SEASONAL EFFECTS ON TRANSPLANTABILITY OF SCARLET OAK, GREEN ASH, TURKISH HAZELNUT AND TREE LILAC

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1 31 Harris & Bassuk: Seasnal Effects n Transplantability SEASNAL EFFECTS N TRANSPLANTABILITY F SCARLET AK, GREEN ASH, TURKISH HAZELNUT AND TREE LILAC by J. Rger Harris and Nina L. Bassuk Abstract. Quercus cccinea (scarlet ak), Fraxinus pennsylvanica (green ash), Crylus clurna (Turkish hazelnut) and Syringa reticulata 'Ivry Silk' (tree lilac) trees were transplanted bare-rt thrughut the spring and fall planting seasn. Pst-transplant respnse was cmpared with the rt grwth activity f established trees at the time f transplanting. Rt grwth rate f established trees at transplanting was nt related t transplantability. Green ash and tree lilac transplanted well at all dates. Scarlet ak and Turkish hazelnut transplanted prly during the late spring and early fall, but survival was gd in early spring and mid fall. Street trees prbably experience mre physilgical stress and mrtality in the establishment phase than any ther time during their life span. Gilbertsn and Bradshaw (5) cncluded that 39% f newly planted trees in Lndn died within five years after planting and that the even a higher percentage f replacements died. This was primarily a result f unfavrable water balance due t prly established rt systems. The half-life f street trees in Lndn was cncluded t be nly 1-15 years. High temperatures and lw relative humidities in inner cities impse high evaprative demands (17), and this undubtedly exacerbates establishment prblems. Rapid transplant establishment is essential in rder t facilitate transplant survival and the lngevity f ur urban frests. A better understanding f the effect that time f year has n transplanting will aid the city frester in managing tree installatins t achieve quick plant establishment. Evaprative demands are greatest n transplanted trees in late spring and summer as temperatures increase, leaves develp, and transpiratin increases. Hwever, warmer temperatures and phtsynthesizing leaves prmte rt grwth, and the capacity fr plant establishment, if favrable water balance is maintained, may be greater than when the plant is drmant (12). Since sht grwth is readily bserved, the relatinship between sht activity f the tree at transplanting and eventual transplant success may be easily bserved. Hwever, determinatin f rt grwth rate at the time f transplanting is cnsiderably mre difficult, particularly fr large trees. Fr this reasn, cmparisns between transplantability and rt grwth rate at transplanting have nt been made fr landscape-sized trees. The purpse f this research was t test the hypthesis that perids f active rt grwth in established trees will be perids f quick transplant establishment. An additinal bjective f this research was t determine if bservatins f sht grwth culd be used t predict active perids f rt grwth during which transplanting wuld be mst successful. Materials and Methds Rt and sht grwth peridicity. Fureach f Quercus cccinea (scarlet ak), Fraxinus pennsylvanica (green ash), Crylus clurna (Turkish hazelnut) and Syringareticulata'lvry Silk' (tree lilac) trees were established n a rhiztrn (9) in spring, Height and caliper f all trees were taken ne year after transplanting t the rhiztrn, just prir t spring, 1992 bud break, and sht and rt grwth data were taken thrughut the 1992 grwing seasn. Five shts with the greatest diameter were marked n each tree fr peridic measurement f sht extensin. The mean f the five shts at each measurement date was the sht extensin fr that tree. At the end f the grwing seasn, the rate f increase in sht extensin fr each measurement day (SE) was calculated fr each replicate by: SE = (A SE /T SE )/1 x 1 ; where A SE = increase in extensin between measurements, T SE = ttal

2 Jurnal f Arbriculture 2(6): Nvember sht extensin fr the seasn and t = time (days) between measurements. Units fr SE are %/day. Rt extensin was measured n the rhiztrn by marking with clred marking pens several individual rts which were grwing mst vigrusly. Rt extensin at each measurement fr each replicate was the maximum extensin measured n a single rt. At the end f the grwing seasn, the rate f increase in rt extensin fr each measurement day (RE) was calculated fr each replicate by: RE = (A RE /T RE )/1 x 1; where A RE = increase in maximum rt extensin between measurements, T RE = ttal increase in maximum rt extensin fr the seasn and t = time (days) between measurements. Units fr RE are %/day. Means f all replicates fr each species and the standard errr f the means were then calculated fr RE and SE and graphed fr depictin f seasnal sht and rt grwth patterns. Spring and fall transplanting. Eighty trees f bth green ash and scarlet ak trees were btained frm Schichtel's Nursery, Springville, New Yrk and established n a research field near the campus f Crnell University in Ithaca, New Yrk, in the spring f Beginning in April f 1992, fur replicates f each species were chsen at randm and harvested bare-rt accrding t American Assciatin f Nurserymen standards (1). Plants were stred in an enclsed barn n site fr tw days befre planting. Rt-balls were cvered with burlap and watered at the time f strage. N additinal water was applied befre planting. Within three days f harvesting the green ash and scarlet ak, fur replicates f Turkish hazelnut and tree lilac were picked at randm and harvested in the manner described abve frm Schichtel's Nursery, Springville, New Yrk. Trees were then immediately transprted in an enclsed van t Ithaca and stred in the manner as described fr green ash and scarlet ak. At the end f the respective tw-day strage perid, trees were planted in a randmized cmplete blck design and irrigated. Irrigatin was applied thereafter when weekly precipitatin ttals were negligible. Mean ttal tree height and caliper f all replicates were taken at the time f transplanting. Beginning transplant dates were April 4, April 24, May 16, June 8, September 6, September 28, ctber 17, Nvember 6 and December 8,1992. This effectively bracketed the spring and fall transplanting seasns. At the cnclusin f the first sht flush (bud set) after transplanting, the lngest pst-transplant sht extensin was measured fr each tree n three separate shts which riginated in the upper 1 /3 f the canpy. Sht extensin fr each tree was the mean extensin f these three shts. Sht extensin f the transplanted trees was indexed against the cncurrent sht extensin f the trees established n the rhiztrn. At the cnclusin f all initial pst-transplant sht extensin (July, 1993), trees were scred fr survival (alive r dead), and the survival percentage at each planting date was calculated fr each species. Trees were cnsidered alive if new sht grwth was evident within the upper 5% f the abve grund height f the tree. Results and Discussin Relatinship between transplant dates and seasnal grwth patterns f established trees. Height and caliper f established trees and transplanted trees are shwn in Table 1. Spring transplanting began befre sht r rt grwth f established trees, and cntinued int the perids f peak sht grwth fr each species (Fig. 1A-D). Fall transplanting began after cessatin f sht grwth, but during active rt grwth, and cntinued until all rt grwth had stpped. At the April 4 planting date there was n visible bud activity, and slight bud swell was evident at the April 24 transplanting date (data nt shwn). Shts had begun extensin n all species at the May 16 transplanting date. Spring and fall transplanting f scarlet ak. N plants survived late spring (June 8) r early fall (Sept. 6) transplanting (Fig. 2A). Early spring (April 4, April 24) and late fall (Nvember 6) survival, hwever, was 1%. Survival f trees transplanted n May 16 was nly 25%. This planting date cincided with the perid f maxim urn sht extensin (Fig. 1A). Scarlet ak had the quickest sht extensin f any species bserved. Yung expanding shts are underdevelped

3 312 Harris & Bassuk: Seasnal Effects n Transplantability Table 1. Mean height and caliper f scarlet ak, green ash, Turkish hazelnut and tree lilac trees established n a rhiztrn and at transplanting.- 2 Species Scarlett ak established transplanted Green ash established transplanted Turkish hazelnut established transplanted Tree lilac established transplanted Height (m) 2.8(.44) x 2.27(.77) 3.32(.18) 3.7(.8) 2.25(.3) 2.(.4) 2.48(.9) 2.22(.4) Caliper (cm)y 3.1(.2) 3.8(.2) 5.1(.1) 6.1(.2) 3.1(.2) 3.4(.1) 2.8(.1) 3.5(.1) Z n=4. Y Caliper = trunk diameter 1 cm abve sil line. >: Standard errr f the mean. S structurally and have little resistance t water lss (4). Water lss thrugh these shts prbably cntributed t whle tree water lss and pr pst-transplant survival. Rt grwth rate n established trees was increasing n the May 16 and June 8 planting dates, but was decreasing n the September 6 and September 28 planting dates, and survival was 1% n trees transplanted n Nvember 6 when rt grwth was ending n the established trees. It appears, therefre, that transplantability f scarlet ak has little t d with rt grwth rate f the tree just prirt transplanting. Survival f scarlet ak increased steadily in the fall, which cincided with the lwer evaprative cnditins f cler sil and air temperatures. Desiccatin tlerance has been demnstrated t increase when trees are in a drmant cnditin, such as n the Nvember 6 planting date (3). Survival was nly 25% n trees transplanted n December 8, hwever. Rt permeability t water can be very lw fr sme species when sil temperatures are cld (7), and plants may nt have been able t take up sufficient water t Figure 1. (right clumn) Daily sht and rt grwth rates (SE and RE) f established scarlet ak (A), green ash (B), Turkish hazelnut (C) and tree lilac (D) fr Transplant dates are indicated by arrws, n = 4. a: < I l I T I I i i 'I ~..7F- SHTS RTS I [ l SCARLET AK SHTS RTS GREEN ASH I I I I I I I I I ' A )- B - SHTS V / RTS TURKISH HAZELNUT i I i l i I i l i I i l i l i I t - + > CD lie SHTS RTS TREE LILAC /f\ A / \ /f\ I I I I I. I. I.I I.I DATE D V- <JJ * l ' \ \ -* N> N> \ \ \ T -> ^1 <T)

4 Jurnal f Arbriculture 2(6): Nvember > en c 75 SCARLET AK (A 1- > 75 3 GREEN ASH a: Q_ ^ 25 x 8 Q? Q I 5 H c5n (5 ID CD \ \ \ \ \ k) - 1 N> \ > (3) ) -" si TRANSPLANT DATE N> ) Figure 2. Percent survival (A) and initial psttransplant sht extensin index (B) f scarlet ak trees transplanted thrughut spring and fall f Bars represent standard errrs f the means. Sht extensin fr transplant dates with 25% survival are nt shwn, n = 4. prevent desiccatin. Sil temperature n December 8 was less than 3 C, but the sil temperature n the Nvember 6 planting date was arund 8 C C (data nt shwn). A dramatic increase in water flw resistance thrugh sme tree species has been demnstrated t ccur when rt zne temperatures drp belw 7 C(1,13). Scarlet ak trees planted n Nvember 6 may have been able t take up sufficient water t ensure survival befre clder sil temperatures caused a decreased rt permeability t water, whereas thse I -fv cjn S> ib d -^ \\\^\\.\ -^ N) N)-' N>\\\ \l ) 3 TRANSPLANT DATE Figure 3. Percent survival (A) and initial psttransplant sht extensin index (B) f green ash trees transplanted thrughut spring and fall f Bars represent standard errrs f the means. n = 4. transplanted n December 8 may nt have. Intimate rt:sil cntact is critical fr the survival f bare-rt transplants (14). Scarlet ak is a carse rted tree (15) and therefre wuld have less ttal cntact with the backfill sil than mre fibrus rted species. The much reduced carse rt system f scarlet ak wuld therefre prbably have mre difficulty supplying sufficient water under high evaprative cnditins r when cld sils reduced rt permeability. This may partially explain the pr survival rates f scarlet

5 314 Harris & Bassuk: Seasnal Effects n Transplantability ak trees transplanted in late spring, summer and early fall when air temperatures were high and n December 8, when sil temperatures were very cld. Sht extensin the fllwing spring, as well as survival, was pr n trees transplanted n September 28 (Fig. 2b). This was prbably a result f water lss thrugh leaves f the transplants since survival was always less than 1% when trees were in leaf. Spring and fall transplanting f green ash. In cntrast t scarlet ak, green ash survival was gd fr trees transplanted n all dates (Fig. 3A). Trees were apparently smewhat mre stressed, hwever, when transplanted in the late spring and early fall, since initial pst-transplant sht grwth n trees transplanted at these dates was generally less than thse transplanted n ther dates (Fig. 3B). These were the warmer transplant dates, and trees were in full leaf. Unlike scarlet ak, survival was excellent fr green ash trees transplanted in December. Green ash has a mre fibrus rt system than scarlet ak and wuld therefre have mre absrptive surface expsed t the backfill sil. In additin, rts f green ash appeared much less darkened than scarlet ak. This suggests a higher cncentratin f suberin depsits fr scarlet ak (11), which culd hinder water uptake n scarlet ak as cmpared t green ash. There is als evidence that green ash has a higher rt initiatin rate than scarlet ak (2,16). Green ash wuld prbably therefre regenerate new rts faster under unfavrable envirnmental cnditins, increasing survival. These data indicate that landscape cntractrs can transplant green ash bare-rt successfully at all fall and spring dates. This is in spite f the fact that shts may be in active grwth r that the capacity fr rt grwth is lw (Fig. 1B). Spring and fall transplanting f Turkish hazelnut. Turkish hazelnut transplanted prly when in full leaf r in December (Fig.4A), similar t results fr scarlet ak. Hwever, cntrary t scarlet ak, survival was 75% when transplanted during active sht extensin (May 16). Survival was % when mst buds had begun t set and rt grwth was well underway (June 8) (Fig. 1C). This is cntrary t ppular thught which says that trees shuld nt be planted during sht extensin, but nly after buds are set. The lw survival n June 8 was perhaps due t the higher evaprative cnditins created by warm temperatures after the June 8 transplant date. Alternatively, sht extensin r leaf size may have been reduced n the expanding shts f Turkish hazelnut at transplanting because f reduced turgr, and subsequent pst-transplant water lss may have been reduced because f the lwered plant evaprative surface area. The much mre rapid sht extensin f scarlet ak (Fig. 1 A) was prbably less able L Q z L I TURKISH HAZELNUT/TN y N> ) -" sj a TRANSPLANT DATE Figure 4. Percent survival (A) and initial psttransplant sht extensin index (B) f Turkish hazelnut trees transplanted thrughut spring and fall f Bars represent standard errrs f the means, n = 4.

6 Jurnal f Arbriculture 2(6): Nvember t adapt t the misture stress created by the massive rt remval at transplanting than the mre sustained sht extensin f Turkish hazelnut (Fig. 1C). Turkish hazelnut, similar t scarlet ak, has a carse rt system and wuld prbably encunter the same limitatins supplying water t the shts n the warmer transplant dates, as discussed abve fr scarlet ak. Pst-transplant sht extensin f surviving trees was lwer fr all fall transplanting dates (Fig. 4C). Turkish hazelnut expressed the same 1% survival pattern as scarlet ak n Nvember 6, but very lw survival n trees planted ne mnth later n December 8. Early Nvember may be the latest that many tree species can be successfully transplanted in the nrtheastern United States. Turkish hazelnut, similar t scarlet ak, did nt transplant with mre success when rt grwth rates were high n established trees. Instead, envirnmental cnditins such as high air r lw sil temperatures were a better indicatr f transplant success. Spring and fall transplanting f tree lilac. In cntrast scarlet ak and Turkish hazelnut, tree lilac had 1% survival n all transplanting dates (Fig. 5A). Surprisingly, as evident by the psttransplant sht extensin (Fig. 5B), trees seemed t transplant very well in the late spring (6/8). Tree lilac trees are apparently able t explit the ptential fr active rt grwth which exists in the warmer mnths (Fig. 1D). verall relatinship t peridic grwth rate f established trees. Established trees brke bud prir t new rt grwth (Fig. 1A-D). The scarlet ak, green ash, Turkish hazelnut and tree lilac trees transplanted in the spring therefre likely began spring sht grwth with nly the resurce gathering capabilities f the transplanted rt ball, withut the aid f new rts. thers have als reprted that spring bud break preceded rt grwth. Arnld and Struve (2) reprted spring bud break befre rt grwth fr green ash seedlings in Indiana, and Struve and Jly (15) reprted similar results fr red ak (Quercus rubra) seedlings, als in Indiana. Headley and Bassuk (8) reprted that rt grwth did nt precede bud break fr Nrway maple (Acer platanides), red maple (Acerrubrum), pin ak (Quercuspalustris) > 1 r ^ 75 us 5 Q_ L Q z LU I N> TREE LILAC en 5) <E i c ) TRANSPLANT DATE Figure 5. Percent survival (A) and initial psttransplant sht extensin index (B) f Tree Lilac trees transplanted thrughut spring and fall f Bars represent standard errrs f the means. n = 4. r nrthern red ak (Quercus rubra) in upstate New Yrk. Trees transplanted n Nvember 6 were transplanted at the end f the rt grwth perid, and thse transplanted n December 8 were clearly beynd the perid when rt grwth ccurs. A lnger perid was available fr rt grwth fr thse trees transplanted n September 6 and September 28 cmpared t thse transplanted n ctber 17. Hwever, temperatures, and thus ptential water lss, were higher at this time f

7 316 Harris & Bassuk: Seasnal Effects n Transplantability year. Since green ash and scarlet ak were transplanted int nursery rws ne year befre the beginning f the experiment, stresses impsed at this time culd have affected the transplant respnse the fllwing year. Tree lilac and Turkish hazelnut were grwn fr several years in the nursery befre the final transplanting, and the number f sht interndes n the new psttransplant sht flush was dependent upn the pre-transplant grwing cnditins f the previus seasn (determinant grwth). Althugh the psttransplant elngatin rate wuld be mstly determined by the limitatins impsed by transplant stress, sme interactin is pssible. Determinatin f when trees are established is dependent n the criteria used. The rt spread:crwn spread rati n trees established n the rhiztrn was statistically similar amng species and averaged 2.4 in the spring f 1992, which is nly slightly less than that thught t be the average fr established trees (6). Summary The predictin f perids f active rt grwth was nt a reliable tl fr the predictin f transplant success. Green ash and tree lilac can be planted with cnfidence thrughut the spring and fall planting seasns. Green ash may respnd better t fall transplanting, and tree lilac may respnd better t transplanting in late spring and early fall. Turkish hazelnut and scarlet ak transplant best in early spring and mid fall. Survival can be expected t be pr in late spring and early fall fr bth species. Turkish hazelnut, but nt scarlet ak, may be transplanted after buds have brken in the spring. Tree lilac and Turkish hazelnut had similar rt grwth patterns, yet they transplanted with very different degrees f success. The same results are evident when cmparing green ash and scarlet ak. Seasnal rt grwth therefre des nt appear t be inherently different n easy t transplant species cmpared t difficult t transplant species. Trees which cannt nrmally be successfully transplanted in late spring r early fall, like Turkish hazelnut and scarlet ak, have nly a small windw f pprtunity fr fall transplanting. Acknwledgement. We wuld like t express ur sincere appreciatin t Gerge Schictel, Schictel'sNurseryy, rchard Park, New Yrk fr plant material used in this study. Literature Cited 1. American Assciatin f Nurserymen American Standard fr Nursery Stck. 2. Arnld, M.A., and D.K. Struve Green ash establishment fllwing transplant. J. Amer. Sc. Hrt. Sci. 114: Chen, T., P. Murakami, p. Lmbard, and L. Fuchigami Desiccatin tlerance in bare-rted apple trees prir t transplanting. J. Envirn. Hrt. 9: Esau, K Anatmy f Seed Plants. Jhn Wiley & Sns, New Yrk. 5. Gilbertsn, P., and A.D. Bradshaw The survival f newly planted trees in inner cities. Arbric. J. 14: Gilman, E. F Tree rt spread in relatin t branch dripline and harvestable rtball. HrtScience 23: Grssnickle, S.C Planting stress in newly planted jack pine and white spruce I. Factrs influencing water uptake. Tree Physil. 4: Headley, D., and N. Bassuk Effect f time f applicatin f sdium chlride in the drmant seasn n selected tree seedlings. J. Envirn. Hrt. 9: Huck, M. G., and H. M. Taylr The rhiztrn as a tl fr rt research. Adv. Agrn. 35: Kaufmann, M.R Leaf water stress in Englemann spruce: influence f the rt and sht envirnments. Plant Physil. 56: Kramer, P.J., and T.T. Kzlwski Physilgy f Wdy Plants. Academic Press, rland. 12. Lee, C.I., and W.P. Hackett Rt regeneratin f transplanted Pistacia chinensis Bunge seedlings at different grwth stages. J. Amer. Sc. Hrt. Sci. 11: Running, S., and C. Reid S/7 temperature influences n rt resistance fpinus cntrta seedlings. Plant Physil. 65: Sands, R Transplanting stress in radiata pine. Aust. Fr. Res. 14: Struve, D.K., and R.J. Jly Transplanted red ak seedlings mediate transplant shck by reducing leaf surface area and altering carbn allcatin. Can. J. Fr. Res. 22: Struve, D.K., and B.C. Mser Rt system and rt regeneratin characteristics f pin and scarlet ak. HrtScience 19: Whitlw, T.H., N.L. Bassuk, and D.L. Reichert A 3- year study f water relatins f urban street trees. J. Appl. Ecl. 29: Urban Hrticulture Institute 2 Plant Science Crnell University Ithaca, NY 14853

8 Jurnal f Arbriculture 2(6): Nvember Resume. Des Quercus cccinea (chenes gcarlates), Fraxinus pennsylvanica (frgnes de Pennsylvanie), Crylus clurna (nisetier de Byzance) et Syringa reticulata 'Ivry Silk' (Was japnais) nt ete transplants a racines nues durant la peride de plantatin du printemps et de I'ete. La repnse psttransplantatin 6tait cmpare avec des arbres deja 6tablis en regard de I'activite racinaire durant la p6ride de transplantatin. Le taux de crissance des racines des arbres etablis durant la peride de transplantatin n'etait pas relie a la transplantabilite. Le frene de Pennsylvanie et le Illas se transplantaient bien a n'imprte laquelle des p6rides. Le chene ecarlate et le nisetier de Byzance se transplantaient mal durant les perides de la fin du printemps et du debut de I'ete, mais le taux de survie etait bn tt au printemps et au milieu de I'ete.