Shoes draw on a surprisingly wide range of natural resources, from animal hides and tree sap to plant fibers and harvested bark. Even a single pair can combine materials sourced from cattle ranches, rubber plantations, cotton fields, and cork forests. Here’s a closer look at each resource and how it ends up on your feet.
Leather From Animal Hides
Leather is the most iconic natural material in shoemaking and still one of the most widely used. The global leather industry converts around 7.3 million tons of hides per year, material that would otherwise go to landfill as a byproduct of the meat industry. Virtually all of it, 99%, comes from livestock: cattle, sheep, goats, and pigs. Cattle hides alone account for 69% of the world’s leather supply.
The journey from raw hide to finished shoe upper involves tanning, a process that stabilizes the protein structure of the skin so it won’t decompose. Traditional vegetable tanning uses plant-based compounds from tree bark, primarily oak, chestnut, and mimosa. Chrome tanning, which is faster and more common today, relies on chromium salts, a mineral resource. Both methods also require large volumes of water. The finished leather is then cut, stitched, and shaped into uppers, linings, insoles, and sometimes entire shoe constructions like moccasins or loafers.
Other animal-derived materials show up in shoes too. Wool felt lines winter boots and clogs. Beeswax waterproofs leather surfaces. Silk occasionally appears in high-end dress shoes. These are niche compared to leather, but they’re all pulled from the same category of animal-based natural resources.
Natural Rubber From Tropical Trees
The soles beneath your feet often start as a milky white fluid inside the bark of rubber trees, grown primarily in Southeast Asia. Workers called tappers carefully shave a thin slice of bark at a 25- to 30-degree angle, starting from the upper left and working down to the lower right. The cut must be precise enough to open the latex vessels without damaging the growth layer underneath. Latex flows out into collection cups, mostly during morning hours when yield is highest.
This raw latex is then processed into solid rubber through coagulation and drying. Natural rubber has properties that synthetic alternatives still struggle to fully replicate: excellent grip, flexibility, and resilience. That’s why it remains the preferred sole material for everything from sneakers to work boots. Indigenous peoples in South America were actually making rubber footwear from latex centuries before modern manufacturing existed.
Beyond soles, natural latex also serves as an adhesive in shoe assembly. Water-based natural latex adhesives bond uppers to soles and attach layers of foam, leather, and textiles together. These provide strong, durable connections while avoiding some of the environmental concerns associated with petroleum-based glues.
Cotton, Hemp, and Other Plant Fibers
Canvas sneakers, espadrilles, and many casual shoes get their upper material from plant fibers. Cotton is by far the most common. It’s spun into thread, woven into canvas or twill, and then cut and sewn into shoe uppers. Growing cotton is resource-intensive: a single kilogram of conventional cotton requires roughly 10,000 liters of water, plus significant amounts of land and, in most cases, pesticides and fertilizers.
Hemp is a less common but increasingly popular alternative. It grows faster than cotton, needs less water, and requires fewer chemical inputs. The resulting fabric is durable and breathable, making it well-suited for warm-weather shoes. Jute, the same plant fiber used in burlap sacks, appears in espadrille soles and some casual shoe uppers. Linen, made from flax plants, occasionally shows up in summer footwear. Each of these fibers represents a different agricultural resource with its own demands on soil, water, and land.
Cork From Mediterranean Forests
Cork, the spongy outer bark of cork oak trees, plays a specific role in footwear. You’ll find it in midsoles, insoles, and the wedge platforms of sandals like Birkenstocks. Cork is lightweight, naturally cushioning, and molds to the shape of your foot over time, which is why it’s valued for comfort-focused shoes built with welt construction.
Harvesting cork is unusually sustainable compared to most natural resource extraction. Trees must reach about 25 years old before the first harvest, and after that, the bark is stripped only once every nine years. Specialized workers called extractors use sharp axes to make horizontal and vertical cuts, carefully peeling away the bark between May and August, the only months when it separates cleanly without permanently damaging the tree. The first two harvests typically yield lower-quality cork. A single cork oak can be harvested for over 150 years, making it a genuinely renewable resource.
Wood and Other Forest Products
Wood appears in shoes more often than you might expect. Wooden lasts (foot-shaped forms) have been used for centuries to shape leather during construction, though many are now plastic. Some clogs and platform shoes use solid wood for their soles. Birch, poplar, and alder are common choices because they’re lightweight and easy to carve.
Tree-derived cellulose also shows up in newer shoe materials. Wood pulp from sustainably managed forests can be processed into fibers like lyocell, a smooth, breathable textile used in shoe linings and uppers. The wood is dissolved and reformed into fiber using a closed-loop process that recycles most of its chemical solvent. Pine resin, tapped from conifer trees in a process similar to rubber extraction, sometimes serves as a base for natural adhesives and waterproofing treatments.
Minerals and Earth-Based Materials
Several minerals mined from the earth make their way into shoe production, often invisibly. Silica, derived from quartz sand, is used as a reinforcing filler in rubber soles to improve grip and durability. Calcium carbonate, essentially ground limestone, serves a similar purpose, adding bulk and structure to rubber compounds while keeping costs down. Clay minerals act as fillers in both rubber and adhesive formulations.
Metal hardware on shoes, including eyelets, buckles, aglets, and shanks (the supportive strip embedded in the sole of dress shoes), comes from mined ores. Steel, brass, and aluminum are the most common. Even the dyes that color leather and fabrics often trace back to mineral pigments, though synthetic dyes dominate modern production.
How These Resources Come Together
A typical leather shoe might combine cattle hide from South America, natural rubber from Thailand, cotton thread from India, cork from Portugal, and metal hardware forged from ores mined in multiple countries. A canvas sneaker swaps out the leather for cotton but still relies on natural rubber, mineral fillers, and plant-based or latex adhesives. Even shoes marketed as “synthetic” often include natural rubber in the outsole or cotton in the lining.
The resource intensity varies dramatically by shoe type. A simple pair of rubber flip-flops draws on one or two natural resources. A handmade leather boot with a cork insole, wooden shank, cotton lining, and brass hardware pulls from at least six distinct categories of natural materials, each with its own supply chain stretching across different continents and ecosystems.