King's Wood and Pentewan Valley circular walk
  1. From the car park, go through the lower gate and follow the waymarked track until you reach a path descending to the right just before a waymark post as a bench ahead comes into view.

    Kings Wood is a relic of an ancient woodland dating back several hundred years. It was originally owned by the realm - hence "The King's Wood" and at some point by the Earl of Lancaster. In more recent times, the woodland was managed by the Forestry Commission who planted some of it with conifers in the 1960s, and in the late 20th Century it was used for shooting. It is now managed by the Woodland Trust who have marked trails through the woods to promote public access, and are slowly clearing the conifers to promote broadleaf species which support more diverse native wildlife. Some rare butterflies have been found here and it is also an important habitat for woodland plants.

  2. Bear right down the path leading into the valley. Continue until it meets a path at the bottom of the valley.

    The Woodland Trust was founded in 1972 and is dedicated to providing a UK rich in native woods and trees. They summarise themselves as "the RSPCA of trees" and have set themselves the ambitious target of doubling native tree cover throughout the UK over the next 50 years. They now look after more than 1,100 woods and over 110 Sites of Special Scientific Interest and are committed to providing free public access wherever possible.

  3. When you reach the bottom, take the main path leading to the right and follow this a short distance to a junction with another path with a waymark inscribed with the Woodland Trust logo. Turn left and follow the path past one waymark post to a second, both with a blue arrow pointing ahead.

    In September and October, look out for the spiny casings of chestnuts on the paths.

    Since chestnuts don't need to hang around for a long time on the ground, they are nutritionally more similar to a cereal - containing principally starch and sugars - than a typical nut. They contain very little fat and are consequently much less calorific than other nuts: the kernels contain around a third of the calories of a similar weight of other nuts.

  4. Follow the main path ahead from the waymark until you reach a clearing with a memorial post and a waymark post with a blue arrow pointing to the right.

    To make blackberry wine, combine 2kg blackberries + 4 litres of boiling water in a plastic container with a lid. Once the water has cooled to lukewarm, mash blackberries and add red wine yeast and pectic enzyme (blackberries contain pectin so this is needed to stop the wine being cloudy). Cover for 4-5 days then strain through muslin.

    Transfer the liquid to a demijohn and add 1kg of sugar. Top up with a little more water to make it up to a gallon. After fermentation, the wine should clear by itself; in the unlikely event that it doesn't, use some finings. Rack off from the sediment and bottle; it's worth allowing the wine a year or two to mature as it massively improves with age. As a variation, you can add 500g of elderberries and increase the sugar content for a more port-like wine which will need a couple of years longer for the elderberry tannins to mellow out.

    Young beech leaves can be used as a salad vegetable, which are described as being similar to a mild cabbage, though much softer in texture. Older leaves are a bit chewy, as you'd expect.

    Compared to many native trees, the beech colonised Great Britain relatively recently, after the last Ice Age around 10,000 years ago. Beech trees have a shallow root system and are therefore often found in areas where water is plentiful such as near rivers. In the 17th and 18th Centuries, tall, stately beech trees were very fashionable in the estates of wealthy landowners and many mature beech woodlands today are the result of 18th Century parkland landscaping projects.

  5. Bear right to follow the path along the walkways and footbridges. Keep following the path until it ends at another Woodland Trust waymark, overlooking the St Austell River.

    The St Austell River is also known as the White River due to the china clay that colours it and was heavily modified during the Industrial Revolution so that the lower parts of it now resemble a canal. Habitat improvement work is being done on the river as part of the South Cornwall River Improvement Project.

    The South Cornwall River Improvement Project is a partnership programme lead by the Westcountry Rivers Trust, and is aimed at improving the river habitats around St Austell Bay. The project focuses on both reduction of river pollution and habitat improvement particularly on the lower sections of the St Austell and Par rivers which have been heavily modified and straightened. One of the major objectives of the project has been the reconnection of the St Austell River's major tributary, the Polgooth river, which was previously isolated through a series of culverts that fish such as trout and salmon would not swim through.

  6. Turn left and follow the path downriver a short distance to where the main track bends left to enter the woods and a smaller path continues ahead alongside the river.

    The Pentewan Valley Trail runs along the trackbed of an old railway. This was originally built as a horse-drawn tramway to transport china clay from St Austell to the new port at Pentewan which was completed in 1826. The line opened in 1829 and used gravity to transport the loaded wagons down the incline from St Austell and then horses to pull them along the flat section to Pentewan, and to return the empty wagons.

    In 1874, plans were made to upgrade the line to a railway with steam locomotives. Although the track strengthening had been implemented, shortly after this, a strategic decision was taken by Great Western Railway to direct its china clay traffic to Fowey. By 1877, the shipments were dwindling and by 1880 the operation became unprofitable. However a boom followed only two years later and the line continued until the First World War. The track was the same gauge as that used to service the trenches in France and both the track and locomotives were acquired by the War Department.

  7. Bear left to follow the main track into the woods to reach a ford and bridge.

    One of the birds you may see, or hear singing, in the trees is the robin.

    Robins are also able to see magnetic fields. Receptors in their eyes make magnetic fields appear as patterns of light or colour which allows them to use the Earth's magnetic field for navigation. They only seem to use their right eye for this as the left half of their brain (linked to the right eye) does the processing.

  8. Cross the bridge and follow the trail until, just after the path emerges from between the fences and the cycle hire hut comes into view, you reach a tree and piece of granite (with a Trail sign on the opposite side) in the middle of the path where a path leads off to the right.

    The lakes beside the wooden railings are the remains of 4 reservoirs.

    The series of 4 reservoirs above Pentewan were used to collect water both from the stream running along the back of the valley and the St Austell River. These were controlled with numerous sluice gates at the entrance to the reservoirs and between them. The body of water was periodically released to flush sediment out of the harbour and the shipping channels approaching it. The sequence of reservoirs and sluices allowed the water to be collected from whichever was the cleaner of the two sources to ensure that the water being released into the harbour was itself free from sediment.

  9. If you want to explore Pentewan before continuing, follow the track ahead to reach the road and turn left to pass the Ship Inn to reach the village and beach. To continue the walk, take the path currently on your right to reach the river.

    Pentewan dates back to mediaeval times when it was mainly a fishing village with a harbour. The harbour was rebuilt in the 1820s both for the pilchard fishery and to create a china clay port. At its peak, a third of Cornwall's china clay was shipped from Pentewan. However the harbour had continual silting problems which meant that it was eventually overtaken by Charlestown and Par. As well as longshore drift carrying sand east across Mevagissey Bay, there was also silt being washed down the river from china clay works and tin streaming. Consequently, the harbour gradually silted up with the last trading ship leaving in 1940 and World War II literally sealing its fate. By the 1960s, the harbour was only accessible to small boats and today the harbour basin is entirely cut off from the sea.

  10. Follow the path upriver (using sections of path away from the edge of the riverbank where possible) until you reach a gate across the path with a gap on the right of it.

    The buildings on the opposite side of the river were originally a bone mill.

    Bone mills used the power from a waterwheel to crush animal bones and produce bonemeal. The bonemeal was primarily used as a fertiliser to release phosphorus into the soil, which is a vital mineral for healthy crops. In the 20th century, fertilisers based on phosphate minerals, which could be mined cheaply, made bone mills uneconomical. However, the known phosphate reserves are expected to run out within a few decades and so organic phosphorus sources such as animal bones, and even urine, may become increasingly important for farmers.

  11. Go through the gap and follow the track ahead alongside the river to reach a footbridge to Heligan. Keep ahead alongside the river to where a path departs to the right, just before the gate into a car park.

    If you happen to notice several hundred yellow rubber ducks on the river, you are likely witnessing St Austell's version of the National Lottery. During the summer, usually on Friday evenings, rubber duck races are held to raise money for local charities. Ducks can be hired for a modest fee and there is a cash prize for the winning duck.

  12. Bear right onto the path running along the car park fence. When you reach the National Cycle Network post, keep left to follow the cycle route alongside the river to where it re-enters the woods.

    During the 18th and 19th Centuries, there were two tin streaming works in the Pentewan Valley. The one towards the bottom of the valley was known as Happy-Union and one further upstream was known as Wheal Virgin. During these excavation processes, they found human remains with charcoal and ash, possibly from Bronze Age burials and bones of animals "of a different description from any now known in Britain". At Wheal Virgin, a tankard was also found from late Roman times made from yew wood and metal bands of a copper alloy. This is now on display at the Royal Cornwall Museum in Truro.

  13. Continue on the cycle track, following it over a bridge, until it ends in a T-junction with a tarmacked track with a wooden signpost.

    The mix of broadleaf trees in the woodland includes oak.

    For such a widespread tree, the oak is surprisingly inefficient at reproducing naturally. It can take 50 years before the tree has its first crop of acorns and even then, the overwhelming majority of the acorns that it drops are eaten by animals or simply rot on the ground. Squirrels play an important part by burying acorns and occasionally forgetting a few which have a much better chance of growing than on the surface.

  14. Turn right onto the tarmacked track (signposted "Kingswood") to return to the car park and complete the circular route.

    Squirrels eyes are positioned on the sides of their head which allows them to spot predators approaching from behind them. When a squirrel spots a predator, its runs away in a zigzag pattern. This confuses many of their predators but unfortunately it doesn't work well for cars.

The National Cycle Network is coordinated by the charity Sustrans. It began with one route in Bristol in 1984 and now consists of around 15,000 miles of signposted cycle routes known as National Cycle Routes. These each have a number and are constructed using a combination of roads typically chosen to have light traffic and some traffic-free tracks which are open to cycles.

National Cycle Route 2 runs for 361 miles along the south coast from St Austell to Dover but at the time of writing, several sections including the one between Par and Plymouth (using the Cremyll ferry to cross the Tamar) haven't been completed yet.

National Cycle Route 3 runs 338 miles from Bristol to Land's End. The route is a mixture of lanes, byways and some tracks not open to road traffic including the upper section of the Camel Trail from Wenfordbridge to Dunmere.

National Cycle Route 304 provides a more direct and less hilly alternative to the coastal section of National Cycle Route 3 between Marhamchurch and Hallworthy.

National Cycle Route 327 runs from Trelash near Warbstow via Launceston to near Tavistock. It forms a link between cycle routes 3 (Bristol to Lands End) and 27 (Plymouth and Tavistock) hence 327.

National Cycle Route 32 splits off Route 3 at Dunmere and rejoins it again at Truro. Using the lower half of the Camel Trail and then predominantly lanes, the route runs through Padstow, St Columb Major and Newquay for a total of 51 miles.

Between Bude and Land's End, National Cycle Routes 3 and 32 are collectively known as the Cornish Way, stretching for 123 miles.

Some estimates suggest the UK has up to half of the world's total bluebell population; nowhere else in the world do they grow in such abundance. However, the poor bluebell faces a number of threats including climate change and hybridisation from garden plants. In the past, there has also been large-scale unsustainable removal of bulbs for sale although it is now a criminal offence to remove the bulbs of wild bluebells with a fine up to £5,000 per bulb!

During periods of cold weather, spring flowers, such as bluebells, have already started the process of growth by preparing leaves and flowers in underground bulbs during summer and autumn. They are then able to grow in the cold of winter, or early spring, by using these resources stored in their bulb. Once they have flowered, the leaves die off and the cycle begins again.

Other species (such as cow parsley or dandelions) require warm weather before they are able to germinate and grow. With the warmer springs induced by climate change, bluebells lose their "early start" advantage, and can be out-competed.

Because bluebells spread very slowly, they're considered to be an indicator of ancient woodland sites. In areas where trees are not very old, the fact there are bluebells around can indicate that there has been a wood on a site for a very long time. Even if there are no trees there at all, bluebells tell us that there was woodland there some time in the past. The bluebells along the coast are a relic of the gnarled oak woodland that used to grow here before it was cleared for grazing. There is still a patch of the ancient oak woodland left along the coast at Dizzard.

Some plant nutrients such as phosphorus tend to be more abundant near the surface of the soil where decaying organic matter collects. Bluebell seedlings start life at the surface so these are OK but as bluebell plants mature and send their roots deeper into the soil to avoid winter frosts, they have a phosphorus problem. They have solved this by partnering with a fungus that extends from their root cells, drawing in minerals from the soil in return for some carbohydrates from the plant.

Bluebells are extremely poisonous, containing a number of biologically-active compounds and were used (probably with varying success) in mediaeval medicine. The sap was used as a glue for book-binding as its toxicity repelled insects. It was also used to attach the fletchings onto arrows.

In Elizabethan times, starch made from the bulbs was used to stiffen collars and cuffs in clothing. The ruffs that were highly fashionable at the time would have needed a lot of starch to prevent them flopping. The toxins in bluebell sap might also have had the desirable property of preventing the starch encouraging the formation of mould.

In folklore, the bluebell is a symbol of constancy, presumably based on the fact that they flower in the same place every year. It was said that anyone who wears a bluebell is compelled to tell the truth. This could be the origin of the "…something blue…" that a bride should wear on her wedding day.

According to folklore, it's unlucky to bring bluebells into a house and also unlucky to walk through bluebells as it was thought that the little bells would ring and summon fairies and goblins.

In Old Cornish, both bluebells and marigolds were known as lesengoc which translates to "flower of the cuckoo". In Modern Cornish, the marigold has remained more-or-less the same but the bluebell has been changed to bleujenn an gog ("plant of the cuckoo"). The association between bluebells and cuckoos exists in Welsh ("bells of the cuckoo") and Gaelic ("cuckoo's shoe"), and in some English folk names such as Cuckoo's Boots and Cuckoo Stockings. It is thought that the association is due to the time that bluebells flower coinciding with the time that the call of the cuckoo is first heard.

Bluebells are also known by folk names based on their shape including Lady’s Nightcap and Witches’ Thimbles.

Other common names for the bluebell include "wild hyacinth" and "wood hyacinth" as they are related to the hyacinth family. Their Genus name Hyacinthoides also means "hyacinth-like".

When photographing bluebells, the flowers that look blue to your eye can end up looking purple in photos.

The first thing to check is that your camera isn't on auto white balance as the large amount of blue will cause the camera to shift the white balance towards reds to try to compensate.

Another thing to watch out for is that the camera's light metering will often over-expose the blue slightly to get a reasonable amount of red and green light and the "lost blue" can change the balance of the colours. You can get around this by deliberately under-exposing the photo (and checking there is no clipping if your camera has a histogram display) and then brightening it afterwards with editing software.

Bluebells are very vulnerable to trampling. The reason for this is that when their leaves emerge in the early part of the year, they are powered by the stored sugars in their bulbs. Sunlight is very limited at this time of the year and even more so in the shady places where they grow. In order to survive, they then need to photosynthesise flat-out to store enough starch in the bulb for next year's growth. If a bluebell’s leaves are crushed, it cannot photosynthesise and and doesn't have enough reserves left in its bulb to grow new ones. It's therefore important to stick to footpaths in bluebell woodland and best to take photos with a zoom lens from there as wandering around in the bluebells to take photos will inadvertently kill them.

A rare genetic mutation occurs in bluebells which results in about 1 bluebell in 10,000 being white rather than blue.

Three-cornered leeks - which have white bell-shaped flowers and are very common - are often misidentified as "white bluebells". The easiest way to tell them apart is that 3-cornered leeks smell strongly of onion. Their flower stems are also triangular (hence the name).

Himalayan Balsam is a tall plant with very pretty pink flowers that can often be seen lining footpaths in the summer and early autumn. It was introduced as an ornamental species in 1839 and unfortunately the plant is now a major ecological problem. It can grow from a seed to 9ft high in a few months, forming dense thickets and wiping out other plant species. It is also extremely invasive as the seed pods open explosively, launching around 800 seeds per plant up to 7 metres and the seeds are also adapted to travel by water. It is a nuisance on riverbanks as its roots are shallow and allow the sediment to become easily eroded into the river. It can be identified by its bright pink flowers and it has a characteristic sweet smell.

Rosebay willowherb is a tall plant with a spike of pink flowers in late summer which can often be seen beside paths and tracks. Their long leaves have a distinctive thin, white vein along the centre.

The name "rosebay" dates from at least Tudor times and is thought to be based on loose resemblances of the leaves to bay leaves and the flowers to wild roses. The overall family are also known as "willowherbs" due to the resemblance of the leaves to willow leaves. The two names have since been brought together resulting in the slightly confusing duplicate description of the leaf shape.

Rosebay willowherb is known as fireweed in USA as it's found on burnt sites after forest fires. For similar reasons it was known as London's Ruin after the Great Fire. In the Second World War it was also known as bombweed due to its rapid colonisation of bomb craters.

It is a pioneer species which is good at colonising disturbed ground as its seeds travel long distances in the wind and remain viable in the soil for many years. It was considered a rare species in Britain in the 18th century but spread along the corridors cleared for railways in Victorian times.

Fungi are often most noticeable when fruiting, either as mushrooms or as moulds but their main part is a network made up of thin branching threads that can run through soil, leaf litter, wood and even living plant tissue.

Fungus is the Latin word for mushroom but is derived from the ancient Greek word for sponge since this is what they were thought to resemble. Biologically, this isn't so far off either as fungi are more closely-related to animals than plants.

95% of all plant life on Earth, including trees, relies on a symbiotic relationship with fungi. It is thought that without fungi, land plants could not have developed at all. Fungal mycelium often grows around or actually within the roots of plants and give the plant access to water and nutrients it couldn't otherwise obtain easily from the soil. In return, the plants provide the fungi with sugars produced through photosynthesis.

The common earthball is a woodland fungus that looks a bit like a scaly white or pale yellow potato and its external appearance could be confused with a small puffball fungus.

Earthballs have a slightly different approach to release their spores than puffballs. When mature, puffballs have a central opening in the top through which the spores puff out. With the earthball, the surface of the cap ruptures when the spores are ready to release.

Since puffballs are edible and earthballs are poisonous, it is a common offender for stomach upsets arising from misidentification. This might seem strange as puffball flesh is pure white whereas the internal earthball flesh is dark (purple/brown/black) when mature. The potential for confusion arises because when very young, the earthball flesh is pale.

Sycamore is a member of the maple family which is why the leaves look a bit like the Canadian flag. Although sycamore doesn't have the striking red autumn colour of other maples, the young leaves and developing seeds are a vivid red colour which is caused by similar red anthrocyanin compounds.

Research suggests that sycamore was common in Britain up to Roman times but then died out due to the warming climate apart from some mountainous regions such as in Scotland. During the Tudor period it is thought to have been reintroduced from southern and central Europe by landowners looking for a rapid-growing tree for their estates and was found to be salt-tolerant - essential in Cornwall.

Sycamores like moist soil and the young trees need a lot of water (equivalent to an inch of rain per week) to get established. For this reason, sycamores are very often found along streams or in low-lying meadows that collect water. Once their roots grow deep enough, the mature trees can withstand drought by tapping into underground moisture.

Sycamores leaves can sometimes be seen with black dots. This "tar spot" fungus reduces the efficiency of the leaves slightly but overall seems not to harm the tree significantly. The fungus overwinters on fallen dead leaves and its spores are released in spring to infect new leaves.

Since its reintroduction, sycamore has spread widely as the seeds are extremely fertile and able to grow just about anywhere where the ground is sufficiently wet. In particular they can grow within the shade of the parent tree, creating dense cover that crowds-out other species. In some areas it is regarded as an invasive weed.

Sycamore flowers are pollinated by flies such as bluebottles rather than the wind. Within the female flower, two of the carpels (reproductive parts) are fused together. These develop into the pair of fused seeds with their "wings" at an angle. When the seeds fall, this creates the "helicopter" action that allows the seeds to be caught and carried by the wind as they slowly spiral downwards.

Sycamore seeds contain a biochemical compound known as hypoglycin A which is poisonous to horses. If a horse eats large numbers of sycamore seeds, this can cause a muscle condition known as Atypical Myopathy. In the most extreme cases, the horse can die from a heart attack.

Sycamore timber was traditionally used for milk pails as it does not impart any flavour or colour. It is still used today for kitchenware and is recognisable by the light colour and fine grain.

Wagtails are easily recognised from the tail pumping behaviour that their name suggests. Despite being very conspicuous, the function of this curious behaviour is not well understood. It is possibly a signal to predators that the wagtail has seen them, so there's no point trying anything.

Two of the wagtail species are easy to confuse as they are both grey and yellow.

Grey wagtails nest close to fast-running streams as they feed on aquatic invertebrates. They have pink (skin-coloured) legs.

Yellow wagtails are more often found in open fields and have black legs.

The third kind of wagtail more often seen in urban environments - the pied wagtail - is easy to distinguish due to the lack of yellow: it's entirely black-and-white.

The yellow water iris (also known as yellow flag) is a native plant but can become invasive and have a negative effect on biodiversity due to its ability to out-compete many other water plants. It is thought by some to be the original plant on which the "fleur-de-lis" heraldic symbol is based.

If heavy metals are present in the soil, the plant is quite effective at absorbing these. This together with its aptitude for growing in pools of shallow water makes it potentially useful for detoxifying mine drainage.

Newts are members of the salamander family, which dates back to the Jurassic period. The newt species you are most likely to encounter in Cornwall is the palmate newt. Great crested newts aren't found in Cornwall at all. Common newts, contrary to their name, were only ever found in the far east of Cornwall and have become rarer over time. In recent years, the newt population has declined in the UK overall due to pollution and destruction of their habitat. Old farm ponds with good weed cover make good habitats as newts prefer still water to fast-flowing streams.

The name "newt" is actually from a mistake. The Old English word was ewt and so it should be "an ewt" but because this sounds the same as "a newt", ewts accidentally gained the "n" from "an".

Newts walk with a side-to-side gait by moving their front-left and back-right legs forward at the same time, followed by the other diagonal pair. This waddling form of motion is the origin of the phrase "pissed as a newt".

However, unlike drunk people, when injured, they have the remarkable ability to regrow limbs, eyes and even their heart! They are consequently of major interest to medical science.

Biologically, there is no such thing as "toads": there are just many species of frog, some of which were given the name "toad" if they were a bit drier- or wartier- looking. However, the 2 species of frog known as the "Common Frog" and "Common Toad" are those you are most likely to encounter in Cornwall, so for discerning fairytale princesses, here's how to tell them apart:

Autumn colours are the result of two different chemical processes - one that gives rise to yellow leaves and one that results in red leaves. They depend differently on temperature so a cold autumn tends to produce more yellow colours whilst a mild autumn produces more red. In both cases, the length of time the colour has to develop is limited by the leaves not being blown off the tree by wind. Much of Cornwall is pretty exposed and breezy so sheltered valleys offer the best chance of good autumn colours.

A normal healthy leaf contains chemicals which are both green (chlorophyll) and yellow (carotene). If chlorophyll stops being produced, leaves turn yellow. This happens when sunlight is reduced either temporarily (e.g. accidentally leaving something on the lawn) or in autumn when there is less sunlight overall and when cold temperatures also speed up the breakdown of chlorophyll.

When a tree prepares to shed a leaf, it creates a barrier of cells to close the leaf off. Sugars produced from photosynthesis which normally flow back into the plant instead build up in the leaf and react with proteins in sap to form red anthrocyanin compounds. Sunny autumn days produce more sugars and result in more red leaves. Frost causes the leaves to drop off quickly so mild, sunny autumns produce the best red colours.

The first method to extract tin was known as "tin streaming" which reached its peak in the 12th Century, though continued until the mid 20th Century.

Alluvial deposits occurred where a river had eroded the tiny crystals out of mineral veins. Due to tin being so heavy, the crystals had become concentrated on the bottom of the stream as the lighter rocks around them were washed away. Over time these deposits were buried in gravel and sand, and eventually soil.

Using quite elaborate banks and channels, the river was diverted to wash away the soil and gravel, leaving the heavy tin-rich rocks behind which could be dug out once the river was diverted away.

One side-effect of all this industry was that the topsoil, sand and gravel washed downriver caused the silting of many river estuaries and once-thriving mediaeval river ports literally dried up and were superseded by sea ports.

Once the relatively rich alluvial deposits had been used up, mostly by the 18th Century, mineral veins were instead mined directly.

Hog's Pudding is a type of sausage produced in Devon and Cornwall which as akin to a haggis. However, more popular recipes do not include offal but typically consist of pork, suet, bread, and oatmeal or pearl barley formed into the shape of a large sausage. These ingredients are similar to a "white pudding" of Scotland and Ireland, but Hog's Pudding is a lot spicier than white pudding as it also contains black pepper, cumin, basil and garlic.

The beach at Pentewan is owned by the holiday park but is open to the public. There's a sandy beach at all states of the tide and is relatively sheltered as it faces east into St Austell bay away from prevailing winds and has headlands either side. The St Austell River divides the beach. The small area to the left can be accessed via the old harbour. The larger area to the right of the river is accessed via the holiday park. A bridge crosses the river into the holiday park near the lock gates of the old harbour.