Chlorine Free Paper Issues

 

LISTENING STUDY Question 40:
How do alternative fibers compare to tree fibers on environmental impacts?

General Comments
Yield per Acre/Over Time
Impacts on Water, Energy, and Pollution
      Pollution from Pulp Processing
      Energy
      Bleaching
Need for Pesticides and Fertilizers
Soil Impacts
Use of Land


General Comments

LISTENING STUDY: Several comments point out the complexity of this question.

It's almost impossible to make such comparisons. We prioritize the fibers based on their overall environmental impact:

  • Combination of ag residues to reduce the waste stream and post consumer waste,
  • Behind that is deinking of preconsumer papers,
  • Next are sustainably harvested virgin fibers,
  • Behind those is tree fiber and agricultural fiber grown in sustainable ways.

      It's hard to make across-the-board statements. If you have a responsibly managed farm for on-purpose crops versus FSC-certified forests where the offcuts are used for pulping, both are good. Sure, it begs the question: Which is better? But both scenarios are great. The answer depends on circumstance: currently, it's easier to get low impact agricultural fiber than FSC off-cuts. However, it's easier to take advantage of FSC certified woods, because the systems are already set up for pulping wood. - Jeff Mendelsohn, President, New Leaf Paper

"Alternative Fibers" is a very broad category. It may be so broad that it will create confusion in the analysis being performed. There are very big differences between the various straws, corn stalks, cotton, kenaf, flax, bamboo, arrundo donax, etc. While it may be useful to categorize alternatives by various characteristics, it may be more useful to rely upon the "Search for New Fiber Crops" work of the USDA, wherein over 500 "alternative" fibers were evaluated and categorized. - Tom Rymsza, President, Vision Paper

It depends on many factors. It's not a black and white comparison. There are many different tree free fibers just as there are many different trees used for papermaking. There are different processing and manufacturing processes and different end use applications. Trees are grown differently, with different inputs depending on where they come from. The same is true with agricultural fibers. They all have such different fiber lengths, amounts grown per acre, ways they are processed from the farm gate to the pulping mill.
      There are too many variables to do anything close to a life-cycle analysis between "ag fibers" and "tree fibers." Now, if you take two specific cases and directly compare them, you could complete a good study. Something that would compare a specific fiber grown in a specific place with specific conditions, processed in a specific way for a specific paper. Then you could compare accurately and with certainty.
      Many times we try to bring it down to science and math - to quantify which is "better" once and for all. For me and many others, it's much more simple. We see forests cut down to make paper and we don't like it one bit. Our forests are being destroyed and replaced with tree plantations, while the pulp and paper industry and the forest products industry is telling us that they are "reforesting." Well, they're not. They're just planting trees for the sole purpose of cutting them down again to make more paper. - Peter Hopkins, Environmental Papers Consultant for Crane Paper Company, Gargan Communications

Compared to wood-based papermaking, the information available on this topic is limited. In the U.S., we only can draw conclusions from a small number of pilot stage projects and an even smaller number of commercial operations. - Environmental Defense Fund Paper Task Force, White Paper 13, Non-Wood Fiber Sources

A Ph.D. candidate at the Yale School of Forestry set out to answer this question and he gave up after several years of research.
      One simplistic answer is to put ag-residues in the same category as recycled fiber, as providing the highest and best use due not only to displacing virgin wood fiber but also providing a higher and better use compared to burning field crop stubble. Like recycled (except for high grade white), residues may not have the highest fiber quality (except maybe with flex and hemp residues). This is what I mean - every time there is a statement about non-wood fibers, there is an exception.
      Considering that non-wood plant fibers and ag-residues were pulped and used for paper going as far back as 150 AD, there are hundreds of sources of non-woods for paper, each with a rich and diverse history that can be explored depending on where one needs the fiber and what the final product needs to be. People point out the negatives about monoculture component of a dedicated fiber crop, such as kenaf, but it is important to remember that a lot of farmers want crop rotation opportunities. - Jeanne Trombly, Fiber Futures

Despite the fact that I wrote this question for Conservatree when we first started the Listening Study, and that the wording represents how environmentalists and paper purchasers often initiate the discussion, it really is not the most helpful framing of the issue in trying to reach a practical answer. There are so many different possibilities for plants that can be used for nonwood paper fiber and each is an individual case, complicated by the fact that geographic region, climate, soil quality, agricultural practices, governmental subsidies, societal customs, and so many other factors also further individualize each case, that there is no one right answer. In addition, some nonwood fibers may be great environmentally but lousy for papermaking or otherwise undermine the sustainability of the system. So I appreciate all the information that respondents have brought to this question, fleshing it out with a great deal of both nuance and detail.
      I do think that it would be good to develop more fiber options for papermaking in order to take some of the pressure off forests, although I expect that they will exist along with forest fibers in most cases for a long time to come. I am most focused on the practical and implementable, not just the theoretical. It takes such enormous effort and dedication to prevail with any kind of alternative to the huge, long-term investments and established system and sub-systems of using forest fibers for paper that I want to cut to the chase: What fibers best fulfill all the steps that are necessary to create a viable new paper; who is willing to put in the time, money and dedication to develop it; and how can we create something good and real in the present or the near future instead of waiting endlessly for perfection. - Susan Kinsella, Conservatree


LISTENING STUDY: Some identify different interests based on specific relationships to the question.

Interests and perspectives vary by constituency. Some members of the environmental community identify the use of non-wood fibers in paper as a way to preserve natural forests. These constituencies strongly support the use of annual crops, such as kenaf and hemp. Unlike trees, these crops are grown and harvested on a yearly basis. Some supporters claim that kenaf and hemp produce more usable fiber per land area than trees, are naturally pest-resistant and can be grown without use of large amounts of herbicides and fertilizers. They further point out the potential for non-woods to be pulped without sulfur and bleached without chlorine. Supporters of bioregionalism consider non-woods as an opportunity for small-scale pulping close to areas of fiber production, thus reducing transportation needs and aiding local communities.
      In contrast, the paper industry, as represented by the American Forest & Paper Association, compares non-wood pulping with prevailing large-scale wood kraft pulping operations. From that perspective, the widespread utilization of non-woods constitutes a fundamental change in the industry's raw material supply and procurement infrastructures. Individual paper companies in areas of wood shortage, however, may explore non-wood fibers to expand their fiber supply. Non-wood industry experts see the highest current potential in agricultural residues, i.e. by-products of the production of food and other crops, because of their immediate availability and relatively low cost.
      Farmers are interested in both annual crops and agricultural residues as additional income sources. Governments in the U.S. and Europe are interested in curtailing surplus grain production by encouraging farmers to grow non-food crops on agricultural land. Annual fiber crops are considered attractive rotational crops. Using agricultural residues would allow fiber production without additional land use. - Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"

Eliminate paper manufactured solely of virgin fiber and fundamentally reduce reliance on virgin tree fibers. . . . Increase the use of other recovered materials (e.g., agricultural residues and pre-consumer recycled) as a fiber source in paper. . . . Use alternative crops for paper if comprehensive and credible analysis indicates that they are environmentally and socially preferable to other virgin fiber sources. - Environmental Paper Network, "A Common Vision for Transforming the Paper Industry," November 20, 2002

"We think finding a replacement for wood fiber is a problem that does not need to be solved," John Mechem of the Washington-based American Forest and Paper Association told Well Journal. - Jim Motovalli, "The Paper Chase"

Overall, the dominance of the wood-based industry perspective and the associated research corpus has strongly tended to overwhelm the debate as it has emerged and to claim the benefit of the doubt. . . . an important example of how a conventional wood-based perspective could undermine the nonwoods idea before it could even be argued. - Maureen Smith, The U.S. Paper Industry and Sustainable Production


LISTENING STUDY: Some responses indicate differences between types of nonwood options.

There are three broad categories of fibers: dedicated fiber crops, agricultural residues and industrial residues.
      There is a need for a complete life cycle analysis of both agricultural residues (e.g. cereal straws) and dedicated fiber crops (hemp, flax, kenaf)to determine the environmental impacts.
      Industrial residues, byproducts of textile production (rags) though limited in volume would have a distinct positive environmental advantage over wood. - Living Tree Paper Company

For over 1700 years paper was entirely made from a variety of non-wood fibres, yet today the vast majority is produced from wood. There are three main categories of non-wood fibres which are used to make paper:

  • Crops purpose-grown for fibre production such as hemp, kenaf, jute and flax;
  • Agricultural residues such as cereal, rice straw and bagasse from sugarcane processing; and
  • Naturally occurring uncultivated crops such as wild grasses, sisal, and bamboo.

- IIED 1996, Towards A Sustainable Paper Cycle

Nonwood plant fibers suitable for papermaking . . . can be placed into four general categories of sources:

  1. Agricultural residues,
  2. Nonwood fiber crops, or industrial fiber crops,
  3. Wild plants,
  4. Industrial or post-consumer textile and cordage wastes (e.g. pure cotton or linen textiles, garments, and manufacturing wastes, cotton linters, which are a byproduct of cotton ginning, old rope, and many others).

- Maureen Smith, The U.S. Paper Industry and Sustainable Production


LISTENING STUDY: Some present a general overview of the issues, both pros and cons.

First, I believe that many ag fibers are byproducts so they have the benefit of being secondary fibers, unlike trees which are harvested for fiber as the primary use. - Jeff Lindenthal, President, Green Field Paper Company

Tree free papers have the advantage of offering the consumer an alternative paper. The impact of tree based papers is a widely publicized problem focused around issues such as deforestation. Tree free papers, however, change the focus of the impact to issues such as transportation. Some of the potential advantages of these alternative sources consist of: less energy required for fiber processing, decreased production time, and increased yield. However, when considering these alternative sources potential disadvantage include excessive water usage, increased pesticide and fertilizer demands, transportation impacts and price. - Green Seal, Choose Green Report: Alternative Fiber Papers

Using agricultural fibers in place of tree fiber is detrimental to the environment. Even some of the most intensively managed forests are much more biologically diverse and hospitable to surface waters, soil, and wildlife, and they require far less chemical treatment than annual agricultural crops. By definition, annual crops like kenaf must be re-established every year, and that means at a minimum the soil has to be disturbed and chemicals applied 25 to 30 times more than the equivalent tree stand for roughly the same fiber yield over 30 years. While managed forests are entirely hospitable to biodiversity, wildlife and endangered species, alternative fibers are agricultural crops, which means they're monocultures requiring the near eradication of any competing plant or animal species. - International Paper

High quality paper can be made from agricultural fiber crops such as hemp and kenaf, and from crop residues of wheat or other cereal grains. In some cases, and particularly those involving crop residues, there are environmental advantages of non-wood paper. However, there are substantial environmental costs of producing dedicated fiber crops that must be considered when comparing paper made from these vs. traditionally used wood fibers. When all environmental impacts are considered, it is debatable whether tree-free paper made of dedicated crops such as kenaf and hemp is environmentally better than paper made of wood. - Dr. Jim L. Bowyer, et al, Dovetail Partners

There are advantages and disadvantages in using non-wood fibres for paper-making compared to wood. There is no strong environmental case for supporting non-wood fibres. With existing agricultural practices and current processing and chemical recovery technologies, non-wood fibres are generally more polluting than wood, although less energy is required to pulp the fibres. There is no doubt that increased utilisation of non-wood fibres would reduce the need for wood. Whether this offers any benefit depends on the sustainability of wood production (or the potential for improvement). The effect on incentives for keeping land under forest cover also needs to be considered. - IIED 1996, Towards A Sustainable Paper Cycle

With some 60-65 million acres of farmland presently idled each year, at a taxpayer cost estimated at up to $15 billion, the subsidy reducing potential of alternative cash fiber crops is . . . compelling. - Maureen Smith, The U.S. Paper Industry and Sustainable Production

The Agricultural Research Service of the U.S. Department of Agriculture (USDA) conducted an extensive study of 500 plant fibers as alternatives to wood in pulp and papermaking in the late 1950s and found kenaf to be the most promising annual fiber crop. - Environmental Defense Fund Paper Task Force, White Paper 13, Non-Wood Fiber Sources

The advantages of alternative fiber paper are many. "Under favorable conditions, kenaf can be several times more productive than trees on a per-acre basis," says fibers expert E. L. Whitely. "Kenaf dry material could be produced at about half the cost per unit of producing pulpwood." Kenaf paper can also be produced without chlorine bleaching, advocates say. A Technical Association of the Pulp and Paper Industry (TAPPI) study called "A Search for New Fiber Crops," demonstrated that alternative fibers require less energy and chemical use in processing than standard wood sources. According to the "Using Less Wood" fact sheet, energy use can be cut by 30 percent in the mechanical pulp and refining process with alternative fibers. - Jim Motovalli, "The Paper Chase"

The kenaf industry wants to take paper-making away from loggers and hand it over to the kinds of farmers who are now leaving the land in droves. Instead of paper being made by large international conglomerates, they see it being made by family farmers, people with an investment in the community and kids in the schools. "It will be a low-input crop," says [Tom] Rymsza [of Vision Paper]. "It doesn't need much in the way of pesticides and herbicides because bugs don't bug it, and it outcompetes most weeds." - Jim Motovalli, "Pulp Friction: Debating the Paper Alternatives"


LISTENING STUDY: Many responses compared nonwood fibers to forest fibers based on specific factors.

Growth in paper and paperboard consumption in the developed countries continues at the rate of 2 to 3% annually. Most of the papermaking fibres are sourced from wood harvested from the primary forests. Because of economic greed, the accessible supplies have diminished considerably during the past 40 years. The demand to increase forest harvesting rate remains unabated. Culturally-valuable and ecologically-important forests are being destroyed unnecessarily.
      It is timely to re-examine the supply of papermaking fibres from a zero-base viewpoint, without technical prejudice. The obvious sensible approach is the reinforcement of the basic tenet: Reduce, Reuse and Recycle, and with the addition of a "4th R". The fourth "R" is replacement of traditional virgin wood fibres with other fibres. Replacement with agricultural cropping residues in paper manufacture, in conjunction with "reduce, reuse and recycle" practices would have a significant impact on "saving trees." - Al Wong, "How Many Trees Can Be Saved?"

The most important factors in assessment of agricultural fibers in paper making is how to define the agricultural fibers. There are several interest groups whose interests are different - for example in kenaf, hemp, straw, etc. The general classification that we or I would apply is first, primary fiber (on-purpose crops) such as Kenaf, cotton, etc. and, second, by- or co-products, such as straws and sugar cane bagasse that are a secondary or by-product of agriculture. Therefore, it depends upon the classification, the yield could be different. For example, kenaf is considered as a good virgin fiber with yield of about 8 tons per acre, but this figure could be misleading because kenaf will grow in Canada, but very poorly. Hemp can grow almost anywhere but many countries prohibit growing hemp. Most of the primary fibers have higher yield per acre per year than wood fibers. - James S. Han, Research Chemist, USDA Forest Service Forest Products Laboratory

Nonwood and wood fiber crops, used for similar grades of paper and grown under similar conditions, generally yield roughly the same amount of paper-making fiber per hectare (original quote from Atchinson 1994). Hence, there does not seem to be any benefit to annual crops in terms of production per acre of land. - IIED 1996, Towards A Sustainable Paper Cycle

The only way to answer this is to specify what kind of tree/wood fiber compared to what kind of non-wood fiber, where.
      Even in comparing the same fiber, such as wheat straw, one may have drastic variations in fiber yield. The density of wheat grown in eastern Washington is 4x that in Kansas, for instance. This is due to climate conditions and soil quality. With bamboo, there are over 1000 varieties that will have a different yield per acre. Flax grown for linen grows much higher than the seed kind, yet the seed kind yields a beautiful fiber. - Jeanne Trombly, Fiber Futures

This section focuses on regions where land could be used to grow either annual fiber crops or trees. To reduce pressure on natural forests and other rare or declining natural communities, we need to obtain fiber from less ecologically sensitive land. The question we explore in this section is whether this land should be used to grow annual crops, such as hemp and kenaf, or trees.
      Supporters of annual crops for paper production claim two environmental benefits of using non-wood fiber rather than wood fiber in paper. They claim that (1) annual crops grown for papermaking generally produce significantly higher yields of fiber and pulp than do trees; and (2) such crops require lower agricultural inputs such as fertilizers and pesticides. The validity of these claims depends on several variables, including the type of non-wood fiber and the type of paper being produced. In assessing these claims, it is appropriate to compare annual crops to wood plantations rather than to natural forests because landowners essentially choose between planting annual fiber crops or planting trees to provide fiber for paper. It is also important to compare not only fiber yields, but also the yields of pulps made from the various fibers. The pulps being compared also must be functionally equivalent, that is, they can be used in the same papermaking application(s). - Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"

 

Click on table for larger version


SUMMARY OF ENVIRONMENTAL FINDINGS

Annual crops

Whether there are environmental benefits from using annual fiber crops to make paper depends on several factors.

  • In regions where tree plantations do not exist or are not economically viable, growing annual crops for paper may provide an additional source of fiber. Hemp cultivation may increase the fiber supply and papermaking capacities of these regions given its broad geographic range (although it is illegal to grow hemp in the United States today.)
  • In regions where landowners can plant trees or annual crops for fiber, planting trees usually results in pulp yields in the same range as those of kenaf or hemp. We did not find evidence to support the markedly higher yields frequently attributed to annual crops.
    • Yields of whole-stalk kenaf mechanical pulps are about 60% higher than those of mechanical pulps made from plantation-grown Southern pine.
    • Yields of kenaf and hemp bast fiber chemical pulps are lower than that of plantation-grown Southern pine bleached kraft pulp, with yields about 70% and 50%, respectively, of that for Southern pine.
    • Land requirements to produce fiber for use in printing and writing paper are somewhat higher for paper made from chemically-pulped kenaf bast fibers or from a combination of bast and core fibers, than for the combination of softwood and hardwood bleached kraft pulps typically used in wood-based paper.
  • On average, pesticide and fertilizer use are lower for trees than for either kenaf or hemp.
  • Annual fiber crop fields can be expected to provide less water quality protection; plant and animal habitat and overall species diversity; and recreational value than do tree plantations.

- Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"

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Yield per Acre/Over Time

Table 2. Fiber and Pulp Yields of Various Fiber Sources
Plant
Fiber yield
Pulp yield
(tonnes/year/ha)
(tonnes/year/ha)
Scandinavian softwood
1.5
0.7
Fast-growing softwood
8.6
4
Temperate softwood
3.4
1.7
Fast-growing hardwood
15
7.4
Wheat straw
4
1.9
Rice straw
3
1.2
Bagasse
9
4.2
Bamboo
4
1.6
Kenaf
15
6.5
Hemp
15
6.7
Elephant grass
12
5.7
Canary grass
8
4.0
Source: Pande 1998

The yield data [in the White Paper] indicate that, on average, annual fiber crops produce higher yields than softwood plantations, but not hardwood plantations. - Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"


LISTENING STUDY: Several experts specifically argue about the yields of kenaf vs. wood. Some present data they consider definitive, while others offer explanations for legitimate variations. The basis for calculations in a key reference document is challenged.

We would argue that where there are not local sources of wood that are accessible for harvesting, the use of agricultural fiber, whether it is ag residues or annual crops, may be a reasonable supplement or alternative to wood fiber.
      The question of yield should be answered by comparing usable pulp yields, rather than simply biomass or fiber yields per acre. For mechanical pulp applications, virtually the entire crop can be used. However, chemical pulping processes result in far lower overall plant usage. A lot of the initial literature on nonwood fibers compares only biomass or fiber yield and not usable pulp yield. In our assessment, the pulp yields for nonwoods may be lower, the same or higher than for wood, depending on the application and pulping process used. In particular, when the whole stalk of kenaf is used, as should occur in a mechanical pulping system, usable pulp yields are on average higher than those for loblolly pine in the South. Typically, plantation-grown loblolly pine has the highest usable pulp yields of the trees. On the other hand, when a chemical pulping process is used, for wood or nonwoods, usable pulp yields are lower for kenaf or hemp relative to yields from loblolly pine. On average, kenaf pulp yields are 70% that of the bleached southern pine pulp. Hemp pulp yields are on average 50% of the southern pine in a chemical pulping system.
      Another way to compare yields is based on the equivalent land requirement: How much land is necessary to grow the equivalent amount of pulp? These comparisons depend on the usable pulp per acre estimates. It follows that for the chemical pulps, a higher land use was necessary for kenaf than for soft or hardwood. Our estimate shows the required land use to be 0.59 acres per ton for separated 100% bast fiber for kenaf, 0.40 acres per ton for a mix of whole stalk-bast and core fibers, and 0.36 acres per ton for a typical mix of hardwood and softwood. These estimates are conservative. - Richard Denison, Ph.D., Senior Scientist, Environmental Defense

Environmental Defense's Paper Task Force White Paper #13, on Non-Wood Fiber Sources, provides data that many organizations still use to make decisions and promote viewpoints on the economic and environmental viability of kenaf fiber compared to forest and other types of fiber. Yet there are serious mistakes in White Paper #13's calculations. When others use these data, they are continuing arguments based on very basic mistakes.
      For example, Table 3 in the White Paper is labeled, "Fiber yields of kenaf, hemp and plantation woods (bone-dry tons/acre)." In fact, there is kenaf data and hemp data, but no plantation woods data. Yet the missing tree yield data is referred to many times throughout the report.
      There are also problems with the conversion factors listed at the top of the table. These conversions are important because much of this type of numeric data from the studies referenced in the table may be presented in either metric terms or U.S. terms and therefore must be converted to consistent measurement. Yet the conversion factors include these mistakes:

  • A U.S. short ton (2,000 pounds) is described as equal to 1.1 metric tons (2,20224 pounds), when in fact a short ton is .9 metric tons.
  • The conversion of tons/acre to metric tons/hectare is off by a factor of 6.
  • A cubic foot of softwood is represented as equivalent to 60.30 tons. Think about that. A cubic foot is a little bit bigger than a gallon of milk. If it was lead, it would weigh 705 pounds. Three tractor trailers weigh 60 tons. A cubic foot of softwood does not weigh 60 tons.
  • A cubic foot of hardwood is listed as being equivalent to 40 tons. First, it's impossible for it to weigh 40 tons. But second, the relative values are wrong. Hardwoods are denser, therefore heavier, than softwoods.

Results are further skewed when the report says that you can only use part of the kenaf plant to make chemical pulp for high-grade papers. But Environmental Defense's own report refers to whole stalk chemical kenaf pulp produced in Thailand in at least three places, contradicting their own assertion. And conclusions are drawn based on confusion of pulp yields with raw fiber yields, two very different types of data.
      How can we have a science-based discussion attempting to arrive at a well-thought-out comparison of the merits of different types of fiber if the basic data - and even the basic conversion factors - are wrong? - Tom Rymsza, President, Vision Paper

Research results from around the world indicate that the kinds of kenaf and hemp yields as seen in Table 1 (U.S. hemp average 2.2 tons/acre/year, Non-U.S. hemp avg. 3.8, U.S. kenaf avg. 6.3) are not attainable without attention to a number of production factors, including soil moisture and fertility, competition from weeds, and problems posed by insects and disease. It appears that regardless of claims to the contrary, production of both kenaf and hemp require regular application of fertilizer and various chemicals, and sometimes irrigation, similar to other forms of high yield agriculture. - Dr. Jim L. Bowyer, et al, Dovetail Partners

. . . [T]he amount of land required to produce printing and writing paper from wood is slightly lower than that required for kenaf. - Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"

Kenaf yields 2-2.5 tons of pulp fiber/acre/yr and 6-8 tons of fiber/acre per 4-5 month growing period. One ton of kenaf has a 52% fiber yield, higher than the average 45% for trees. Awhile back, International Paper grew test plots in Texarkana and presented negative yield results. They yielded only 3-3.5 tons of fiber/acre/yr, but that was due to poor harvesting methods. - Tom Rymsza, President, Vision Paper

On the yields - If you take 100 lbs. Arundo donax, 100 lbs. kenaf, and 100 lbs. wood, kenaf yields about 25 lbs. usable material, wood 44, Arundo donax 49.5 lbs. - Ernett Altherimer, Founder and Chairman, Nile Fiber

Compared with trees, kenaf, at 6-10 tons per acre, produces 3-5 times more fiber per acre per year. The yield depends on the specific "alternative" fiber. The yield for kenaf is roughly 50%. The yield for trees is about 46%. - Tom Rymsza, President, Vision Paper

There are lots of opinions, though not sufficient documentation on how contradicting claims can be reconciled. For examples, kenaf advocates will claim that yields per acre of kenaf are greater than for trees. Wood proponents will make the opposite claim. Clearly, there are underlying discrepancies on how we arrive at these numbers. In short, it is impossible to compare an acre of trees grown in the northwest to an acre of kenaf grown in the southwest. The different climates give these areas different growth potentials for different plants. A true comparison of yields would look at the growth potential for the softwood and the kenaf on the same acre of land. - Russell Clark, Environmentally Preferable Purchasing Program, US EPA

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Impacts on Water, Energy, and Pollution

LISTENING STUDY: Some responses refer to factors involved in acquiring the fiber, whether through logging or farming.

Several initiatives [in the U.S. and other countries] have looked at utilising waste straw, particularly since a number of countries no longer allow straw burning. - IIED 1996, Towards A Sustainable Paper Cycle

Sorghum is a low input crop (Kent Kaulfuss) - less irrigation (2/3 less water on average). - Lieberman 1995

In terms of environmental impacts of growing ag fibers vs. trees, I don't have specific data. My general impression is that those sources of cellulose fibers which are most pure (cotton) compared to those with a lot of impurities (wood) are much less chemically intensive to process. - Jeff Lindenthal, President, Green Field Paper Company

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LISTENING STUDY: There are significant differences in environmental impacts when specific types of fibers are pulped for papermaking. Many respondents went directly to evaluating the result of using different fibers for pulping. While all the factors are inter-related, some responses bring out details of one over another.

Pollution from Pulp Processing

There is uncertainty when comparing the effluent quantity and quality of tree free versus tree pulping processes because of mill scale issues. In many cases, non-integrated nonwood mills are small compared to tree based pulp mills, and may not possess comparable systems for recovery or treatment of effluent, in which case effluent quantity and quality will likely be worse than for a larger wood-based mill. In a larger mill, recovery of pulping chemicals and effluent treatment are far more prevalent and economic. If annual crops are integrated into existing mills that already have effluent recovery or treatment, they would be able to take advantage of these technologies and the result would be very different than for small mills like those we see in developing countries.
      In mechanical pulping processes, effluent quantity and quality are better compared to chemical pulping processes, regardless of fiber source. In our study, the quantity of effluent from a soda-process kenaf bleached pulp mill should be comparable to a softwood bleached kraft mill, and effluent quality should be similar as well. However, the soda process, which is more common in Europe, is almost non-existent in the US. For the typical kraft process applied to kenaf, the effluent flow is almost twice that of the same process applied to softwood. Effluent quality should be fairly similar.
      A note on the [Paper Task Force] study: there is a much greater range in the numbers obtained for wood mill effluent quality parameters than for kenaf. This may be due to there being less data for kenaf mills. - Richard Denison, Ph.D., Senior Scientist, Environmental Defense

Small mills are preferable for nonwoods because of limited fiber supply, therefore capital costs are lower. However, small mills by nature will be more polluting because chemical recovery does not make economical sense.
      
The higher proportion of silica in most nonwood fibers makes traditional chemical recovery processes ineffective. This results in a highly polluting effluent and an uncompetitive production process since the chemicals are not recovered and cannot be reused. In addition, the cost of installing chemical recovery systems is prohibitive for most small mills. This is one of the most serious problems associated with the use of nonwood fibers compared to wood, although the small capacity of many non-wood mills means that the overall impact is relatively low. . . with sufficient investment, a cost-effective and suitable process could be developed.
      The pollution levels from non-wood mills can be improved by reducing the amount of silica going into the effluent, developing a more efficient chemical recovery system for effluent with high silica content or introducing an alternative pulping process where there is less need for chemical recovery. - IIED 1996, Towards A Sustainable Paper Cycle

Silica can pose a significant problem for some agricultural fibers. Silica accumulates and hardens on machinery creating the need to frequently stop production and clean with caustic chemicals. Regularly shutting down machinery in a pulp mill decreases any chance of creating an economically viable product. Some agricultural residues such as straw and corn stalks have high levels of silica. Kenaf does not contain silica. - Tom Rymsza, President, Vision Paper

One Indian mill solved silica removal problems by washing the straw before processing, but they still had problems disposing of the silica water. - Atchison 1999

Non-woods generally use less energy and less water and fewer chemicals for pulping, but the pollution impacts to recover the chemicals have been a real bugger. Only now are there actual and affordable chemical recovery technologies that are emerging out of the laboratory and just past pilot stage. Once the silica issue is solved, the resource "footprint" of most nonwoods (cereal straws, grasses and reeds) will clearly be less than wood-based pulping. With papermaking there is very little difference. - Jeanne Trombly, Fiber Futures

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Energy

Agricultural fibers have a slight advantage in energy consumption and pollution due to low lignin contents, but wood fibers have high cellulose contents. See below, Table 3. Dimensions and Chemical Composition of Some Common Straw Fibers - James S. Han, Research Chemist, USDA Forest Service Forest Products Laboratory

Table 3. Dimensions and Chemical Composition of Some Common Straw Fibers
Type of Fiber
Cellulose
Lignin (%)
Fiber Dimension (mm)
Length
Width
Cereal straw
31-45
16-19
1.5
0.023
Corn straw
32-35
16-27
1.5
0.018
Wheat straw
33-39
16-23
1.4
0.015
Rice straw
28-36
12-16
1.4
0.008
Coniferous wood
40-45
26-34
4.1
0.025
Deciduous wood
38-49
23-30
1.2
0.030
Source: James S Han, Research Chemist, USDA Forest Service Forest Products Laboratory

The total energy consumed to produce a ton of whole-stalk kenaf mechanical pulp is about 35% lower than the total energy consumed to produce a ton of softwood mechanical pulp. The total energy consumed to produce a ton of kenaf soda pulp using an ECF bleaching process is about 37% lower than the total energy consumed to produce a ton of softwood bleached kraft pulp using an ECF bleaching process. However, the purchased energy [electricity purchased off the grid and fossil fuels burned on-site] consumed by the kenaf soda mill is about 50% higher than the highest purchased energy consumed by a wood-based kraft mill. - Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"

If you look just at purchased energy, the kenaf processing uses 50% more. This is because the wood-based mill generates considerable energy by burning wood-derived materials that are by-products of the chipping and pulping process. The wood industry tends to argue this energy is "free" and even claim that they use less total energy than nonwood mills. However, the entire tree - both the part that becomes usable fiber and the part burned for energy - has to be grown and harvested. Therefore, any impacts of harvesting and growing trees, including natural resource depletion or damage, and air pollution from combusting the wood-derived materials, applies to this energy source. - Richard Denison, Ph D, Senior Scientist, Environmental Defense

Summary of Environmental Findings:

  • The total energy consumed to produce a ton of kenaf mechanical pulp is about 35% lower than the total energy consumed to produce a ton of softwood mechanical pulp.
  • The total energy consumed to produce a ton of kenaf soda pulp using an ECF bleaching process is about 37% lower than the total energy consumed to produce a ton of softwood bleached kraft pulp using an ECF bleaching process. However, the purchased energy consumed by the kenaf soda mill is about 50% higher than the highest purchased energy consumed by a wood-based kraft mill.
  • Effluent flow and quality are similar for the kenaf and the wood-based chemical pulps.

- Environmental Defense Fund Paper Task Force, White Paper 13, "Non-Wood Fiber Sources"

Since there is no such kenaf soda mill in the world, how can EDF make this assertion? - Tom Rymsza,, President, Vision Paper

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Bleaching

LISTENING STUDY: The relative need for bleaching can be determined, in part, by the lignin quantity in the fiber. Table 4 compares the chemical properties of various nonwood fibers.

Table 4. Chemical Properties of Various Nonwoods
Fiber Source Alpha Cellulose (%) Lignin (%) Pentosans (%) Ash (%) Silica (%)
Bast Fibers
Jute (1)
21 - 26
18 - 21
0.5 - 1
<1
Kenaf
31 - 39
15 - 18
21 - 23
2 - 5
Oilseed flax tow
34
23
25
2 - 5
Textile flax tow
45 - 68
10 - 15
6 - 17
2 - 5
Leaf Fibers
Abaca
61
9
17
1
<1
Sisal
43 - 56
8 - 9
21 - 24
0.6 - 1
<1
Seed Hull Fibers
Cotton staple
85 - 90
3 - 3.3
1 - 1.5
<1
Cotton linters
80 - 85
3 - 3.5
1 - 1.2
<1
Stalk Fibers
Canes sugarcane bagasse
32 - 44
19 - 24
27 - 32
1.5 - 5
0.7 - 3
bamboo (wide range)
26 - 43
21 - 31
15 - 26
1.7 - 5
1.5 - 3
Cereal straw barley
31 - 34
14 - 15
24 - 29
5 - 7
3 - 6
oat
31 - 37
16 - 19
27 - 38
6 - 8
4 - 7
rice
28 - 36
12 - 16
23 - 28
15 - 20
9 - 14
rye
33 - 35
16 - 19
27 - 30
2 - 5
0.5 - 4
wheat
29 - 35
16 - 21
26 - 32
4 - 9
3 - 7
Grass arundo donax
29 - 33
21
28 - 32
4 - 6
1.1 - 1.3
esparto
33 - 38
17 - 19
27 - 32
6 - 8
2 - 3
sabai
17 - 22
18 - 24
5 - 7
3 - 4
switchgrass
43
34 - 36
22 - 24
1.5 - 2
Reeds phragmites communis
45
22
20
3
2
Woods - for comparison
Coniferous
40 - 45
26 - 34
7 - 14
1
<1
Deciduous
38 - 49
23 - 30
19 - 26
1
<1
Note: For well cleaned raw material - the composition of uncleaned raw material will be different with respect to pentosans, solubles, ash and silica content in many cases.

Source: Hurter 2001

Most annual crops, when compared with trees, contain lower levels of lignin. Since chemical pulping methods remove non-cellulose components, many annuals can be pulped using milder chemistry and less energy.
      The ability to bleach a fiber with low or no chlorine depends on the fiber properties. Al Wong has previously reported that hemp is difficult to bleach. Kenaf is naturally whiter than tree pulp and can be bleached in a totally chlorine free environment. - Tom Rymsza, President, Vision Paper

On bleaching, it is generally clamed that agricultural fibers can have less lignin so less bleach is needed to get paper white. I haven't seen the scientific studies demonstrating this, but they're probably out there. The claim that nonwoods might use less water in the pulping and bleaching process might have to do with the type of bleach used. For a smaller run, it might be more economical to use a more expensive process where the chemicals are reused rather than thrown out because it uses less bleach. In this case, the smaller process may allow a better technology. - Russell Clark, Environmentally Preferable Purchasing Program, US EPA

The brightness of rice straw paper is 88 and wheat straw is 80-85, in comparison to hardwood 85-90, and softwood 88-90. Thus, wood fibers have a slight advantage over agricultural fibers. - James S. Han, Research Chemist, USDA Forest Service Forest Products Laboratory

Bleaching of nonwood pulps, however, typically is easier than woodpulp and requires fewer bleaching stages and lower chemical consumptions. - Hurter 1998

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Need for Pesticides and Fertilizers

LISTENING STUDY: Some argue that agricultural crops require more pesticides and fertilizers than plantation trees.

We found relative little data characterizing agrichemical use on annual crops. The available data indicate that pesticide and fertilizer usage even for plantation-grown trees is generally lower than it is for kenaf and hemp. The main reason for this is that trees are grown on multi-year rotations with chemicals applied at most every few years, in contrast to annual crops, where such chemicals are applied annually. With respect to pesticide use on annual crops, there is geographical variation based on endemic pest problems. Fertilizer input can also vary, but it is important to realize that fertilizer use and yield go hand in hand. In our yield estimates, the highest yields corresponded to the highest fertilizer inputs.
      In our comparisons, a typical pine stand planted on a 25 year rotation receives 8 lb. fertilizer/acre/year. Kenaf received a greater range and a considerably higher average amount of nitrogen based fertilizers: from 0-130/150 lb./acre/yr. Most of the hemp information indicated more than 100 lb/acre/yr. - Richard Denison, Ph D, Senior Scientist, Environmental Defense

Most farmers use pesticides and fertilisers on their non-wood fibre crops, although it is possible to grow most types of fibre without those inputs. Amounts applied vary significantly, as with tree plantations, but generally, it would seem that approximately the same amount of pesticides and fertilizers are used on a single rotation of trees (minimum seven years) as for a single rotation of agricultural crops (one year). - IIED 1996, Towards A Sustainable Paper Cycle

Most annual plants need pesticides and fertilizers, including virgin fibers. - James S. Han, Research Chemist, USDA Forest Service Forest Products Laboratory


LISTENING STUDY: There are situations in which each alternative might use more.

Any farm fiber used for large scale papermaking will require some level of pesticides and fertilizer. Since the farmer is harvesting for fiber instead of fruit or grain, less herbicide and no insecticide are used for a crop such as kenaf. Agricultural waste fibers would have a different chemical use profile, since they are grown for grain or fruit.
      EDF and the Paper Task Force reported in its White Paper #13 that tree farms used fertilizer at rates between 0-34,000 pounds per acre per year. Compared to the high- end estimate, a kenaf field has less inputs. - Tom Rymsza, President, Vision Paper


LISTENING STUDY: There are also arguments that agricultural crops used for papermaking require less pesticides and fertilizers, often because of beneficial properties of the plants.

There are specific studies on particular fibers, such as hemp and kenaf that insist they need fewer chemicals than wood plantations, which can be resource intensive, depending on the grower. But again, there are no broad studies to provide the data that is needed to answer this question. - Jeanne Trombly, Fiber Futures

[Sorghum is a] fast grower, so less weed competition, less cultivation requirements. Low pest pressures (both kenaf and sorghum) - kenaf is host to beneficial insects. - Lieberman 1995

High growth of above-ground biomass corresponds to high nitrogen fertilizer uptake a law of nature. See for example, my presentation, "Socio-Economic and Technical Issues of On-Purpose Fiber Cropping and Food Cropping." - Al Wong, Founder, Arbokem

Currently, the only legal chemical to use on kenaf is Treflan, made by Dow AgroScience. Though not benign, it is generally safer than others. Most kenaf fields do not use fertilizer, as kenaf is ideal to rotate in after soybeans. No post-planting herbicides are needed. The fast growing tall stalks shade out other plants. Application would be too difficult anyway because the plant grows too tall. - Tom Rymsza, President, Vision Paper

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Soil Impacts

Arundo donax is a carbon sequestration giant. It takes in carbon and effluents and stores them in the leaves, stems, etc. Compared with wood it is 90% more efficient at sequestering carbon. Arundo donax enhances the soil by processing toxic chemicals to an inert form. For example, Alabama had a five-year drought but everything growing around the Arundo donax did fine. Arundo donax uptakes toxins from air and soil and every kind of effluent from the air. - Ernett Altherimer, Founder and Chairman, Nile Fiber

Kenaf's long roots remove salt deposits in the soil and can be used as an excellent rotation crop for improving the soil and can pull up lost nitrogen leached farther down in the soil (originally quoted from Steve Shaffer of California Department of Food and Agriculture). - Lieberman 1995

The disturbance of soil, which has carbon loss implications relevant to global warming, is typically much higher for agriculture than for silviculture. The frequency of entry for tree plantations is lower, and the impacts of such entries are less intense, than for annual crops. There are lower-impact crop practices such as conservation tillage, though we are unaware of data as to how often these are applied on kenaf and hemp fields. Soil conservation is an important consideration because it also has erosion and runoff rate implications, a particular concern when agrichemicals are applied. - Richard Denison, Ph.D., Senior Scientist, Environmental Defense

Before we advocate the use of a particular non-wood fiber from an identified area, we always pull in the expertise of a soil scientist. Some soils need the biomass from ag-residues. Other soils cannot absorb the density of material. With wheat straw, many Agriculture Extension representatives and farmers are discovering that they prefer not to till the straw back into the earth because that exacerbates erosion. This is why they prefer to burn it, and it would point to another advantage for removing the straw for a fiber use. - Jeanne Trombly, Fiber Futures

The specific blend of fibers in each material, coupled with how the product is made, affects the sustainability. Diversity is the key for an economically and strategically positioned fiber supply. In theory, the wear and tear on the land (topsoil) over ten years growing trees would be less than an annual crop, while the production of pulp from trees would require more energy and water based on lignin content, etc.
      Perennials such as Arundo donax and switchgrass have the same arguments. You've still got a tractor going in every year for harvesting. This causes more damage to the soil than trees. Generally, the harvesting, baling, etc. are never factored in comparisons between agricultural fibers and trees. Arundo donax would be somewhere in between an annual and a tree. While you have to cut it out every year rather than every 12 or so years, it has a lower energy consumption in the pulping process. You only have to handle the tree once every life cycle, but the entire life cycle of the tree is always going to expose the soil to the elements for the least amount of time. Annual crops have the greatest mean exposure to the elements. Next are the herbaceous crops.
      If we hold Arundo donax as a token fiber, as the U.S. Dept. of Energy has done with switchgrass, then we shoot ourselves in the foot, because diversity is the key. Each fiber source has a growing condition and other environmental factors that make it superior in a given application. - Peter A. Nelson, President, AgroTech Communications, Inc.

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Use of Land

The forest plantations that cover ancient forest soils are not the answer.. These plantations tie up useful land, and after only a few rounds, leave the soil decimated. We cannot pretend that we will turn these areas back into forests. Kenaf offers us a viable alternative. Kenaf, unlike tree plantations, can be integrated as a rotation crop. Plantations tie up land for six to 17 years, while a kenaf crop reaches a harvestable height of 12 to 18 feet in only 150 days and yields five to 10 tons of fiber per acre annually (as opposed to two to three for southern pine). - David Brower, "Kenaf: A Tree-Free Alternative"

Eradicating creek beds of the non-native (Arundo donax) has provided some production material and the seed stalk. We harvested rhizomes to cultivate. We are also researching stem cell cultivation. - Ernett Altherimer, Founder and Chairman, Nile Fiber

The Stockton Pacific Enterprises pulp mill [in Samoa, California] says it has abandoned plans to grow a giant reed in the Central Valley and ship it to Humboldt County to make wood-free pulp. The pulp company also will not ship the invasive reed, Arundo donax, from sites in Southern California where it is being eradicated [because t]he costs of moving a raw material over such long distances are too high . . . That may be just as well, according to some who worry that the giant reed could become a giant pest, like it has as far north as the Russian River. The reed grows up to 30 feet tall, and spreads when floods break off pieces of cane, which root downstream. It isn't thought to sprout from seed.
      . . . It was also planted around bridge abutments and erosive areas to shore up problem spots, but it has spread like wildfire. Experts say an infestation in the North Coast's salmon streams could be disastrous. Stockton Pacific was Samoa Pacific when the Arundo plan was hatched in 2002. That former company planned to ship the reed north in tightly covered trucks. But it takes only a little Arundo to spawn a big problem. - John Driscoll, "Pulp Mill Forgoes Wood-Free Pulp Plan"


LISTENING STUDY: Further debates about the appropriate land-use of trees vs. different kinds of agricultural crops are presented in Question 42.

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