Firth Management Process 2013

Old growth forests with limited influence by native Americans existed in this area from the time of warming, after the most recent glaciation, until the arrival of white settlers and the logging which they performed. The forest types that evolved after the initial logging era are very different from those that existed before. The forestry practices that have evolved recently emphasize the retention of the mid-successional species that we presently have rather than a natural succession to the old growth forest, comprised of mainly climax species, which existed before the arrival of the white colonist. This isn’t necessarily bad because certain environmental changes would probably prevent the reversion to old growth forest type. These changes include the loss of several species to alien pests, the ongoing fragmentation of forested areas, the uncertain habitat changes that are going to result from a warming climate and the consumer desires for certain kinds of wood that are going to drive the logging practices on most woodlots.

Our goal is to maintain a forested landscape that doesn’t necessarily replicate the old growth forest of a bygone era, but rather to help in the maintenance of a forest capable of sustaining its various parts and still providing a flow of forest products for human needs. If this can be accomplished, then the forest will continue to provide the unquantifiable benefits that the old growth forests provided for many millennia. These benefits include such things as clean air, clean water, habitat for plants and animals, and the positive aesthetic effects received from a forest of large trees within a healthy and well functioning landscape. The purpose of this planning process is to develop and implement a silvicultural system that provides these ecological necessities while still paying its own way economically. My belief is that this is going to require a management approach that more closely mimics a natural forest. The forest that existed in the eastern U.S. prior to the arrival of white settlers is considered “natural” but it was certainly influenced by native Americans. The important point is that their influence was limited and they didn’t attempt to impose their will on the forest at a landscape level.

All lands with in the certified pool of properties are to be managed within the general criteria of maximizing the long-term economic value of the timber resource without compromising the ecological integrity of the land. In order to attempt to achieve this lofty sounding goal we will draw upon the knowledge of scientific forestry that has been accumulated for the Appalachian hardwoods growing on the Allegheny Plateau. But we must also be aware that the accumulated information for this region only covers one rotation of trees. For this reason we must be keenly aware that our knowledge is very limited and that continual observation is probably going to reveal unique information relating to a particular set of circumstances. This ongoing observation will make change inherent within our future plans.

The prevailing view of sustainable forestry for the Appalachian region entails relatively short rotations (approximately 80 years) with one or two intermediate thinnings and medium sized clearcuts (10 to 100 acres). The system that we are going to try to implement includes longer rotations (100 to 150 years), many more intermediate thinnings and salvage cuts, and much smaller openings (1 to 5 acres). From an economic viewpoint I am confident that this system will perform much better because (1) the percentage of a rotation spent in the non-commercial poletimber stage is considerably less, (2) loss due to mortality is less because of increased emphasis on salvage cuts, (3) growth rates on preferred trees will be slightly greater, (4) and most importantly because a higher percentage of individual trees are allowed to reach their biological maturity. I am here completely discounting the “old foresters’” concept of economic maturity as simply being a rationalization for cutting trees within the lifetime of the “old forester.” Because of rapidly escalating prices that have exceeded interest rates, the true economic maturity of a tree arrives at some point in the future when that particular tree has reached its maximum value, this point roughly corresponds to the biological maturity of that particular tree.

Ecologically speaking this system will maintain a somewhat more open canopy which may more closely resemble the somewhat broken canopy of an old growth forest. A more open canopy will allow more light to reach the forest floor and should result in a more diverse understory. This condition can be seen to be happening in the glaciated areas of northwestern Pennsylvania. In the higher elevations of the Allegheny Plateau that were unglaciated and which have a longer history of overbrowsing by deer, much of the understory diversity has been lost and it will thus be much harder to reestablish diversity.

A common argument against the increased number of thinnings that are proposed here is that much more damage will be done to the residual stand and much more soil compaction will occur. It is true that with conventional logging practices the resulting damage often outweighs the benefits of more frequent thinnings. By placing a strong emphasis on well planned directional felling by the log cutters and by using horses to skid the logs the resulting damage to the residual stand can be nearly eliminated. The reduced damage to residual trees is very easy to observe. The lessened amount of soil compaction is much harder to prove conclusively, but my observation has been that skid roads used by horses are likely to revert to tree seedlings or to mixed understory vegetation, whereas skid roads used by rubber-tired machines are more likely to grow various grasses after abandonment. Some research has been done comparing soil compaction near mechanized skid roads and away from skid roads, and the results have shown reduced regeneration and reduced growth near the roadways. People tend to focus on the negative aesthetics of ruts that are caused by large machines but in reality much damage has already occurred before ruts develop. Soil compaction occurs in just a few skids with a rubber-tired machine. Horses on the other hand cause virtually no damage with just a few skids.

My argument in favor of more frequent thinnings is that the density of the canopy will remain more consistent and therefore allow more diversity to develop in the understory over a long period of time. Present cutting practices often allow a large amount of sunlight to reach the forest floor for a time until the canopy closes and then very little sunlight to reach the ground while the canopy is closed. Thus a profusion of vegetation develops for a short time and there is a lack of understory vegetation while the canopy is closed. Old growth forests tend to have a steadier rate of mortality and thus openings are created on a regular basis.

Another benefit of more frequent thinnings is the creation of a more consistent supply of coarse woody debris. This material is going to be provided mostly by tree tops and small cull trees rather than the larger tree trunks, therefore it can’t be expected to last as long before it completely decomposes. Most logging provides a profusion of tree tops for a short period of time and after they all decompose the forest often takes on a park-like appearance with very little debris on the ground. More frequent thinnings will provide a more consistent source of coarse woody debris and thus the complex ecological web that is dependent on this material should remain more stable. Treetops and numerous cull trees will be left on the ground to provide this coarse woody debris.
A major component of horse logging is the need for more mileage of trucking roads. These are necessary for shorter skids and in order to maintain downhill skids. Thus a major part of the planning process will be to establish truck roads where necessary and to establish main skid roads that will be used many times. These skid roads will use culvert pipes or wooden bridges that remain in place where they are needed across small drainages. These temporary wooden bridges can usually be left to rot.

In most stands, thinnings will occur approximately every ten years with the goal of maintaining a basal area of about 100-120 square feet per acre. Some cherry stands may be maintained at a higher level of stocking and some oak stands may be lower. Also some stands that have been abused in the past and left with low numbers of good quality trees will be managed on a crop tree selection basis and thus have lower stocking levels. When a particular stand has achieved a high percentage of desirable trees, thinnings will then be timed according to natural occurrences such as wind or insect damage, large seed crop years, the presence of advanced regeneration, or attainment of biological maturity. Small clearcuts will be used in areas that have very good advance regeneration and low numbers of good overstory trees or numerous biologically mature trees. Particular emphasis will be placed on having more than adequate regeneration throughout an opening rather than spotty regeneration that may statistically provide sufficient average regeneration, but which often results in an understocked stand.

Markings will emphasize the retention of the best quality trees and even spacing within the residual stand. The volume of timber removed will be less than the growth in most stands because maintaining a consistent basal area as a stand matures results in increased board footage per acre. Species preference will be site specific. The hardwoods which do the best on a particular site will be favored on that site. Hemlock and pine will be favored in wet areas and around spring seeps and watercourses.

More frequent thinnings will allow more sunlight to reach the forest floor which will provide better conditions for advanced tree regeneration. In cases of interfering trees and shrubs such as beech brush and water beech, emphasis will be placed on cutting these species especially in years when more desirable tree seedlings develop. Hopefully this will allow the tree seedlings to outgrow the brush species. By maintaining different ages of regeneration, the stand will be better able to respond to sudden changes caused by things such as defoliation or wind damage. When openings are naturally made the regeneration will be there to fill the gap. We can reasonably assume that this is what happened when the stands of old growth timber were cut throughout Pennsylvania. At the time there was no consideration given to regeneration, but the forests still recovered extremely well. Many people will say that the reason for this was the lack of deer during the logging boom of the late nineteenth and early twentieth centuries. Certainly the reduced deer herds helped tree regeneration during this period. However two other aspects of this era were also instrumental in the development of our present forest. The greater diversity in the understory and the much better health of that understory were certainly instrumental in the recovery of the forest. Also the fact that horses were used for skidding the logs was very important in regard to less soil disturbance and less soil compaction.

When stands have neared or reached biological maturity, particular attention will be given to amounts of and the quality of advance regeneration. Previous thinnings will have attempted to develop this regeneration in adequate amounts. If sufficient regeneration isn’t present then the understory removals and other strategies to allow more light on the forest floor will be used during years when a good seed crop is present. Ideal regeneration will be 6”-24” in height and in excess of 20,000 seedlings per acre. Advance regeneration of less than 6” in height should be in excess of 100,000 seedlings per acre. Regeneration cuts of 1 to 5 acres in size can then be used to begin a new stand.

When laying out the boundaries of these regeneration cuts particular attention needs to be paid to skid roads and trees around the edges of the remaining overstory stand. If possible, roads that are going to be used in subsequent thinnings of other areas will be routed around the openings. Also trees that are leaning into the opening should be cut at the same time that the opening is made. This is to prevent trees from being felled into the openings in later cuts and smashing the young trees.

The approach that has been outlined above is based on much of the same science as traditional even-aged silvicultural systems. I think the differences are sufficient that a different type of forest will evolve. I must emphasize that thinnings will definitely be based on a philosophy of cutting the worst trees first and cutting only limited numbers at any particular time. Thinnings will also attempt to keep our options flexible and open-ended. Shelterwood cuts or any aggressive thinnings limit future options, whereas we want to increase our options. We are trying to mimic natural mortality. Openings are going to be structured with the philosophy of “group selection openings” rather than the industrial “patch clearcut.”

Large clearcuts have a tendency to produce monocultures. They rely on one thinning to provide light to the forest floor and often receive a good seed crop from one species of tree. We are going to have numerous thinnings and develop a larger number of seed crops and hopefully a greater variety of species. Traditional even-aged management fits in well with industrial logging practices where larger quantities of high value logs can be harvested at one time. We are taking a much more labor intensive approach that is going to yield smaller but more frequent economic dividends.

Insect defoliation and tree disease problems will be dealt with by using this same sort of holistic approach to forest management. By maintaining a healthier forest, disease problems should be lessened. Historically, insects and diseases have been one of the primary shapers of our forest. Presently, the substantial economic value that we place on our forests requires that we pay particular attention to potential tree losses. Through close monitoring most economic losses can be avoided with prompt salvage cuts if mortality does occur. In the case of particularly severe defoliations, especially from alien pests, we will consider spraying with insecticides when and where it is appropriate.

Herbicide spraying will also be considered in situations where other options don’t work. Alien species such as multiflora rose are particularly hard to control by any means other than spraying. Herbicides may also be used on ferns at times but this can be avoided if we are successful in maintaining more diversity in the understory. In all cases, pesticide use will be done only as a last resort, after exploring alternatives such as biological control, mechanical removal, cultural controls and other parts of an Integrated Pest Management (IPM) system.

This management approach is intended to be one where we are attempting to be more reactive than proactive. Our goal is to maintain a healthy forest where trees can be periodically harvested. The trees that we do harvest are going to be trees that developed naturally and we intend to harvest them as a reaction to naturally occurring events such as biological maturity, overcrowding, or threat of mortality. Extremely proactive forest practices are exemplified by such practices as the clearcutting-planting-clearcutting cycles which I suspect are unsustainable. Less radical proactive practices such as strict adherence to even-aged rotations of a set period of time are also somewhat suspect. I think that we will probably have more chance of success reacting to nature’s lead rather than forcing our design on a forest.

Wildlife considerations will be centered on keeping a more consistent stand over a longer period of time rather than the drastic changes that occur in regular clearcutting cycles. More varied vertical structure can be maintained by keeping a wider variety of age classes within the stand. Den trees and potential den trees will be retained for their wildlife values. Snags will also be retained for their wildlife values except where they pose a danger for the logging crew. A target of two to four snags and den trees per acre is probably a reasonable goal but this is going to be dependent on what is available on any particular acre. Mast trees, particularly red oak, will be encouraged but red oak regeneration is oftentimes difficult to grow. Buffer zones for wildlife cover will be maintained around spring seeps and along streams and around wetland areas. In these wetter sites hemlock will be encouraged whereas hardwoods will be encouraged on the more productive upland sites. Buffer zones along streams and other protected areas are going to vary in width according to topography, site conditions and the inherent natural value of the area being protected. These buffer zones are going to include more hemlock and thus also provide good wildlife cover. They will also be utilized as travel corridors. Since the management system is going to emphasize longer rotations and much smaller clearcuts, the forested areas will also provide numerous travel corridors.

Since plants remain in one place throughout their lifetime, we can have a considerable influence on what happens to the plant community within the boundaries of a particular property. Wildlife moves about without regard for property boundaries and since all of our properties are small when viewed on a landscape level our influence upon wildlife populations is going to be much less than upon plants. For this reason, our actions would have to be coordinated with adjoining landowners in order to have much influence on larger animals. We are willing to do this, but since our objectives often vary greatly among different landowners implementation is often difficult. It is intended that our lands will remain open to hunting, hiking, etc. Conversely, more effort will be made to prevent usage by four-wheelers and any other motorized vehicles.

If a more diverse plant community can be developed, this will probably lead to a more diverse wildlife community. In the eastern U.S. trees are naturally going to be the dominant life form in a natural landscape. By taking care of the trees a very important step has been made toward taking care of the rest of the system.
Improved water quality is certainly one of the benefits of careful forest management. The biggest problem here is that truly high quality water is going to be dependent on what happens within the entire watershed. Since land ownerships are rarely going to cover entire drainages in Pennsylvania, we are going to be dependent on the actions of many others who influence what goes into streams. The small wooden bridges that were previously mentioned have proven quite successful in keeping mud out of streams and the maintenance of buffer zones along streams is going to be a major factor in keeping water temperatures lower. Areas that are wet enough that trees don’t grow in them will be treated similar to streams, in that a buffer zone of hemlocks will be retained around them. In wet areas that grow trees, logging will be greatly restricted. Hemlock will be favored in most of these areas and any logging that is done will be restricted to very dry conditions
Unusual situations such as highly erodible areas, rare or endangered species and special management zones will be approached on a more specific site by site basis. Steep and erodible areas will probably be logged with a small bulldozer (or skidsteer) and a winch using a minimum number of roads. The roads can then be water-barred to prevent erosion. Special management zones will be identified and either not logged or logged much less intensively than other areas. Areas where there may be rare, threatened, or endangered species can be identified through the PNDI (PA Natural Diversity Index). If such species are found these areas will be designated as special management zones.

Special management areas can be defined as highly unusual areas such as where old growth timber exists or highly sensitive areas such as where rare, threatened, or endangered species exist. The best way to manage these areas is simply to avoid them and to try to keep others from disturbing them.

The forestry system outlined here has tried to place a strong emphasis on growing high quality trees in a diverse environment. We know that high quality trees can readily grow in northwestern Pennsylvania because they were here in large numbers before the arrival of European colonists. Rather than planning for the growth of these trees, possibly we should simply avoid the hindrance of their growth. In the absences of high-grading and other destructive forest practices very high quality trees will grow here.

Harvestable volumes are thus not going to be determined by the rate of growth of a forest but rather by the rate at which trees can be removed without sacrificing the future viability of a forest.
This management planning process is intended to be as flexible as possible, with emphasis being placed on reacting to the developments that occur within a particular stand. Rather than relying on the cookbook formulas of even-aged forestry, we will attempt to allow the forest to develop naturally. This is neither an even-aged nor a true uneven-aged system, but rather a combination of the two that hopefully will result in a more mixed and diverse forest. From past observations this system has resulted in far higher amounts of advance regeneration within the stands than what I have seen in other cutting regimes. The amounts of regeneration present are going to be a major factor in determining when and where cuttings take place. One of the major objectives of this system is to allow just enough light on the forest floor to maintain significant amounts of advance regeneration.

The silvicultural system outlined here is for the purpose of sustainably harvesting wood products from the lands within the certified pool of properties. Those properties that we own are intended to remain open for other non-destructive human activities as well. The only other current economic use of any of our properties is for the production of natural gas and the production of maple syrup. Many properties have had existing gas leases when we purchased them, thus limiting our control over them. New leases will aim to limit gas well sites to old fields or other unproductive sites and prohibit them from wetlands and highly productive timber areas. Any new leases will also pay particular attention to access and the degree of control given to the leasor. Maple syrup will continue to be produced on some of the properties and I believe that this fits in very well with sustainable human use of the forested resource. Other human activities could be related to any unique cultural or historical sites that may exist on any of the properties. No such sites are presently known to exist on any of the properties. If they are found in the future they will be treated on a case by case evaluation depending on their importance.

Documentation pertaining to particular woodlots will be oriented toward stand histories and evaluations of what has happened in the past rather than trying to be specific in predicting the future.
This document has been written as a broad overview of how we intend to manage forested lands for the sustainable production of wood products. I have intentionally tried not to be too specific because I feel that would simply lead to inflexibility. Examples of bureaucratic inflexibility would be such things as limiting logging on hillsides with certain percentages of slope or not logging within a certain distance of a stream. Rather I would prefer to look at the whole picture, and if a slope has numerous spring seeps and unstable ground, then we should not log that slope. Whereas a slope of the same steepness may not have any seeps and does have stable productive soils, then possibly it can be logged. The same goes for streamside buffer zones. Should they be 50 feet wide or 100 feet or 200 feet? Many factors should be considered such as the type of plant communities, the slope of the ground, and the condition of the stream.

The quality of land management is determined by the soundness of the ecological principles used, by the mechanics or technological techniques used, and primarily by the overall land ethic that is employed. Hopefully the silvicultural system outlined here has some chance of success. That success, or lack of, is going to be determined on the ground rather than on paper. Given the increasing ecological pressures (air pollution, climate change, alien species, etc.) and human pressures (increasing population and a large sprawling population), the land ethic portion of any management plan is going to become increasingly important in the future. There is no bureaucratic or systematic fix for the problems of the future. In fact, such fixes may worsen the situation by providing a temporary “glossing over” of the underlying problem.

Three Guiding Principles of Forest Management

  1. Be reactive rather than proactive. Let conditions recommend management rather than trying to dictate conditions through management.
  2. Maximize options. To accommodate future variables management should create diversity and opportunity.
  3. Emphasize art, not just science. Our scientific understanding of forests is limited to the study of a single generation of trees. Therefore personal experience and intuition must play a large role in forestry.

Factors Determining Rate of Cutting

The annual rate of cutting is going to vary from property to property. The primary factors determining this rate are going to be a combination of the past history and the present stocking levels of a property, rather than a predetermined rate dependent upon the volume of timber that is presently growing on a particular property. Average growth rates have been determined for Appalachian hardwoods and these numbers have been used to determine annual allowable cuts. These average rates apply to a landscape level where there are all age classes of trees. Often they aren’t applicable on a stand or individual property level because when growth rates are expressed in terms of board feet, the rate of growth is going to vary dependant upon the age of a particular stand.

A sapling or poletimber stand may be growing very well but there won’t be any increases in timber volume because the trees are too small to be classified as sawtimber. Traditional wisdom has depicted small sawtimber stands as having the highest growth rates because of the large volume of ingrowth and the rapid percentage increase in volume per acre. Traditional wisdom has also deemed these stands as economically mature when they grow into the large sawtimber category because the amount of ingrowth decreases and the rates of growth in percentage terms decrease.
When growth rates are stated in volume of growth per acre or increase in value per acre, then large sawtimber performs better than small sawtimber because the increases may be larger in absolute terms and will almost certainly be greater in dollars per acre. This is because a smaller percentage of a higher volume can easily exceed a larger percentage of a smaller volume in absolute terms. Secondly and more importantly, in large timber the added growth has a much higher percentage of veneer and high quality lumber associated with it. The growth in large timber is usually clear lumber for a considerable height up the bole of the tree whereas in small timber a lot of growth is occurring where knots are still present.

Past cutting practices are also very important when determining the rates at which a stand will be cut in the future. The scenario most often presented at landowner meetings and similar forestry gatherings is that the virgin timber in most of Pennsylvania was cut between 1880 and 1910 and the resulting second growth is now reaching maturity. This is true of the Allegheny National Forest and most state lands, but it is not necessarily true of most private lands. In northwestern Pennsylvania the pioneer settlement period occurred in the early 1800’s and logging activity also started occurring at this time. This logging was done for numerous reasons and when viewed on a large scale it was quite haphazard. Some areas were cut and cleared for fields and then allowed to revert back to woodlands. In many woodlots the hardwoods were cut except for the hard maple which was then used to produce maple syrup. A large number of woodlots were pastured to varying degrees and thus damaged to varying degrees. In later years when the hardwoods had greater stumpage values most woodlots were highgraded in varying degrees.

For these reasons and others, virtually all of the private woodlands in northwestern Pennsylvania have been abused in one or more ways. When considering this past history the woodlands of northwestern Pennsylvania and in fact those of the whole eastern United States have proven to be very resilient. Since different properties have all had their own unique history, then future cutting practices should be specific to each particular property.

In some situations where old fields have reverted to trees the larger trees are the ones which were the first pioneers and they are mostly limby “wolf” trees with the smaller trees having more future lumber potential. In other woodlots the two-aged stands have developed because of a very hard cut in the past. In these stands the residuals from the previous stand may be the larger trees, but since they would have been classified as intermediates or suppressed in that stand they simply don’t have the potential to become much larger trees. Therefore these trees should be removed first in order to allow the dominants and co-dominants within the younger age class to reach their maximum potential. Other stands may have been clearcut in the past and here the smaller intermediate and suppressed trees should be removed first.

Other stands are going to have their future determined for them by insect or disease occurrences. Some stands have grown species that aren’t well suited for that particular site and thus have less potential than ones where species occur that are optimum for that site.
For these varying reasons the future cut is going to be specific for each property. But since all of the properties that we presently own have been purchased because they have good timber growing potential, some generalizations can be made. The first cut will probably remove 15-20% of the basal area and the trees that are removed will mostly be of low value. The second cut will occur about ten years later and if there are still quite a few poor quality trees, then it will be similar to the first cut. But if most of the poor trees were removed in the first cut, then fewer trees will be removed in the second cut and the stand will be closer to an optimum growing condition. Also small openings (1/2 to 5 acres) may be made during any cut if those particular microstands have good advance regeneration and low potential in the overstory.

The first one, two or possibly three cuts could be termed improvement thinnings or cutting from below. Once a stand has reached a stage where it contains a large percentage of high-quality trees, then cuts will probably occur more often with a smaller percentage of the stand removed in any one cut. These cuts can be termed salvage thinnings. The objective of these cuts is to remove individual trees as they reach their biological maturity and to maintain a more open canopy in order to allow enough sunlight to reach the forest floor so that different age classes of advance regeneration can be maintained. After an undetermined number of these salvage thinnings the stand will reach a point of general biological maturity and more small openings or possibly medium sized openings can be made.

The properties that we presently own have a combined growth rate that exceeds 5%. Since our goal is to purchase properties with above average potential and allow them to develop into stands of large, high quality timber, our rate of cutting is going to be less than the rate of growth for the foreseeable future. Our annual rate of cutting is going to be determined mainly by the stocking levels of particular stands. Our goal is to maintain a basal area of approximately 100 square feet per acre. This means that as a stand ages and the trees become larger the board footage per acre becomes greater. Therefore rates of cutting will remain less than the rate of growth until a stand nears biological maturity. Determining the length of time it will take for a stand to reach biological maturity is virtually impossible because of our lack of a precise stand history.

We can measure diameters and we can take cores samples to determine age, but we still can’t conclusively identify a co-dominant or an intermediate from the original stand because we don’t know what trees were removed in the past. If we have true dominants or co-dominants the stand can then achieve a much larger average diameter than if we have intermediates. It is also very difficult to determine precisely how well a particular species is suited to a particular microsite, and to what stress factors (drought, insect damage, etc.) a stand has been subjected. Because of all of these factors, cruise data expressed in terms of board feet per acre is not particularly useful in determining projected rates of removal. Basal areas, tree vigor, and relative age are much more useful in predicting future cutting schedules. Of these measures, basal area is the only one that can be expressed in absolute terms, therefore we intend to rely heavily on subjective stand evaluations in order to determine when a stand will be cut. This concept denigrates the usefulness of much of the information gathered in a typical stand analysis because we are relying on subjective evaluations rather than quantifiable numbers.

This reliance on subjective interpretation rather than what is usually considered to be scientific stand analysis is not a repudiation of scientific forestry. Rather it is a realization that we simply don’t know all of the factors that have led to the present condition of any particular stand of timber. An exact set of circumstances can never be exactly replicated in forestry situations; there is always a need for human evaluation. I realize that this reliance on individual interpretation is going to subject the whole system that I have here proposed to abuse. One person’s interpretation can easily be influenced by external factors, the greatest of which is likely to be short-term dollars.

The annual sustainable cut is going to be measured in terms of forest health rather than board feet per acre. This measurement is going to necessitate a rate of cutting that is less than the rate of growth, because none of the timber stands that we presently own have attained or even approached biological maturity. As the presently owned stands mature, the rate of cutting can probably be increased to a level that approaches the present rate of growth.