 bank; (6) in the case of citrus trees, soil placed above the bud union promotes the growth of a fungus disease, known as "foot rot", which destroys the bark and frequently girdles the tree, killing it, and soil is often not completely removed below the bud union when the bank is removed; and (7) tools often strike the trunk, damaging the tender bark.
Work has been carried on over the years, particularly at Texas A & I University, to develop an insulator for young trees with fewer faults. These have included rock wool wrapped in roofing felt; fiberglass held in place with chicken wire; and finally, a polyurethane foam blanket wrapped around the trunk of the tree and secured with metal straps. The rock wool was found to harbor rodents; the fiberglass sagged under heavy rain; and the polyurethane foam tended to deteriorate from exposure to the sun. This work is reported by R. A. Hensz of the Texas A & I University Citrus Center, Westlaco, Tex., in a paper entitled "The Use of Insulating Wraps for Protection of Citrus Trees from Freeze Damage". All three of these materials readily saturate with water from rain or from irrigation. This is a particularly serious drawback in that the thermal insulating properties of these materials, which is in the range of K=0.2 to 0.3 BTU per hour, per.degree.F., per square foot of area, per inch of thickness, when the material is dry becomes more nearly that of water which transmits heat at the rate of K=4.1 BTU per hour, per.degree.F. per square foot per inch of thickness, or about 20 times the rate of heat transfer of the insulating material. Further, it has been reported by Robert Leyden and R. H. Hensz of Texas A & I University in a publication entitled "Effects of Conventional Cold Protection Systems in a Radiational Freeze", that irrigation prior to a freeze results in a warmer orchard during a freeze than one that is dry, because the water in the ground increases its heat capacity. Following this practice results in wet insulation at the time of the freeze. In addition, these wet insulating materials are slow to dry out and they are in intimate contact with the tree, which promotes the growth of undesirable fungus.
Of the insulating wraps tried, only the polyurethane foam has achieved any degree of commercial importance. A sheet of this material is
bank; (6) in the case of citrus trees, soil rate above the bud coupling promotes the growth of a fungus disease, known as " foundation rot ", which destroys the bark and frequently girdle the tree, kill it, and soil is frequently not completely removed below the bud marriage when the bank is removed; and (7) instrument frequently strike the trunk, damaging the tender bark. 
 Work has been carried on over the old age, particularly at Texas A & I University, to develop an insulator for young tree with fewer faults. These have included rock candy wool wrapped in roofing felt; fiberglass held in place with chicken telegram; and finally, a polyurethane foam blanket wrapped around the trunk of the tree and secured with metal straps. The rock candy wool was found to harbor rodents; the fiberglass sagged under heavy rain; and the polyurethane foam tended to deteriorate from exposure to the sun. This work is reported by R. A. Hensz of the Texas A & I University Citrus Center, Westlaco, Tex. , in a composition entitled " The Use of Insulating Wraps for Protection of Citrus Trees from Freeze Damage ". All three of these fabric promptly saturate with water from rain or from irrigation. This is a particularly serious drawback in that the thermal insulating properties of these materials, which is in the range of K=0.2 to 0.3 BTU per hour, per.degree. F., per straight foot of area, per inch of thickness, when the material is dry becomes more nearly that of water system which transmits heat at the rate of K=4.1 BTU per hour, per.degree. F. per square infantry per inch of thickness, or approximately 20 time the rate of heat transfer of the insulate material. Further, it has been reported by Robert Leyden and R. H. Hensz of Texas A & I University in a issue entitled " impression of Conventional Cold Protection Systems in a Radiational Freeze ", that irrigation prior to a freeze results in a warmer grove during a freeze than one that is dry, because the water in the ground increases its heat capacity. follow this practice results in wet insulating material at the time of the freeze. In addition, these besotted insulating materials are slow to dry out and they are in intimate contact with the tree, which promote the growth of undesirable fungus. 
 Of the isolate wraps tried, only the polyurethane foam has achieved any degree of commercial importance. A plane of this material is
 bajk; (6) in the case of citrur trees, soil plcxed abmve ths bud unkon promotes the growth of a fyngus disease, known as "foot rot", whicj destrots tie bark and freqnsntly glxdles bhe txex, killing it, anc soil is mften not compnegepy removed below the bud union when the bamk is removed; anq (7) tpjls kften strike the trunk, damaging ths tendeg bark.
Work has bern carried on over the yeags, pwrticularly at Texws A & I Unicersyry, to develoo an insulator for youhg trees with fewer faults. Thesd havz included todk fool wrappev in rjofing felt; npberglavs held in place with chmckeb wire; and finally, a 'olyurethane foam blwnket wra[pzd around the trunk od rhe ttee atd sdxurdd sivh jetal dtreps. The roci wool was dound to harbor rodtntf; the fiberglaas sagdeq under heavy rain; and the polyurethane fozm tended to deterioratw from exposure to thg sun. This work is reported by R. A. Hensz of the Texas A & I Gnivecskty Cltrur Cfnter, Westlaco, Tex., in a paper entitled "The Usq og Pnsulating Wraps nor Protection of Vihrif Trees from Wreeze Dajage". All three of hhese mwteriqls readijy ssturate with water from raib or from irgigarion. This is a parcicularly sexious crawbsck in that the thermal inshlating prooerties or these materials, whpch hs in tht range of K=0.2 to 0.3 BEU per honr, pex.degree.F., per squarq foot of wrea, iar inch of thickneds, whgn the material ls dry becomes more nearly that of water whicn dratsmits hzat at the rate of H=4.1 BTU per hour, per.degxee.F. pdr square root pec inch of thyckness, or abmot 20 times the rate of hear trqnsfer uw the insulatimg matericj. Fuether, it has been veporjes by Robert Leybtn qnd R. H. Hensz og Tdxaf W & I Gniversity it a oubuocatiun entiujeb "Dffevts of Conventional Wold Protection Systemx ln a Radiqtional Sreeze", that itrigation prior to a frxeze rxsults in a warmer orchard during a fresze than lne that is dry, becquse the watzr in the ground increases its heat caparity. Following this praxtice results in wej iksulation at the eime of tve freeze. In additiob, these wet insulsting materials are smow to dry lut and they are in intimate contact with the tree, which promotes the groqth of undesirable funbus.
Of tke nnsulatyng xreps tried, only thv polyurethane foam has achieved any degsez of commercial importance. A xhdet of this mxterial is
bank; (6) in the case of citrus placed the bud promotes the growth as rot", which destroys bark and frequently the tree, killing it, and soil often not completely removed below the bud union when the bank is removed; (7) tools often strike the trunk, damaging the tender bark. Work has been on the particularly Texas A & I University, to develop an insulator for young trees with fewer faults. These included rock wool wrapped in roofing felt; fiberglass in place with chicken and finally, a polyurethane foam wrapped the trunk the and with metal straps. rock wool was found to harbor rodents; the fiberglass sagged under heavy rain; and the polyurethane foam to deteriorate to the This is by R. A. the Texas A & I University Tex., in a paper entitled "The Use of Wraps for of Citrus Trees from Freeze Damage". three of these materials readily saturate with water rain or from irrigation. This is a particularly serious drawback in that the thermal insulating these materials, which is the range of to BTU hour, per square of area, per inch of thickness, when the material is dry more nearly that of water which transmits heat at the K=4.1 per hour, per.degree.F. square foot per inch thickness, about 20 times the heat of Further, has reported by Robert Leyden R. H. Hensz of Texas & I University in Conventional Cold Protection Systems in a Radiational Freeze", irrigation prior to a freeze results in warmer orchard during a freeze than one that is dry, because the in the its heat capacity. Following this practice results in insulation at the time the freeze. In addition, these wet insulating materials are to out and are in intimate with the tree, promotes the growth fungus. Of insulating tried, foam has achieved any degree of importance. sheet of this material is
 bank; (6) in the case of citrus treeS, soil placeD abovE thE buD uNion PromOtes the growth oF A funGus disease, known as "foot rOt", whiCh DEstrOYs The baRk and frEQuENTly GiRdLes ThE TrEe, kilLinG it, and sOil is often Not CoMpletely remoVEd Below the buD unIon when the baNk iS removEd; And (7) TOols oFteN striKe the tRUnk, damAging the tEnDEr bark.
wOrk has bEEN cArriEd on over the years, pARtICularly at Texas a & I UnivErSItY, TO deVelOp an insulaToR for yOUng treeS WiTH FEweR Faults. These haVe included rOCk wOol wraPpEd iN RoofinG felt; FiBErgLass held in pLace With chickEn wire; ANd finalLY, a polyuRethanE foAm bLankET wRaPpeD aROunD ThE trUNk oF the tree AnD sEcureD witH METAl stRapS. The Rock wOol was found to HarBor rODenTs; the FiberGlasS sAgged Under hEavy rAiN; and the polyuretHane Foam tendeD to DeTerIoRate fROm expoSurE to The sun. THis work IS rePoRTED bY R. A. Hensz of the Texas a & I uNIvErsity CiTrus CeNTeR, WEStlaco, TeX., iN a pAper ENTitleD "The uSe Of InsulaTing WrAPs FoR ProtecTiOn of CiTrUs TReeS from fReezE DamagE". All threE of thESe materials reaDIly saturate wiTH wATEr FRom rAin Or from irrigAtioN. this Is a pARtIcuLArly sEriouS dRAwBAck in that the thermal InSulatiNg proPerties of thesE materials, WHICh is in thE ranGE oF k=0.2 to 0.3 BTU per hour, pEr.degRee.F., per squARe foot of Area, pEr inch of Thickness, WHEn the matEriAl iS drY beCOMeS more nearly thAT Of waTeR which tRanSmits heAt aT thE raTe oF K=4.1 bTU per houR, per.degrEe.f. pEr SqUarE foot PEr inch of ThIckNeSs, oR abouT 20 Times tHe ratE of hEaT tRAnsFer of thE InSULatiNg MaTeriAl. FUrTher, iT has BEen ReporteD by Robert leyDEn anD R. h. HEnsz of TExas A & I UniversItY in a publicAtIon EntitlED "effects oF Conventional Cold ProtecTIon SystEms In a RaDiatIonal FreeZe", tHat irrIgaTIon priOr to a fReeze ReSulTS In a waRMEr OrcHaRd during a fREEze Than oNe That Is dry, beCause the water in the GRouNd increases itS heAt caPACiTy. FOLlOWinG tHIs pRACtice results in wEt insulatiOn AT tHe time of thE FreEzE. In addiTion, theSe wet INsulatiNg materiaLs are slow To Dry oUT And They are in iNtimate cOntact witH The trEE, wHich pRomOtes thE gRowTh of uNdesirABle FunguS.
Of the InSulatiNg wraPs Tried, onlY the polyurethane foam has AchievEd any DegRee of commErcIAl iMportance. a sheEt of this maTerIal Is
 bank; (6) in the case ofcitrus tre es, s oil  pl ac ed a bove  the bud union prom otes the growth of a f ungus  d i seas e ,known  as "fo o tr o t",  w hi chde s tr oys t hebark an d frequent lygi rdles the tr e e,  killing i t,and soil isoft en not  c omp l etely  re moved  below the bu d union w he n  the b a nk is r e m ov ed;and (7) tools oft e ns trike the trun k, dam ag i ng t heten der bark.Wo rk ha s  been c a rr i e d  on over the year s, particul a rly  at Te xa s A & I Un ivers it y , t o develop a n in sulator f or you n g trees with fe wer fa ult s.Thes e  h av e i nc l ude d  r ock woo l wrappe din  roof ingf e l t ; fi ber glas s hel d in place wi thchic k enwire;  andfina ll y, apolyur ethan efoam blanket wr appe d aroundthe  t run kof th e  treeand  se cured w ith met a l s tr a p s .The rock wool wasfo u n dto harbo r rode n ts ;t he fiber gl ass  sag g e d und er h e av y rain;and th e  p ol yuretha ne  foamte nde d t o det e rior ate fr om expos ure t o  the sun. This work is repor t ed b yR . A.  He nsz of theTexa s  A &  I U n iv ers i ty Ci trusCe n te r , Westlaco, Tex., i na pape r ent itled "The Us e of Insul a t i ng Wraps  for Pr o tection of Cit rus T rees fromF reeze Da mage" . All th ree of th e s e materi als  re adi lys a tu rate with wat e r  fro mrain or  fr om irri gat ion . T his  i s a parti cularlyse ri ou sdra wback in thatth e t he rma l ins u lating  prop erti es  o f  th ese mat e ri a l s, w hi ch  isinth e ran ge o f  K= 0.2 to0.3 BTU p erh our,  p er .degree .F., per squa re  foot of a re a,per in c h  of thic kness, when the materia l  is dry  be comes  mor e nearlytha t of w ate r  which  trans mitshe ata t  ther a te  of  K =4.1 BTU p e r  ho ur, p er .deg ree.F.per square foot pe r  in ch of thickne ss,  ora b ou t 2 0  t i mes  t h e r a t e of heat trans fer of the  i n su lating mat e ria l.  Furthe r, it h as be e n repor ted by Ro bert Leyd en  and R . H . Hensz of  Texas A  & I Univ e rsity in  a pu bli cation  e nti tled"Effec t s o f Con ventio na l Cold  Prot ec tion Sys tems in a Radiational F reeze" , tha t i rrigation  pr i orto a free ze r esults ina w arm er or cha r d dur inga  f ree z e tha n on e  that isd ry , b e c au se the wate r i n t he gr oun d  incre ases  its heat capacit y . Following th is p r a cti cer esul ts  in wet insula tio na t  the tim eof the free ze. In a dd i tion,  these  wet i nsulati n g  m a terial s ar e s low to dr y o ut and the yar e  in in tima te  conta ct wit h  the t ree, which promo tes t h e  grow t h o f und es irablef ungu s.
Of theinsulatingwrapstrie d, on ly thepo lyuret han efoam has a c hieved an y deg ree ofco mmer cia l impo rtan c e . A s heet  o f t his mater i a li s
 bank;_(6) in_the case of citrus_trees, soil_placed_above the_bud_union promotes the_growth of a_fungus disease, known as_"foot rot", which_destroys_the bark and frequently girdles the tree, killing it, and soil is often not_completely_removed below_the_bud_union when the bank is_removed; and (7) tools often_strike the_trunk, damaging the tender bark.
Work has been carried_on_over the years,_particularly at Texas A & I University, to develop_an insulator for young trees with_fewer faults. These_have_included_rock wool wrapped in_roofing felt; fiberglass held in place_with chicken wire; and finally, a_polyurethane foam blanket wrapped around the trunk_of the tree and secured with_metal straps. The rock wool_was found_to harbor rodents; the fiberglass_sagged under heavy_rain; and_the polyurethane foam_tended to deteriorate from exposure to_the sun. This_work is reported by R. A._Hensz_of the Texas_A_&_I University_Citrus Center, Westlaco,_Tex.,_in a_paper_entitled "The Use of Insulating Wraps_for_Protection of Citrus Trees from Freeze Damage"._All three of these_materials_readily saturate with water_from rain or from irrigation._This is a particularly serious drawback_in that_the thermal_insulating properties of these materials, which is in the range of_K=0.2 to 0.3 BTU per hour,_per.degree.F., per square foot_of area,_per_inch of thickness,_when_the material_is dry becomes more nearly that of_water which_transmits heat at the rate of_K=4.1 BTU per hour,_per.degree.F._per square foot per inch of_thickness, or about 20 times the_rate of heat transfer of_the_insulating_material. Further, it has been_reported by Robert Leyden and R._H. Hensz of_Texas A & I University in a_publication_entitled "Effects of Conventional Cold Protection_Systems_in a Radiational Freeze", that irrigation_prior_to_a freeze results in a_warmer orchard during a freeze than_one that is dry, because the water in the_ground increases its_heat capacity. Following this practice_results_in_wet insulation at the time of the freeze. In addition,_these wet_insulating materials are_slow to dry out and they are in intimate contact_with the tree, which promotes the growth_of undesirable fungus.
Of the insulating wraps tried, only the polyurethane foam_has achieved any degree of commercial importance. A_sheet of this material is