheries. Both are at the University of Tennessee based in Jackson. 30 International Year of Forests, 2011 Tree Farmer MAY/JUNE 2011 https://utextension.tennessee.edu/publications/Documents/PB1780.pdf https://utextension.tennessee.edu/publications/Documents/PB1780.pdf

Table of Contents for the Digital Edition of Tree Farmer - May/June 2011

Tree Farmer - May/June 2011
Contents
Cover Story
Select the Right Tree for Your Site
2011 North Central Regional Tree Farmers of the Year - Sponsored by Stihl, Inc.
Wildlife Matters
Taxing Issues
Woodland Security
Forestry 101: Conduct a Simple Timber Inventory

Tree Farmer - May/June 2011