Treesearch

A tube-type gage is economical, easy to make, and is a reliable indicator of frost depth. Gage reading were within ? 5 centimeters of indicated true frost depth 95 percent of the time.

Wood has been the principal product of trees from the first hunting club or digging tool of ancient man to the rich variety of industrial and decorative uses of modern civilization. The universal practical value and aesthetic appeal of wood may be traced to the seemingly infinite variation in its characteristics. These variations arise from the structure and arrangement of the individual cells, which vary not only among tree species but also within individual trees. The variability in these wood characteristics is what I shall refer to as wood quality.

A relatively few animal species are responsible for most of the reported damage to the birches. White-tailed deer, yellow-bellied sapsuckers, porcupines, moose, and hares are the major animals involved. We will review reports of damage, discuss the underlying causes, and describe possible methods of control. For example, heavy deer browsing that eliminates birch regeneration can be especially damaging, regardless of how well birch is managed. Here the immediate action may well be direct control of the deer population; but the basic long-term need is for action through a better understanding...

There are 605,000 acres of commercial forest land on the White Mountain National Forest (based on a 1960 timber inventory). Of this, 258,000 acres are classed as northern hardwood timber type. In general, this would include some 27 percent yellow birch, 16 percent sugar maple, and 31 percent beech in trees that are 6 inches and larger.

Paper birch occurs on New Hampshire's state forests in association with almost all other upland species. The quality wood is found as far south as the Sunapee Range and the Lake Winnipesaukee area. In this northern zone, there is a ready market that recognizes grade and makes paper birch management worthwhile. In the white pine area in the southeastern part of the State, paper birch wood is generally of poorer quality and is apt to bring but little better price than the cheaper hardwoods.

I have no revolutionary ideas to offer concerning the management of white and yellow birch. The most I can hope to accomplish is to acquaint you with Brown Company's current and past operating procedures in northern hardwoods, and to relate some of my observations of the results we are getting from harvesting substantial volumes of birch and other commercial species from nearly 800,000 acres of timberland in northern Maine, New Hampshire, and Vermont.

The management of any species for wood implies that there is a market, or confidence that there will be a market, for the wood. Certainly public programs to encourage forest owners to grow wood are based on the premise that markets exist and will continue to exist. Although the growing and cultivating of birches for wildlife and aesthetic quality also has direct costs, it has no clear market, no selling price. Thus the cost of managing forests for these uses must be borne by the public whenever the desired results incur costs over and above those that are a part of management for wood...

When paper birch and yellow birch are managed for aesthetic and recreation purposes, timber values become secondary, although in some instances compatibility exists among the several objectives. At times, timber and wood-products production is excluded entirely in the interests of aesthetics and recreation. In keying forest-management practices to the appearance characteristics of trees, it is appropriate to examine in some detail the tree qualities that relate to appearance.

The list of wildlife species known to prefer paper birch and yellow birch as food ls a long one. To mention a few: beavers and porcupines chew on the bark and wood; sapsuckers feed on the sap; other songbirds—notably the redpoll, pine siskin, and chikadee—relish the seeds; ruffed grouse eat the catkins, buds, and seeds (in northern Maine and Canada this bird is often called the "birch partridge"); and snowshoe hare, moose, and whitetail deer browse on the twigs. At least 24 different kinds of animals are known to feed on birches.

Yellow birch and paper birch are similar in that both are light-demanding throughout most of their life and require freedom from competition to produce high-value products. However, the two species differ markedly in other silvical characteristics. Yellow birch seldom constitutes a large proportion of the stand: it grows slowly and is long-lived. In contrast, paper birch sometimes makes up a high proportion of the stand: it has rapid early growth, and tends to be short-lived (Cooley 1962, Powells 1965). Both birches are responsive to intermediate cuttings and other cultural practices that...