Dorset's Purple Patch

Dorset’s Purple Patch Dorset Heathlands from Pre-History to the Present Day Origins of Dorset Heathland We have lost so much of our heathlands, that we often forget that the whole of South East Dorset was once a continuous heath, interrupted only by river valleys. This booklet is a brief guide to how heathland was formed, how it has been lost and is now protected. The story of its origin has been pieced together using many different methods as described in the following pages but it is far from complete. The Poole Basin Lying between the sea and the Dorset chalklands and separated from the New Forest by the River Avon, the Poole Basin (see map) is an area of sands and clays formed some 50 million years ago. Our story begins here at the close of the last ice age and ends with the establishment of heathland. 0 5 miles The extent of the Poole Basin Note that the position of the coastline would CHALK UPLANDS have been different at the time of our story. In 7000B.C. the coast was approximately 5 miles out from the present shoreline of Poole Bay. POOLE BAY The landscape The Ice Sheet Retreats - first woodlands before the heath During the last ice age Dorset lay just south of the The rise of heathland permanent ice sheet. The landscape would have began in the Bronze Age but for 10000 resembled the treeless tundra of present-day Lapland. years before that Then, from about 12000 BC the climate began to the landscape was improve. Plants from warmer areas expanded their range not changeless. and colonised Dorset.*Our first direct evidence of what The amount of was happening here comes from pollen preserved in woodland cover and the corresponding peat from Morden Bog, near Wareham. abundance of grasses and heather varied in This pollen records an ancient landscape of open birch response to climatic woodland - birch, being a good coloniser, was the first and other factors. tree to arrive. The open character of these woods is evident from the abundant grasses and herbs. These herbs include the heather that several thousand years later would form the Dorset heathlands. New Trees Arrive - the woodland closes in * We were still connected to the For over 1000 years the open birch woodland remained Continent by a land relatively unchanged. Then the pollen from several peat bridge over the bogs in the Poole Basin records the expansion of pine. southern North Sea. For a time birch and pine coexisted in still quite open **Oak, hazel and elm woods but fundamental changes were imminent. became common. There are a few Within a relatively short period six tree species,**all records of lime, beech characteristic of our present deciduous woods, are found and ash. for the first time. Why this sudden change? Everywhere temperatures were rising. The ice caps melted, the sea level began to rise, a rise that later lead to Britain becoming an island (this occurred about 5000 BC). In this warm, dry climate (the climate was warmer than the present day) deciduous trees spread. Woodlands (the wildwood) now reached their maximum extent. In many places grasses and heather were shaded out, but they persisted where natural gaps in the canopy occurred. Hazel and oak, the species most tolerant of the light sandy soils in our area, were the dominant trees. Lime, the most abundant tree over much of southern England, needed more fertile soils and was uncommon here. The Climate Changes It would be wrong to think that the Poole Basin was covered with one uniform oak and hazel wood at this time. On the coast there were reed beds and mudflats, while in the valleys of the Avon, Stour and Frome, reed beds and alder woods flourished. Alder is a tree that grows on waterlogged soils and a rise in the abundance of alder is one sign of the next major change that occurred. Remarkably, the English climate had stayed warm and dry for 2500 years. Then an increase in the rate of peat accumulation in the bogs, together with the spread of alder in the river valleys, indicates the arrival of a new, wetter climate. Peat Bogs and Pollen Peat bogs consist of a waterlogged mass of partly decayed vegetation - peat. Things rot very slowly in these acidic conditions and so the level of the bog rises as plants grow and die. Pollen lands on the bog surface and becomes incorporated into the accumulating peat. Preserved in the peat, it provides a record of the local vegetation at the time of its deposition. *The peat contains an Hunters and Gatherers inwash of clay indicating increased soil erosion. By 8000 BC, Mesolithic people had established There are also large themselves in the Poole Basin (see over). They lived here numbers of bracken for 5000 years, witnessing the wildwood flourishing in a spores. Both these warm climate, and the change produced by more rainfall. features could be the result of tree clearance Did their activities alter the environment in any way? (see also below) In peat from Studland Heath there are signs*suggesting that somewhere in that vicinity there had been local Reconstructing clearance of the wildwood. Peat from other sites contains Ancient Landscapes fragments of charcoal. Such evidence has led to Pollen preserved in suggestions that with fire these people created habitats peat bogs provides more suitable for their game animals. This is an intriguing the background idea. Deciduous woodlands are highly resistant to information about these burning but pine, a tree that declined at this time, burns ancient landscapes. easily. Whatever the effect these people had on their Archaeological evidence fills in details and environment, it was small compared to the changes that gives insights about occurred a few thousand years later. Man’s influence on the environment. The Neolithic Peoples Avoid the Poole Basin The Neolithic people were a farming people, the first British farmers. Bones of goats, sheep and cattle have been found on their settlement sites and they grew wheat and barley. But whilst Neolithic sites are abundant on the chalklands to the north, they are rare in our area. Living off the Wildwood - hunting and gathering LivingThe Mesolithic off the Wildwoodpeople of this - hunting region made and gatheringfull use of all aspects of their environment. They lived in seasonal settlements on the coasts and in the The Mesolithic people of this region made full use of all aspects of their environment. They livedvalleys, in seasonal eating settlements a variety ofon birds,the coasts fish andand in shellfish. the valleys, The eating wildwood a variety providedof birds, fish andfruit shellfish. and hazelnuts The wildwood as well provided as boar, fruit anddeer hazelnuts and ox. as To well catch as boar, and deer prepare and ox. their To catchfood and they prepare used theira range food ofthey spears used a andrange cutting of spears tools and made cutting from tools flint,made bone from flint, bone and wood. and wood. Why did they stay away? Their success would have depended on their Whyjudgement did they of staythe soilaway? types Their best success suited towould their have agriculture depended and wheaton their and barley judgementdo not grow of well the onsoil sandy, types acidbest soils.suited Their to their use agriculture of the Poole and Basin wheat was and restricted barley doto hunting.not grow Arrowheads well on sandy, form acid a large soils. proportion Their use of Neolithicthe Poole remains Basin was found restricted here. to hunting. Arrowheads form a large proportion of Neolithic remains found here. The Bronze Age People Clear the Wildwood TheWhere Bronze the Neolithic Age people people clearavoided the our wildwood area, their Bronze Age successors settled here in significant numbers. They built over 300 tumuli, which still remain Wheresome 3000 the Neolithic years later. people Yet in avoided most respects our area, their their way Bronze of life Age was successors similar to the settledNeolithic; here they in significantgrow wheat numbers. and barley, They kept built the over same 300 domestic tumuli, which animals. still Soremain why somedid they 3000 come years here? later. What Yet inwas most their respects impact theiron the way environment? of life was similar to the Neolithic; they grow wheat and barley, kept the same domestic animals. So why didPollen they from come the here? ancient What soils was buried their underimpact their on thetumuli environment? records a mostly open landscape, a landscape in which tumuli were designed to stand out on the Pollenskyline. from Heather the ancient was a dominantsoils buried plant; under there their was tumuli some records hazel, abut mostly few otheropen landscape,trees. a landscape in which tumuli were designed to stand out on the skyline. Heather was a dominant plant; there was some hazel, but few other trees. The wildwood has mostly gone. It must have been cleared by the tumulus- The wildwood has mostly gone. It must have been cleared by the tumulus- buildersbuilders butbut thethe purposepurpose behindbehind theirtheir labourslabours isis notnot obvious.obvious. CerealCereal pollenpollen isis mostlymostly absentabsent fromfrom tumulustumulus soilssoils butbut presentpresent inin smallsmall quantitiesquantities inin peat.peat. TheThe PoolePoole BasinBasin wasn’twasn’t coveredcovered inin goldengolden wheatwheat fieldsfields butbut possiblypossibly areasareas werewere cleared,cleared, croppedcropped forfor aa fewfew yearsyears andand thenthen abandoned.abandoned. PasturalPastural farmingfarming maymay havehave beenbeen important,important, grazinggrazing animalsanimals preventingpreventing thethe regrowthregrowth ofof trees.trees. WhateverWhatever thethe detailsdetails ofof thesethese events,events, wewe knowknow whatwhat eventuallyeventually happened.happened. WithWith thethe treetree covercover removed,removed, rainrain washedwashed thethe nutrientsnutrients throughthrough thethe sandysandy soilssoils andand theythey becamebecame tootoo poorpoor toto supportsupport agriculture.agriculture.

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