Fiber Sources

Part of Paper Making

Paper is fundamentally a mat of plant fibers bonded together by their own natural adhesion. The type of fiber you start with determines the paper’s strength, texture, color, and suitability for writing, printing, or packaging. Choosing and harvesting the right fiber source is the first step in any papermaking operation.

Why Fiber Sources Matter

Not all plant fibers make equal paper. Some produce strong, durable sheets that last centuries; others make soft, weak paper that tears easily. Some fibers are available year-round while others are seasonal. Some require hours of processing; others are ready almost immediately. Knowing your fiber options lets you produce the right paper for each purpose — strong paper for books that must endure, soft paper for everyday writing, rough paper for wrapping and packaging.

How Plant Fibers Work in Paper

Paper depends on cellulose — the structural polymer that gives plants their rigidity. When plant material is broken down into individual fibers and suspended in water, then drained on a screen, the fibers mat together and bond through hydrogen bonding as they dry. The result is paper.

The best papermaking fibers are:

• Long (1-5 cm) — longer fibers interlock more, producing stronger paper
• Thin and flexible — they conform and mat tightly
• High in cellulose — more cellulose means stronger bonds
• Low in lignin — lignin makes paper brittle and yellow over time

Bark Fibers

Inner bark (bast) fibers from trees and shrubs produce the strongest, most durable paper. These are the traditional fibers used in the oldest surviving papers.

Mulberry (Kozo)

Property	Detail
Fiber length	7-12 mm (very long)
Paper quality	Extremely strong, flexible, translucent
Availability	Warm temperate to subtropical climates
Harvest time	Late fall to early spring (dormant season)

The gold standard for handmade paper. Japanese washi paper, some of which has survived 1,000+ years, is made from mulberry bark.

Harvesting:

1. Cut year-old stems (1-2 cm diameter, straight growth)
2. Steam the stems for 1-2 hours until the bark peels easily
3. Strip the bark in long ribbons
4. Separate the thin inner bark (white-green layer) from the outer bark (dark, rough layer)
5. The inner bark is your papermaking fiber

Elm

Strong, abundant in temperate regions. The inner bark makes excellent paper.

1. Harvest from branches or recently felled trees in spring when bark peels easily
2. Peel long strips of inner bark
3. Dry for storage or process immediately

Willow

Widely available near water. Produces moderate-strength paper.

1. Harvest flexible young shoots in late winter
2. Peel bark after brief soaking or steaming
3. Fiber is shorter than mulberry but still serviceable

Bark Harvest Season

Bark peels most easily in spring when sap is rising, and in fall after leaf drop. Summer bark is difficult to separate and winter bark (mid-winter) is brittle. Time your harvest to the easy-peel seasons.

Leaf and Stem Fibers

These fibers are shorter than bark fibers but often more abundant and easier to harvest.

Cotton and Cotton Rags

Property	Detail
Fiber length	15-40 mm (the longest of all)
Paper quality	Premium — smooth, strong, archival
Availability	Subtropical climates for fresh; salvage rags everywhere
Processing	Easy — already nearly pure cellulose

Cotton is the finest papermaking fiber. Cotton rag paper was the standard for European paper for centuries and is still used for currency and archival documents.

From rags:

1. Collect cotton and linen rags — old clothing, bed sheets, towels
2. Cut into small pieces (2-3 cm squares)
3. Soak in water for days or weeks until they soften and begin to break down
4. Beat into pulp (see Pulp Preparation)

Cotton Rags are Paper Gold

In a rebuilding scenario, save every scrap of cotton and linen fabric. Old clothing, sheets, sails, and canvas make the best paper available. Establish a rag collection system in your community early.

Hemp and Flax (Linen)

Both produce extremely strong, long-lasting paper. Many of the oldest surviving documents were written on hemp or linen paper.

Fiber	Length	Strength	Availability
Hemp bast	5-55 mm	Very strong	Grows anywhere with 100+ frost-free days
Flax bast	10-65 mm	Very strong	Cool to moderate climates

Harvesting hemp/flax for paper:

1. Ret (soak) the stems in water for 1-3 weeks until the outer bark softens
2. Break the stems to separate the woody core from the bark fibers
3. Hackle (comb) to separate individual fibers
4. Cut to 2-3 cm lengths for pulp processing

Straw and Grass

Abundant but produce weaker paper. Good for rough paper, packaging, and practice.

Source	Quality	Notes
Wheat/rice straw	Fair	Short fibers, needs heavy cooking
Bamboo	Good	Excellent paper — used in China for centuries
Esparto grass	Good	Traditional Mediterranean papermaking fiber
Cattail leaves	Fair	Abundant in wetlands
Corn stalks	Poor-fair	Very common, short fibers

Straw Paper for Practice

While straw makes inferior paper compared to bark or cotton fibers, it is so abundant that it is ideal for learning the papermaking process. Master your technique on straw paper before investing effort in premium fibers.

Wood Fibers

Modern paper is almost entirely made from wood pulp. For the rebuilder, wood is a plentiful fiber source, but it requires more processing than bark or rag fibers.

Softwoods (Preferred)

Spruce, pine, and fir produce the best wood-pulp paper:

• Longer fibers (3-5 mm) than hardwoods
• Produce stronger paper
• Easier to pulp chemically

Hardwoods

Oak, maple, birch, and poplar:

• Shorter fibers (1-2 mm)
• Produce smoother but weaker paper
• Good for blending with softwood pulp

Processing Wood for Paper

Wood requires significantly more processing than bark or rag fibers because it contains 25-35% lignin (the polymer that makes wood rigid). Lignin must be removed or the paper will be weak, brittle, and yellows rapidly.

1. Chip the wood into small pieces (1-3 cm)
2. Cook in an alkaline solution (wood ash lye) for 4-8 hours to dissolve lignin
3. Wash thoroughly to remove dissolved lignin and cooking chemicals
4. Beat into pulp

See Pulp Preparation for detailed cooking and beating instructions.

Recycled Paper

Used paper can be re-pulped and made into new paper. The fibers are shorter each cycle (they break during beating), but recycled paper is a valuable resource.

Process

1. Tear old paper into small pieces (2-3 cm)
2. Soak in warm water for 1-2 hours
3. Beat or stir until the fibers separate into a smooth slurry
4. Add to fresh pulp (30-70% recycled mixed with fresh fiber) for best results
5. Form sheets as normal

Recycling Limits

Paper fibers get shorter each time they are recycled. After 5-7 cycles, the fibers are too short to bond effectively. Always blend recycled pulp with a proportion of fresh, long-fiber pulp to maintain sheet strength.

Fiber Comparison Table

Fiber Source	Fiber Length	Paper Strength	Processing Difficulty	Availability
Mulberry bark	Very long	Excellent	Moderate	Warm climates
Cotton/linen rags	Very long	Excellent	Easy	Salvage everywhere
Hemp bast	Long	Very good	Moderate (retting)	Grows widely
Flax bast	Long	Very good	Moderate (retting)	Cool climates
Softwood	Medium	Good	Hard (cooking needed)	Forests
Bamboo	Medium	Good	Hard (cooking needed)	Tropical/subtropical
Straw	Short	Fair	Moderate	Agricultural areas
Recycled paper	Short	Fair	Easy	Existing paper stock

Harvesting and Storage

Best Practices

1. Harvest at the right time — Bark in spring or fall; stems after maturity; straw after grain harvest
2. Dry before storage — Wet fiber rots. Dry all harvested material completely before storing
3. Store dry and ventilated — Bundle dried fiber and store in a dry, airy location
4. Process when ready — Dried fiber re-soaks and processes the same as fresh, often better
5. Manage your supply — A single sheet of paper requires a surprising amount of raw fiber. Plan to harvest and store large quantities.

Quantity Estimates

Fiber Type	Raw Material per kg of Paper
Cotton rags	1.2-1.5 kg
Bark fibers	2-3 kg (fresh)
Straw	3-5 kg
Wood chips	3-4 kg

Common Mistakes

1. Using lignin-rich fibers without cooking — Wood and straw contain lignin that makes paper brittle and yellow. Cook in alkaline solution first, or accept short-lived paper.
2. Harvesting bark at the wrong season — Summer bark does not peel cleanly, wasting material and damaging the tree. Harvest in spring sap-rise or after fall leaf-drop.
3. Not separating inner from outer bark — Outer bark is woody and does not make good paper. Always separate and use only the thin inner bark layer.
4. Discarding cotton rags — Every piece of cotton and linen cloth is premium papermaking material. Establish community rag collection immediately.
5. Underestimating quantities — Beginners are surprised by how much raw fiber is needed for even a small batch of paper. Harvest generously and maintain a stockpile.

Summary

Fiber Sources — At a Glance

• Best fibers for paper: mulberry bark, cotton/linen rags, hemp, and flax — long, strong, archival quality
• Cotton rags are the most accessible premium fiber — save every scrap of cotton and linen fabric
• Wood pulp requires cooking in alkaline solution to remove lignin; bark and rag fibers need less processing
• Straw and grass make adequate paper for everyday use and are excellent for learning
• Harvest bark in spring or fall when it peels easily; dry all fibers before storage
• Recycled paper can be re-pulped but fibers shorten each cycle — blend with fresh fiber
• Budget 2-5 kg of raw material per kg of finished paper depending on fiber type