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In the past, foresters have relied almost exclusively on natural reproduction for regenerating lodgepole pine. The combination of low value and low volumes per acre of the species made artificial regeneration an unattractive alternative. Furthermore, availability of suitable planting stock has been, and still is, limited because of problems associated with seed procurement and nursery production of lodgepole pine. Artificial regeneration of this species may become more common with changing economic conditions and progress in nursery technology. However, natural regeneration will probably remain the principal mode of stand establishment for lodgepole pine for the time being.

The presence of lodgepole pine on severe sites and the often thick carpets of seedlings along roadsides and in clearings under powerlines has led many foresters to believe that natural regeneration of lodgepole pine can be obtained easily everywhere. Old burns and recent clearcuts which failed to regenerate demonstrate the fallacy of this notion. Comparing the suitability of different silvicultural systems for natural regeneration of lodgepole pine in Oregon is difficult because commercial harvesting of the species commenced only in the 1950's. Consequently, information concerning the advantages and disadvantages of different cutting methods for regeneration of lodgepole pine is very limited.

Clearcutting

In contrast to ponderosa pine, clearcutting is probably the silvicultural system best suited in general for regeneration of lodgepole pine in Oregon. Lodgepole pine produces good seed crops almost every year in northeastern and central Oregon, although size of crops in the same year may vary with location. Lodgepole pine produced 5 crops of 200,000 or more sound seeds per acre in a stand in the Winema National Forest, and 6 crops of 200,000 or more sound seeds per acre in the Pringle Falls Experimental Forest during the 11-year period from 1959 through 1969, inclusive. Seed crops at both locations were near failures in only two years, 1961 and 1966. Crops in the remaining years ranged from about 50,000 to 180,000 sound seeds per acre.

Most lodgepole pines in Oregon are nonserotinous. That means that cones usually discharge most of the their seeds in fall and all of them within a year of cone ripening. Awareness of this general lack of cone serotiny is important in planning for harvest and slash disposal where natural regeneration of lodgepole pine is desired. Slash does not contribute more than the current year's production of seed which is lost if timber harvest precedes seed ripening. Lodgepole seeds usually begin to fall in early October so that harvest of timber at this or later time has no effect on seed supply. This situation is quite different from that of lodgepole pine in the Rocky Mountains where production of several years is commonly held in closed, that is, serotinous cones and where unburned slash usually contains a good supply of seed.

Clearcuts must be kept small because seed dispersal of lodgepole pine is limited to short distances. In general, seed dispersal decreased rapidly as distance from timber edge increases and becomes very low, less than 2 percent of the total, beyond 2 or 3 chains from stand boundaries. For this reason, a maximum width of 400 feet has been recommended for clearcut strips, patches, or blocks. On severe sites, harvest cuts should be narrow strips less than 2 tree heights wide.

Some of the failures with natural regeneration following clearcutting in lodgepole pine were probably a result of too large harvest areas. Leaving seed trees on large cutover areas may aid in obtaining adequate regeneration. For northeastern Oregon, a spacing of seed trees at 2- to 3-chain intervals has been suggested. Trees with long crowns and d.b.h. of 6 to 12 inches are considered best for this purpose because of their windfirmness. Trees infected with mistletoe are unsuitable as seed trees.

In central Oregon, however, failures are perhaps less a consequence of an inadequate seed supply than of an unusually severe microclimate on exposed pumice soils of that region. Leaving a light cover of slash on the ground improves the chances for obtaining natural regeneration.

With natural regeneration of lodgepole pine, it is often either feast or famine. Where conditions are favorable for establishment of natural regeneration, overstocking is common. When this occurs, young stands will soon stagnate unless they are thinned out. Circular cuts containing seed trees may lessen this problem, at least in northeastern Oregon. This technique will probably minimize the need for thinning because overstocking is less likely away from edges of the cut.

Partial Cutting Practices
Experience with shelterwood and selection cuttings in stands of lodgepole pine is generally lacking in Oregon. Particularly with overmature stands, clearcutting should be favored for the following reasons:

1) Trees in dense lodgepole stands are seldom windfirm.
2) Residual trees are of poor vigor and growth is minimal or nil.
3) Partial cutting may encourage the spread of dwarf mistletoe.
4) Disposal of large quantities of unmerchantable material may be difficult with a partial cut regime.

However, presence of advance regeneration in lodgepole pine stands is common, particularly in northeast Oregon. It may be an indication that either shelterwood or group selection cuttings are feasible in this type. Lodgepole pine seedlings grow slower under shelter than in the open but will respond quickly to release and may be undamaged by logging if less than three feet tall. Slash disposal will aid natural lodgepole regeneration in northeastern Oregon, but in contrast, a light slash cover is essential to successful regeneration in central Oregon. Mixed Pine-Fir

The mixed pine-fir forests are the ecologically most diverse forests in the ponderosa pine region of Oregon. Species composition of these forests is extremely variable depending upon site and history of natural and manmade disturbances. The principal species composing this forest type are ponderosa pine, lodgepole pine, Douglas-fir, grand fir, and western larch. Fire has played perhaps the most important role in shaping structure and composition of these forests. Present forests are either even-aged or have even-aged overstories with younger understories. Fire and blowdown have favored the pines and larch by arresting succession to Douglas-fir at lower elevations and toward true fir at higher elevations.

Silvicultural treatment of stands in this forest type will have to be highly flexible because of their varied structure and composition. Success with natural regeneration may reasonably be expected in stands with a well-established understory if the overstory can be removed without excessive damage to the remaining trees. Small clearcuts, the seed-tree method, or shelterwood method, each of these in combination with site preparation should permit natural reproduction of the light-demanding pines and larch. If the intent is favoring establishment of Douglas-fir or true fir, density of the residual stand has to be adjusted accordingly.

Although presence of mistletoe usually limits available options, the limitations are often less severe in the mixed pine-fir than in other timber types. Because of the composition of the mixed pine-fir forests, natural regeneration can still be attempted by employing a cuttting method which will be favoring the disease-free species. However, if all the species in the stand are infected, natural regeneration would be a poor choice.

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