Why we must save our trees

In his birth­day mes­sage to the coun­try­side, His Royal High­ness The Prince of Wales urges us all to work to­gether to safe­guard our em­blem­atic Bri­tish tree species from pests and lethal dis­eases

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In his birth­day mes­sage to the coun­try­side, The Prince of Wales urges us all to work to­gether to save our trees from dis­ease and pests

One of the many things I love about the Bri­tish coun­try­side is its en­dur­ing time­less­ness which cre­ates a tan­gi­ble link with our past, while con­tin­u­ing to pro­vide con­tem­po­rary liveli­hoods, food pro­duc­tion, a home for wildlife and abun­dant scope for re­cre­ation and re­lax­ation among nat­u­ral beauty. Some of those things have an eco­nomic value, oth­ers are im­por­tant in dif­fer­ent ways. But they all mat­ter deeply to me and, I know, to a great many other peo­ple too.

Those of us who care about the coun­try­side know that it is more frag­ile than it may ap­pear. In a world of heavy machin­ery, in­ten­sive agri­cul­ture, blan­ket forestry and in­sen­si­tive land drainage and de­vel­op­ment —com­pounded, of course, by the im­pacts of ac­cel­er­at­ing cli­mate change—strin­gent safe­guards and con­stant vig­i­lance are nec­es­sary to en­sure we main­tain and im­prove the best of our nat­u­ral in­her­i­tance.

A great deal of at­ten­tion has rightly been given to the plight of our en­dan­gered wildlife and wild flow­ers, and there have been some en­cour­ag­ing suc­cesses, such as the re­cov­ery of the cirl bunting and the rein­tro­duc­tion of the large blue but­ter­fly. On a per­sonal note, I am proud of hav­ing en­cour­aged the cre­ation, so far, of more than ninety Corona­tion Mead­ows, each full of lo­cal, na­tive wild flow­ers, and am im­mensely grate­ful to Plantlife and the many landown­ers now par­tic­i­pat­ing.

At the same time, and de­spite stren­u­ous ef­forts to turn the tide, our na­tive red squir­rels re­main un­der threat as do many species of ground-nest­ing birds, but most of all the curlew, whose pop­u­la­tion has suf­fered an alarm­ingly se­vere and rapid de­cline partly as a re­sult of in­creas­ing pre­da­tion. Their haunt­ing, evoca­tive cries, which led Ted Hughes to write that ‘Curlews in April, hang their harps over the misty val­leys… wet-footed god of the hori­zons’, are just a mem­ory in many places where they used to breed in their hun­dreds.

An­other dis­tant mem­ory, from a time be­fore the 1970s, is of hedgerows punc­tu­ated by bil­low­ing english elms, pro­vid­ing height in the land­scape, shade for live­stock and a haven for wildlife. More than 25 mil­lion are es­ti­mated to have been lost to Dutch elm Dis­ease, spread by the elm beetle that car­ries a deadly fun­gus. A few ar­eas have es­caped the worst of the de­struc­tion, but to­day the elm sur­vives mainly as a suck­er­ing hedgerow plant, cut down by the dis­ease as soon as it gets above head height.

I have al­ways been mor­ti­fied by the loss of ma­ture elm trees from al­most ev­ery part of the coun­try­side I knew and loved as a child, so I had high hopes for an Amer­i­can va­ri­ety that ap­peared to be re­sis­tant to the dis­ease. I planted an av­enue of them at High­grove and then watched, mis­er­ably, as many of them suc­cumbed just like the na­tive va­ri­ety.

Los­ing al­most ev­ery size­able english elm from our coun­try­side—par­tic­u­larly in Glouces­ter­shire and Som­er­set—was such a pro­found change that I sus­pect ev­ery

Coun­try Life reader will have heard of Dutch elm Dis­ease. The wider prob­lem is that a great many more pests and dis­eases are now se­ri­ously threat­en­ing the health of all our na­tive trees, yet pub­lic aware­ness of this si­t­u­a­tion seems to be fright­en­ingly low.

These new threats are not just to the ap­pear­ance of the coun­try­side, im­por­tant though that is. Trees have an im­por­tant role in many as­pects of our lives, con­tribut­ing to our well­be­ing and pro­vid­ing us with a wide range of es­sen­tial en­vi­ron­men­tal ser­vices, as well as tim­ber, fruit and fuel.

It is easy to ap­pre­ci­ate that tree roots, by pen­e­trat­ing deeply into the soil and bind­ing with it, pro­vide sta­bil­ity and pre­vent soil ero­sion. But that same process also cre­ates a more open soil struc­ture, rich in or­ganic ma­te­rial, which can ab­sorb more wa­ter, thereby im­prov­ing drainage. Fol­low­ing the dev­as­tat­ing floods of re­cent years there is a lot of in­ter­est in any mea­sures which can slow the rate at which wa­ter runs off the land. There are no sim­ple an­swers, but it cer­tainly ap­pears that sen­si­tive tree plant­ing has a role to play, both in the up­lands and in the sus­tain­able drainage schemes which are in­creas­ingly be­ing de­vel­oped in ur­ban ar­eas.

As part of one of na­ture’s many cycli­cal pro­cesses, tree roots also bring nu­tri­ents needed by other species to the sur­face. The roots ab­sorb what the tree needs to grow and make leaves, seeds and fruit, and when they fall and de­cay the nu­tri­ents be­come avail­able on the ground. This is one of the rea­sons why our woods are so rich in wildlife.

‘I have al­ways been mor­ti­fied by the loss of ma­ture elm trees from the coun­try­side

At a larger scale, trees and other plants are the lungs of our planet, soak­ing up car­bon diox­ide from the air and help­ing to com­bat —in a los­ing bat­tle if we do not tackle it with ap­pro­pri­ate ur­gency—the cli­mate change that threat­ens hu­man­ity with in­creas­ing, cat­a­strophic con­se­quences. Trees also fil­ter pol­lu­tants from the air and ab­sorb wa­ter from the ground into their leaves, which starts the all-im­por­tant wa­ter cy­cle that pro­vides the rain needed by all ter­res­trial life, in­clud­ing our­selves.

Trees con­tinue to con­trib­ute to our well­be­ing long af­ter they have been felled, as any­one read­ing this while sur­rounded by wooden fur­ni­ture or un­der a tim­ber-framed roof will be quick to ap­pre­ci­ate, and par­tic­u­larly if they are be­ing warmed by a log fire or wood-burn­ing stove. Adding mush­room soup or roast chest­nuts to the scene would be a bonus, for the pro­duc­tion of each of these items will have pro­vided some­one with a liveli­hood and avoided the use of man-made ma­te­ri­als such as plas­tic or other de­riv­a­tives of fos­sil fu­els.

Against that back­ground, the ben­e­fits of healthy trees, wood­lands and forests are clear, which is why we should all be se­ri­ously alarmed by the re­cent rapid in­crease in tree pests and dis­eases in this coun­try. I am told there ap­pears to have been a step change in the early Nineties, with the av­er­age num­ber of new pest species be­com­ing es­tab­lished in­creas­ing to nine per year. Not all of these have caused se­ri­ous prob­lems, but the threat is very real. The causes of this si­t­u­a­tion are not clear, but are likely to in­clude the ease and speed of trans­port, with the use of con­trolled en­vi­ron­ments; the re­sponse of the trade to con­sumer de­mand for new plants; and cli­mate change, which makes the United King­dom ever more suit­able for warmth-lov­ing or­gan­isms.

My per­sonal ex­pe­ri­ence ex­tends be­yond the High­grove elms. A fun­gal dis­ease known as Phy­toph­thora ramo­rum has af­fected ma­ture larch trees in the Duchy of Corn­wall wood­lands. Ash Dieback has af­fected trees at High­grove and at a Welsh prop­erty owned by the Duchy. The term ‘dieback’ is some­thing of an un­der­state­ment as there are no reme­dies and each is ef­fec­tively fa­tal, not least be­cause in­fected trees must be felled promptly to slow the spread of the dis­ease. I am far from be­ing the only one who has watched trees they have planted and nur­tured suc­cumb­ing in this way. Trees that were care­fully cho­sen for a par­tic­u­lar site, or that have grown there nat­u­rally for thou­sands of years, have to be felled and burnt, and can­not be re­placed with the same species. Al­ready, some of this coun­try’s most his­toric park­land set­tings with an­cient oak trees that have stood for 800 years, are threat­ened with dev­as­ta­tion. It is a hor­ri­ble ex­pe­ri­ence for any­one who loves trees, or de­pends on them for their liveli­hood, and one that is be­com­ing more com­mon by the day.

This is a topic in which I have been tak­ing a wider in­ter­est over the past few years, in­clud­ing con­ven­ing meet­ings of sci­en­tists, foresters, amenity groups and reg­u­la­tors, all of whom are as alarmed as I am by what is go­ing on and the im­pli­ca­tions for the land­scape, en­vi­ron­ment and a wide range of eco­nom­i­cally im­por­tant ac­tiv­i­ties.

At these meet­ings I have heard about the wide range of ex­otic pests and dis­eases now be­ing en­coun­tered and the ef­forts be­ing made to pre­vent and man­age out­breaks. To me, the most telling ex­pe­ri­ence comes from that great Bri­tish in­sti­tu­tion, the Royal Botanic Gar­dens at Kew, of which I am Pa­tron. Their sci­en­tists not only have an ex­traor­di­nar­ily valu­able col­lec­tion of plants to pro­tect, they also have the ex­per­tise and vig­i­lance to de­tect the first sign of new prob­lems.

The staff at Kew are cur­rently watch­ing care­fully for any sign of a wide range of po­ten­tial pests, in­clud­ing the Asian Longhorn Beetle, cur­rently con­fined to one site in Kent, and the Emer­ald Ash Borer, which is not known to be in this coun­try but presents a ma­jor threat to add to the dieback from which many of our un­for­tu­nate ash trees are al­ready suf­fer­ing.

One very se­ri­ous pest is al­ready es­tab­lished at Kew, as well as at Hamp­ton Court, Hamp­stead Heath, Green­wich Park and many other lo­ca­tions across at least 25 Lon­don bor­oughs and parts of Sur­rey. The Oak Pro­ces­sion­ary Moth is de­scribed as ‘an ag­gres­sive, per­ni­cious in­sect pest with se­ri­ous con­se­quences for hu­man and plant health’. The moths in­stinc­tively tar­get the tallest, bushi­est and health­i­est look­ing trees to lay their eggs. These then hatch into nests of cater­pil­lars which eat the oak leaves, weak-

‘Ev­ery­one has a part to play and we can work to­gether to safe­guard our iconic Na­tional species for the en­joy­ment of fu­ture gen­er­a­tions

en­ing the trees and po­ten­tially killing them over the course of sev­eral years. As if this were not bad enough, the cater­pil­lars are cov­ered in long hairs that are eas­ily shed and cause un­pleas­ant, itchy rashes on hu­man skin.

Fe­male Oak Pro­ces­sion­ary Moths can fly up to three miles to lay their eggs so it is no sur­prise that their im­pacts are spread­ing. Chem­i­cal spray­ing and re­mov­ing nests has slowed the spread to around one mile per year, but new out­breaks are be­ing re­ported all the time and it seems un­likely that to­tal con­tain­ment is pos­si­ble.

Trag­i­cally, this is not the only ma­jor threat to the oak trees which grace so much of our coun­try­side. A few years ago a se­ri­ous dis­or­der of oaks, known as Acute Oak De­cline, was de­tected and found to be spread­ing nat­u­rally from tree to tree. Not all the trees af­fected die, but some do and many more are weak­ened. The prob­lem was first de­tected in the East of Eng­land, but seems to be spread­ing North and West. A lot of re­search has been con­ducted into the causes, sup­ported by the fund-rais­ing ef­forts of many valiant peo­ple, in­clud­ing the late Peter Good­win of Wood­land Her­itage.

Fur­ther re­search—and, of course, fund­ing—is ur­gently needed, but Acute Oak De­cline ap­pears to be caused by a com­plex as­so­ci­a­tion of na­tive or­gan­isms, in­clud­ing a beetle and a fun­gus. How­ever, all of the other pests and dis­eases I have men­tioned, and a great many more, have been in­tro­duced to this coun­try. The fungi that cause Dutch Elm Dis­ease, Phy­toph­thora ramo­rum and Ash Dieback were all prob­a­bly im­ported on in­fected plant ma­te­ri­als. The Asian Longhorn Beetle ar­rived in poorly treated wood pack­ag­ing ma­te­rial from Asia and the Oak Pro­ces­sion­ary Moth is be­lieved to have ar­rived as eggs on im­ported trees from South­ern Europe.

Im­ports of live plants, bulbs and cut flow­ers into this coun­try have more than dou­bled in the past 25 years, to around 350,000 tonnes, with a value of £1.4 bil­lion. Last year, sur­veil­lance at points of en­try iden­ti­fied more than 320 pest species, of which 6% had not pre­vi­ously been recorded. But we can­not rely on these border con­trols alone. Gar­den and land­scape de­sign­ers, and in­deed any­one spec­i­fy­ing plants for im­por­ta­tion, should un­der­stand the threats and be ask­ing search­ing ques­tions about plant health and biose­cu­rity, in­clud­ing the ur­gent ne­ces­sity for quar­an­tine pe­ri­ods.

These threats to our trees, wood­lands and forests are ex­tremely se­ri­ous and far­reach­ing. Those of us who value their role in the coun­try­side need to do three things. We must highlight the na­ture and scale of the threat, en­cour­age more sci­en­tific re­search and, above all, en­sure that good prac­tice is im­ple­mented. These are not, if I may say so, tasks for other peo­ple. Ev­ery­one has a part to play, start­ing with rais­ing aware­ness of how much is at stake; and with con­certed ac­tion I am sure we can work to­gether to safe­guard our iconic Na­tional species for the en­joy­ment of fu­ture gen­er­a­tions.

‘threat­en­ing Pests and dis­eases are now se­ri­ously the health of all our na­tive trees

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