TREES, GRASS, AND WATER

Joseph F. Pechanec

IN WESTERN OREGON and Washington the question is grass or trees. It is not a problem of coordinating all the uses but of using the type of cover that conduces to soil stability and sustained, timely stream flow.

Here there can be little dual use of the forests because of their nature. Except in the ponderosa pine and sugar pine forests of southern Oregon, the forest cover is dense and the tree canopy almost closed. Shrubs like Oregon-grape, salal, blueberry, vine maple, and salmonberry, with little or no palatability to stock, far outnumber the palatable species in the understory. Grazing values of the forest areas, consequently, are negligible.

Even after logging or accidental fire, native vegetation on these forest lands provides only a temporary forage resource. Succession of vegetation on cut-over and burned-over lands follows a fairly uniform trend. A spectacular growth of annuals and short-lived perennials immediately after logging is almost entirely replaced by a perennial cover in 5 to 12 years. Much of the perennial cover is shrubby, and if the area is not reburned, a coniferous forest gradually will suppress and replace the brush if there is a seed source.

With this trend in the succession, the period is short during which cut-over or burned Douglas-fir lands are graze-able. Only during the first 3 to 7 years is much feed available. Then it can be expected to dwindle because of the encroachment by bracken, shrubs, and tree growth until in 11 to 15 years little grazing use is possible.

Light grazing that removes competing vegetation might be beneficial, but in the past it has been found all but impossible to obtain uniform light grazing use. From the standpoint of forestation, grazing during this early period on newly logged lands may be harmful to the tree seedlings, especially where forests are planted with nursery stock. Severe cropping of the young tree seedlings has occurred in some localities.

Forage Values

Even though an estimated 300,000 acres of the west-side forest lands are logged-over yearly, the temporary forage value of the newly logged-over lands contributes little to the forage resource. Most of the area now being logged-over is on the mountain slopes in the more remote sections of the region. The forage is therefore inaccessible to livestock. Moreover, the temporary nature of the forage resource does not justify the establishment of new livestock enterprises, because most of the areas now being logged provide seasonable forage supplies usable only in spring and summer. There is now little shortage in grassland for use during this period, the critical shortages being in forage for fall, winter, and early spring use.

As a result of the low value of forest lands for grazing, less than one-fifth of the total land area in the northern Pacific coast region is grazed by livestock. Some forested land included in farms is being grazed. But by far the greater part of the grazeable area is formed by the valley and coastal grasslands, the croplands used for pasture, the hill pastures of the oak-madrone type, and the forest lands that have been converted to grassland. In the higher mountains lie subalpine grasslands, numerous small and grassy glades, and hillsides that furnish excellent summer range. To these must be added the grazeable lands of the ponderosa-sugar pine type where it merges with the Douglas-fir type in southern Oregon.

Any further increase of the livestock industry of this region can come about only in two ways through the improvement in productivity of present grasslands and additional conversion of suitable forest lands. The extent to which the total grassland production can be increased by the former procedure is limited because of the restricted area involved.

The likelihood of further attempts at conversion of forest land to grassland has aroused concern because in the past unwise attempts have laid waste to large acreages in this region. Forest lands were denuded with no thought to the future. Fire protection was inadequate and recurrent fire ran rampant over newly logged areas. Timber operators hastened to liquidate their holdings after logging, and promoted the conversion to grassland.

These speculative efforts recognized no limitations of climate, soil, topography, or economic feasibility. As a result, a militant competing vegetation composed of brush, ferns, moss, and trees marched in and lowered grazing capacities to the point where it was no longer profitable to graze livestock on any except the best soils. Failure was widespread, homesteads and farms were abandoned, and human energies wasted; society was the loser. Natural resources suffered seriously because soils were impoverished and erosion accelerated by the recurrent burning resorted to in an attempt to keep down the encroaching species. Stream courses were scoured out by the silt-laden streams. And finally, the competing ground cover of brush, ferns, or moss that had come in made efforts at rehabilitation either as grassland or forest an extremely costly and difficult task.

During this period both poor grassland and forestry practices have laid waste to large areas. But it is hardly fair to compare these uses on the basis of such history because both the science of grassland management and forest management have made great strides during the past two decades.

Forest conversion to grassland and the grazing of cut-over lands have influenced forest productivity in several ways. Large areas of highly productive forest land have been removed from production, grazing of cut-over lands has in some cases damaged the incoming tree reproduction, and, of major importance, the recurrent and uncontrolled fires used in clearing the land have run over land not intended for conversion and destroyed the tree reproduction and stands of timber.

Grassland in Tree Farming

About the relative effects of grassland and forest on soil stability relatively little knowledge is available. Ample evidence is apparent throughout western Oregon and Washington of the failure of mismanaged forests and mismanaged grasslands to protect the soil and the watershed. It is also clear that in this region of heavy precipitation, from 40 to 100 inches, the undisturbed forest cover provides excellent protection to the soil, retards runoff, lengthens the time required for waters to congregate in streams, and insures continuity of stream flow throughout the dry summer. But there is no evidence on the relative values of well-managed, utilized forests and grasslands on soil stability and water yield.

Because of the nature of the soils and topography in the northern Pacific coast region, grassland and tree farming can go on together on the same farm, and they should. The soils and topography more suitable to grassland can be used for that purpose with the steeper parts, the poorer soils, and the north slopes left to trees. The forests will furnish posts, fuel, and other products essential to farm management. Moreover, with the present high prices for forest products, the forest can furnish cash income supplemental to the income obtained from grassland, and nearby forest industries will afford part-time employment.

Possibilities for successful conversion of forest land to grassland are not widespread. But the conversion can be effected in some places. It requires considerable effort and, since it precludes the alternate use of the land for tree farming, it should be undertaken only after careful study has assured success.

It is to direct such efforts to the areas where success is likely that five guides are offered.

Conversion to grassland should be confined to areas near established farming enterprises or where some land suitable for production of supplemental feeds and crops is present. This is more important in the northern part of the region than in the southern. Studies reported in Washington Agricultural Experiment Station Bulletin 179, Grazing on Cut-over Lands of Western Washington, specify that a ton of hay for a cow or five sheep be provided for a winter feeding period of 3 months.

Soils should be favorable. Because of the highly variable quality of soils throughout western Oregon and Washington, it is important that conversion be considered only on the better soils. It is economically unsound to use costly intensive grassland practices on lands of low potential production. Soils vary widely in their ability to produce grass and in their ability to withstand erosion under a grass cover. Soil survey and land use maps need to be consulted before attempting conversion. Site classification for Douglas-fir production is not a reliable guide to possibilities for grassland production.

The character of competing vegetation should be carefully considered. The character of the vegetation which comes in after a burn varies widely from southern Oregon to northern Washington. Shrubby species that sprout rather readily, such as salal, Pacific poisonoak, and blueblossom ceanothus are formidable competitors. The importance of competing species as indicators of chances of success are emphasized by Washington Agricultural Experiment Station Bulletin 179, which points out that the vine maple areas generally offer much better chances for success than those characterized by western bracken fern.

Slopes should be slight to moderate, not more than 30 percent, and will vary with soil types. Steeper slopes should be left in tree cover to protect the soil surface and to prevent land masses from slipping when saturated by the 60- to 100-inch annual rainfall. South-, southwest-, and southeast-facing slopes generally offer better chances of success than north-facing slopes. The north-facing slopes are more favorable to forest cover and the encroachment by forest cover or undesirable brush species is more likely.

The best practices of grassland establishment and management should be used; the importance of their use cannot be overemphasized.

In converting forest to grassland, man is working against nature. A militant brush, fern, and moss growth is ever ready to take over the site. Hazards of loss of soil fertility and soil erosion are high under the characteristic high precipitation of the north Pacific coast region. Failure to establish grassland not only is personal loss but it also means loss in soil fertility, probable damage to watersheds, and the creation of a formidable barrier to bringing about either a forest or grassland cover.

Land classification is sorely needed to provide guidance to opportunities for successful conversion of forest to grassland. Facts upon which to classify lands are, however, lacking. Further research bearing on this subject is critically needed.