单选题 ForestsincountrieslikeBrazilandtheCongogetalotofattentionfromenvironmentalists,anditiseasytoseewhy.SouthAmericaandsub-SaharanAfricaareexperiencingdeforestationonanenormousscale:everyyearalmost5millionhectaresarelost.ButforestsarealsochanginginrichWesterncountries.Theyaregrowinglarger,bothinthesensethattheyoccupymorelandandthatthetreesinthemarebigger.Whatisgoingon?ForestsarespreadinginalmostallWesterncountries,withthefastestgrowthinplacesthathistoricallyhadratherfewtrees.In199028%ofSpainwasforested;nowtheproportionis37%.InbothGreeceandItaly,thegrowthwasfrom26%to32%overthesameperiod.ForestsaregraduallytakingmorelandinAmericaandAustralia.PerhapsmostastonishingisthetrendinIreland.Roughly1%ofthatcountrywasforestedwhenitbecameindependentin1922.Nowforestscover11%oftheland,andthegovernmentwantstopushtheproportionto18%bythe2040s.Twothingsarefertilisingthisgrowth.Thefirstistheabandonmentoffarmland,especiallyinhigh,dryplaceswherenothinggrowsterriblywell.Whenfarmersgiveuptryingtoearnalivingfromfarmingorherding,treessimplymovein.Thesecondisgovernmentpolicyandsubsidy.Throughouthistory,governmentshaveprotectedandpromotedforestsfordiversereasons,rangingfromtheneedforwoodenwarshipstoadesiretopromotesuburbanhouse-building.Nowadaysforestsareincreasinglywelcomebecausetheysuckincarbonpollutionfromtheair.Thejustificationschange;thedesireformoretreesremainsconstant.ThegreeningoftheWestdoesnotdelighteveryone.Farmerscomplainthatlandisbeingtakenoutofusebygenerouslysubsidisedtreeplantations.PartsofSpainandPortugalsufferfromterribleforestfires.Otherssimplydisliketheappearanceofforestsplantedinneatrows.Theywillhavetogetusedtothetrees,however.ThegrowthofWesternforestsseemsalmostasunstoppableasdeforestationelsewhere.问：Whataccountsforourincreasingdesireforforests?