A fence is only as good as its posts. Rails and boards can be replaced in an afternoon, but when posts rot at ground level the whole fence leans, and digging out old posts is slow, heavy work. The best wood for fence posts is naturally durable in ground contact, strong enough to take wind loads and gate weight, and dense enough to resist insects, so the posts last for decades rather than a few years.
In this guide we compare the durable African hardwoods that farms, councils, landscapers and fencing contractors use for posts, and we explain why they often outlast treated softwood. At Global Timber Trade Hub we supply posts, rails and heavy sections from Central Africa. We also cover sizes, installation, cost per year of service and buying in volume.
In short
- Fence posts fail first at ground level, where wood stays wet and fungi thrive.
- Azobe, okan, tali, bilinga and mukulungu are among the most durable woods in the ground.
- Iroko is a good, slightly cheaper option for lighter fencing.
- Dense hardwood posts need no chemical treatment.
- Typical sizes are 75–150 mm square, 1.8–3.0 m long.
- Higher upfront cost is offset by a much longer service life.
Why fence posts rot
The zone just above and below the soil surface is where wood stays damp but still gets oxygen. These are perfect conditions for wood-decay fungi. Termites and other insects attack posts from the ground too. Most softwoods have little natural durability, so they rely on chemical preservatives forced into the wood under pressure. Even treated posts can fail early if the treatment did not penetrate deeply, or if the post was cut after treatment. Naturally durable hardwoods resist decay because of the extractives in their heartwood, all the way through the post.
What makes a good fence post wood?
- Natural durability: heartwood that resists fungi and insects in ground contact.
- Density and strength: to take wind loads, livestock pressure and gate weight.
- Stability: posts should stay straight as they dry and weather.
- Heartwood content: sapwood is not durable, so posts should be free of it.
- Cost per year: the price divided by the years of service.
Fence post woods at a glance
| Species | Density (kg/m³, dry) | Ground contact durability | Best for | From (USD/m³, FOB) |
|---|---|---|---|---|
| Azobe (ekki) | about 1,000–1,100 | Very high | Heavy fencing, gate posts | $650 |
| Okan | about 900–950 | Very high | Posts, rails | $650 |
| Tali | about 900–950 | Very high | Posts, rails | $650 |
| Bilinga | about 750–800 | Very high | Posts, lighter sections | $700 |
| Mukulungu | about 900–950 | Very high | Heavy posts | $700 |
| Iroko | about 650–700 | High | Garden fences, rails | $950 |
Durability ratings are general guidance based on published testing. Real service life depends on soil, climate, post size and installation. Prices are indicative starting points for sawn sections.
Azobe: the heavy-duty choice
Azobe, also called ekki, is one of the hardest and heaviest commercial timbers in the world. It is widely used in Europe for river bank protection, lock gates and bridges, so ground and water contact are no problem. As a fence post or gate post it is extremely strong and long lasting. The downside is weight: a 150 mm square post 2.4 m long weighs well over 50 kg, so handling needs planning. See our azobe price guide.
Okan and tali: strong all-rounders
Okan and tali are both very dense, durable hardwoods used for heavy outdoor construction, sleepers and marine work. They are slightly lighter than azobe and are often easier to source in standard post sizes. Both are excellent for farm fencing, equestrian fencing and gate posts. Read our okan wood and tali wood guides, or compare them in okan vs azobe.
Bilinga and mukulungu
Bilinga is a golden-yellow hardwood with very high natural durability, often used for marine piles and sleepers. It is lighter than azobe, which makes posts easier to handle. Mukulungu is very dense and durable, a good alternative when azobe is scarce. See our bilinga wood guide.
Iroko for garden fencing
For garden fences, screens and decorative fencing where loads are lighter, iroko is a good choice. It is durable, stable, easy to work and weathers to an attractive silver-grey. It is less dense than azobe or okan, so for heavy gates and livestock fencing choose one of the denser species.
Hardwood vs treated softwood posts
| Factor | Durable hardwood | Treated softwood |
|---|---|---|
| Upfront cost | Higher | Lower |
| Typical service life in ground | Often several decades | Often 10–20 years, varies with treatment |
| Chemicals | None needed | Preservative treatment |
| Strength | Very high | Moderate |
| Weight | Heavy | Light |
| Cut ends | Durable all through | Need re-treating |
For long fences in remote places, councils and farms often find that hardwood posts cost less over their life, because replacement labour is the biggest cost of fencing.
Cost per year of service
Suppose a treated softwood post costs a third of the price of an azobe post but lasts 15 years, while the azobe post lasts 40 years. Over 40 years you would install the softwood post about three times, paying for labour, machinery and disposal each time. In many cases the hardwood post works out cheaper per year, especially where labour is expensive or access is difficult. Your figures will depend on local prices and conditions, so run the numbers for your own project.
Standard post sizes
- Intermediate posts: 75 × 75 mm to 100 × 100 mm, 1.8–2.4 m long.
- Strainer posts: 125 × 125 mm to 150 × 150 mm, 2.4–3.0 m long.
- Gate posts: 150 × 150 mm to 200 × 200 mm, 2.7–3.6 m long.
- Rails: 38 × 87 mm, 50 × 100 mm and similar, in lengths to suit post spacing.
Posts can be supplied with pointed ends for driving, or square-cut for setting in holes. Sizes can be adjusted to suit local standards.
Installation tips
- Depth: set posts about a third to a quarter of their length into the ground, deeper for gate posts.
- Drainage: a layer of gravel at the bottom of the hole helps water drain away.
- Backfill: compacted soil and stone often lasts longer than concrete, which can trap water.
- Top cut: cut or chamfer post tops so rain runs off.
- Fixings: use stainless or hot-dip galvanised fixings, and pre-drill dense hardwood.
Working with dense hardwood
Very dense species such as azobe and okan are hard on tools. Use carbide-tipped saw blades, drill pilot holes for all nails and screws, and plan for the extra weight on site. Driving dense posts with a post driver works well, but pointed ends should be cut carefully to avoid splitting. Some species can cause skin irritation, so gloves are a good idea.
Equestrian and livestock fencing
Horse and cattle fencing must take repeated pressure, rubbing and occasional impacts. Dense hardwoods do not splinter easily and resist chewing better than softwoods. Smooth, rounded rails reduce injury risk for horses. Okan, tali and azobe are all common choices for paddock and arena fencing in Europe.
Moisture content and supply
Fence posts are usually supplied fresh sawn or air dried, not kiln dried. Dense hardwoods can check slightly on the surface as they dry outdoors, which is normal and does not reduce strength. Store posts flat and off the ground before installation. See kiln dried vs air dried lumber.
Buying fence posts in volume
Fencing contractors, farm suppliers and distributors usually buy posts and rails by the container. A 20 ft container holds less volume of very dense timber than of lighter timber, because the weight limit is reached first. Mixing posts, rails and other heavy sections in one shipment is common. Browse our heavy construction and marine timber range, and see timber shipping cost for freight guidance.
Legal and sustainable sourcing
Buyers in the EU and the UK must meet due diligence rules for imported timber, and the US Lacey Act applies to imports into the United States. Ask for proof of legal origin, export permits and, where needed, certification. See our sustainability page and our EUDR timber compliance guide.
Fencing near water and in wet soils
Riverbanks, coastal paths, marshes and clay soils keep posts wet for most of the year. Here the gap between durable hardwood and softwood is widest. Azobe and bilinga have long records in river and harbour works, where wood is wet all the time, so they are natural choices for fencing along waterways, flood defences and boardwalk edges. In salty coastal air, use stainless steel fixings to avoid rust stains on the timber and early failure of the fixings themselves.
Common mistakes
- Posts with sapwood: sapwood rots quickly, even in durable species.
- Concrete collars that trap water: they can speed up decay at the base.
- Undersized gate posts: gates sag and posts lean.
- No pilot holes in dense wood: nails bend and posts split.
Our honest advice
For heavy farm, equestrian and public fencing, azobe, okan and tali give the longest life and highest strength. Bilinga is a lighter durable alternative. For garden fences, iroko looks good and lasts well. Ask for heartwood-only posts, install them with good drainage, and compare cost per year of service rather than price per post.
Sources
- The Wood Database for density and durability data.
- USDA Forest Products Laboratory, Wood Handbook
Related guides
- Hardwood railway sleepers
- Azobe vs greenheart
- Hardwood beams
- Best wood for marine construction
- Best hardwood for decking
Frequently asked questions about the best wood for fence posts
What wood lasts longest in the ground?
Very durable dense hardwoods such as azobe, okan, tali, bilinga and mukulungu.
Do hardwood fence posts need treatment?
Heartwood of durable species needs no chemical treatment for ground contact.
Should fence posts be set in concrete?
Compacted gravel and soil often drains better; if you use concrete, slope the top away from the post.
Are hardwood posts worth the extra cost?
Often yes, because they last much longer and save replacement labour.
Get a quote for fence posts
Send us your species, post sizes, lengths and quantities through our quote form. We will reply with a firm price and shipping options.