This walk follows a typical "dry valley" cut into the chalk probably after the ice age when streams of melt water were released.  Since then the water table has fallen steadily so that only in very rare years does the spring emerge higher than the hamlet of Stubhampton further down the valley.  In medieval times the area marked the most western boundary of Cranborne Chase Forest.  A very early map dated 1618 indicates that those parts of the slopes which have a cap of clay-with-flints resting on top of the chalk were covered by woodland managed on a coppice-with-standards rotation.  The remaining areas were chalk downland grazed by sheep.  The car parking area takes its name, "Washer's Pit", from the now dry pond to the west of the fence which was probably used as a sheep dip.  Major changes came in the 1930s and 1950s when conifers were planted in the valley.  In the 1950s the Forestry Commission took a long lease on the eastern slopes.  They planted the former ancient woodland site and replaced the old coppices with commercially viable conifers and Beeches.  As the conifers matured the valley gradually became too shady for many species of butterfly.  Discussions began in the late 1980s between the Forestry Commission and Butterfly Conservation and a plan for widening the rides was begun.  The work was started in 1989.  Simultaneously the owners of the woodland on the west slopes also began to rethink their management.  The Gardiner estate to the north-west of Stubhampton Bottom opted to remove their woodland and attempt to restore sheep-grazed downland.  The Woodhouse estate to the south-west planned a series of wide rides and glades.The walk has three areas of fascination.  First, for those with the inclination to play detective, is the challenge of trying to spot the underlying "ghost" landscape which can still be found beneath the more recent Forestry Commission forest.  Look out for the clues:  large ant-hills marking the remains of the former chalk downland; ancient trees and coppice stools which once formed the woodland of Cranborne Chase.  Second are the plants and butterflies.  These are also in some ways part of the "ghost" landscape.  Downland flowers like the Pyramidal Orchid, the Rock Rose, Horseshoe Vetch and Harebells can be seen close to old woodland indicators like Wood Spurge.  Downland butterflies like the Marbled White jostle with woodland butterflies like the Silver-washed Fritillary and the Ringlet.  Third is the future challenge of watching how the new conservation plans work out.  Will the once common Chalkhill Blues re-appear? For those wishing to explore further, the village of Ashmore with its ancient pond (but no pub!) is nearby.  The walk along the bottom can be prolonged by continuing into the hamlet of Stubhampton or even further into Tarrant Gunville.

SECTION 1: BEECH WOOD TRACK  (Length 694m).

Walk through the gap to the right of the gate.  Just follow the gravelled track until it is joined by a steep path from the left.  Notice immediately on your right a pleasant group of trees including Hornbeams more commonly found in Essex and Suffolk.  On your left is the Beech forest started by the Forestry Commission in the 1950s.  Further down the track on the right the start of the Gardiner estate's plan to restore the original chalk downland can be seen.  Also on the right, look out for a stately line of ornamental Poplars with their leaves fluttering in the breeze.  In the spring this is a good section of the walk for the Orange Tip.  Their eggs, which are bottle shaped and very quickly turn orange, can be found quite easily by examining the stems below the flower heads of both Lady's Smock and Garlic Mustard.

SECTION 2: CONIFER WITH BIRCH TRACK - BAY NUMBERS 1-12  (Length 518m).

Keep walking along the bottom track until you reach the next major junction.  Here, as a prelude to timber extraction, the Forestry Commission have built a new gravelled track which sweeps away uphill to the left.  At the start of the section, high up the slope on the left, notice the big clearing which was made in 1989.  Explore it if you have the time and energy.  Watch out for the yellow ant hills and chalk downland flowers like Rock Rose and Horseshoe Vetch which have now magically re-appeared after the removal of the conifers.  In the 1970s one of the commonest butterflies here was the Chalkhill Blue.  But the new conifers shaded out its foodplant, the Horseshoe Vetch, and by the 1980s the butterfly had vanished.  Now one or two are beginning to re-appear.  As you continue down the main track you will immediately be aware that the Beeches on the left-hand side have now given way to conifers and Birches and that large semi-circular "scalloped" clearings have been made.  These are part of the Forestry Commission conservation plan.  Each clearing has been numbered to make recording easy.  This section of the walk includes numbers 1 to 12.  It has been estimated that the width of a ride or track needs to be approximately one and a half times the height of the trees adjacent to it if it is to be sunny enough for butterflies.  The new clearings should compensate for the rapid growth of the conifers and their shading effect.  Already there has been a welcome expansion in numbers of Dingy and Grizzled Skippers in the spring and Large and Small Skippers later in the summer.  The most numerous butterflies however are the black and white "chess-board" Marbled Whites and the dark brown-black Ringlets.  These butterflies flourish where the grass is long and in some years in late July their numbers can be astronomical.Two interesting day-flying moths should be watched for.  On sunny April days there is the Orange Underwing and in May-June the striking black and white Argent and Sable.  They occur here because their caterpillars feed on Birch.

SECTION 3: CONIFER RIDE - BAY NUMBERS 13-28 (Length 534m).

Do not climb up the Forestry Commission track to the left but keep along the valley bottom where the track now ceases to be gravelled.  The track curves left and then right.  The section ends when the next junction is reached where another ride, now heavily shaded by conifers, comes in from the left.  From Section 3 onwards is where the very rare Pearl-bordered Fritillary butterfly used to be found, gliding rapidly along the tracks or through the clearings.  It is now known that this butterfly thrives only after coppicing.  In the old days this was how the wood was managed.  The Hazel was cut down to ground level and the poles were sold off for making things like hurdles.  A whole area of almost bare ground was created and very soon this blazed with colour as flowers such as Primroses, Wood Anemones, Bugle and Violets were stimulated into growth by the sunlight and the warmth.  The Pearl-bordered Fritillary caterpillar feeds on the common Dog Violet but only where the "micro" climate at ground level is hot and dry.  These conditions only lasted for a few years because soon coarse grasses smothered the Violets and the Hazel coppice began to grow again.  However, this was no problem because by then an adjacent area had been coppiced and the Fritillaries could move across to this to lay their eggs.  After another 7-10 years the original coppice was ready for cutting, the coarse grasses had been shaded out by the Hazel, and the whole cycle could begin again.  Unfortunately coppicing is no longer a common method of managing woodland as there has been little demand for coppice products for many years.  The Forestry Commission and Butterfly Conservation are trying to revive the practice.  Notice that in this section some of the clearings on the left have been kept unusually short by rabbit grazing.In addition the Forestry Commission have started an experiment involving the use of black plastic to repress the growth of coarse grasses and make bare patches.  Look for this in some of the scallops.Look out for some fine old gnarled Field Maples in the clearings on the left which may be relics of the older woodland.  Close to them are some Spindle trees which you will probably not notice unless you do the walk in Autumn.  At this time the fruits hang like fuchsia-pink lanterns fitted with orange "light bulbs".  The whole sight looks almost tropical and, in a sense, it is, because the Spindle Tree is the only British member of a tropical plant family.  The tree derives its name from the fact that its hard smooth wood was useful for making spindles for wool spinning by hand.

SECTION 4: BEECH RIDE - BAY NUMBERS 29-41 (Length 508m).

Keep walking along the bottom track.  The woods to the right belong to the Woodhouse estate and are private.  The end of Section 4 is reached when you come to a fork in the track.This section is the best place to look out for the Silver-washed Fritillary butterfly.  The bright orange males and the lighter orange females can be seen from mid-July feeding on Bramble blossom and thistles.  When the sun goes in, they glide majestically up into the trees.  If you are lucky with the timing of the walk you may be able to witness the magnificent aerobatic courtship flight of these impressive butterflies.  The males are attracted to the females partly by shape and colour but also by a scent given out by the females when they are ready to mate.  During the courtship flight the male also uses scent; this is stored in the herring-bone patterns on his forewings which burst open and shower the female.  These pheromones persuade the female to settle and the final act in the courtship is when the male draws her antennae gently over his scent scales.  Watch out too, but earlier in the year in May, for the tiny Green Hairstreak butterfly which looks brown in flight but has green underwings which almost transform it into a leaf when it settles on a Hazel or Hawthorn bush.

SECTION 5: HAZEL TRIANGLE - BAY NUMBERS 42-44 (Length 318m).

At the fork take the left upper track.  Keep going until you reach a gate.  Pass through the gate and you are standing at a cross-roads.  Two paths lead off left into the woods.  Take an often rather overgrown path diagonally to the right which leads downhill into the valley.  At the bottom you turn right and head back up the valley.  A left turn would take you out on to the road which leads to Stubhampton and Tarrant Gunville.  Keep heading up the valley until you regain the fork in the track which you encountered at the start of Section 5.  Unless you have made other plans, retrace your route back up the valley.On your left as you take the upper path is a magnificent bank covered in Rock Rose.  This is the best place to see the tiny Brown Argus butterfly which, despite its name, is a member of the blue family.  Look out for its rich chocolate-brown base colour and bright orange spots.  The bank is also popular with the Green Hairstreak and Common Blue.  Below on your right is a slope which was previously planted with conifers but has now been cleared.  This has made way for Hazel coppice to grow up.  When you reach the lower path look in the often muddy track for the "slotted" footprints of Roe Deer which are common in the wood.  Track intersections are the places for lingering in late May to June to see if a male Duke of Burgundy has taken up territory.  Dukes were once quite common all the way along the bottom from Sections 3 to 7 but the growth of the conifers shaded out the rides and the Primroses which are their larval food plant.  However the opening up of the new clearings all along the bottom path has led to what looks like a small recovery.A flash of scarlet across the track in July probably means you have seen the day-flying Scarlet Tiger Moth which has recently colonised this section.  In August clumps of Hemp Agrimony and Marjoram attract large numbers of butterflies ranging from Silver-washed Fritillaries, Peacocks and Red Admirals down to the diminutive Brown Argus.  As you make your way back along the valley watch out for birds and mammals.  Buzzards can usually be glimpsed above the trees and although most mammals tend to avoid this part of the wood as it is popular for walking, you never know what might turn up.  Stoats, Weasels, Fallow and Roe Deer, Grey Squirrels are all often seen, and watch for Adders sunning themselves on the banks.  An interesting experiment on the return journey is to see how many of the "perching" territorial butterflies are still guarding the same patches.