Page arnoldia 4 Wilderness Horticulture: Himalayan High- lands on the Hudson John Gwynne Volume 50 Number 1 Winter 1990 13 Landscaping for Realism: Simulating the Natural Habitats of Zoo Animals Arnoldia (ISBN 004-2633; USPS 866-100) is published Donald W. Jackson quarterly, m winter, spring, summer, and fall, by the Arnold Arboretum of Harvard University. 22 An African Tropical Forest in Boston Matthew A. Thurlow Subscriptions are $20.00 per calendar year domestic, 24 The Arnold Arboretum in Winter: A Photo $25.00 per calendar year foreign, payable m advance. Single copies are $5.00. All remittances must be in Essay U.S. dollars, by check drawn on a U.S. bank, or by in- Istvdn Rdcz and Zsolt Debreczy ternational money order. Send subscription orders, remittances, change-of-address notices, and all other 30 Why Do Rhododendron Leaves Curl? subscription-related communications to: Helen G Erik Tallak Nilsen Shea, Circulation Manager, Amoldia, The Arnold Arboretum, 125 Arborway, Jamaica Plain, MA 36 Kolomikta Kiwi 02130-3519. Telephone (617) 524-1718. Gary L. Koller

Postmaster: Send address changes to: Amoldia, Circulation Manager The Arnold Arboretum 125 Arborway Jamaica Plain, MA 02130-3519.

Copyright @ 1990, The President and Fellows of Harvard College. Front cover: A close-up of the male inflorescence of Salix gracilistyla at the Arnold Arboretum. Photo by Gary Mottau. Peter Del Tredici, Editor Inside front cover: Rhododendron Helen G. Shea, Circulation Manager yakusimanum curled up m response to the cold. Judith Leet, Copy Editor Back cover: Actmidia kolomikta m full variegation. Photographed at the Royal Horticultural Society at Wisley, England, by Nan Smton. Arnoldia is set m Trump Mediaeval typeface and Inside back cover: Rhododendron yakusimanum in prmted by the Office of the University Publisher, the uncurled and curled state. Photos by Racz and Harvard Umversity. Debreczy. m Special Issue Zoo Horticulture: Plants and Animals Together at Last

For most of this century, the term zoological behaviors and, if all goes well, will reproduce garden has seemed a misnomer, mocked by successfully. Indeed, habitat exhibits evolved frustrated animals pacing back and forth in partly out of public concern and, in some barren cages. Over the past twenty years, cases, outrage over the conditions endured by however, the reality of this grim image has many of the animals. slowly been eroding. New zoo design strate- A second force driving the evolution of gies have transformed animal enclosures into habitat exhibits is their powerful influence on "habitat exhibits" which combine plants with the way visitors perceive zoo animals. other naturalistic elements to simulate the Designers of habitat exhibits supplant the look and feel of "wild" nature. often depressing experience of viewing Horticulture has come of age in the field of animals in metal cages with that of being zoo management, as carefully crafted plant- immersed in a wild landscape, where barriers ings are seen as contributing both to the wel- between animals and the visitor are fare of the captive animals and to the minimized. In some exhibits, traditional roles enjoyment and education of visitors. This are reversed, and the visitor gets the feeling issue of Arnoldia displays a small sampling of being confined, while the animal roams of the creativity and skill that can be found free. in the modern zoological landscape. The net result of these changes is that the The creation of realistic habitat simulations visitor’s appreciation of the animals is in zoos serves two important purposes. It enhanced, and the link between animals, their recognizes, first, that in nature animals exist habitats, and conservation is permanently in specific environments and, second, that the etched on the mind of the viewer. At long last closer an enclosure can approximate the zoological gardens across the country are animal’s natural home, the greater the proba- beginning to live up to their names. bility the animal will exhibit more natural

A field of small boulders used to protect grasses and wildflowers from the constant pressure of half-grown snow leopards at play. New York Zoological Society Photo. Wilderness Horticulture: Himalayan Highlands on the Hudson

John Gwynne

Plants are playing an increasingly important role in the "immersion" exhibits of leading zoos.

Imagine searching for a glimpse of the elusive come across a flimsy rustic bridge of rope-tied snow leopard in the high Himalayan wilds. logs fitted between great boulders spanning a Your imagined trek would depart from main steep-sided mountain brook where ferns, roads to wander narrow uphill footpaths, past Ligularia, and candelabra primula grow in the thickets of wild magnolias and overarching moist soil. bamboo, through groves of fir and birch, and Terrific! A mother snow leopard with two up steep grassy meadows dotted with purple- cubs is spotted among the talus boulders of blue Geranium himalayense. Perhaps you’d the grassy slope. Crouching behind boulders,

Millions of Amencans can now witness a snow leopard m the snow - a sight previously seen by only a few field scientists. New York Zoological Society Photo. 5

The Himalayan Highlands exhibit has room for people to read graphic messages about conservation. the cats are almost perfectly camouflaged, Asia. Together, they moved mountains of soil tails slowly twitching, as a scarlet-chested and scree, planted thickets of bamboo and tragopan pheasant works its way down the twenty-five-foot firs, and even sculpted rocky hillside, pecking at wind-scattered grass seeds. outcrops and a great fallen tree of steel, con- Just such an experience formed the basis for crete, and epoxy to match the site’s geology the design of a new type of ecological exhibi- and woodlands. Named "Himalayan High- tion recently created, not in the mountain lands the exhibition at the Bronx Zoo offered wilds of Nepal or China, but in an oak wood the opportunity to build a sanctuary for snow in New York City. Here a determined team of leopards, red pandas, white-naped cranes, and zoologists, field scientists, exhibition Temminck’s tragopans. The design team also designers, landscape architects, horticul- purposely created a dynamic place where visi- turists, sculptors, welders, and graphics tors are encouraged to learn about wilderness, specialists-all employed by the New York about the importance of plant-animal inter- Zoological Society-joined efforts to build a actions, and of the urgent need for special con- place that captures the feeling of montane servation efforts. 6

Potential for Public Education ways, so that visitors would feel immersed in While conceiving of Himalayan Highlands as the same environment as the animals. a naturalistic place for animals, the design Without having to read, they would see a team also recognized the potential to enhance snow leopard teaching her cubs or a crane the visitor’s appreciation of wild places and probing for tubers along a pond edge, and they wild species. The challenge was to transcend would be able to learn how this bit of nature typical zoo formulas, which concentrate on works. Unlike traditional zoo design where exhibiting animals within containments that the manmade dominates, here the intent was are clearly manmade (buildings, architectural to recreate a wild environment worth explor- moats, fences, faux rock cliffs) and that deal ing, worth learning about, and worth with the animals’ natural ecology only preserving. second-hand by means of signs or explana- The primary educational goal for tions by docents. Himalayan Highlands was to impart an over- Himalayan Highlands was to be different, all affective message-to get people to care. a place that would try to create the primary Educational graphics were carefully designed experience of a trek across an Asian hillside. to provide a subtle yet important sublayer of While transporting an actual mountain slope interpretation; for example, a replica of a intact would have been optimal, the more weathered ibex skull encourages people to practical challenge was to recreate enough read a small sign discussing leopard diets. similar elements, combined in appropriate Messages deal with plants, habitats, animal

Visitors wander through a simulated wilderness landscape in the Himalayan Highlands exhibit. 7

ecology, and conservation; and a concentrated insured that such manmade elements as effort was involved in their writing, fabrica- structural poles were hidden by rocks or tion, and siting so that they seem to fit into plants, or disguised within the rustic vernacu- the landscape. lar architecture of Nepal. Authentic cultural details were used to reinforce the sense of with Bulldozers Sculpting place: prayer flags marked exhibit entrances, Because zoo biology mandates a barrier a pile of prayer stones were placed along the between animals and visitors, it was decided public path, and architectural details were to separate the two by giving most of the painted by a Nepalese artist. When setting woodlands to the animals and by restricting boulders to support rustic bridges, skilled people to a winding path that leads around New York masons were asked to transcend rocks and plantings to several viewing struc- their usual professional neatness by building tures. So in one place a wood ramp was walls in a haphazard and unsound-looking designed to bring people up to a viewing deck fashion with no mortar showing, a detail that that cantilevers toward the woodland treetops helps achieve the look of nature reclaiming favored by red pandas for their daytime roost- human efforts. ing. In another spot, a blind of rough poles was Special efforts were made to bring in many built in a wild-looking, ten-foot-tall thicket of tons of topsoil and talus and to regrade the giant Miscanthus grass providing an open site-where possible around existing trees- view into a marshy pond for the cranes. to create a rough undulating topography and In another location, the rustic underside of multiple microclimates for new plant com- a Nepalese bridge provided the model for a munities. To make Himalayan Highlands shaded public structure at the edge of a grove believable as a wild place necessitated of black cherry trees frequented by snow developing a new attitude towards naturalis- leopards. Here a gauzy screen of fine piano tic gardening, which might be termed "wilder- wire, stretched tautly vertical and dark- ness horticulture." The horticultural intent stained, is attached to the underside of the was to create an Asian planting with a feel- rustic bridge, as if emerging from the scree ing of wildness-a landscape that did not look below. Easy to see through, especially in the newly planted, or even planned at all. shadow of the bridge, this flimsy-looking film The woodland site in the Bronx Zoo was of wire is sufficiently strong to separate chosen in large part for its existing bedrock animals and people. Two of the nearby cherry outcrops and cool northeastern exposure. It trunks are actually thirty-foot aluminum was dominated by natural stands of oak, tulip poles, covered with a skin of epoxy, sculpted tree, and ash, their trunks measuring up to and painted to match the living trees. These three feet in diameter. The understory poles support a tentlike aviary of fine wire included black cherry, swamp maple, a few mesh that keeps the cats in the foreground invading Ailanthus, and some previously where visitors can see them but is itself nearly planted flowering dogwood. Although Ameri- invisible in the flickering light of a natural can rather than Himalayan species, most were woodland backdrop. Near the visitors, what kept to enhance the final exhibition by provid- looks like a large flat boulder is actually fabri- ing not only important shade for the animals cated of fiberglass-reinforced concrete cast but also a sense of scale and timelessness. For- from a mold taken of a real boulder. Its secret tuitously, these genera have close relatives is internal heat coils, which create a warm dry that form part of the Asian forest. perch for the cats to enjoy on wintery days. By the careful siting of viewing places, Hardy Himalayan Plants for New York designers could screen undesirable views and Finding authentic, hardy Himalayan plants focus attention on handsome vistas deep in was no easy task. The results of an exhaus- the woods. Painstaking attention to detail tive search of stock available from American 8

The graceful habit of Cedrus deodara, an important feature in the Himalayan Highlands exhibit. Photo by Racz and Debreczy 9

nursery catalogues were cross-referenced with obtained for experiment in a cool niche. Few research into the flora of sites in Nepal, Tibet, of the true Himalayan wild "species" or South China that might serve as a model rhododendrons, so distinctive of Asian forests, for Himalayan Highland’s planting list. Nepal are hardy enough. Some were tried (including was initially favored, especially oak woodland Rhododendron campanulatum, R. cam- sites near Annapurna, as ideal for this project pylocarpum, R. forrestii var. repens, R. nivale because of the remnant presence of both snow ssp. boreale, and even R. cinnabarinum and leopards and red pandas, plus the distinctive R. barbatum) and managed tentative beauty of local cultural artifacts. However, footholds in protected locations, but could not since New York’s winter climate is harsher be relied upon for mass effect. Consequently, than that of much of the Himalayas and since several locally hardy rhododendron hybrids hardy Nepalese plants (especially in large had to be used. Forms were chosen that are sizes) are relatively scarce in nurseries, a deci- not immediately recognizable to most people sion was made to expand to a generalized (to avoid connotations of suburbia) or that plant list of Sino-Himalayan flora, with a have relatively small flower trusses similar to sprinkling of North American analogs. This the wild species. Several good-sized plants of compromise was necessary to achieve the the white-flowered hybrid ’Dora Amateis; proper sense of scale and the desired effect. with one Himalayan parent (R. ciliatum), For example, it was frustrating to envision the were donated. A few plants of the North Asian dappled shade of a spectacular grove of white- R. mucronulatum ’Cornell Pink’ were barked Betula jacquemontii from Asia when included for their unexpected sparkle early in plants here were only available in one-gallon spring and their willowy forms reminiscent pots. To achieve the immediate effect of of Himalayan lepidote thickets. mature birch groves required the substitution The marvelous tree-sized blood-red R. of non-Himalayan species. arboreum that so impressed explorers in the In spite of frustrations, a remarkable num- early twentieth century would have been an ber of hardy Asian plants could be located, appropriate and spectacular plant for the sometimes in sizes large enough to plant on Himalayan Highlands exhibit, especially as a site accessible to the public. More than a their groves are now being decimated by fire- dozen deodar cedars over fifteen feet tall were wood gatherers in Nepal and elsewhere in located in a mid-Atlantic nursery. Other Asia. R. arboreum is, however, impossibly appropriate woody plants included Callicarpa tender for New York winters, so large plants bodinieri, Acer griseum, Hippophae rham- of the dark currant-red Consolini/Dexter noides, Pieris japonica, Potentilla fruticosa, hybrid ’Francesca’ were substituted, chosen for Mahonia bealei, Cotoneaster salicifolius, their distinctive color and upright stature. Viburnum ssp., Sarcococca hookerana var. Planted on berms, someday these red-flowered humilis, and Hydrangea. Large clumps of trees may arch over visitors’ heads as the true bamboo (Phyllostachys aureosulcata) were R. arboreum does in Asia. transplanted from Long Island. Herbaceous goatsbeard (Aruncus dioicus), bugbane Crucial Wilderness Planting Details (Cimicifuga simplex), and geranium (G. Since the intent was not to create a garden but himalayense) were deemed tough enough to to recreate a wild place, care was taken dur- survive and eventually may be joined by tem- ing installation to site plants in appropriate perate aroids and other specialties. places and with correct associations and to A number of especially desirable plants space them irregularly. Where possible, larger- posed special problems. The fabled blue poppy sized plants were located in the center of a (Meconopsis betonici folia) was considered too cluster to replicate natural growth patterns. intolerant of New York summers to warrant Bamboo and magnolia fit naturally together initial planting, but seeds of it have been on lower portions of the site, with fir and low- 10

Seeing snow leopards in a green environment enhances the quality of the interaction between visitors and animals. e New York Zoological Society Photo. 11

growing rhododendrons on the rocky promon- Not only were spacings between plants pur- tories. To suggest "krumholtz" wind pruning, posefully irregular but understory trees were distinctive of treeline firs, the team even dis- planted at tilted angles to suggest their reach- cussed sandblasting lightly the northwest side ing for light. Plants with uneven shapes were of some plants. This idea was rejected, only obtained from nurseries in preference to sym- because of the inappropriateness of this wind- metrical plants (undoubtedly to the delight of blown look under overtowering oaks. the local nursery). Where "saucers" of bark Much of the site was heavily bermed to mulch were built around recently installed exaggerate the roughness of the topography plants to facilitate watering, these regular and to screen visitors’ views of one another. forms were disguised with dead leaves. Much The zods own aged manure was used liberally of the site, including mulched areas, was in the topsoil mix to retain moisture, espe- seeded irregularly with a fine-textured, cially on slopes. While grounds keepers of "uncut" red fescue. On an irregular terrain, most gardens and public parks carefully this clumping grass cover was effective in remove dead vegetation, old gnarled stumps helping to disguise a newly planted look, to and deadfall were purposefully incorporated unify the massings of plants visually, and to into the plantings to make this site seem enhance the impression of naturalness. wilder. All visible saw-cut ends were buried While not needing the maintenance typical or disguised by "aging." Deadfall limbs were of many public displays, Himalayan High- carefully sited among new plantings both for lands does require eyes trained in naturalis- natural effect and to form low barriers to dis- tic horticulture. Weed species need to be courage people from wandering from paths. recognized and removed. Pruning needs to be

People in an elevated viewing area can observe a red panda in the trees only a few feet away; the native forest lies beyond. 12

discreet and done with knowledge. The com- increasingly insularized, inadequate, and paratively unorthodox beauty of a tuft of degraded. The rate of tropical deforestation brown grass in winter needs to be recognized, has recently accelerated to one hundred acres appreciated, and left untouched, while a each minute. To try to combat the losses, zoos viburnum branch needs inconspicuous prun- now are changing rapidly in order to become ing when crowding a neighboring fir. Unlike more effective sanctuaries. a static museum exhibit, a planted site is a While public interest in zoos has burgeoned living place-its continual change creates and awareness of environmental destruction new horticultural opportunities but also has increased, the idea of building educational necessitates constant, subtle observation. wilderness immersion exhibits to reveal the Certain species, such as the bamboos, are beauty and ecology of wild places does not now maturing sufficiently to allow thinning need to be the sole province of zoos. Imagine for fresh browse for bamboo-eating red pandas. a botanic garden encouraging visitors to Other species require replacement, such as wander through a moody, beautiful, Car- the initial short-lived plantings of American boniferous swamp forest of giant horsetails, birches. The project will never be "done." cycads and tree ferns, along with an occa- Indeed, the goal is that, over time, the analo- sional primitive reptile. A huge greenhouse gous North American plants will be replaced nearby could shelter a spectacular arid south- by more authentic Himalayan species. While western Madagascar spiny forest, complete the exhibit needed to look established when with eroded stream beds for people to explore, it opened, it is also a living place that can as well as baobabs, rare tortoises, and mar- develop and change. velously specialized endemic flora. To lobby effectively for wild places, we must Exhibits to Encourage Saving the make their values evident. If we cannot actu- Wilderness ally bring thousands of people to primitive The Himalayan Highlands exhibit is both a tree fern forests, montane Ethiopia, or a subtly complex and popular place for visitors vanishing Himalayan forest, we do have the but, as an experiment in environmental ability to convey some of the fascination and "immersion" and "wilderness horticulture ;’ it beauty of those places here. The words of the is not unique. In the Bronx Zoo alone, Senegalese philosopher Baba Dioum suc- Himalayan Highlands is joined by huge new cinctly express this intent: wild habitats where visitors can wander through an extensive and dramatic Asian rain In the end, we will conserve only what we love. We will love what we understand. forest, visit a rhino wallow, or a sparse Afri- only We will understand only what we are taught. can alpine habitat. Serious commitments to expansive landscape replication and special- ized horticulture are now found in several at Graduate American zoos aided by the recently formed Trained as a landscape architect Harvard’s American Association of Zoological Horticul- School of Design, John Gwynne is currently Deputy Director for Design at the New York Zoological Society. ture. We are a world with its wild witnessing He is an avid gardener and has illustrated several books lands and biological diversity fast disappear- on the birds of Panama, Costa Rica, Venezuela, Colum- ing and with its scarce refuges becoming bia, and China. Landscaping for Realism: Simulating the Natural Habitats of Zoo Animals

Donald W. Jackson

In Atlanta, Georgia, horticulturists have created the illusion of a West African rain forest and an East African savanna with hardy, woody plants.

What does a horticulturist or landscape resemble the acacias of arid Kenya and Tan- architect strive to attain when choosing plants zania in a lowland gorilla exhibit. for a naturalistic animal exhibit in any major In order to simulate a particular geographi- zoo? Should visitors come upon bananas and cal area as closely as possible, zoo horticul- tropical figs complementing an exhibit featur- turists must have a thorough knowledge of the ing giraffes or zebras that naturally roam the region’s overall geology, climate, economy, and hot, arid Serengeti? Let’s hope not. Likewise, social customs-all critically important for they should not be confronted by trees that installing an appropriate habitat for zoo

Lowland gorilla in the African ram forest exhibit at Zoo Atlanta. 14

The lush feeling of the Ford liopical Rain Forest at Zoo Atlanta. animals. To create a lowland gorilla habitat in out the world, and the rain forest canopy has Zoo Atlanta, our goal was to gather as much more levels or strata than we are familiar with information on the region as possible in order in the deciduous woodlands of eastern North to simulate its home convincingly. America. The tremendous diversity of animal life Rain Forests Simulating Tropical strikes anyone who has seen or read about a What botanical characteristics tend to tropical rain forest. An almost unimaginable dominate the lush rain forests of Cameroon, array of mammals, amphibians, reptiles, birds, West Africa, the home of the lowland gorilla? fish, and especially insects lives in the If we think back to our childhood and recall tropics-a great number of which scientists old movie footage of Tarzan, numerous lianas have yet to describe. Although the variety of or tropical vines probably come to mind, a plant life is equally diverse, many plants have fairly accurate representation of the flora of certain features in common, such as large the region. Brief but frequent rains and high leaves with a relatively smooth, waxy upper humidity also characterize tropical areas in surface and long "drip tips," two features that Cameroon as well as similar areas through- help shed excessive rainfall in the humid 15

tropics. In contrast, species native to the Although such choices would be optimum, Serengeti and other arid regions tend to have this goal is obviously not realistic. Since very small leaves that help them conserve as much few American zoos are located in climates precious moisture as possible through reduced without frost, such an endeavor would make transpiration. little sense in an outdoor exhibit. Even in an The ideal method of landscaping a indoor exhibit, the costs of obtaining native naturalistic exhibit of animals from tropical plants both for the initial landscaping and for regions is to use exclusively those plant spe- replacements over the long term-even if it cies that are native to tropical forests. To be were possible to procure them-would be pro- truly accurate, only flora indigenous to Came- hibitively expensive. roon, West Africa, should be used to landscape However, even when we substituted non- a lowland gorilla enclosure, and only those native material in our lowland gorilla complex plants that grow in the rain forests of Borneo at Zoo Atlanta, well over $40,000 worth of and Sumatra should be selected for an orang- non-hardy tropical plants were used outdoors, utan exhibit. including up to 20-foot-tall scheffleras, 16-foot-

The foliage of Magnolia macrophylla, the bigleaf magnolia, at the Arnold Arboretum. Photo by Rdcz and Debreczy. 16

tall areca palms, and countless numbers of lia (M. macrophylla) and the umbrella mag- philodendrons, anthuriums, and bananas. nolia (M. tripetala) are both superb simulators These plants are overwintered in large poly- with their extremely large leaves. Those of the houses and simply add a tropical flair to the bigleaf magnolia measure two to three feet in exhibit during the warmer months. They length; those of the umbrella reach one to two must be viewed as "icing on the cake," feet. An added bonus is the huge flowers, however, since the real horticultural backbone produced in early summer; those of the bigleaf of nearly any zoo exhibit is made up of cold- magnolia can grow to over twelve inches in hardy species and cultivars that simulate the width; those of the umbrella reach from seven indigenous flora of the animal’s native habitat. to ten inches. The biggest deterrent to using either of Trees with a Look Ibmperate Tropical these two species to create a tropical-looking The large, glossy evergreen leaves of the landscape is not their appearance but their southern magnolia (Magnolia grandiflora) poor availability within the nursery trade. resemble the foliage of a number of tropical Because their coarsely textured foliage makes species, especially figs, quite effectively. A them difficult to incorporate successfully into number of other magnolias are frequently either a residential or commercial landscape used by zoo horticulturists to simulate the design, few nurseries grow either the umbrella world’s tropical habitats. The bigleaf magno- or bigleaf magnolias. And those that are avail-

The attractive compound fohage of Rhus typhina, the staghorn sumac. From the Archives of the Arnold Arboretum. 17

Aralia elata m full bloom at the Arnold Arboretum. Photo by Rdcz and Debreczy. able in nurseries are usually only an inch or appealing in that they have a delectable so in diameter and at best six to eight feet in fragrance of vanilla and green and orange height. coloring. Unfortunately, they are not produced Two other magnolias valuable for simulat- in quantity until the tree reaches the age of ing a rain forest environment are the sweet- fifteen years or more, and a height of twenty bay (M. virginiana) and the cucumber tree (M. to thirty feet. acuminata), with leaves that can reach ten Among the best of the cold-hardy plants for inches in length and bearing a reasonably long use in simulating the tropical rain forest are "drip tip." The sweetbay is readily available; the empress tree or royal paulownia its glossy leaves and fragrant flowers are highly (Paulownia tomentosa) and the northern attractive but unfortunately do not grow as catalpa (Catalpa speciosa). The paulownia is large as those of most other magnolias. The particularly fast-growing and, like the catalpa, cucumber magnolia is much harder to locate boasts very large heart-shaped leaves and although, with persistence, large specimens tropical-looking flowers. Neither of these spe- can be found in the fields of old wholesale cies is much sought after for planting in the nurseries. My experience with the cucumber home landscape or as street trees, so both are magnolia corroborates the general opinion rather difficult to locate in large sizes within that it is difficult to transplant. the nursery trade. Likewise, the ailanthus Two additional members of Magnoliaceae (Ailanthus altissima) with its large pinnately often used in a simulated rain forest exhibit compound leaves remains a good choice for are the native American tulip tree or tulip the zoo horticulturist striving to introduce a poplar (Liriodendron tulipifera) and the tropical flair to the landscape. Japanese anise tree (Illicium anisatum). The The long pinnately compound leaves of the flowers of the tulip poplar are particularly smooth sumac (Rhus glabra) and staghorn 18

Creative Methods for a Rain sumac make these species possi- Simulating (R. typhina) Forest ble candidates for use in rain forest habitats. Both grow exceedingly fast and, except for the As mentioned, vines or lianas are very impor- cut-leaf varieties, are not frequent compo- tant components of the world’s rain forests. nents of the home landscape. The lan- We found one of the best vines to use to simu- tanaphyllum viburnum (Viburnum x late Cameroon, West Africa, is the trumpet rhytidophylloides), hardy rubber tree (Eucom- vine (Campsis radicans) with its long tubu- mia ulmoides), devil’s walking stick (either lar, two-inch-wide flowers and rampant Aralia spinosa or Aralia elata), and cultivars growth. Its blooms can range in color from of the common rose mallow (Hibiscus scarlet to orange or even yellow, depending on moscheutos) are other hardy plants that can the cultivar; its Zone 4 cold hardiness allows effectively simulate the atmosphere of tropi- it to be planted in most zoos throughout the cal rain forests. country. The trumpet vine’s large pinnately The various species of temperate bamboos, compound leaves, along with its wide availa- particularly within the genus Phyllostachys, bility, make it a first-rate choice to simulate can be extremely important in habitat the tropical habitats of many diverse exhibits. In general, they are available from animals-from a shy tapir to an agile and wholesale nurseries in sizes and quantities inquisitive siamang. sufficient to meet the demands of landscap- Although a wide variety of vines, ranging ing large exhibit areas, and their cold- from the sweet autumn clematis (Clematis hardiness is greater than many horticulturists paniculata) to the Chilean jasmine (Man- realize. devilla laxa), can be used by zoos located in While the leaves of the white mulberry more southern climates, some of the best (Morus alba) are the food of silkworms, the vines are just not available in nurseries. As a fruitless (male) cultivars are valuable to the substitute, the simple stringing of dead grape- zoo horticulturist not only for their vigorous vines throughout the trees can give an amaz- growth and spreading form but also because ingly realistic effect to a rain forest exhibit. their foliage provides an excellent browse for Also the strategic placement of deadfalls and many zoo animals from colobus monkeys to brushpiles along public walkways can dramat- giraffes. ically add a touch of authenticity to a rain Willow (Salix sp.) is another multi-purpose forest exhibit. plant for the zoo horticulturist. Although the At Zoo Atlanta, a dead twenty-two-inch- leaves are not particularly large, their long nar- caliper southern magnolia-with a wide row shape somewhat simulates the foliage of multi-branched crown-was hoisted up by the bamboos characteristic of tropical areas. crane, and a portion of its lower trunk sim- Branches of small diameter can simply be cut ply "planted" in concrete near one of the in early spring and stuck into moist soil where exhibit’s main animal viewing areas. The tree they quickly take root. These willow saplings had died a number of weeks before, but we soon form impressive thickets that can be eas- used it to help convey an image of the strug- ily and cheaply used to screen unsightly vistas gle of life and death in the forest. More impor- or to hide the backs of small buildings. As the tant, the use of deadfalls and brush- willows continue to mature and become too piles-when combined with interpretive tree-like, they can be thinned out to keep the graphics-depicts the destructive effects of colony dense and shrubby. Like white mul- slash-and-burn agriculture within the world’s berry, the leaves of willow are an excellent tropical rain forests and can provide an educa- source of browse for many zoo animals and, tional message regarding the wise use of our with their fast growth, they can be frequently world’s natural resources for visitors of all harvested for this purpose. ages. 19

The flowers and foliage of Albizia julibnssin. From the Archives of the Arnold Arboretum.

the East African Plains Simulating Simulating East African acacias is most In addition to the tropical rain forests, another often accomplished in zoos by planting broad- environment that affords the zoo horticul- crowned, irregularly shaped honey locusts turist a challenge is that of the plains of Kenya (Gleditsia triacanthos var. inermis) and and Tanzania in East Africa. The plants used removing the lower branches to make them to simulate the authentic habitat of giraffes, appear to have been browsed. Like those of the lions, zebras, elephants, and fleet-footed honey locust, the small leaflets of the mimosa Thomson’s gazelles look much different from (Albizia julibrissin) make it an excellent those chosen to complement a lowland gorilla simulator of the acacias of the Serengeti. or a white-handed gibbon exhibit. Although seldom recommended for the home Unlike tropical plants with large leaves and landscape for a number of reasons, its broad- "drip tips," the trees and shrubs that a zoo hor- spreading crown provides unique opportuni- ticulturist would choose to depict the plains ties to zoo horticulturists. of Kenya and Tanzania would almost all have In the southeastern United States, the thorns or spines and small leaves to simulate yaupon holly [Ilex vomitoria) is a common the native flora’s need to conserve water. Spe- and often overused plant in the general land- cies and cultivars of selected ornamental scape. Although its small leaves are valuable grasses would also be appropriate, as are in simulating an arid environment, the form associated landscape features, such as artifi- of specimens sold in nurseries is seldom very cial termite mounds. natural in appearance. We were fortunate 20

Large naturalistic yaupon holly (Ilex vomitoria), mtentionally planted on an angle, in the Masai Mara East Afri- can Savanna Exhibit.

enough to locate some very large and over- restricted to areas that can be easily seen and grown yaupons growing in the back corner of appreciated but are totally inaccessible to both a large wholesale nursery, and they are now the animals and the visiting public. one of the premier focal points of Zoo The following list of plants will help zoo Atlanta’s new East African plains exhibit. horticulturists simulate the arid plains of The two- to three-inch thorns of the cock- Kenya and Tanzania: Adam’s needle (Yucca spur hawthorn (Crataegus crus-galli) also filamentosa); small soap weed (Yucca glauca); make it a valued addition to any exhibit hous- Russian olive (Elaeagnus angustifolia) ; ing lions, zebras, giraffes, and similar animal Japanese barberry (Berberis thunbergii); species. While its thorns are very realistic, Siberian pea shrub (Caragana arborescens); they are also potentially dangerous, particu- Warminster broom (Cytisus x praecox) ;¡ larly to small children. The use of this haw- pampas grass (Cortaderia selloana); ravenna thorn in a zoological landscape is, therefore, grass (Erianthus ravennae); Chinese pennise- 21

turn (Pennisetum alopecuroides); maiden the drip lines of trees to guard against soil grass (Miscanthus sinensis ’Gracillimus’); compaction. eulalia grass (M. sinensis); and hardy orange Plants must also be protected against the (Poncirus trifoliata). sheer strength of a lowland gorilla. Fiberglass tree casts can be used to protect the bark of and Other Tbxicity Constraints mature shade trees within gorilla enclosures. Whether it be the simulation of a rain forest Final texturing and coloring give the casts a in tropical West Africa, the arid plains of realistic appearance when fitted around the Kenya and Tanzania, or some other region of tree’s trunk. the world, zoo horticulturists are constrained Significant damage to plants can be caused in many ways in their efforts to create the by a wide range of other animals. The bark of "natural" habitat of a specific animal. For any tree must always be protected against the example, oleander (Nerium oleander), com- sharp claws of lions or leopards. Likewise, the monly seen in gardens throughout the deep playfulness of tiger cubs can be particularly South, is not used in a zoological setting rough on any landscaping within their exhibit because of its toxicity. Likewise, while some if care is not taken. Finally, in areas where plants may be difficult to locate in the nurs- ducks and geese are allowed to range freely ery trade, others are impossible to obtain over lawn areas, the effects of grazing and soil except through professional contacts at compaction can be much more significant arboreta or botanical gardens. One example than most visitors would ever imagine. that comes readily to mind is the Chinese In some cases, human behavior can cause toon tree (Cedrela sinensis). Few public problems, as in the case of the Chinese chest- gardens can even claim it as part of their col- nut (Castanea mollissima), which cannot be lection, although its large pinnately com- located near our gorilla exhibit because of its pound leaves, strongly resembling those of the nuts. The nuts can be thrown by children, and ailanthus, evoke a tropical feeling. While its spiny fruit husks can present additional lia- widely available, certain varieties and culti- bilities along pedestrian walkways. Suffice it vars with variegated foliage or with crimson- to say that some plants that superficially colored leaves, such as zebra grass (Miscan- appear useful in complementing an animal thus sinensis ’Zebrinus’) or the ever-popular exhibit cannot even be considered by zoo hor- red-leaved Japanese barberry (Berberis thun- ticulturists. bergii var. atropurpurea), are of little use for Despite its constraints, zoo horticulture has creating a natural-looking habitat. come a long way in the past decade or two in Animal-related damage to plants can be an effort to display animals in a convincing quite extensive if precautions are not taken. simulation of their native environments. Look Elephants and rhinos can be particularly des- closely at the types of plants used around the tructive as a result of their immense weight exhibits on your next visit to a major zoo. You and strength. Both animals must always be may be pleasantly surprised by what you kept well away from the trunks and lower recognize. branches of trees within their exhibits. Boul- as ders and other large-sized barriers, such Donald Jackson is Curator of Horticulture at Zoo Atlanta logs, can also be strategically placed around m Atlanta, Georgia. An African Tropical Forest in Boston

Matthew A. Thurlow

The newest indoor exhibit at Franklin Park Zoo in Boston is the centerpiece for revitalization.

The "African Tropical Forest" is the newest (Ceiba pentandra). Many of the hundred birds exhibit at the Franklin Park Zoo in Boston. flying freely through the forest have found The object of this three-acre indoor-outdoor that the upper reaches are fine places to perch. exhibit is to take the zoo visitor on a safari The Hadada ibis roost throughout the upper through a West African tropical forest. Each story. turn in the path offers a new chance to sight To exhibit some animals, such as the pygmy African wildlife in naturalistic habitats. No hippos and yellow-backed duikers, a forest- bars or cages separate the visitors from the clearing effect was required. Medium-growth animals. Moats disguised as stream beds per- plants were installed to create this effect: mit unobstructed views of the animals, and banana plants, bird-of-paradise, Australian tree strategically placed glass allows visitors to ferns, dracaenas, and philodendrons surround come face to face with some of the forest’s these cleared areas. The giant white bird-of- more impressive animals. paradise plants (Strelitzia alba) have been a The African Tropical Forest is housed in the great success and bloom repeatedly to the largest free-standing building of its kind in the delight of zoo visitors. United States, measuring 45,000 square feet, Throughout the entire building, a lush with over 28,000 square feet of general exhibit understory planting features elephant ears area. The tripod support beams rise 75 feet at (Alocasia sanderana), ginger (Zingiber the apex supporting the coated white cloth officinale), heliconias, and many fern species. roof. Artificial rockwork throughout the Where streams from the waterfalls flow, building was designed to provide over 75 umbrella plants (Cyperus alternifolius), Egyp- planting beds, which hold the largest collec- tian paper plants (Cyperus papyrus), walking tion of tropical plants in New England. The iris, and bamboos were planted. Epiphytes, or planters are placed so that the flora will air plants, hang from the rock faces and trees. develop into a lush canopy of vegetation above Creeping figs (Ficus pumila) are rapidly grow- the public walkways. The 150 animals may be ing out of any crack or crevice in which they the centerpiece of the African Tropical Forest, can get a roothold. but it is the 3,000 plants that create the tropical-forest setting that makes the gorillas, A Developing Ecosystem hornbills, and bongos feel at home. The plants in the African Tropical Forest were The upper level of this indoor forest is sup- installed in 1989, one year ago. Since that time ported by fiddleleaf ficus (Ficus lyrata), rub- many interesting changes have been noticed. ber trees (Ficus elastica), banyan trees (Ficus Most rewarding is the tropical forest retusa), schefflera (Brassaia actinophylla), ecosystem that is developing. With the thick- fishtail palms (Caryota mitis), and kapoks ening of the forest canopy, light to the under- 23

A lowland gonlla m its tropical habitat at Metro- parks’ Franklin Park Zoo. story is being reduced, creating a mosaic of Tropical Forest. Normal means of control, microclimates. Just as in an actual tropical such as contact pesticides, systemics, or injec- forest, the plants compete for access to the tions, are not used because of their toxicity light. In open areas where light is more to the animals. In general, infested plant intense, the plants grow and spread at their material is cut off and removed immediately. own rate. In the shaded areas, shade-tolerant Insecticidal soaps are used widely because plants have overtaken other species. The vines they are nontoxic to the animals. (Tetrastigma voinieranum and Clerodendrum Predatory insects are also being used on an thomsoniae) planted in the forest floor are experimental basis, with some noteworthy beginning to creep up the stalks and trunks surprises. To combat the spread of aphids, of other plants to fill in the gaps in the canopy. 150,000 ladybird beetles were released within Certain trees partially defoliate in response the pavilion. The aphids, which are deleteri- to the reduced levels of light. Part of the rou- ous to the plants, produce a honeydew on tine maintenance inside the pavilion is the which ants feed. The forest’s resident ant selective pruning of the trees to allow more population has begun to protect the aphids light to reach the lower areas. Care is taken from the beetles. The symbiotic relationship in the pruning to make sure that the trees that has developed between the ants and the maintain their natural appearance. The birds aphids is yet another reminder that the forest in the forest help in this endeavor. In landing is a living, evolving ecosystem that humans on perches that will not support their weight, cannot always control. the birds break off branches in a random pattern. Matthew A. Thurlow is the Director of Landscape Design Pest control presents special problems in and Maintenance for MetroParks Zoos in Boston and the controlled environment of the African Stoneham. The Arnold Arboretum in Winter A Photo Essay

Istvdn Racz and Zsolt Debreczy

Pmus pungens, the Table Mountam pme 25

Miscanthus sinensis by the pond 26

Pinus mugo and Roxbury puddmg stone near the old dwarf conifer beds 27

The legume collection 28

Picea abies ’Pendula,’ the weepmg Norway spruce 29

The tracks of skiers and hikers among the lilacs

The pictures in this essay were photographed on ORWO NP 15 and NP 22 film using a Pentacon Six camera, both made m East Germany. Why Do Rhododendron Leaves Curl?

Erik Tallak Nilsen

A physiological ecologist looks at the significance of temperature-sensitive leaf movements in Rhododendrons.

For more than two hundred years, the genus drooping of Rhododendron arboreum in his Rhododendron has been a focal point for Himalayan Journals of 1855, and explorers scientists and horticulturists. During the mid- such as E. H. Wilson, F. Kingdon-Ward, and R. nineteenth and early-twentieth centuries, a Farrar made frequent notes on the fascination with the genus stimulated many temperature-sensitive (thermotropic) leaf botanists to visit its center of diversity in movements in rhododendron. In addition, remote parts of Burma and China in search both amateur and professional rhododendron of new species. The renowned botanist J. D. enthusiasts have made countless reports of Hooker of Kew noted the leaf curling and leaf curling in various rhododendron species.

Rhododendron maximum in winter. Photo by Racz and Debreczy. 31

Leaf movements in plants were first catego- rized by Charles Darwin in 1880 in his groundbreaking book The Power of Movement in Plants. Darwin pointed out that many plant parts, and particularly leaves, move in response to a number of extrinsic (environ- mental) and intrinsic (physiological) factors. The most important extrinsic factors are light intensity (phototropic), light direction (heliotropic), water content (hydrotropic), and temperature (thermotropic). The most fre- quently observed case of thermotropic move- ments occurs in plants in hot, dry environments where leaves move upward and become vertical to avoid excessive light absorption. The thermotropic leaf movements of Rhododendron are unusual because these movements are in response to cold tempera- tures and the leaves become rather pendent the than vertical. Figure 1. A diagrammatic representation of leaf movements in Rhododendron maximum. Changes in Research on the movements thermotropic leaf orientation move from curled and pendent at 9:00 of rhododendron leaves began in 1899 with a.m. to flat and more horizontal by 9’20 a.m. the work of Harshberger. In 1933, a Japanese scientist, Y. Fukuda, studied the leaf-curling patterns of Rhododendron micranthum, mak- know how cold it is by looking at my rhodo ing the important observation that its leaves leaves." Most authors believed that this could be kept from curling if he covered them curling served one of two purposes: either it with snow, thereby insulating them from cold prevented water loss in a dry winter environ- air temperatures. Based on these observations, ment where the soil water was frozen and Fukuda concluded that the thermotropic leaf unavailable; or it protected the leaves from movements were correlated with leaf rather damage by repetitive freezing and thawing. than air temperature. Six Possible Theories My research on thermotropic leaf move- ments of Rhododendron began in 1984 with My training in plant-stress physiology allowed three main questions: (1) What are the specific me to propose six possible scenarios for the seasonal and daily patterns of leaf movements, adaptive significance of thermotropic leaf and how are they affected by climatic factors? movements in rhododendron. I will discuss (2) What is the physiological cause of ther- each possibility in turn, along with suppor- motropic leaf movements and how does it tive or contradictory evidence from my relate to the leaf ultrastructure? (3) What is research program. the adaptive significance of leaf movements Evolutionary Relict Theory. This theory is to rhododendrons in their native habitats? the hardest to support or refute because it is Before I began my research project, I was based on a long-term evolutionary perspective. well aware of the popular dogma concerning Theoretically, thermotropic leaf movements the significance of leaf-curling and drooping could have evolved in response to climatic movements, which claimed that this conditions in the geological past, perhaps dur- phenomenon was an accurate air temperature ing the ice ages of the Pleistocene. Current sensor. Frequently, I heard the statement: interglacial conditions differ from those that "When I look out of my kitchen window, I led to the evolution of these leaf movements. 32

Thus thermotropic leaf movements in these movements do not require energy, there rhododendron are a relict and have no adap- is no reason why evolutionary processes tive significance to plants under the current would select against them. climatic conditions. Mechanical Theory. The leaves simply This theory is plausible because Rhododen- droop to protect themselves from mechanical dron is an ancient genus, with a fossil history damage due to the accumulated weight of extending through several glacial and intergla- rime, ice, and snow. Rhododendron leaves are cial periods. In addition, this species is long- subject to a considerable buildup of ice, up to lived and clonal, two characteristics that 1.5 centimeters thick, during winter months. reduce the rate of evolutionary change. Even under these conditions, however, the One argument against the evolutionary leaves are tenaciously held to the branches, relict theory is that those rhododendron spe- and I have never observed them damaged by cies that demonstrate cold tolerance are those ice buildup. Quite clearly mechanical protec- species with the leaf movements. For exam- tion is not a likely explanation for the adap- ple, R. ponticum and R. macrophyllum show tive significance of thermotropic leaf little if any leaf movement in the same garden movements. in Virginia, and these two species are not cold Desiccation Theory. Many reports suggest hardy. On the other hand, two extremely that thermotropic leaf movements are a hardy species, R. maximum and R. cataw- mechanism to prevent desiccation during cold biense, show prominent leaf movements. In periods. In fact, until recently this has been addition, my experiments on the physiologi- the main explanation for the significance of cal causes of leaf movements clearly indicate rhododendron leaf movements. According to that they require no metabolic energy and that this theory, the action of curling is thought they occur after complete turgor loss. Since to reduce the transpiring leaf area by creating a moist microsite around the stomata of the lower leaf surface to reduce water loss and pro- tect against desiccation. Several lines of evidence can be brought against this theory. First, the leaf stomata are not open during cold periods. In fact, they can- not be induced to open during the cold months. When stomata are closed, the inter- nal leaf water is unaffected by changes in atmospheric humidity. Therefore, leaf curling can have no impact on the leafs water balance. The fact that there is only a very small evaporative demand placed on the leaf during cold weather further suggests that very little water is conserved by the leaf-curling behavior. Second, the waxy cuticular layer on the upper surface of the leaf is relatively thick and effectively inhibits the flow of water through the epidermal cells. Theoretically, tension placed on the cuticle layer by curling could induce fissures in this cuticle and actually Figure 2. The relationship between leaf curling and increase the loss of water from the epidermis. leaf temperature for four Rhododendron species grow- Third, I have taken many thousands of ing in a common garden. rhododendron leaf-water potential measure- 33

should have no impact on the response of the leaf to the lack of water moving up from the root zone. Heat Balance Theory.The thermotropic leaf movements of many desert plants, in which the leaves move upward into a vertical posi- tion, serve the purpose of reducing leaf tem- perature by reducing the total quantity of light absorbed by the leaf. Thermotropic leaf move- ments in rhododendron are different because these movements occur in response to cold rather than hot temperatures. Leaves that are horizontal and flat have a greater exposure to the sky than those that are pendent and curled. Energy budget calculations made with a model rhododendron leaf indicate that a Figure 3. A diagrammatic representation of leaf treat- horizontal leaf could have a leaf ments used to determme the adaptive significance temperature 3 to of leaf movements m the genus Rhododendron. 6 degrees Centigrade lower than the air temperature while the pendent and curled leaf temperature will match the air temperature. ments during the winter and the summer in Temperatures between -25 and -35 degrees Virginia. These data provide no indication of C. are usually considered lethal to water stress during the winter months. I have Appalachian rhododendrons. Air tempera- found that leaf-water potentials (an index of tures in the mountains frequently reach -15 the energy in water in the leaf) are directly to -17 degrees C., suggesting that leaf tem- related to temperature. When I measure the peratures could come close to the lethal water potential of a leaf on a cold day, then values if leaf curling did not occur. let the leaf warm up and measure again, the Interpreting the heat balance data is further warmed measurement will be larger than the complicated by the type of canopy trees shad- cold measurement even though there has ing the rhododendron plant. The presence of been no change in the leaf-water content. This a thick deciduous canopy or a moderate ever- means that the low water potentials measured green canopy would cut down on heat loss. by other workers in the winter are not the One might compare the canopy to a blanket result of desiccation, but rather the direct for the subcanopy plants. In several wild influence of temperature on the leaf water. rhododendron populations, with and without As a final point, the desiccation theory a forest canopy cover, I forced leaves to remain depends upon a limited availability of water flat and horizontal during the winter months. from the soil as a consequence of its being Repetitive measurements of leaf temperature frozen. The evidence does not support this throughout several nights at all sites never notion because leaf movements in rhododen- found more than a 4 degree C. difference dron begin months before the soil freezes. between leaves with or without curling and Also, the fact that leaf curling can be repeti- drooping movements. Actually, only the tively stimulated on detached leaves indicates leaves on plants without an overhead canopy no influence of the roots on the leaf curling showed more than a one degree difference or uncurling processes. The observation that between the flat horizontal leaves and the curling fails to occur when the leaf is covered night air temperature. This small effect of leaf with snow further contradicts the desiccation movement on leaf temperature is not likely theory. If leaf curling were dependent upon to be significant in preventing leaf damage due desiccation, the presence of snow on the leaf to freezing. In general, the canopy over the 34*

rhododendron plants has a strong ameliorat- ing effect on winter nocturnal leaf tempera- tures, and leaf movements have little to no effect in most of the wild rhododendron habitats on the East Coast. Photoinhibition Theory. A very active field of research in plant-stress physiology is the influence of multiple environmental factors on plant physiology. One of the first case studies involved the interaction of cold tem- peratures and bright light on leaf physiology. These studies demonstrated that leaf cell membranes are susceptible to damage by intense radiation when they are cold. The membranes most susceptible to damage are those in the chlorophyll-rich chloroplasts. In particular, the membranes supporting photosystem-2 (a group of proteins that cap- tures light energy and converts it to chemi- cal energy) are most susceptible. The damage occurs cold leaf when during temperatures Figure 4. Thermal emission (freezing point) and the there are no outlets for the light energy cap- temperature range for leaf curlmg of Rhododendron tured by photosystem-2. In this situation the maximum and Rhododendron ponticum. protein-membrane association between photosystem-2 and the chloroplast mem- branes is disturbed, resulting in a physiologi- During this leaf manipulation study, it was cal dysfunction termed photoinhibition. significant that leaf curling had little The quantity of light absorbed by the leaf influence on the potential for photoinhibition. during the winter is the critical determinant Rather, it was the drooping of the leaves that of the potential for photoinhibition. Irradiance protected the leaves from photosynthetic conditions under a canopy of leafless trees are damage. Indeed, leaf angle and leaf curling higher in the winter than in the summer, should be treated as distinct phenomenon. which means that rhododendron plants Leaf curling responds directly to temperature, experience the highest radiation of the year while leaf angle responds to the water poten- during the coldest weather. Under these con- tial of the petiole. To be accurate, one should ditions, leaf drooping and curling act to reduce separate these movements in terms of both the quantity of light impinging on the leaf their physiological cause and their adaptive during the coldest temperatures, thereby significance. preventing or limiting photoinhibition. Freezing damage theory. Along with many I tested the possibility of cold-induced pho- others, Jacob Levitt has demonstrated that toinhibition by high light in my leaf manipu- most of the damage caused by leaf freezing is lation studies. My measurements of leaf a result of ice crystals piercing cellular mem- photosynthesis decreased by as much as 50 branes, followed by too rapid a rate of rewarm- percent in leaves prevented from moving dur- ing after freezing. The field of cryogenics has ing the winter. In addition, diagnostic tech- clearly demonstrated that tissues are best niques using the interaction between light preserved by rapid freezing and slow rewarm- intensity and photosynthesis clearly pointed ing. Leaf freezing points of rhododendron in to photoinhibition as the root cause of the the Appalachian mountains are -8 degrees C. decrease in photosynthesis. on the average. Of course there is variability 35

between species and times of the year, but this References amounts to a range of less than 2 degrees C. Bao, Y, and E. T. Nilsen. 1988. The ecophysiological sig- Winter temperatures in these mountains are nificance of leaf movements m Rhododendron maximum 1578-1587. normally -10 degrees C. or lower. Conse- L. Ecology 69(5): the rhododendron leaves freeze on quently, Darwm, C. 1880. The Power of Movement in Plants. New most evenings. Daily temperature is normally York: D. Appleton. near -2 degrees C., so the leaves also thaw daily. Rhododendron is one of the few ever- Fukuda, Y. 1933. Hygronastic curling and uncurlmg move- ment of the leaves of Rhododendron micran- green genera on the East Coast that has the thum Turcz with respect to and to tolerate freeze and thaw temperature capacity frequent resistance to cold. Tap Tour. of Bot 6: 199-224. cycles. Energy budget models (as well as our field measurements) indicate that horizontal Havis, J. R. 1964. Freezing of Rhododendron leaves. Proc. flat leaves will thaw more rapidly than the Amer. Hort. Soc 84: 570-574. pendent curled leaves. In particular, leaf Nilsen, E. T. 1985. Seasonal and diurnal leaf movements will reduce the leaf area to curling exposed in Rhododendron maximum L. in contrasting light and thereby slow the rate of thaw, pro- irradiance environments. Oecologica 65: tecting the leaf from freezing damage. 296-302. Summary Nilsen, E. T. 1985. Causes and significance of winter leaf movements in Rhododendrons. /our. Amer. Our research on leaf movements in Rhod Soc 40(1): 14-15. Rhododendron over the past five years has answered several questions. Leaf curling and Nilsen, E. T. 1986. Quantitative phenology and leaf sur- of Rhododendron maximum L. in leaf drooping are distinct behaviors with vivorship contrasting irradiance environments of the different responses to climatic factors and pos- Appalachian mountams. Amer four Bot 73: sibly different adaptive significances. Leaf 822-831 angle is controlled by the hydration of the petiole, as affected by water availability from both the soil and the atmosphere and by air Nilsen, E. T. 1987. The influence of temperature and water relations components on leaf movements in In leaf is a temperature. contrast, curling Rhododendron maxunum L. Plant Physiol. 83: specific response to leaf temperature, and the 607-612. leaf hydration state has little effect. The phys- iological cause of leaf curling is not well Nilsen, E. T, and Y. Bao. 1987. The influence of age, sea- and microclimate on the understood, but the mechanism must lie in son, photochemistry of Rhododendron maxunum L. I: Chlorophylls. the of the cell wall or physiology regional Photosynthetica 21(4): 535-542. changes in tissue hydration. The thermotropic drooping of rhododen- Nilsen, E. T, D. A. Stetler, and C. A. Gassman. 1988. The dron leaves most likely serves to protect them influence of age and microclimate on the pho- tochemistry of Rhododendron maximum L. from membrane damage due to high irradi- leaves. II: Chloroplast structure and photosyn- ance and cold the temperatures during long thetic light response. Amer. Tour. Bot. 75: Appalachian winters. In addition, the ther- 1526-1534. motropic leaf curling in Rhododendron may serve to prevent damage to cellular mem- branes during the process of daily rethawing that often occurs during the early morning. Our initial results with species comparisons indicate that leaf movements may be an Enk Nilsen is Associate Professor of Biology at Virginia factor cold important determining hardiness Polytechnic Institute and State University m Blacksburg, in Rhododendron species. Virginia. Kolomikta Kiwi

Gary L. Koller

The 1990 Membership Dividend from the Arnold Arboretum.

Exceptional hardiness, vigorous growth, deli- remaining a uniform dull green throughout cious fruit, and brightly variegated leaves are the whole process. the attributes that make the kolomikta kiwi The upper-surface variegation generally (Actinidia kolomikta) the choice for the 1990 lasts several weeks until chlorophyll produc- plant distribution to the Friends of the Arnold tion returns to normal, masking the showy Arboretum. Native to Manchuria, Korea, colors. While both male and female plants Japan, and northeastern China, the plant was produce colorful leaves, growers report that first described by Carl Maximowicz in 1856 the male plants produce the best foliage dis- from specimens he collected in the northern play. This has led to the selective propagation Amur river valley of Manchuria, where the of male plants by nurseries, and may partially plant was called "Kolomikta or Kotomikta" by explain why very few plants in cultivation the local inhabitants. produce fruit. First introduced into Europe shortly after its It is not known what function these leaf- discovery, Actinidia kolomikta was growing color changes serve in nature. Peter Del in France prior to 1872 and reached England Tredici, of the Arboretum staff, has speculated by 1877. The Arnold Arboretum introduced that they may function to attract pollinators the plant into North America when it to the flowers, which are largely hidden obtained plants from Lavalle Nursery in beneath the leaves. It may be that the bright Segrez, France, in 1880 and from Veitch and colors function like the red bracts of the poin- Sons Nursery in Chelsea, England, in 1881. settia plant (Euphorbia pulcherrima), which The plant has been growing at the Arboretum attract pollinators to the tiny flowers in their ever since. In Western gardens, kolomikta kiwi midst. From a distance, the colored leaves of is cultivated primarily for its pink-and-white Actinidia kolomikta make the plant look as variegated leaves. if it is covered with showy flowers. If the plant The variegation pattern in Actinidia appears this way to insects, then it may well kolomikta is both distinctive and unpredic- be that the brightly colored leaves function to table. The new leaves emerge green and attract pollinators from a greater distance than remain so until near the time of flowering in the flowers by themselves could. All this is mid-May when the youngest leaves begin to speculation, however, and field work planned change colors. The half of the leaf adjacent to for this spring at the Arboretum will deter- the petiole holds its green color while its dis- mine just how closely flower production and tal tip first turns a light metallic green. This leaf coloration are linked. light green tip eventually turns white, which Although this plant has been cultivated in then becomes tinged with pink or raspberry- North America for over a century, gardeners rose, producing a dramatic tricolored effect. have only recently considered the genus Interestingly, these color changes are limited Actinidia as a fruit-producing crop suitable for to the upper surface of the leaf, the underside northern landscapes. Just two or three years 37

The vanegated foliage of Actinidia kolomikta. From the ArchIves of the Arnold Arboretum. ago it was virtually impossible to locate fruits were selected for their earliness, size, kolomikta kiwi in nurseries, but now many flavor, sugar, and vitamin C content, as well offer it as a newly introduced plant. Unlike as for their greater ability to stay on the vine many other worthy species, the kolomikta once ripe. kiwi was able to escape the confines of botan- In 1986, a number of these Russian culti- ical gardens to reach a wider audience. vars were imported from the Vavilov Institute Agricultural Experiment Station in Leningrad Russian Research by Northwoods Nursery in Molalla, Oregon. After a century of testing, considerable infor- During the spring of 1989, Northwoods shared mation has been gathered about this plant. It the following cultivars with the Arnold possesses exceptional cold hardiness, for it is Arboretum for evaluation: ’Aromatnaya,’ said to be able to survive winters as low as ’Krupnopladnaya,’ ’Matovaya,’ ’Nahodka,’ -40 degrees Centigrade (-40 F.) in parts of ’Paukste,’ ’Pavlovskaya,’ ’Sentyabraskaya,’ and the Soviet Union. Such hardiness, coupled ’Urozainaya.’ According to Northwoods Nurs- with its ability to produce a large crop of tasty ery the cultivar ’Krupnopladnaya’ means fruits 18 millimeters long by 10 millimeters "large" in Russian, and this is the cultivar with wide (0.7 inches by 0.4 inches), has made it the largest fruit presently cultivated in North a home-gardening success in the Soviet America. Michael McConkey of Edible Land- Union. Over the years, Russian horticulturists scapes in Afton, Virginia, reports that ’Krup- have introduced a number of cultivars whose nopladnaya’ has proved the strongest, most 38I

vigorous grower of the new Russian introduc- tions in their area, and that it has attractive purplish winter stems. The cultivar’Ananasnaya Michurina; deve- loped by the famous Russian fruit breeder I. V. Michurin, has been represented in botani- cal gardens in this country for many years. The name translates as "Michurin’s Pine- apple" and refers to the flavor of the fruit. Michurin has written that ’Ananasnaya’ was a selection from a group of third-generation Actinidia kolomikta seedlings raised in 1925. European growers who have seen and grown this plant believe it is probably a hybrid of Actinidia arguta and A. kolomikta. Several American growers have shortened this culti- var name to ’Anna,’ a practice that is bound to lead to confusion since many will think they represent two different cultivars. These new Russian cultivars will require a few years of trial to determine how they differ from one another, and which will perform best in our climate. Cultivating the Kolomikta Kiwi Both vigorous and adaptable in its growth, kolomikta kiwi can climb to heights of fifteen meters (50 feet) in its native woodland habitat. Vines twine into the canopy of large shrubs and small trees, and then sprawl out across Actinidia kolomikta. Tab. 9093 from Curtis’s Botani- their crowns. The plant explorer Radde cal Magazine, 1925. reported that the kolomikta kiwi thickets on the middle Amur were so thick that the forest was almost impenetrable. Barry Yinger, a con- throughout the summer. At the edges of the temporary plant explorer, reports finding this forest, and near the top of the canopy where plant at high altitudes in northern Japan, in light levels are high, the distal tips of many open woods of birch, spruce, and fir. It is an leaves become suffused with the characteris- amazing experience, Yinger says, to encoun- tic white and rose-pink. Yinger reports that ter brightly colored leaves hugging the tree variation in leaf color in natural populations trunks in the shade of the forest. This provides offers future growers the opportunity to select us with a clue for using the plant in urban individuals with leaf colors and patterns more conditions. Imagine the columns used to sup- distinctive than those now in cultivation. At port a porch or shed transformed into pillars present, the introduction of new cultivars of tricolored leaves. from Japan is restricted because of Puccinias- In its native haunts, this forest plant trum actinidiae, a rust that infects plants in remains in varying degrees of shade for most that country. of the day. In dense shade, growth lacks vigor The vines thrive in full sun in northern and the foliage of kolomikta kiwi stays green areas, but as one moves south to areas with 39

longer, hotter summers, plants benefit from Because of its exceptional hardiness and shal- some shade. Best growth of kolomikta kiwi low root system, kolomikta kiwi deserves to occurs on well-drained, fertile loam. Once be tested for use in containers on terraces and planted, young vines usually require two to rooftops. three years to get established before they for Fruit produce either their tasty fruits or their color- Planting ful foliage. Several growers in the South have For a fruit crop, gardeners need to keep in reported that the spring growth often breaks mind that this species produces both dormancy early, only to be cut back by frost. staminate (male) and pistillate (female) plants, However, the plants resprout readily and are and that both sexes are required for fruit set. only seldom killed outright. To complicate the matter, some plants may Where soils are heavy or drainage is poor, occasionally bear flowers of the opposite sex this plant becomes susceptible to phytophora while others are reportedly bisexual. Nurser- root rot. Mark Houston of the California ies and fruit breeders have selected plants that Kiwifruit Commission reports that Actinidias are reliably male or female for more depend- are also susceptible to nematodes. Because able crop production. A ratio of at least one Actinidias are shallow-rooted, they require mulching and supplemental irrigation during periods of drought. Actinidias grow best in acid soils with the pH between 7.0 and 5.0. The literature reports that roots are sensitive to fertilizers, and care must be taken with these chemicals. Actinidia kolomikta is the slowest-growing species in the genus. In Massachusetts, annual growth is generally about one to two meters (three to six feet) with a maximum spread of three to six meters (ten to twenty feet) dur- ing a single growing season. Kolomikta kiwi also tends to produce a lighter structural framework than other Actinidia species, mak- ing it a good choice where growing space is limited or labor required for pruning is in short supply. This characteristic is useful to the gardener, for it allows one to construct a support structure that is more delicate and open in its detailing than those needed for most other Actinidias. When the vine is grown primarily for fruit, it is better to set the plant on an arbor that one can walk beneath to facilitate the harvest. When grown primarily for foliage, kolomikta kiwi can be beautifully displayed on a lattice set directly against a wall or woven through a free-standing wire fence. It is also delight- ful when grown on a structure that can be seen from an upper-story window, allowing a The blossoms of Actinidia kolomikta. Photo by clear view of the most brightly colored leaves. Racz and Debreczy. 40

male plant to five to eight female plants is found in supermarkets. Because the fruits are recommended to maximize fruit production. smooth-skinned, they can be eaten without Bear in mind, however, that even in Man- peeling-much as one would eat a grape. In churia, when both sexes are planted together Asia, fruits of Actinidia kolomikta are used in gardens, fruit set can be problematic. for jams and jellies, are dried or salted; and are While other Actinidia species have been used for winemaking and as desserts and gar- known to pollinate Actinidia kolomikta, it is nishes. According to Tanaka’s Encyclopedia of best to use a male of the same species so that Edible Plants, the Japanese also use the leaves both plants will flower at approximately the in a variety of ways: they parboil them for same time and there will be no sexual incom- soup, preserve them in salt, or use them as an patibilities. Where multiple species of ingredient in cooking. Actinidia have been grown together, both People who are interested in learning or natural and artificial hybrids have been sharing the latest information about the genus reported to occur. It is these plants that offer Actinidia should consult the Actinidia the promise of increased fruit size, yield, Enthusiasts Newsletter, P.O. Box 1466, Cha- vigor, and more colorful foliage for the gardens lan, Washington 98816. This publication is on of tomorrow. file in the library of the Arnold Arboretum. In Massachusetts the flowers are produced in mid-May and stay in good condition for a Bibilography week to ten days. The blossoms are white Goodell, E. 1982. TWo promising fruit plants for north- with dark-purple stamens, 1 to 1.5 cen- ern landscapes. Arnoldia 42: 103-132. timeters across (1/2 inch), and are borne in Hui-Lin. 1952. A taxonomic review of the clusters of one to five flowers. They produce Li, genus Actinidia. Journal of the Arnold Arboretum a mild similar to that of fragrance, lily-of-the- 33(l):1-61. valley (Convallaria majalis), and are largely hidden beneath the foliage. Flowering occurs O. S. 1925. Actmidia kolomikta. Curtis’s Botamcal Maga- only on wood produced the previous growing zme, vol. 151, tab. 9093. so is to reduce the season, pruning required B. ed. 1974. Flora U.S.S.R. Vol. of older Shishkm, K., of the 15, buildup non-flowering growth. pp. 138-142. Translated from the Russian. Jerusa- In Massachusetts, kolomikta kiwi fruit lem : Keter Publ. House. matures in late August or early September, about one month earlier than Actinidia Woeikoff, A. D. 1941 What Can the Manchurian Flora Give to Gardens. San Francisco: Paul Kourenoff. arguta. Depending on the cultivar, fruits range from the size of small grapes (1 to 1.5 cm) to that of a small plum to 2.5 They are (1.5 cm). Gary L. Koller is the Assistant Director for Horticulture bear a and smooth-skinned, dark-green flesh, at the Arnold Arboretum and teaches in the Landscape have a taste more intense and flavorful than Architecture Department at the Graduate School of the commercial kiwis (Actinidia deliciosa) Design, Harvard University. NEWS~ F R 0 m T-H E A R NO L i) A R130RETUM

ARBORETUM A WINNER AT SPRING FLOWER SHOW Lilacs bloomed in March when the Arnold Arboretum presented a display focusing on the diversity of lilacs at the Massachusetts Horticultural Society’s Spring Flower Show. Since lilacs are rarely shown as forced plants, the exhibit drew applause from both the public and judges. On open- ing day it received the Ruth S. Thayer Prize, the Massachu- setts Horticultural Society’s $1000 cash prize, a Silver opening night. During the ten-day run of Medal, an Educational New Englanders are the show lilacs and other known for a Award, and a Cultural having great plants were monitored, affection for lilacs - witness Commendation. groomed and changed on a the crowds that visit the One of the premier daily basis. The efforts were awards in the show, the Ruth Arboretum each Lilac Sunday rewarded with the prestig- S. Thayer Prize, was given for (May 20,1990!). Peak visita- ious Arno H. Nehrling tion of is said to have the Arboretum’s presentation 43,000 Award, judged on Thursday of Syringa vulgaris ’Frederick been reached in 1941. But and presented "to the exhib- their Law Olmsted.’ In keeping during ten-day appear- itor who executes an original with the rules of the ance at the show more than award, design, who stages a display this visitors had an free-flowering, lightly 180,000 op- of excellence, who sets up on scented white lilac has not yet portunity to look, sniff and schedule, and maintains the been introduced commer- "select" their favorites. The exhibit in top condition cially. A seedling of ’Roches- exhibit included some of the throughout the Show." ter’ with a globose habit, classic French hybrids (’Mme The Arboretum thanks ’Frederick Law Olmsted,’ was Lemoine,’ ’President Grevy’) Kurt Tramposch of Weir selected by Richard (Dick) as well as the eye-catching Meadow Nursery and Dale Fenicchia, formerly Park Syringa vulgaris ’Sensation’ Chapman for assistance in Superintendent, Highland with its picotee edging of obtaining plants, Chris De white on the blossoms. Park, Monroe County Parks purple Rosa for the loan of stone, and Commission, Rochester, New Syringa x prestoniae ’Charles David Kersey for the teak x York. Hepbum’ and Syringa bench. The exhibit was The Arboretum’s Chief chinensis added tones of warm designed and coordinated by Plant Propagator and resident mauve-pink. Two "standard" Nan Sinton and Jack Alexan- lilac specialist, Jack Alexan- Syringa meyeri ’Palibin’ der with much help from all der, won high praise from marked the entry to a rustic the Arboretum staff and both experts and the public pathway and a small weath- volunteers. for achieving the "impossible" ered bench surrounded by in forcing the plants for Syringa patula’Miss Kim’. 1 CHINESE and unusual annuals to give a PENJING range of color in flower and AND foliage and keep a garden JAPANESE glowing into the fall. BONSAI Plant Hunting in Kashmir. Despite the fact Thursday, April 26, by that the Chinese Christopher Chadwell. originated the This lecture on the concept of mini- woody trees in plants, perennials, and aturizing of Kashmir will containers over alpines include cultural as well as 1200 years ago, most Westerners botanical information about this beautiful of the are familiar with part this absorbing world by a knowledgeable form of gardening and well-travelled botanist. only by way of the All lectures are to much younger open Japanese bonsai. the public and will be held at the Hunnewell For a variety of his- Mr. Hu Yun Hua. Photo by Peter Del Tredici Visitor Center from 7:00 to torical reasons, distinctive 8:00 PM. The fee is $12 for penjing styles are virtually tion. The fee is $8 for mem- unknown to Americans. bers, $10 for non-members. members and $15 for non- The Arnold Arboretum, members. which has recently acquired THURSDAY EVENING ten specimens of penjing from LECTURES is honored to have the China, Gardens of America, Thurs- THE opportunity to present a day. April 12, by Diane RHODODENDRONS lecture/demonstration on Kostial McGuire. ARE COMING penjing styles and techniques the herb of by Mr. Hu Yunhua, a leading From simple gardens The Massachusetts Chapter connoisseur and practitioner of New England colonists the American Rhododendron of the ancient art. Among his through the imposing Society will be hosting the publications, Chinese Penjing, gardenesque designs of the annual National Convention Miniature Trees and Land- Victorians to contemporary at the Tara Hyannis Resort outdoor scapes, and Penjing the Chinese California rooms, and Hotel from Wednesday, Art of Miniature Gardens have this slide-lecture will illus- May 30 through Sunday, June been translated into English. trate the themes inherent in 3,1990. This one-of-a-kind event an astonishing range of The theme of the conven- will be held on Friday, April American garden visions and tion is "Rhododendrons for 27, from 6:30 to 8:30 at the their relationship to the the 90’s: The Northeast Hunnewell Visitor Center. cultural patterns of their Perspective," and will feature The fee is $15 for members times. hardy, adaptable plants with and $18 for non-members. attractive foliage, improved On Tuesday, April 10 Mixing It Up in the Mixed color, and an extended from 3:30 to 4:30 at the Border. Thursday, April 19, blooming season. The Con- Hunnewell Visitor Center, by Elsa Bakalar. vention will offer numerous tours, lectures, and work- Arboretum staff member Creating a long-blooming Peter Del Tredici will present "mixed border" entails going shops, a flower truss show, and a sale. Additional a slide-lecture on the history the familiar range of plant beyond information be obtained of the Larz Anderson bonsai While perennials are may plants. from Anne Reisch at collection, the oldest in North the backbone of the summer (508) America. The lecture will be garden, the adventurous 371-0755 after business hours. followed by a rare behind- gardener goes a step further the-scenes tour of the collec- and introduces summer bulbs 2 and a grid map for locating special price is $205. plants on the grounds. The Vol. 1. Orchidaceae $20 cost is $21.00 including Vol. 2. Pteridophyta $25 postage and handling within Vol. 3. Monocotyledoneae $35 the United States. Foreign Vol. 4. Dicotyledoneae,1 $75 orders with payment in U.S. Vol. 5. Dicotyledoneae, 2 $85 funds should add $4.00 per Vol. 6. Dicotyledoneae, 3 $85 book. Send orders to: The Checks should be made Bookstore, Arnold Arbore- payable to the Arnold Arbo- tum, 125 Arborway, Jamaica retum andall orders should be Plain, MA 02130. addressed to the attention of: Frances Maguire, Arnold Flora of the Lesser Antilles Arboretum, 125 Arborway, The Arnold Arboretum is Jamaica Plain, MA 02130 proud to announce that the six-volume Flora the Lesser BOOKSTORE of OFFERINGS Antilles, a long-term project of Dr. Richard A. Howard, The recently expanded Book- formerly Director of the store wants to remind all Arnold Arboretum and members of their benefit in TWO NEW BOOKS recently appointed Vice- of their 10% AVAILABLE taking advantage President for Science, New discount. Realizing that many The Arnold Arboretum York Botanical Garden, are members are out of state, we Plant Inventory now available. will offer book and other These six volumes ’New and merchandise selections via improved, updated constitute the first compre- the Arnoldia insert. will and easy to use" may sound They hensive flora of the area, include new and like but it publications advertising copy, presenting a keys to genera as serves to describe the products developed espe- recently well as For each Plant A species. cially for the Arboretum. published Inventory. and a revision of the inven- genus species complete Your purchases help support major modem is of in the Arnold description given the Arboretum and its tory plants which includes color as well Arboretum collection has programs. as measurements of floral been made from the recently parts. The descriptions are completed computerized followed a of each records data base. Each by listing plant general distribution as in the now is plant’s plant Inventory well as a list of its distribution listed: within the Lesser Antilles. All 2022 alphabetically by scientific volumes are profusely name illustrated with line drawings 2022 in clear, readable type that are both highly artistic 2022 with an indication of and accurate. All known collection in the wild species reported from the Lesser Antilles, both intro- 2022 with Arboretum map coordinates duced and native, are in- cluded. This three times the edition, All volumes in the series size of the Arnold previous are either individu- Arboretum Plant available, Inventory, or as of a full set, contains a wealth of informa- ally part which is available at the tion about the approximately taxa that make the special price, including 6,000 up of $260 (add $5 for Collections of the shipping, Living outside the US). For Arboretum. It also includes shipping volumes 4, 5, and 6 the an index of common names only,

3 TREE Arnold Arboretum, CHEERS FOR continues to be in KIDS AN strong evidence and ARBOR DAY make contributions EVENT there. Our Mainte- nance Unit helps with To herald the routine maintenance of coming spring, such as the repair of and as part of a benches. And, for the tradition of tree first time in recent planting, the history, under the Arboretum will initiative of the hold its annual Major’s capital plan Arbor Day for the city, we have celebration on been able to allocate Sunday, April 29. funds for some Winning elemen- capital repairs. tary school poets In 1989 $100,000 who have been was spent on the selected from Walter Street wall. At among this year’s the community Tree Cheers for meeting in which this Kids poetry con- was 1988 Arbor Day poetry contest winner, Julia Turner, helps decision made, testants will be the need for plant a tree at the Arnold Arboretum repair present to read paving of the much at the tree- poetry PARKS DEPART- travelled Bussey Hill road planting ceremony. "Billy B.," and sidewalks as well as the talented natural science MENT AND ARBORETUM drinking fountain repairs was song-and-dance man, will This fall I met WORKING articulated. host this engaging ceremony Director the TOGETHER with the of that honors the bond between Arnold Arboretum, Dr. children and their feelings The following memorandum was Robert Cook, and this need and about trees. imaginings recently issued by Lawrence A. was again brought to my These events, which will Dwyer, commissioner of the attention. The Parks Planning begin at 2:00 p.m., will be Boston Parks and Recreation and Development unit has followed B. in concert by Billy Department. examined the full range of such now-famous performing needs determined by a master songs as "The Rock and Roll The 1000-year lease the written by the Arnold of plan Photosynthesis." Parks and Recreation Depart- staff and feels this is an A of other activi- variety ment has with the Arnold appropriate project. As a ties will occur the throughout Arboretum constitutes the result of this and my discus- day including vegetable and oldest park partnership in the sions with Dr. Cook, I have fruit printing, talks with a City of Boston. Under the asked that bid documents be state tree-seed forester, terms of the lease the Arnold prepared and work begin on in take-home con- planting Arboretum is responsible for this project. I thank you for tree and visits tainers, games, the "living collection" as well your continued interest in the from urban wildlife. as buildings. The Parks Parks and Recreation Depart- If you would like to be Department is responsible for ment and the Arnold Arbore- involved as a volunteer for the infrastructure-the roads, tum. of the contact part day, please drainage, walls, etc.-and If you have any questions Diane Syverson, Children’s safety. please contact Victoria at Program Director, (617) We enjoy a good relation- Williams at 725-4505. 524-1718. ship with the Arnold Arbore- tum. The Boston Park Rang- ers, begun as a program in the