TIMBER RESOURCES

In order to manage woodlands for timber production, it is necessary to know

(1) What timber is growing on the land and where it is located? What is the condition of the timber? What species? How many acres of the various kinds of timber? How many board feet, cubic feet, or cords?

(2) What are the site capabilities? What practices should be applied to obtain maximum yields of high-quality timber, and what density of stocking in the various stands will provide this?

(3) How will harvesting proceed: What areas will be cut, in what years, and in what manner? What method of cuting will be used? What species will be favored?

The framework of management is therefore (1) information about the woods, (2) the kinds of treatment needed, and (3) planned harvesting. The remainder of the booklet will discuss these basic elements. It can be readily seen that (2) and (3) cannot be determined without (1), and that obtaining information about the woods is the first step in management.

Inventory and Examination

Data based upon field examination may be obtained for a forest of any size, from a small farm woodland up to extensive industrial or public holdings. Occasionally whole counties, or states, are inventoried. Inventories may be made by federal, state, or local agencies; or by private companies or individuals. The nationwide Forest Survey maintains a continuing inventory of the country's timber resources. This and similar large-scale inventories are carried out in the 4 states by the Central States Forest Experiment Station of the U.S. Forest Service. Cooperating and assisting in each state are the Division of Forestry of the state conservation department, and the state agricultural experiment station. In some

cases, the state extension service and state college of forestry participate also.

Management plans for small woodlands are based upon examination of the tracts, with service (farm) foresters and extension foresters usually playing an important part, providing technical advice and in-the-woods assistance.

Woodland owner examines his tract with an extension forester, who is tagging trees to be cut.

Aerial photographs are used extensively in examinations and inventories. Trained men are able to identify not only forest-cover types, but also broad age-classes and stand densities in the photographs. Certain stands of timber are selected on the photographs, these are found on the ground, and trees in sample plots within the selected stands are measured and tallied. Principles of sampling are applied. Trees in small plots usually 1/5 acre in size are measured, and the data obtained for the sample are then applied to the whole tract. The plots that are measured are either selected at random or mechanically spaced at given intervals in order to preserve the principle of the "chance sample."

A modern mechanical system of computing is coming into wider use in inventorying. It is called mark sensing. Instead of longhand entries on paper forms, followed by arithmetical computa

tion and summaries of field data, entries are marked directly on cards in the field when the individual trees are measured. The marks are made with a special pencil, the cards are run through business machines sensitized to record the marks, and totals are quickly available.

Forest Types

Land may be classified in a number of ways. One way might be on the basis of cover: forest, grassland, marsh, cropland, water, and urban development. In the same manner that urban development may be segregated into zones-industrial, commercial, residential, and suburban- forest land may be segregated and classified.

The purpose of classifying forest land is to separate out meaningful units for inventory, analysis, and control. For some purposes it is more meaningful, for example, to know whether people "are Brazilians or Japanese or Turks, and if they are Brazilians, whether they are men or women." It is likewise useful to know acreage and volume of the pine type in our central region where pine is valuable and relatively scarce. It is helpful to know how much of the lowland-hardwoods type we have in comparison with an upland type because different species are involved, with corresponding differences in rate of growth and value in the market. If we are to manage a woodland we must know how much old growth we have in relation to young growth, etc.

Segregating parts of the forest into species-groups is a common method of classification. Species-groups are known as forest types. The species dominating a stand in either volume or number of stems, depending upon the basis used, determines the name of the type-oak-hickory, for example, or oak-pine, elm-ash-cottonwood, or sugar maple-beech. Types are seldom if ever "pure" but contain species not represented in the type name. Within an area typed sugar maple-beech, the principal species, there might be found some oaks, elms, and ashes, a dozen or more species in all.

Each type is usually further segregated into one or more condition classes as to age, diameter, volume, or products to be obtained, or a combination of these. Within the type, stand-size classes such as scedlings and saplings, poletimber, small sawtimber, and large sawtimber might be differentiated; broad age groups immature, mature, and overmature; or age 0-40 years, 40-80, 80-120, 120

plus, etc. Or the basis of condition classes might be diameters breast high-stands predominantly 0-4 inches, 4-10 inches, 10 plus, etc. A complete designation for a type might be "oak-hickory, overmature;" or "sugar maple-beech, small sawtimber;" or "mixed hardwoods, 0-4 inches."

A forest plantation provides an example, simplified and exaggerated, of a forest type. A plantation is an artificial unit, an evenaged forest made up of trees of approximately the same diameter, height, and product class such as fence posts; ordinarily it would contain but one dominating species, too. An all-aged forest composed of many species usually contains more than one type.

Forest Area

The acreage, volume, and ownership data which follow are principally based upon the Forest Survey.

About 13 percent of the central region is forest land, of which nearly 99 percent is commercial forest land.' Ohio is 20.5 percent forested, Indiana 17.5 percent, Illinois 11 percent, and Iowa 7 percent. Iowa still retains 1/2 its original forest cover; about 1/4 remains in Illinois, 15 in Indiana, and 1/5 in Ohio.

Land bearing or capable of bearing usable crops of wood (usually sawtimber), economically available now or prospectively, and not withdrawn from commerical utilization.

In Ohio and Indiana about 50 percent of the commercial forest area is in sawtimber' stands, 46 percent in Illinois, and 36 percent in Iowa; the remainder is in the smaller sizes. A part of the commercial forest land is denuded and not stocked with trees - 14 percent in Iowa, 10 percent in Illinois, and around 1 percent in Indiana and Ohio. The preceding figures were drawn from the following table. All figures for Iowa in the tables are preliminary as the project in that state has not been completed.

The areas of sawtimber stands are at first glance encouraging; but these stands are composed predominantly of low-quality trees and the less-valuable species, an extremely important factor which naturally does not appear in acreage statistics. The data above therefore are largely indicative of production potential rather than present worth.

About 75 species of trees are common enough to be important in the central region out of several times that many found here, and of these about 20 species are produced in quantity sufficient to be a factor in the commercial market. Species are listed in the Appendix on pages 119-121.

Acreages of the major forest types in the 4 states are shown in the following table. To be classified in a certain type, at least 50 percent of the more dominant trees (those with larger crowns) in the stand had to be of the species named in the type, except in the case of oak-pine, where 25 percent pine in the stand was sufficient for classification as oak-pine.

1 Sawtimber tree: coniferous tree over 9.0 inches d.b.h. or hardwood tree over 11.0 inches d.b.h. Sawtimber stand: stand having minimum net volume of 1,500 board feet per acre in living merchantable trees.