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Home , Castanopsis, Fagaceae, Lithocarpus, Nothofagus, Quercus ellipsoidalis, Trigonobalanus

TEMPERATE ECOSYSTEMS / 1419

Trees; Genetic Systems of ; Population, Conservation and Ecological Genetics. Temperate and Mediterranean : Subalpine and Boreal Forests; Temperate Broadleaved Forest. Phy- siology: Physiology of in Trees.

Further Reading

Argus GW (1973) The Salix in Alaska and the Yukon. Ottawa: National Museums of Canada. Chase MW, Zmarzty S, Lledo MD, et al. (2002) When in doubt, put it in Flacourtiaceae: a molecular phylogenetic analysis based on plastid rbcL DNA sequences. Kew Bulletin 57: 141–181. Figure 1 Cork () plantation in Portugal Chen ZD, Manchester SR, and Sun HY (1999) Phylogeny showing tree trunks whose bark has been stripped for cork. and evolution of the Betulaceae as inferred from DNA Photograph courtesy of Heinrich Speicker, Institut fu¨r Waldwach- sequences, morphology, and paleobotany. American stum, Albert-Ludwigs-Universita¨t Freiburg, Freiburg, . Journal of 86: 1168–1181. Furlow JJ (1990) The genera of the Betulaceae in the Southeastern . Journal of the Arnold Arboretum 71: 1–67. Hibbs DE, DeBell DS, and Tarrant RF (1994) The Biology The family contains from six to nine genera and Management of Red Alder. Corvallis, OR: Oregon (Fagus, , , , Co- State University Press. lombobalanus, Castanea, , Quercus, and Newsholme C (1992) Willows. The Genus Salix. Portland, ) and includes between 600 and 900 OR: Timber Press. , although numerous classification issues exist Savill PS (1991) The Silviculture of Trees used in British which accounts for the variation in the number of . Wallingford, UK: CAB International. genera (Table 1). Perhaps the best-known members of the beech family are the which are recognized by their distinctive , the (Figure 2). The genera of Fagaceae as we know them probably became Fagaceae established about 60 million years ago during the late period in geologic history following R Rogers, University of Wisconsin–Stevens Point, Stevens Point, WI, USA migration from areas centered in tropical mountains. Characteristics that unite members of the family & 2004, Elsevier Ltd. All Rights Reserved. include with a single blade that are either persistent or deciduous and which often remain on the tree after withering and dying. Leaflike appen- dages (stipules) are present at the base of a relatively short stem (). Leaves are arranged in an Introduction alternate pattern on the stem. Veins of the leaves are The following sections characterize members of the featherlike and have branches that are laterally beech family (Fagaceae) in relation to their taxon- connected to a central stem. omy, distribution, ecology, and silviculture. Also Male and female flowers are found within the included is information about their botanical im- same tree. Female flowers are wind pollinated. Male portance as well as their significance in meeting flowers are pendulous spikelike structures while human needs. female flowers are on short spikes with few flowers The beech family contains some of the world’s or may be grouped in clusters near the base of the most important trees to human culture. Uses are male flowers. Although female flowers may contain myriad and include such things as woven baskets, one or two ovules, only one develops to maturity. toys, storage containers, ship timbers, and food The fruit is distinctive and consists of a that is sources. However, members of the beech family are surrounded by an outer somewhat firm yet elastic generally acknowledged as most important sources coat that is partially or completely enclosed by a of hardwood timber (oak (Quercus), beech (Fagus), cluster of bracts (Figure 3). The nut contains only and (Castanea)), chestnut, and cork and one which lacks food reserves associated with from the oaks (Figure 1). the embryo but which has large, fleshy primary 1420 TEMPERATE ECOSYSTEMS / Fagaceae

Table 1 Distribution of the beech family (Fagacaeae)

Genus Number of species Range

Beech (Fagus) 10 Oak (Quercus) 400 Northern hemisphere; red oak group (Lobatae) restricted to Southern beech (Nothofagus) 40 , Chile, Argentina, , , and Chestnut (Castanea) 10 Southern , northern Africa, southwestern and eastern , and eastern United States Chinkapin (Castanopsis) 150 North America, , India, and Malayan archipelago Tanoak Lithocarpus 100–200 North America (1 species), Asia Chinquapin (Chrysolepis) 2 Western United States Colombobalanus 1 Columbia, South America Trigonobalanus 2 China, Malaysia

found in North America, one is European, one is found in the Caucasus Mountains on the border between Europe and Asia, and the rest are found within the temperate regions of eastern Asia. Although the beech genus is relatively small, the European beech has been used extensively for ornamental purposes and many horticultural vari- eties exist which display a vast array of morpholo- gical characteristics such as coloration and form (Figure 4).

Oak (Quercus)

Figure 2 of northern red oak (). Worldwide there are about 400 species of oaks, and they are taxonomically divided into three groups: (1) the red oak group (Quercus section Lobatae), (2) the white oak group (Quercus section Quercus), and (3) the intermediate group (Quercus section Protobalanus). All three groups include tree and species. The red oaks and white oaks include and deciduous species, whereas the inter- mediate oaks are all evergreen. The red oaks are found only in the western hemisphere where their north–south range extends from Canada to Colom- bia. In contrast, the white oaks are widely distributed across the northern hemisphere. The intermediate group comprises only five species, all of which occur within southwestern USA and northwestern Mexico. Many of the world’s oaks occur in regions with arid Figure 3 Fruit of tanoak (Lithocarpus densiflorus). climates, including Mexico, North Africa, and Eurasia, where they are often limited in stature to leaves that it uses for its initial nourishment upon and small trees. About 80% of oaks occur germination. The fruit matures in one or two below 351 N latitude and fewer than 2% (six or seasons. A botanic comparison of the well known seven species) reach 501 N. genera is given in Table 2. The most reliable distinction between the white oaks and red oaks is the inner surface of the acorn shell. In the white oaks it is hairless or nearly Beech (Fagus) so, whereas in the red oaks it is conspicuously There are 10 species of all of which are hairy or velvety. In the intermediate group, this found in the northern hemisphere. One species is characteristic is not consistent among species. The TEMPERATE ECOSYSTEMS / Fagaceae 1421

Table 2 Summary of characteristics of the more common genera in the beech family

Genus Leaves Fruit

Beech (Fagus) Deciduous Male are in heads, female are in A triangular nut occurring in twos short spikes with two to four enclosed by a bur covered by flowers weak unbranched spines; matures in one season Chestnut (Castanea) Deciduous Male, female, or both borne on A rounded nut occurring singly or erect many-flowered apetalous in twos or threes covered by a spikes bur having sharp, rigid, branched spines; matures in one season Chinkapin Persistent Similar to chestnut The same as chestnut but takes (Castanopsis) 2 years to mature Tanoak (Lithocarpus) Persistent Similar to chestnut An acorn which matures in 2 years Oak (Quercus) Deciduous or persistent Male are borne in many-flowered An acorn which matures in 1 or 2 apetalous spikes; female are years borne in several-flowered spikes Southern beech Deciduous or persistent Male are bell-shaped of varying Similar to beech (Nothofagus) which are small, oval, and numbers; female are generally have finely toothed edges few in number and borne on stalks Chinquapin Persistent Chestnutlike spikes of creamy- Spine-covered bur which (Chrysolepis) white; male flowers are borne encloses from one to three in the leaf axils; female flowers nuts usually occur in a cluster at the base of male spikes

Figure 4 Leaves of copper beech ( ‘Purpurea’). Figure 5 Leaves of white oak (). Note absence of Photograph courtesy of Heinrich Speicker, Institut fu¨r Waldwach- bristles at the ends of the leaf lobes. stum, Albert-Ludwigs-Universita¨t Freiburg, Freiburg, Germany.

two seasons. The white oaks and intermediate oaks leaves of the white oaks are usually rounded and are characterized by the presence of tyloses (occlu- without bristle tips (Figure 5), whereas the leaf lobes sions) in the latewood vessels (water-conducting of the red oaks are usually pointed and often bristle- cells) of the xylem whereas tyloses are usually absent tipped (Figure 6). To many botanists and others, the in the red oaks. These vessel-plugging materials most important difference between the white oaks confer greater decay resistance to the wood of the and red oaks is the length of the acorn maturation white and intermediate oaks than the red oaks. Other period. Acorns of species in the white oak group morphological features that differentiate the three require one season to mature whereas species in the groups and species within them are presented in intermediate and most of the red oak group require various taxonomic treatments. 1422 TEMPERATE ECOSYSTEMS / Fagaceae

break-up of the Great Southern land. Forests of Nothofagus were noted as early as the mid-nine- teenth century by the botanist Sir Joseph Hooker who accompanied James Ross on exploratory trips to the Southern Ocean between 1839 and 1843.

Chestnut (Castanea) Castanea is the generic name for the whose alternate name is chinkapin, not to be confused with Castanopsis and Chrysolepis, genera whose species are also commonly referred to as chinkapins or chinquapins. Castanea is a relatively small genus consisting of 10 species distributed across southern Europe, northern Africa, southwestern and eastern Figure 6 Leaves of northern pin oak () Asia, and the eastern United States. Prior to the showing bristle-tipped leaves. 1930s in the eastern USA, the (Castanea dentata) was prized for its high-quality, durable wood and sweet fruit but it is now relegated Of the more than 250 oak species occurring in the to a shrubby form because of its susceptibility to a western hemisphere, the largest number occur in pathogenic organism, the chestnut blight (Endothia Mexico and Central America. About 10 species parasitica). The blight eventually kills the stem but occur in Canada while 90 species of oaks are native the root system is resistant to infection and results in to the continental USA. Oak hybrids are not sprout growth which is in turn killed back in a never- uncommon where species ranges overlap as evi- ending cycle. denced by the more than 80 hybrids recognized in the USA alone. Chinkapin (Castanopsis) The oaks are distinguished from other members of Most botanists agree that the taxonomy of Casta- the beech family (e.g., the beeches and chestnuts) by nopsis is poorly understood. Only two of about 150 their fruit, the acorn. With one exception, all species of Castanopsis are found in North America that produce acorns are oaks. The exception is the whereas the rest are found in the forests of China, genus Lithocarpus, which includes the tanoak of India, and the Malayan archipelago. These two are Oregon and . Although represented by distinct from their Asian relatives, and systematists only one North American species, Lithocarpus is have created a new genus for them called Chryso- represented by 100 to 200 species in Asia. Some lepis. The American species have a flower structure taxonomists think Lithocarpus may be an evolu- that is intermediate between Castanopsis and Litho- tionary link between the chestnut and the oak. carpus suggesting a more primitive form within the family Fagaceae. The new scientific names for the Southern Beech (Nothofagus) American species, with the older names in parenth- eses, are (Dougl.) Hjelmq- Southern beech or Nothofagus is a genus of some 40 vist (Castanopsis chrysophylla (Dougl.) A. DC.) for species that only occur in the temperate regions of giant chinkapin and Chrysolepis sempervirens (Kell.) the southern hemisphere. The name Nothofagus Hjelmqvist (Castanopsis sempervirens Dudl.) for means ‘false beech’; however, Notofagus meaning evergreen chinkapin. ‘southern beech’ might have been more appropriate and in fact the original intent of the nomenclature. Some historians have suggested that the Ecology original name was mis-spelled by inserting the h. Beech (Fagus) Nine species of Nothofagus occur in South America while three occur in Australia. The importance of Approximately 12% of all species in Fagaceae their timber is second only to that of the eucalypts. appear in the 2003 IUCN Red List of Threatened Besides Australia, Chile, and Argentina, Nothofa- Plants. gus is also represented in New Zealand, New Guinea, Beech is found mixed with other temperate and New Caledonia. Paleobotanists believe the deciduous species and requires a site with a well- current distribution of Nothofagus species resulted drained with good moisture holding capacity; it from the continental drift that occurred following the is more particular in that regard than many of the TEMPERATE ECOSYSTEMS / Fagaceae 1423 species it associates with. However, it does not Southern Beech (Nothofagus) tolerate that experience either prolonged flood- ing or dry periods. Beeches are extremely tolerant of The temperate regions of the southern hemisphere do shade and can persist under the shade of other not have direct counterparts of the northern tempe- species for decades. rate broadleaf deciduous forest. Instead the humid European beech (Fagus sylvatica) is a dominant subtropical climate regions have a mixed (broadleaf species in the broadleaved forests of Europe located and needleleaf) evergreen forest whose biogeo- principally in the foothills of mountainous areas. It graphic interest stems from the occurrence of was once more extensive in its distribution and Gondwanan relicts: pines (South America composition than nowadays because of forest ex- and Australia), Podocarpus pines (South America, ploitation practices of past centuries which resulted Africa, and Australia), and the evergreen southern in reforesting former broadleaved forests with faster beech Nothofagus (South America, Australia, and growing species such as Scots pine (Pinus sylvestris) New Zealand). and Norway spruce (Picea abies). Efforts are under In general, southern beeches are slow-growing way to increase the proportion of broadleaved forests trees found in temperate rainforests of the southern in Europe and in Germany in particular in order to hemisphere whose origins are believed to have been return to the ‘more natural’ forest conditions of derived from a time when there was a single former times. Sessile oak (), English primordial landmass in the southern hemisphere oak (Q. robur), and European hornbeam (Carpinus called . Continental drift is presumed to betulus) are frequent associates. be the reason for the widespread occurrence of the Similarly, the American species, American beech genus across the southern hemisphere in essentially (F. grandifolia) enjoys a wide range covering all of similar in such places as South America, the eastern part of the USA on mesic sites and is Australia, New Zealand, New Caledonia, and Papua associated with a large number of trees in a number New Guinea. Trees of some species can be quite large of forest types. Like its European cousin, it has a and may reach a height of 30 m or more with distinctive smooth light-gray bark that remains so diameter at 1.3 m above the ground (diameter at until maturity. Some of its principal associates breast height, dbh) of 1 m and occasionally up to include sugar maple (Acer saccharum), red maple 2 m. The strong similarity of form and the persistence (A. rubrum), yellow (Betula alleghaniensis), of these trees in comparable habitats across southern American basswood (Tilia americana), black cherry hemisphere landmasses supports other evidence that (Prunus serotina), eastern white pine (Pinus strobus), these trees have survived largely unchanged since and red spruce (Picea rubra), as well as several continental separation. In fact, Nothofagus hickories and numerous oaks and, in the southern leaves have even been found on the Antarctic part of its range, southern magnolia (Magnolia continent. Interestingly, other plant and animal grandiflora). Beech is an important component of species exclusively associated with southern beech 20 forest cover types in eastern US forests and is one forests also have close relatives associated with the of the dominant species in three types; sugar maple– comparable trees all across the southern landmasses. beech–yellow birch, red spruce–sugar maple–beech, Beech orange fungus and the bugs are and beech–sugar maple. It is found in lesser amounts good examples. in 17 other types. The extent of southern beech forests has been American beech reproduces by seed which germi- reduced in certain places. Southern beech forests in nates on mineral soils but is best on forest soils Australia were once far more widespread, when the containing humus. It is prevalent on podzolic soils. climate was wetter and fire was less frequent. The largest species are found on alluvial bottom The subantarctic forests of evergreen southern lands of Ohio and the lower Mississippi River beech in are threatened with . valleys, and along the western slopes of the southern They occupy a 60-km wide strip along the base of the Appalachian Mountains. American beech also re- Andes and extend, in pockets, 1500 km from the produces by root sprouts which can develop into Province of Neuque´n south to Tierra del Fuego. Two desirable trees. Root systems are generally shallow indigenous species – the lenga () compared to species with which it associates. Beech and n˜ ire (N. procera) trees – dominate the forest, are long-lived trees only being exceeded by white oak which serves as home to pumas, guanacos, southern (Q. alba) and sugar maple. Crown spread typically is river otters, geese, Andean condors, and huemul . wide compared to its associates. However, they can Logging and forest clearing have been extensive in prune themselves well provided that stand density is the region’s northerly latitudes, and now threaten the not too low. southern forests of lenga and n˜ ire. However, the 1424 TEMPERATE ECOSYSTEMS / Fagaceae boundaries of Perito Moreno National Park in 2000-acre (800-hectare) reserve is in northern Co- Patagonia are being expanded through land donated lombia in the Eastern Cordillera Montane Forest and by the Patagonian Land Trust in an effort to preserve is part of a ‘globally outstanding’ ecoregion. Oak these forests of evergreen southern beech. prefers high altitudes, 1000–2600 m above sea level, with annual precipitation of 1500–2500 mm and The American Chinquapins (Chrysolepis) temperatures of 16–241C. Ecologically very plastic, it can be found both in moderately fertile and deep soils The uniqueness of the two species of the American and in degraded, almost barren soils. Nevertheless, it genus Chrysolepis in relation to the species within grows better on shallow soils with a thick layer of Castanopsis level does not translate to differences humus, and relatively loose soils with good drainage between the American species. The ranges of the and a pH between 5.8 and 7.0. It is intolerant of shrub form of giant chinkapin and of evergreen shade and will dominate competing species. chinkapin overlap from northern coastal California The oaks are widely distributed throughout the into the Cascade Range of Oregon. The two species temperate regions of the northern hemisphere. probably hybridize where they co-exist. An appar- Generalizing about the ecological relations of the ently continuous intergradation of characters can be genus is dangerous at best given the enormous found in the Cascades in southern Oregon and in the number of species and their genetic, morphological, Siskiyou Mountains. and life history diversity. The reader is directed to The two growth forms of giant chinkapin are local or regional guides to the various species. probably not the result of plastic phenotypic The oaks of the Mediterranean region of southern response to site conditions, although they may be Europe and northern Africa typically are shrubby or in portions of the species range. In the northern low-growing trees that are adapted to dry growing Coast Ranges of California, the tree form occupies conditions. They typically are found in savanna like relatively moist conditions; the shrub form grows on environments and may co-exist with various agri- dry, sterile ridgetops in chapparal communities. In cultural crops. The world’s cork supply comes chiefly the central part of the Cascades of Oregon, the from cork oak growing in Portugal, Spain, and north pattern is reversed – the tree form is found primarily Africa. in relatively open and dry ridgetop forest commu- Conversely, oaks can be found on extremely dry nities, and the shrub form is spread through the more sites to those inundated by flood waters and span the mesic forest stands. Only the shrub form is found at shade tolerance spectrum from intolerant to moder- high elevations in the Cascade Range. ately tolerant. Oaks have been known to reproduce This variation is due to the probable existence of at by seed and by sprouting from stumps, seedlings, and least three ecotypes of giant chinkapin: (1) a dry-site rhizomes. Regeneration strategies are largely species- chaparral shrub ecotype of southwestern Oregon and site dependent and the anomalies in regeneration northwestern California which probably matches the strategy among the oaks emphasize the difficulty of taxonomic category of Castanopsis chrysophylla var. generalizing their regeneration ecology across species minor; (2) a high-elevation ecotype adapted to heavy and habitats. Different oaks have solved their snowpack, cool temperatures, and short growing regeneration problems in different ways and some seasons found along the Oregon Cascades and in are more flexible than others in reaching a successful eastern Oregon; and (3) a tree form that occurs in establishment. Each species, environment, physiol- forest stands at lower elevations. The latter ecotype ogy, and genetics determine its ability to regenerate seems well adapted to dry, relatively infertile sites but successfully. can and does do well in more mesic conditions that Oaks are one of the most, if not the most, have a history of disturbance by fire. important hardwood species of the USA. The genus is represented throughout the USA except for the Oaks (Quercus) Great Plains area to the west of the Mississippi and It is an understatement to say that oaks are found on east of the . The greatest variety of a wide variety of sites, soil conditions and landforms oaks occurs in the eastern deciduous forest most of throughout its range in the northern hemisphere. It is which is classified as the oak-hickory forest region. worth noting that one species () Of the 145 forest cover types defined by the Society crosses the equator and is found in Ecuador. of American Foresters in the USA 31 contain oak in Located between 5900 and 8600 feet (1800 and the name or are included as part of a species list 2600 meters) above sea level, the Cachalu´ Biological defining a name. Of these, 23 oak types are found Reserve in Colombia features one of the last east of the Mississippi River. In addition, many of the remnants of pristine oak forests of this species. The non-oak types have oak as a common associate. TEMPERATE ECOSYSTEMS / Fagaceae 1425

Although oaks are relatively intolerant of shade, 60 cm dbh in 110–140 years at a density of 80–110 species vary considerably in this regard. In some trees per hectare. Thinnings are restricted to these habitats, oaks are vulnerable to replacement by more ‘crop trees’ to keep their crowns in a free-to-grow tolerant species such as maples and beeches. Com- condition. This sometimes means that thinnings must pared to other competitors, oak seedlings grow more be from above (i.e., removing some dominant trees). slowly during the years following establishment. When young oaks are overtopped and heavily shaded Southern Beech (Nothofagus) few survive for very long. However, oaks tend to be Clear-felling has been the common way of harvesting relatively drought tolerant and often survive on sites southern beech in New Zealand and other areas that limit the establishment and development of across its distribution in the southern hemisphere. associated species with less drought tolerance. On However, research is ongoing in New Zealand to find droughty sites oak stems and shoots often die back out if group selection (an uneven-aged silvicultural but have a remarkable capacity to sprout from the method) could be used to sustain southern beech roots when growing conditions become favorable forests. The group selection method is a modification again. These sprouts often have the capacity to of the single-tree selection method whereby openings outgrow competitors. Oaks tend to accumulate on larger than the crowns of the largest trees are made in these dry sites and may eventually dominate the the forest canopy. Typical openings range from 0.1 to overstory vegetation. 0.25 hectare. In large part, this method requires Most forest ecologists class oaks as a genus whose adequate advance regeneration to successfully regen- species for the most part become established follow- erate the stand. ing disturbances to the forest overstory. These disturbances may be natural such as fire and wind- Oak (Quercus) storm, extensive or intensive, or may result from harvesting activities. Much of the current oak forest As a genus, oak has a wide ecological amplitude, that in the USA is the result of early forest exploitation is it has a wide range of conditions that and fires used to clear land for agriculture during individual species can tolerate. Therefore making settlement times. Oak opportunistically occupied silvicultural generalizations is difficult at best and an sites in the Appalachian Mountains following the interested reader is best advised to seek regional or destruction of the American chestnut (C. dentata)by local information about the oak species and the the chestnut blight in the 1930s. location in which it is found. Having said that, the potential exists for applying Silviculture both even-aged and uneven-aged silvicultural meth- ods to stands dominated by oak. In order for uneven- Beech (Fagus) aged silvicultural methods to succeed there must be a Beech is classed as very tolerant of shade and hence sustained, periodic recruitment of oak reproduction possesses the ability to regenerate beneath tree into the overstory. This is a necessary prerequiste to canopies. However, on very poor soils or in very create and maintain a negative exponential diameter cold climates, beech may be less tolerant. This distribution, a stand structure characteristic of suggests silvicultural systems that retain an overstory uneven-aged stands. Although it may be possible, component such as individual tree selection or group through thinning, to create the requisite diameter selection methods of harvesting. Beech prune them- distribution without adequate regeneration, it cannot selves in well-stocked stands but open-grown trees be sustained. Any event, natural or otherwise, that tend to have wide crowns and lower limbs close to interrupts this process, will disrupt the recruitment of the ground. Often other species are purposely stems into succeeding size classes. The single-tree introduced into beech stands to increase stand selection method is one way of creating this type of density and act as ‘trainers’ in order to promote stand structure. From outward appearances, the self-pruning. For example, European hornbeam is single-tree selection method may seem to represent used to ‘train’ European beech in order to promote the most ‘natural’ of the silvicultural systems. The straight stems and encourage early self-pruning of naturalness of the method nevertheless may be lower branches. Beech responds readily to thinnings deceptive because there must be silvicultural control even at late ages and rapidly expands its crown of the rate of natural reproduction, stand structure, following thinning. Thus beech is capable of produ- and density. For all but the most shade-tolerant cing high volume increment even to relatively old species, greater silvicultural control is obtained ages (130–150 years). When grown for high-quality through single-tree selection than any other silvicul- wood the silvicultural target is to grow beech to tural method. Applying this method to the relatively 1426 TEMPERATE ECOSYSTEMS / Fagaceae shade-intolerant oaks with their erratic seed pro- density of silkworms that feed on the leaves. In the duction cycles, seedling establishment, and other cork oak forests of Portugal and Spain, silviculural regeneration uncertainties is problematic. However, techniques focus on the timing, method, and despite these problems, there is evidence that the intensity of stripping bark from the trees. method is suited to some oak forests. Stands that are managed using even-aged silvicul- Chinkapin, Chinquapin tural methods are regenerated naturally at the end of Chinquapins are vigorous sprouters and most trees their rotation by one of three techniques: (1) clear- originate as root crown sprouts. Mature trees tend to cutting, (2) shelterwood, or (3) seed tree. Although have straight boles and narrow crowns. They exist all three methods can be used to regenerate the singly or in small groves. Natural regeneration is spectrum of shade tolerant to shade intolerant oaks, usually sparse or lacking. The best evidence suggests they are most suited to the intolerant to mid-tolerant that the greatest success in regenerating chinquapin is species. If clear-cutting is contemplated one should achieved by covering seed in partially shaded, moist consider the suitability of the ecosystem for meeting conditions. oak reproduction requirements, the likelihood of regeneration success, and economic, social, and ecological implications. Clear-cutting is successful if Utilization oak regeneration of sufficient size is present in the A small market exists for chinkapin wood for stand before it is harvested. furniture and cabinet stock and decorative veneer. The shelterwood method is employed principally However, it is difficult to dry without the wood to create conditions suitable for the establishment checking (splits and cracks). Southern beech is noted and development of tree reproduction. Typically, for its high-quality timber that is used for fine there is a preparatory cut to facilitate crown expan- woodwork. The genus is second only to the eucalypts sion and seed production, an establishment cut to in wood production in the southern hemisphere. prepare a seedbed, and a removal cut to release the Beech is excellent for turning and steam bending. It newly established regeneration. There are several wears well, is easily treated with preservatives, and is variants of this system in the way the cuts are carried used for flooring, furniture, veneer, and containers. out and how long trees are retained. The key to using The nut is eaten by people and is an important source shelterwood successfully to establish and maintain of food for wildlife. European beech has many oak stands is in manipulating stand density in order horticultural varieties used in cultivated landscapes. to control light and competition on the forest floor. Similar uses can be described for oak. Other well- This may entail controlling the understory vegetation known uses of oak include staves for barrels used for in addition to manipulating the overstory. whiskey and wine, and cork for wine and other The seed tree method leaves 20 or fewer seed trees stoppers. The wood of tanoak (Lithocarpus) is hard, per hectare. Although applied successfully in certain strong, and fine-grained but is mostly used for pulp locations, the seed tree method generally provides and firewood. is extracted from tanoak bark too little regeneration too late. However, it could be (as well as oak) and used for tanning leather. useful in providing for wildlife and may have a greater visual appeal than a clear-cut. See also: Non-wood Products: Cork Oak. Silviculture: Tree diameter growth is sensitive to stand density. Coppice Silviculture Practiced in Temperate Regions; If the goal of a forest management program is to Natural Stand Regeneration; Silvicultural Systems; Un- produce large diameter trees in the shortest time evenaged Silviculture. Temperate and Mediterranean possible, then stand density needs to be reduced as Forests: Mediterranean Forest Ecosystems; Southern early as 15 years for some species to provide the Coniferous Forests; Temperate Broadleaved Deciduous maximum amount of growing space needed by the Forest. Tree Breeding, Practices: Genetics of Oaks. average tree. However, this approach may not be Tropical Forests: Tropical Montane Forests. economically feasible. Thinning only around a smaller number of ‘crop’ trees ensuring that they Further Reading have sufficient growing space may be a more cost Burns RM and Honkala BH (tech. coords.) (1990) Silvics effective solution. of North America, vol. 2, Hardwoods. Agriculture Special situations require special considerations. Handbook no. 654. Washington, DC: US Department The leaves of Mongolian oak (Q. mongolica) furnish of Agriculture Forest Service. food for the silk worm in northeastern China. The Eyre FH (ed.) (1980) Forest Cover Types of the United silviculture of these stands aims to create large States and Canada. Washington, DC: Society of Amer- crowns with nutritious leaves and to manage the ican Foresters. TEMPERATE ECOSYSTEMS / Juglandaceae 1427

Faculty of Forestry, University of Zagreb (1996) Pedun- moist temperate zone forests were dominated by culate Oak in Croatia. Zagreb, Croatia: Vinkovci. giant redwoods and deciduous trees such as beech, (In Croatian with English summaries and articles.) chestnut, and elm, while cycads, magnolias, and fig Johnson PS, Shifley SR, and Rogers R (2002) The Ecology trees flourished in Alaska. The walnut family reached and Silviculture of Oaks. Wallingford, UK: CAB Inter- its greatest extent in numbers and distribution at that national. time after which it has steadily declined. Royal Botanic Gardens, Kew (2002) Electronic Plant Information Centre. Available online at http://www.ke- w.org/epic/ Taxonomy Spiecker H, Mielikainen K, Kohl M, and Skovsgaard J (eds.) (1996) Growth Trends in European Forests. The most recent taxonomic information indicates European Forest Institute Research Report no. 5. Berlin, that the walnut family (Juglandaceae) comprises eight Germany: Springer-Verlag. genera (Alfaroa, Carya, Cyclocarya, Engelhardtia, van den Berg AKJ, Matos AP, Ferreira A, et al. (1979– Juglans, Oreomunnea, Platycarya, and Pterocarya) 2001) Investigacao em Sobreiro e Cortica. Lisbon, with about 50 species (Table 1). However, some Portugal: Centro de Estudos Florestais, Instituto Superior taxonomists report as few as seven genera (Cyclo- de Agronomia, Tapada da Ajuda. (CD Rom.) Available online at http://www.isa.utl.pt/def/cef/ carya omitted) and as many as nine genera (Anna- Watson L and Dallwitz MJ (1992) The Families of mocarya added) that include 60 species. Flowering Plants: Descriptions, Illustrations, Identifica- Members of the walnut family are mostly trees tion, and Information Retrieval. Available online at (often resinous), but a few are shrubs. All family http://biodiversity.uno.edu/delta/ members have more or less aromatic leaves which are mostly deciduous and consist of individual leaflets arranged like a feather with a central axis and lateral branches (pinnate) or arranged similar to pinnately Juglandaceae compound leaves but leaflets are arranged groups of three (ternate). The leaves of the majority of the R Rogers, University of Wisconsin–Stevens Point, species are spirally arranged on twigs but they are Stevens Point, WI, USA oppositely arranged in two genera, Alfaroa and & 2004, Elsevier Ltd. All Rights Reserved. Oreomunnea. Superposed buds are common (bud found above lateral bud). Male and female flowers are usually found on the Introduction same tree although occasionally sexes are found on separate trees. Flowers are wind pollinated and are The following sections characterize members of the mostly in the form of . walnut family (Juglandaceae) in relation to their Fruit is a nut encased within a husk (drupe-like) or taxonomy, distribution, ecology, and silviculture. a disk-winged nutlet. A drupe is usually a one-seeded Also included is information about their botanical fleshy fruit with the outer layer (husk) fleshy and importance as well as their significance in meeting the inner layer bony. Husks may split to release human needs. The walnut family contains tree species that Table 1 Distribution of the genera of the walnut family produce some of the world’s finest high-quality (Juglandaceae) hardwood that is used to manufacture cabinets and Genus Number of Range fine furniture (walnut). Moreover, there are species in species this family that are important sources of edible nuts (walnut and pecan). Members of the family are Juglans 20 North, Central, South America; Europe, and Asia found in the north temperate and subtropical regions Carya 16 North America (13) and Asia of the world, extending to India, Indochina, Malay- (3) sia, and Andean South America. The family is not Platycarya 1 China, , Korea, and present in Africa and Australia. Vietnam The walnut family originated during the Englehardia 7 Southern and southeastern Asia, and northern India epoch of the Tertiary period of geologic time about Cyclocarya 1 China 65 to 55 million years ago. The climate of Eocene Pterocarya 6 Eastern and southwestern times was subtropical and moist throughout North Asia America and Europe. Palm trees and alligators were Alfaroa 5 Central and South America found as far north as the Dakotas in the USA, while Oreomunnea 3 Mexico, Central and South America at high northern latitudes in Greenland and Siberia,