PLENTERUNG, AN AGE-OLD PARADIGM FOR SUSTAINABILITY

[Copyright R.W. Becking. Released with permission of the author to the users of BEN on Internet. For any questions, additional information or potential applications of Plenterung contact the author directly.*]

The earliest protocols regulating harvest of trees date from 1200-1300 A.D. in Central Europe. These regulations dictated tree harvest at specific locations in the communal forests, specified quantities or volumes to be removed and the harvest times under supervision of an elected official, the forester! The original harvest method was selective or individual tree harvest, named Plenterung. In medieval times, these communal forests played a vital role in local rural economies by supply- ing fuel wood that was used daily for cooking meals, heating homes, and for the manufacturing and processing of forest products and foods. The population explosion caused the emer- gence of commerce, the industrial revolution and urbanization around 1600. During 1600--1800, Central Europe was ravaged by religious and feudal wars resulting in concentrating political powers in large industrial cities, with a capitalistic economic control over the lands and their natural resources. Forest resources were rapidly depleted and logging activities encroached deep into the valleys and mountains. All the European forests would have disappeared, except the last remnant forests were saved by the discovery of new energy sources like coal, oil, gas, and electricity to fuel the industrial plants.

The remaining heavily degraded forest, the so-called "Mittelwald", was an open forest dominated by a few overstory trees and a dense coppice of repeatedly-cut and resprouting hardwoods to be used as a fuel wood. The conifers, lacking sprouting ability, mostly disappeared. The age-old conservative Plenterung system was effectively destroyed. In the 1870's, the new science of forestry was born in Germany and France, primarily to remedy these degraded forest wastelands for economic reasons. The initial techniques were to remove the entire Mittelwald and start replanting the cleared areas with conifers, notably Norway spruce (Picea abies), white fir (Abies alba), and Scots pine (Pinus silvestris). Thus, even-aged forest management was born, and with it silviculture, mensuration, forest economics, forest engineering and forest genetics. Im- provements were made in thinning and harvesting schedules, soil amendments, insect and pest controls, and trees were projected as unsawn planks with $ returns! In spite of vigorous political control efforts, Plenterung survived in isolated mountainous communities of the Alps.

During the 20th century with an unprecedented world population explosion, the long-term global effects of the capitalistic even-aged forest management system created international con- cerns and controls about global warming, preserving global biodiversity and gene pools, threatened or endangered species, clearcutting tropical and temperate rainforests, and loss of top-soil and soil fertility by erosion and monocultures.

Plenterung emerges today as an alternative method to even-aged forest management. Its science was perfected by Adolphe Gurnaud, Henri Biolley and others around 1875, but its acceptance and publication was severely limited. Plenterung is the only proven silvicultural system regarding the forest as an ecosystem in which all its components closely interact with the site, soil and climate. Plenterung is also the unique forest management system to maintain constantly a dynamic all-aged stand struc- ture, volume and area controls. Plenterung relies heavily upon local natural regeneration, intensive 100% inventories to monitor stand growth in all size (age) classes every 5-7 years, and harvesting trees only upon complete inventories to control all its stand variables. Individual trees are selected for harvest to improve spacing, growth, stand composition, diversity in age and species, and the maintenance of the top canopy in- fluence. Plenterung requires a permanent intensive road net, with major haul roads and skid roads adapted to directional tree felling, no landings, and no heavy equipment entry into the stands. All the stand treatments are carried out simultaneously every 5-7 years within the same permanent compartment. Before any stand treatment, 100% inventories monitor the effects of past treatments and adjust to maintain constancy of stand struc- ture, volume and growth. Only the volume that can be grown within the harvest intervals may be removed. Stand treatment consists of maintaining a constant stand structure curve cover- ing the entire range of 2-inch DBH-classes. Harvesting is done on those trees in excess of the desired stand structure over the entire DBH range. Stand growth is precisely calculated using repeated inventories including stand ingrowth and mortality. Using dual inventories, stand growth can account precisely for intermediate windstorm or insect losses on a tree-by-tree basis! Plenterung will automatically adjust to long-term cumulative impacts and stand changes with its built-in most intensive monitoring of stand performance and the significant stand parameters. One of the unique features of Plenterung is that time is no factor at all in the decision-making or stand invest- ment. Economically it has proven to be a very stable and secure investment with steady periodic returns while maintaining full sustainability! This implies the total abandonment of even-aged concepts including clearcutting.

Plenterung strives for maintaining natural processes on a com- partment basis and, by extrapolation over all the compartments, on a landscape basis. Another incalculable advantage is that niches and natural habitats within the managed compartment will be rotated among gaps and preserved within the same unit area. This preserves natural biodiversity and gene pools.

Applications of Plenterung within the US have been hampered because current stand conditions in a severely depleted forest would require a lengthy period of restoration and investment. Long time is needed to attain a suitable and profitable stand structure of a mature late seral forest to implement and manage for a dynamic and constant multi-storied and all-species/all- aged stand structure. The current controversies over policies implementing the preservation of the endangered/threatened species like the Spotted Owl, Marbled Murrelet and Coho Salmon, coupled with the re-enactments of the Clear Air and Clean Water Acts, may provide a strong impetus to apply and practice Plen- terung on a broad commercial scale, at least on public lands, within the Pacific Northwest and the Redwood Region of Califor- nia. Elsewhere, Plenterung has wide applications. The natural forest types of the Cascades, Sierra Nevada and Rocky Mountains are ideally suited for Plenterung application before they are clear-cut. The Eastside forests of ponderosa pines and their mixtures in the interior of the West are naturally structured for Plenterung applications. Similarly, the mixed oak and con- ifer forests of the eastern United States, including the Smoky Mountains, have been observed to have a well defined Plenter- structure in their original state. At the present, Plenterung remains unknown to many foresters or is misunderstood.

Republished from Listserv (BEN # 89 15-January-1995)