Guidelines for Low-Impact Forestry

The following is available by permission of the Maine Low Impact Forestry Project

I. Introduction
Why this document? Too often, landowners who care deeply about their woodlands have been dismayed at the aftermath of cutting on their land. The logger promised to cut the lot "selectively"--and he did. He "selected" the best trees and left the rest, with little care for the future. The resulting stand is so sparse that it offers little shade. Runoff from rutted and compacted trails (which seem to run everywhere) and from poorly planned crossings have silted up the once-beautiful trout brook. Many of the remaining trees (most of which are small diameter or culls) are bruised, broken, or bent. The yard is a large, muddy mess, with unsightly slash piles. Understandably, after such an experience, many landowners are discouraged from having any more logging done to their land.

There is an alternative--low-impact forestry (LIF). Low-impact forestry reduces known harmful impacts so that after the cutting is done, there is still a functional forest. The landowner, with the help of a forester, plans for the long term, not just one cut. The residual stand not only functions like a forest, it looks like a forest. There are enough trees, including some with large diameters, to ensure that the forest floor is shaded. Very few trees are damaged. Indeed, after the cut the average tree quality is higher--the logger removed high-risk, low-quality trees. Trails are relatively narrow and unobtrusive. They are favored by those who want to cross-country ski or hunt. The yard is small with minor soil disturbance. The stream remains clear and cold, and the trout seem happy. And so is the landowner.

For LIF to work, good communication between the landowner, forester, and logger is essential. If the logger and landowner do not have common expectations and do not communicate well, the job will not come out the way the landowner wants. Often loggers are responding to immediate economic pressures that reward more volume for lower costs, while many landowners have woodlots as a sideline rather than as a primary income source. This document is intended to give landowners a better understanding of the reasons behind LIF so they can better communicate their objectives. Indeed, for the system to work well, it is best if landowners have their management objectives in writing. This document lists recommended guidelines and standards for foresters and loggers that, if followed, would help meet the LIF objectives.

LIF takes more skill and care than conventional logging. For the increased effort on the part of the logger, the landowner should be prepared to pay in a different way. With conventional logging, the landowner usually pays by the cord cut. This encourages the logger to cut the best trees as fast as possible with little regard for the residual stand or the future. LIF is different. LIF is for those with patience--it is not a get-rich-quick scheme. The time horizon for the landowner is generations, not just one cut. The landowner pays the logger for the quality of what is left behind as well as the quantity of what is cut. Standing forests have value, and with LIF, this value should increase.

Why Hancock County?
A recent timber inventory survey by the USDA Forest Service shows that Hancock County went from being the region of the state with the second lowest volume per acre in 1982 to the second highest volume per acre in 1995. Although some of this volume increase was from longer-lived species with potential high values, such as red spruce and white pine, much of the increase was from shorter-lived species such as red maple, balsam fir, aspen, and white birch. Hancock County landowners have an opportunity to improve the value and stability of their forests, but this will take decades of careful management.

The Hancock County Planning Commission did a survey of woodlot owners that showed a strong desire to improve forest practices. Two thirds of all respondents wanted to work cooperatively with a logger over an extended period of time to maximize economic returns and minimize environmental impacts. Nearly half of respondents would be willing to receive less for stumpage in order to improve the land's future health and productivity. More than one third were interested in low-impact logging services.

The Planning Commission co-sponsored a Low-Impact Forestry conference in May of 1997 that brought more than 140 enthusiastic landowners, loggers, and foresters. The interest level of participants was very high and many made it clear they want more follow-ups to the conference. Participants wanted more workshops on a wide range of subjects, but they also wanted to get LIF going.

To get LIF going will require committed landowners, knowledgeable foresters, trained loggers, suitable equipment, and some kind of guidelines that landowners, foresters, and loggers would agree to follow. This document is intended to be a start towards creating such guidelines.

II. Principles and Goals
With low-impact forestry, the whole forest is considered, not just its value for pulpwood or sawlogs. Foresters must look at the crowns (tree foliage), the trunks, the roots, the soil, the water, forest stand structure, and the distribution of wildlife habitat across the landscape. For a forest to be "functional," it must have all the required parts, and all the required processes. Forests, however, are always changing due to human management and natural disturbances (such as wind, insects, diseases, or fire). LIF foresters must be prepared to accommodate this change so that over time, the parts and processes are still functioning in the forest landscape.

Looking up in a forest, one should see the crowns of individual trees forming the forest canopy. The crown includes the limbs, twigs, and leaves. The leaves are where photosynthesis takes place, capturing the carbon from carbon dioxide to build the fibers in wood. They are also where trees release water, drawn from the soil by the roots, back into the atmosphere. This helps to regulate both the water table and the climate. Tree canopies (both living and dead) are habitats to numerous species of birds, insects, spiders, and even lichens. Damage to tree crowns, especially to the leader, can impact both the form and health of the tree. Excessive crown damage can lead to tree death.

The degree to which the canopy is closed (where the foliage of one tree tends to merge into the foliage of the next), can have profound effects on forest productivity, tree quality, forest regeneration, wildlife habitat, windfirmness, (the ability of trees to withstand falling over in heavy winds), and water quality. The more the canopy is filled with foliage, the more efficient the use of the growing space and the higher the productivity of the mature trees. As the canopy opens, more energy goes to the understory--the developing growth below the canopy.

Degree of canopy closure also affects the quality of many tree species. Increased sunlight from heavy cutting can lead to epicormic sprouting (sprouts coming off the trunk) leading to lowered quality. When the canopy is open, more growth goes onto branches. Trees therefore can have more knots, shorter boles, more taper, bigger crowns, and thus worse form for lumber. With higher degrees of crown closure, tree growth goes up rather than out. Increased density leads to trees with longer boles and smaller crowns. Lower branches tend to self-prune, yielding more limb-free logs.

Degree of shade influences the regenerating stand. Some trees, such as birch and aspen, are adapted to heavy disturbances, such as fires, and thrive under direct sunlight. These trees, along with plants such as raspberries and pincherries, are shade intolerant--they must have direct sunlight. The majority of our most valued tree species, however, are shade tolerant--they are adapted to growing under some degree of shade.

Species such as red spruce, hemlock, or sugar maple can grow under a dense shade. White pine, yellow birch, or ash do well under partial shade and are considered intermediate tolerant.

Openings in the canopy are called "gaps." Gaps, depending on their size, produce different types of habitat. If they are small, they might just stimulate the growth of existing shade-tolerant seedlings and saplings, leading to a stratified canopy (a canopy with multiple layers) and uneven-aged stand structure (having three or more age classes).

If the gaps are bigger than two tree heights in diameter, the forest floor may be bathed in sunlight, encouraging shade-intolerant species, starting the process of succession. Since shade-intolerant species cannot grow under their own shade, more shade-tolerant species tend to succeed them. Young trees and shade-intolerant trees are found in early-successional stands, which are even-aged (having only one or two age classes of trees). Mature and old intermediate and shade-tolerant species are found in late-successional stands.

In Maine's presettlement forest (the forest before Maine was settled by Europeans), most of the northeastern portion of the state was in relatively closed-canopy stands of more shade tolerant species. Large, severe disturbances (such as fire or windthrows) happened on a given acre hundreds of years apart and early-successional stands only represented a small percentage of the landscape. Stands dominated by seedlings and saplings may have represented only 2% of the landscape. Smaller disturbances led to an uneven-aged structure and stratified canopy, with most stands having trees older than 150 years.11

In some counties, such as Aroostook, Piscatiquis, Somerset, and Washington, seedlings and saplings now make up around 30% of the landscape with most trees under 80 years. Mature saw-timber stands (stands dominated by trees large enough for saw timber) are a minority in these counties.2

Low-impact practitioners will strive to manage for well-stocked (having optimal spacing for productivity and quality) stands with minimal crown damage. The forester will favor, over time, late-successional species and canopy structures. Large gaps and early-successional stands should be a minor part of the landscape.

Tree trunks, or boles, hold up the canopy to catch the sunlight. The trunk carries food made from the leaves down to the roots through the inner bark (phloem), and the water and minerals are taken by the roots up to the leaves through the sapwood (xylem). A thin layer (one cell thick) called the cambium is where the tree trunks grow. Tree trunks are most vulnerable to damage when the sap is flowing, in the spring and early summer. Damage to tree trunks leads to a response called "compartmentalization" to isolate the wound. This takes up precious energy, slowing growth. If the damage is severe, this can cause extensive rotting and decay, lowering value for timber products and eventually killing the tree.

As the diameter of the trunk increases, its value for timber and wildlife increases as well. The highest-quality trunks are formed in relatively closed-canopy stands where limbs self-prune. There can be a major jump in economic value as a tree becomes big enough for sawtimber, rather than pulpwood. A softwood sawlog starts at 8-10 inches and a hardwood sawlog starts at 10-12 inches, while prime veneer starts at 16-18 inches. The difference in value between a 12-inch sawlog and an 18-inch veneer log can be 400-500%.3 One therefore grows more value per acre on trees than on saplings, on sawlogs than on pulp, and on veneer than on sawlogs.

Tree trunks create habitat for many forms of wildlife. Some, like certain types of lichens, prefer the rough bark of very old trees. Many bird and mammal species use cavities in dead or dead-topped trees. The bigger the trunk, the more wildlife varieties that can be accommodated.4

Low-impact practitioners will encourage an increase in average diameter, and an increase in quality leading to the highest value forest products. They will also leave some large-diameter "wildlife trees" for cavity-nesting species. They will take special care not to break the bark, especially during seasons of highest vulnerability.

The roots are where the tree takes up water and nutrients. The roots are also the anchors that prevent the wind from blowing trees over. Damage to tree roots, especially at the drip line, can degrade the value of forest products by leading to rot and decay in the stem, and can slow growth or even kill the tree.

The tree takes in nutrients through the finer roots, which are mostly in the top six inches of soil around the drip line of the tree, but can extend more than two times the distance of the tree canopy. Many varieties of fungi, called mycorrhizae, have adapted to extending these fine roots and increasing the uptake of nutrients and water. For this service, the trees supply carbon for the fungi. Recent research indicates that these fungi can connect one tree to another--even trees of different species--and supply carbon from trees growing in sunlight to those growing in shade.5 Severe soil disturbance, changes in soil chemistry, and lack of dead-woody material on the ground can harm these important tree allies.

The bigger the tree crown, the bigger the root system. Suppressed trees (trees that do not have dominant crowns in the canopy), often have weaker root systems. If the canopy is opened by removing the larger, dominant trees, these suppressed trees will not be windfirm and can blow over. This is one problem with diameter-limit cuts (where the logger cuts all trees over a certain diameter) of softwoods.

When large trees blow over, the roots pull up nutrients from lower soil layers, making them available at the surface. The uprooted large trees create a pit and mound structure on the forest floor that creates very different microhabitats due to differences in topography, moisture, and nutrients. Pit and mound forest floors are typical of old growth forests.

LIF practitioners will strive to minimize root damage by minimizing impacts of heavy equipment on the soil. LIF practitioners will also ensure that residual stands in vulnerable stand types are windfirm by avoiding opening the canopy too much and by leaving the dominant, windfirm trees.

The soil is the forest foundation and nutrient recycling center. The soil provides nutrients to growing plants and receives nutrients from dead plants and animals. A key area in the soil horizon is the organic pad, where decomposing organic matter meets the mineral soil and forms humus. This area has the most biological activity, and is where fine roots thrive.

The organic layer is built up by fallen leaves, branches and trunks. Hardwoods tend to have deeper roots than softwoods, and can pull nutrients from deeper soil layers to deposit them on the surface in the form of leaves and branches. The organic litter is deepest and breaks down more slowly under softwood stands. Soil under softwoods also tends to be more acidic. Organic matter is broken down by fungi, bacteria, soil invertebrates, and other organisms. The organic material is thus not just a nutrient source, it is also an important habitat for many species. Organic matter acts as a sponge and retains water, even during dry periods. Because of this, large rotting logs can be an important reliable site for regeneration of some tree species, such as red spruce.

Disturbance of the organic pad has impacts on nutrient cycling and availability. Approximately half of upper soil volume is made up of pore space filled with air and water. Compaction and rutting can compress these pores between soil particles, preventing air from getting to tree roots and halting much of the biological activity. Water no longer can slowly filter through the soil, but instead forms pools or runs off, taking soil particles and nutrients with it. Soil disturbance is less of a problem when the ground is frozen or dry.

Exposing the soil surface to direct sunlight through large openings can lead to increased temperatures and more rapid breakdown of organic matter, leading to a leaching of nutrients if there is inadequate living vegetation to take it up. This leaching, combined with removal of large amounts of biomass from a heavy cut, can have a major impact on available nutrients. It can also change soil chemistry, making the soil more acidic and less fertile. Whole-tree removals have the most severe impacts since more than half of the nutrients are in the branches, tops, and leaves.6

An ecological rotation is the time it takes for the soil to recover organic matter and available nutrients. Although the time period depends on site and forest type, the more intense the removals, the longer the recovery time. If removals and leaching occur faster than the recovery time, the soil experiences nutrient capital depletion, eventually lowering productivity.

LIF practitioners will strive to cause minimal soil disturbance, and where damage is unavoidable to isolate it to the smallest possible area. They will pay attention to timing of cut, entering stands when conditions are least vulnerable. They will leave plenty of organic matter, including tops, branches, and even trunks, to rot. Where there has been a soil disturbance or nutrient depletion, the LIF practitioner will allow ample time for recovery.

The purest water is that which comes from a relatively undisturbed forest. The closed canopy shades the soil, keeping water cooled. The canopy also protects the soil from the impact of direct rain drops and erosion. The organic matter and soil structure act as a filter to keep water clean. Forest vegetation and wetlands help to moderate extreme water level fluctuations. Forest vegetation also takes up nutrients as organic matter rots and breaks down. When there has been extensive removal of forest vegetation, some of these nutrients can leach out of the forest and become pollutants in streams.

Water quality is most impacted by exposed, disturbed, or compacted soils where particles are apt to be washed away with the rain. This happens most often on roads, yards, trails, and stream crossings. States with forest industries all have Best Management Practices (BMPs) standards to reduce siltation and other water-quality problems from such areas. In Maine, BMPs are voluntary.

Where water meets the forest are found some of the richest wildlife habitats, the riparian zones. These areas are rich in both plants, which take advantage of increased moisture and nutrients, and animals, which appreciate the lush plant life as well as access to water. Riparian zones, if wide enough to be functional habitat, can also be corridors for migrating animals.

The smaller the streams, the more sensitive they are to changes in temperature, siltation, and water-level fluctuations. Opening the canopy by as little as 25% in the zones near sensitive water bodies can have an impact on water quality.7 Some water bodies, such as vernal pools (which can be breeding grounds for amphibians), intermittent streams, or small wetlands might be wet for only part of the year, but they are important for both wildlife habitat and flood control and the surrounding forest needs to be managed carefully.

LIF practitioners will carefully control stocking and soil disturbance to maintain high quality water from the forest. Special attention will be paid to riparian zones, especially around the most sensitive streams where these management zones should be wider, not smaller.

Wildlife habitat
When most people hear the word "wildlife," they think of moose, deer, grouse, and ducks. Occasionally they might include fish, raccoons, or even bald eagles. When biologists say "wildlife" they mean all animals (including insects and spiders), plants, and fungi. The diversity of all wildlife at all levels of organization, from genes to ecosystems and biomes, is called biodiversity. The diversity of wildlife helps build resistance to severe disturbances and resilience in recovery from such disturbances. Another word for this resistance and resilience is stability.

Forests are not just trees. They are complex ecosystems that include plants and animals. Plants create food from light, water, and minerals. When animals, such as deer, rabbits, or insects, browse intensively they can change plant distribution. Other animals, such as moths, birds, or bats, aid in plant pollination. Many types of birds and mammals help with plant seed dispersal. Some animals, such as spiders, salamanders, foxes, or coyotes, prey on others, preventing over-population and over-grazing. Other creatures, such as insects or fungi, decompose the dead plants and animals, helping them to break down into nutrients usable by plants.

Wildlife cannot survive without acceptable habitats to give them food, shelter, and other necessities. Thus the way to ensure the persistence of all species is to ensure the presence of all required habitats. The habitats must be large enough to support viable populations. A major threat to biodiversity is from habitat fragmentation, where the habitat is reduced so that it is too small or too isolated to support breeding, dispersal, or migration. While some species thrive on the edge between two habitats, others shun the edge and prefer the interior where there may be less predation or competition.

Fragmentation can make a habitat so small that it is all edge, and thus not be able to support interior species. In Maine, the Land Use Regulation Commission requires minimum 75 foot buffers around small streams. When these buffers are surrounded by clearcuts, they are too narrow to support viable populations of forest interior song birds, such as bay-breasted warblers.8 Fragmentation is most severe in populated areas where species such as cats, raccoons, or cowbirds can harm nesting interior birds.

To have all habitats requires having all the successional stages for each forest type. While some habitats, such as rock outcroppings, change very slowly, others, such as those dominated by early-successional species, can change in a matter of decades. Even late successional stands can be changed, after centuries, by fires or severe winds. While early-successional species tend to be aggressive recolonizers of disturbed areas, late-successional species tend not to be as good at rapid dispersal and recolonization.9

Recolonization of disturbed areas by these slower-responding species is best assured if they have sources within (biological legacies, such as the habitats offered by live or dead-standing trees, that survive a disturbance), adjacent to, or near the developing stand. In the presettlement forest, late-successional forests made up the majority of the landscape, and there was enough time between severe disturbances to ensure recolonization and thus the survival of all species.10

LIF practitioners will strive to provide habitats adequate to support viable populations of all native species and assure the presence of these habitats in the landscape over time. This means having representation of all successional stages--with an emphasis on later-successional stages. This also means identifying habitats of rare or sensitive species and giving these a higher level of protection.

III. LIF Logging Guidelines and Standards
How does one get the generalizations of the principles and goals turned into more specific practices? Who is responsible for their implementation?

Low-impact forestry is a partnership between the landowner, the forester, and the logger. It starts with the landowner who has to know what LIF is and has to make the decision to do it. For LIF to happen, however, the landowners (if they do not do the work themselves) must be able to contact qualified foresters and loggers. They have to agree to work within LIF standards. Otherwise the cut may not turn out as the landowners wish.

Low-impact forestry is not just a single cut--it involves long-term planning. The forester needs to incorporate LIF goals and principles into the management plan as well as ensure that loggers meet performance standards. To the extent that the forester can locate the highest paying markets, this makes LIF more viable for all participants.

Without the logger, LIF could not happen, despite the best long-term plans. The logger must understand the techniques and have the appropriate equipment to perform LIF. Before cutting a stick of wood, the logger must know the best markets to ensure that the wood is cut to the optimal lengths considering diameter and grade.

For low-impact forestry to work, therefore, the landowners, foresters, and loggers involved must all understand the goals and principles of LIF. And they must all agree to abide by those goals and principles. And the foresters and loggers must follow basic guidelines and standards.

Forester Guidelines
Stand assessment. Before coming up with a management plan, the forester must assess and map the stand taking into consideration such factors as stand types, species, volume, quality, watersheds, and wildlife habitat.

Landscape planning. Watersheds, ecosystems, wildlife ranges, and disturbance patterns do not normally coincide with property boundaries. For landowners who own thousands of acres, landscape planning starts to become possible. With smaller ownerships, the foresters and landowners should try to cooperate on a community basis to ensure that wildlife needs (such as effective corridors for migration and dispersal) are met. Cooperation of this sort, involving government, industry, and small landowners, is now being done, for example, in New Brunswick's Greater Fundy Ecosystem.11

Where landscape planning is possible, foresters should ensure that a representation of ecosystem types and sensitive habitats are protected in reserves. Reserves can serve many functions from baseline "controls" for the long-term experiment of forest management, to refugia (source areas for future recolonization of disturbed forests). Maine currently has less than 2% of its forest in reserves. A number of organizations such as the Forest Stewardship Council have called for at least "representative samples of existing ecosytems".12

In general, the bigger the landscape planning unit, the bigger the reserve system. Bigger reserves can survive the largest expected disturbances without losing essential habitats and habitats are more apt to support viable populations of species needing larger ranges. Large reserves in the landscape, generally, are publicly owned, but small baseline reserves on private land can be important as well.

Allowable cut. A number of methods can be used to calculate allowable cut. In doing these calculations, the forester must account for areas where there will be no cutting or less cutting because:
  1. The site has such low productivity that sustainable management is not economically viable,
  2. The site is environmentally sensitive (riparian zones, deer yards, slopes, species of special concern), or
  3. The site is in a baseline reserve.
Because the degree of tree crown closure (and thus residual stocking) is so important for both productivity and wildlife, one favored method is to classify stands as "operable" when they have more than a minimum above a recommended stocking level to allow a commercial cut. The quantity above the minimum stocking is the allowable cut.13

Another method is to ensure that cut is less than growth. Over a rolling ten year period (for larger management units), cut should average less than 70% of growth, allowing some growth to be reinvested into the ecosystem. This calculation is normally not done at a stand or woodlot level. The area is too small and the harvest too infrequent to use 10 years as the base.

Often harvests occur at 20 or more year intervals, so a longer time frame can be used. On large ownerships with balanced age classes and logging occurring annually the ten year time frame can be used. Cut can, of course, exceed growth for species that are over-represented (such as balsam fir or red maple) and less desired for long-term stability.

Because the majority of land should eventually be classified as sawtimber (to ensure that relatively closed-canopy mature and late-successional stands are the landscape context, not just a small content) even-aged management (where a cut is made that reduces the stand to seedlings and saplings, leading to a single age class) should only be done if uneven-aged management will not work for the stand. Priority for even-aged management should first go to irregular shelterwood (where some of the overstory is retained), and only go to regular shelterwood (where regeneration is well-established before cutting the overstory) if retention of residuals is not possible. Rotation (the interval between stand establishment and the final cut) for even-aged stands should be based on stand type and should allow enough time for soil recovery and habitat recovery, including tall, large diameter trees.

Cutting cycle. More frequent, light cutting (every five years, for example) creates the potential for increased residual damage. Less-frequent (every 20 or 25 years), heavier cuts create potential for more drastic stand changes. The forester must reach a compromise between these two possibilities. Low-impact logging creates an opportunity to more successfully do lighter cutting and still minimize damage on 10 to 15 year cutting cycles.

Residual stocking. The forester will consult silvicultural guides appropriate to the stand type. To ensure relatively-closed canopy areas in large blocks (for adequate interior species habitat), minimum stocking should be at least 65% of crown closure, increasing to 75% of full crown closure for riparian areas. Near riparian areas, to prevent changes to water quality and flow, cuts should not exceed 25% of standing volume.14

Crop trees. The forester will identify crop trees and potential crop trees--trees that have good form and quality. These are the trees to leave after harvest and should be given special attention to avoid any injury that would diminish value. The normal target is around 50-75 per acre. Common terminology calls trees acceptable growing stock (AGS) and unacceptable growing stock (UGS). Using this approach of AGS and UGS a harvest can be designed to improve stands and focus on the future crop trees.15

Pecking order. The forester should mark trees to be cut based on a "pecking order" that would prevent highgrading and thus stand degeneration. First to be cut should be high risk (trees that would not survive to the next cut), low vigor, and poor quality trees (UGS).16 With a pecking order, the logger would be more likely to cut short-lived, poor quality medium-sized suppressed trees than long-lived, high quality, large-diameter dominant trees that are still growing well.

Mast trees. Mast trees are those that produce edible nuts, seeds, and fruits that are important for wildlife. If no high-quality (for lumber) trees are suitable for mast, some low-quality mast-producing trees (such as beech) should be retained.

Dead wood. The forester will consult recommendations from forest wildlife guides to determine a minimum of snags, dead trees, and dead-downed trees.17 Preference will be given for larger-diameter (over 18 inches) leave trees (trees left behind), and allowance will be made to develop recruitment trees (trees that will be allowed to eventually develop into large-dead trees), since current dead-standing trees eventually fall over. The additional factor of safety must be considered since dead snags and branches have a frightening record of injuring loggers.

Logger Guidelines
Felling and limbing. LIF loggers will use directional felling to avoid damaging residual trees. Limbs will be left in the woods to provide wildlife habitat and to rot and supply nutrients.

Getting trees to trails. LIF loggers will move single large stems or a few small stems (but not winch whole trees) to the trail. If winching, the logger will, if necessary, use snatch blocks to avoid damaging valuable crop trees. The logger will avoid digging up the soil during winching and use such items as grapples or cones when needed.

Wood trails. Wood trails will not exceed 10 feet wide (to give several feet clearance to machinery), allowing crown closure over the trails. Machinery wider than 7.5 ft. should be avoided, unless trees are very large and smaller equipment will not do the job.

LIF practitioners should strive to distribute trails more than 100 feet apart to minimize damage to soil and roots. Some low-impact practitioners with radio-controlled winches distribute trails 150 feet apart. With horses, trails can be up to 300 ft. apart.

Getting trees to yards. Loggers should run machinery on permanent trails, with little or no driving to the stump or creating single path trails. The LIF preference is to carry, rather than drag bunches of logs. A forwarder is thus preferred over a skidder. Use of short logs, rather than tree-length logs, minimizes damage when going around curves.

The result, however, is more important than the method used. If a logger can use a small skidder and do minimal damage, then the skidder is acceptable. Whole-tree removal with a grapple skidder, especially of hardwoods, violates too many LIF principles and has the potential to cause too much residual damage to be acceptable.

Residual damage. For long-term forestry, it is essential not to damage the residual, or "crop" trees. During cutting, winching, and transporting trees, every attempt will be made to avoid such damage. While damage to tops and branches is of concern, it is even more important to avoid damage to trunks and roots.

Some LIF practitioners in New England guarantee that they will damage less than 5% of crop trees. This figure is also a goal in Sweden, where any opening in the bark bigger than a matchbook is counted as "damage."18 William Ostrofsky has developed a method for measuring damage levels for the American Pulpwood Association.19

Yarding. LIF yarding areas can be kept to a minimum in size with minimum damage to soil if short logs are piled with a loader, rather than pushed with the dozer blade of a skidder. LIF practitioners need less than 1200 square feet for yards on average. Whole-tree yarding with grapple skidders and delimbing in the yard requires too much space, is too damaging to residuals and soil, and removes and damages too much organic matter to be suitable for LIF.

Truck roads. Road width and densities should be minimized. Road rights-of-way should be kept between 15-30 feet with a maximum of 33 feet.20 Road density becomes an issue in bigger blocks of non-settled forest depending on heaviness of traffic and need for ditching. Managers in the Greater Fundy Ecosystem a recommended to keep road density to less than 0.9 miles per square mile due to impacts on large predators and other sensitive animals.21 For narrow truck roads that are infrequently used, the density can be more than 2 miles per square mile.

Landscape conversion. Loggers and managers should strive to keep the percent of forest taken out for permanent trails, yards, and roads to less than 15%.

Water quality. LIF loggers will follow state BMPs to prevent soil damage leading to siltation of waters. In addition, foresters will take into account soil type, watershed characteristics, and season of cut to further advise loggers as to when logging standards should be even stricter than BMPs.22 Preference for LIF practitioners is to log when the soil is frozen or dry.

IV. Economic Considerations
Low-impact forestry is not for those who want a quick return on investments. It is for those who can accept modest returns now, knowing that larger economic benefits may come decades ahead, or even to another generation. Income from forests involves trade-offs. High-grading can maximize present returns, but endanger future returns as well as degrade the forest.

LIF landowners have a broader definition of wealth that includes the value of the standing forest as well as the value of what is removed. Leaving mostly poor-quality, damaged residual trees after a cut lowers the residual value of the landowner's forest, although a few of these trees should be retained to develop into wildlife trees. Some of the values of a standing forest, such as wildlife habitat, water quality, and aesthetics, are not easily translated into dollars, but are important none-the-less. A key challenge is to make LIF economically viable to both landowners and loggers over the long term.

In the short-term, the logger is taking more time to remove less wood. This means more cost per unit of wood removed than with more conventional logging. For LIF to be viable for the logger, the landowner should pay based not just on what is removed, but also for the quality of what is left behind. If conventional loggers were assessed fines for the costs they create to the residual stand, highgrading would not be as attractive.

How to Pay
There are a number of ways to pay for LIF. No matter which method is used, the logger needs to know his costs to ensure that he will be adequately compensated. The simplest method for most landowners is to accept lower stumpage rates.

Another simple method is to pay by the hour, thus assuring that the logger's time is adequately compensated, despite the difficulty of operations. Some landowners pay by the volume removed, regardless of the wood value, thus taking away the incentive for highgrading. Another option is to have contractors give bids per acre with incentives for the quality of the work. In Sweden landowners pay based on a complex formula that includes allowance for stems per acre, average diameter of trees, the slope, accessibility, number of "difficult" trees, snow depth, and degree of stand damage.23 The landowner can be assured that low-impact practices are used by writing it into the contract and having the forester supervise the operation.

Better Returns
Because of the increased short-term costs and smaller cuts, often of low-valued wood, it is essential that LIF practitioners find ways to get better returns. A number of ways this can be done include:
  • Locate better paying markets. Aggressive attempts to find the highest-paying markets can make a very large difference on returns. Sometimes small, "niche" markets are available for odd species, sizes, or shapes of logs. Other times, some mills with special needs pay more than others.
  • Bucking and sorting for best markets. The logger needs to know the markets before the wood is cut. Otherwise he might cut logs to the wrong length and have to ship to lower-paying markets. A knowledgeable bucker and sorter can make a big difference in returns.
  • Bargaining for better prices. Sometimes the same mill buys wood at different prices from different sellers. Ability to bargain is increased with volume--so cooperating with other landowners can increase bargaining leverage. The season at which the wood is sold can also make a difference.
  • Cut and leave. Some mills buy wood at a price that is lower than the cost of cutting and hauling it. LIF loggers should accurately know their costs of production to be able to make such a decision. In such a case, it makes sense for the logger to just cut the undesirable trees and leave them on the ground to rot. This will at least benefit the forest. If enough woodlot owners did this, maybe the mills would get the message to pay enough to make management worthwhile.
  • Subsidies. The government offers a number of tax breaks and incentives for thinning, stand improvement, and wildlife habitat improvement. LIF foresters should be well aware of such programs. In New Brunswick, some woodlot cooperatives have worked out incentives for thinnings that are partly funded by landowners, contractors and mills.24 These incentives are justified on the grounds that such cutting has long-term benefits to the whole community.
  • Premiums. There are a number of certification programs operating in Maine now that can give landowners the potential to sell their wood at a premium. Anyone following the LIF guidelines should be able to qualify for certification.
One cut is not sufficient to qualify as long-term forestry. But that one cut should keep the possibility of long-term forestry open. After that cut, there should still be a well-stocked forest to work with. After a heavy high-grade operation, there isn't. One way to ensure continuity of management is to offer the logger a long-term contract with incentives for stand improvement. The logger would have a chance at the next cut, but that right could be transferable.

Landowners could explore ways to ensure that the LIF program continues after they are gone. Management restrictions can be put into the deed. The land could be put into a trust with LIF guidelines specified as a requirement. Any lawyer can tell you, however, that contracts and deeds can be changed. The ultimate way to ensure continuity of management is to pass on the LIF ethic as part of the culture. We need to act now as if we intend to have future generations, not as though this is the last. Forests, which by their nature require a long-term perspective, are a good place to put this ethic into action.

References Consulted
Biodiversity in the Working Forest Committee. Biodiversity in the Working Forest. Maine Forest Biodiversity Project. (in press)
Briggs, R. et al. 1996. Assessing compliance with BMPs on harvested sites in Maine. UM CFRU, Orono, ME.
Bureau of Public Lands. 1988. Public Reserved Lands of Maine Integrated Resource Policy. BPL. Dept. of Cons., Maine. 60 pp.
Cormier, Janet. 1996. Review and Discussion of Forestry BMPs. MEDEP & USEPA. Orono. 29 pp.
Certified Logging Professional Program. A Guide For The Maine Logger, March 1997
Forest Stewardship Council. 1996. Principles and Criteria for Forest Management.
Forest Stewardship Council, Acadian Forest Region. 1997. Certification Standards for Best Forestry Practices in the Acadian Forest Region.
New Brunswick Greater Fundy Ecosystem Research Group. 1997. Forest Management Guidelines to Protect Native Biodiversity in the Fundy Model Forest. New Brunswick Co-operative Fish and Wildlife Research Unit, UNB, Fredericton. 35 pp.
Griffith, D.M., and Carol Alerich. 1966. Forest Statistics for Maine, 1995. Resource Bulletin NE-135. USDA Forest Service, N.E. Exp. Sta. Broomall. 134 pp.
Hammond, Herb. 1996. Pacific Certification Council Standards for Ecologically Responsible Forest Use. Pacific Certification Council, Slocan Park, BC. 51 pp.
Kahl, Steve. 1996. A Review of the Effects of Forest Practices on Water Quality in Maine. Water Research Institute, UM, Orono. 52 pp.
Lansky, Mitch. 1996. After the Cutting is done, What's Left? An Evaluation of Forest Practices in Maine 1991-1993. 27 pp.
Leak, W.B., D.S. Solomon, P.S. Debald. 1987. Silvicultural Guide for Northern Hardwood Types in the Northeast (revised). USDA Forest Service, Northeastern Forest Experiment Station Research Paper NE-603. 38 pp.
Lorimer, Craig. 1977. The presettlement forest and natural disturbance cycle of northeastern Maine. Ecology 58: 139-148.
Maine Council on Sustainable Forest Management. 1996. Sustaining Maine's Forests: Criteria, Goals, and Benchmarks for Sustainable Forest Management. Dept. of Conservation, Augusta, ME. 54 pp.
McEvoy, Thom. 1995. Introduction to Forest Ecology and Silviculture. University of Vermont Extension. Burlington. 72 pp.
New Hampshire Forest Sustainability Standards Work Team. 1997. Recommended Voluntary Forest Management Practices for New Hampshire. New Hampshire Division of Forests and Lands, DRED, and the Society for the Protection of New Hampshire Forests. 65 pp.
Simeone, R., M. Krones, L. Nesper. 1992. Sustainable Management of Temperate Hardwood Forests: A Review of the Forest Management Practices of Menominee Tribal Enterprises, Inc. Submitted to Green Cross Certification Company.
Scientific Certification Systems. 1995. The Forest Conservation Program: Program Description and Operations Manual. Oakland CA. 65 pgs and appendices.
Seixas, Fernando, et al. 1996. Forest Harvesting in the United States: A Search for Sustainable Management in Balance with the Ecosystem. USDA Forest Service. Auburn AL. 28 pp.
Society of American Foresters. 1993. Task Force Report on Sustaining Long-term Forest Health and Productivity. SAF. Bethesda, MD. 83. pp.
USDA Forest Service. Land and Resource Management Plan White Mountain National Forest. USDA Forest Service Eastern Region.

(1) Minimum Tree Diameters For Cavity - Using Species
(2) "Practices To Minimize Logging Injuries" presented by William O. Ostrofsky at Low Impact Forestry in Hancock County Conference, May 1997
(3) Residual Damage Measurement Worksheet from "Professional Mechanical Harvesting Practices". American Pulpwood Association, Inc. Sept. 1997
(4) Greater Fundy Ecosystem Research Group (GFE) "Principles of Forest Management to Conserve Biodiversity," New Brunswick, 1997
(5) Habitat Differences in Successional Stages From "Biodiversity in The Working Forest" (draft), 1997