Art03 Journal of Applied Botany and Food Quality 80, 19 - 24 (2006) 1Department of Wood Science, Hamburg University, Germany 2Centro Agronômico Tropical de Investigaciôn y Enseñanza, Turrialba, Costa Rica 3Museum of Natural Science, Karlsruhe, Germany Study on the wood anatomy, annual wood increment and intra-annual growth dynamics of Podocarpus oleifolius var. macrostachyus from Costa Rica Josef Bauch 1, Ligia Quiros ², Guna Noldt 1, Petra Schmidt ³ (Received October 10, 2005) Summary Tropical countries in the future will have an increasing demand for softwoods which favours mixed plantations possibly with minor portions of native conifer species. In this context numerous tropical species of the Podocarpaceae can be of ecological and economical interest. In Costa Rica the native species Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz & Gray could be attractive for the establishment of manmade forests. However, profound knowledge on growth characteristics and wood properties is missing. In particular, information on the annual wood increment and intra-annual growth dynamics under natural site conditions at higher altitudes where P. oleifolius var. macrostachyus competes with hardwood species is not available and therefore the objective of this study. At the Cordillera de Talamanca (approx. 2,700 m a.s.l.), Costa Rica, an old-growth stand was chosen from which in total 5 trees (40 to 80 cm diameter at DBH) were sampled by taking stem sections and discs (2 trees)or increment cores (3 trees). During the period from October 1998 to December 2000, two trees of the site were pinned monthly for exact determination of the annual wood increment and the intra-annual growth dynamics in relationship to climate. The results of one of these pinned trees are demonstrated. It turned out that at high altitude the annual wood increment of old growth trees amounts to 1-2 mm (diameter) only. The tracheids show a rather constant cell wall thickness (2.5-4.5 µm) throughout the year, but a very variable radial cell diameter from 29 to 61 µm. The exact age of the tree cannot be determined anatomically, as there are no distinct tree-ring boundaries, but only very moderately developed terminal bands of flattened tracheids which do not circle the entire circum- ference of the stem. The monthly pin-labelling documents that during the dry season from about January until March in 1999 and 2000, virtually no cells were formed. However, with the beginning of the rainy season, about 59 % of the wood increment resulted from the months April to June. This increment rate already decreased from July to September to 32 %. Due to a distinct decrease in precipitation towards the end of the year, only 9 % of the wood increment were formed in the last quarter of the year, mainly consisting of the hardly visible terminal and flattened tracheids. The wood of this species is of very homogeneous structure and certainly attractive for high- quality wood production. Introduction In the tropical country Costa Rica the demand for commercially important softwoods will increase in the future, whereas in former decades the limited portion of native conifer species was considerably exploited already (ARIAS and DOHRENBUSCH, 2001). In particular, species of the Podocarpaceae family would be of interest for their cultivation, for which they are also estimated in other tropical countries (e.g. GÜNTER et al., 2004). However, preliminary results indicate that natural regeneration does not guarantee fertilized female cones due to increased distance between the individual trees. The establishment of mixed plantations enables the cultivation of minor portions of the native species Podocarpus oleifolius var. macro- stachyus (Parl.) Buchholz & Gray, which reaches a height of up to 30 m and a diameter of more than 1 m in old-growth sites (BUCHHOLZ and GRAY, 1948; LAUBENFELS, 1990) and with good wood properties (MALAVASSI, 1995; BAUCH et al., 2006). Unfortunately, there is hardly any documentation (BLASER and CAMACHO, 1991; OROZCO, 1991) on the annual wood increment for this native species in Costa Rica and in particular no data exist on the intra-annual growth dynamics in relation to exogenous influences such as precipitation and day/ night temperature gradients at high altitudes. In the subsequent study an old-growth site of Podocarpus oleifolius var. macrostachyus of the Cordillera de Talamanca was chosen for a preliminary investigation on wood characteristics, annual wood increment and intra-annual growth dynamics. This qualitative and quantitative wood characterization will further allow us to evaluate the potential of this species for mixed plantations at high altitudes. Material and methods Site and tree selection of a natural forest In order to obtain information on wood structure and growth cha- racteristics of the native species Podocarpus oleifolius var. macro- stachyus (Parl.) Buchholz & Gray in a natural forest (Fig. 1a) at high altitude stem sections, discs and increment cores of in total 5 old growth trees were selected at the Cordillera de Talamanca, approx. 2,700 m a.s.l. (9°33´ north, 83°40´ west), Costa Rica. In former years, this species was studied taxonomically (e.g. LAUBENFELS, 1990; HAMMEL et al., 2003) and finally determined as a var. of Podocarpus oleifolius and thus no longer as a separate species (Fig. 1b). Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz & Gray only contributes a few per cent portion (~7%, QUIROS unpubl.) to the mixed hardwood species (e.g. predominantly Quercus costaricencis, Quercus copeyensis, Drimys winteri, Weinmannia pinnata), attainable heights of about 30 m and a diameter of more than 1 m. In October 1997 discs of one tree (DBH approx. 60 cm) were collected for wood structural studies. At October 16, 1998 we started with the cambial analysis by 26 monthly executed pin-markers (December 1999 left out) ending in December 2000 on two trees of the same site (DBH approx. 40 cm). Due to a complete prohibition for tree felling at that site only one tree of both could be felled on April 26, 2001 and the pinned stem sections collected (1m - 4m tree height). For additional microscopic observations and confirmations of the anatomical results, six increment cores from three other trees at the same site were collected in July 2003. The annual precipitation at that site amounts to about 2,500 mm, exhibiting high variation during the rainy season from April to about November/December and the dry months from January to March (BLASER, 1987; ANONYMUS, 2001, Fig. 2, Tab. 1). These intra-annual dynamics of the water supply with distinct dry months leads to a drastical water deficit in the soil (comp. BLASER, 1987). The average monthly temperatures are fairly constant ranging between 10.0 and 11.8° C (Fig. 2), however, the day/night temperature gradient is Fig. 1: Experimental site. a. Old growth trees of Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz & Gray. b. Leaves and female cones of an investigated tree. Fig. 3: Wood structure of Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz & Gray. a. Segment of a disc with very weak growth increment zones. S sapwood, H heartwood. b. Cross section containing a moderately developed band of radially flattened tracheids formed in November/December (→→→→→ border of an increment zone). All tracheids exhibit more or less constant wall thickness. Diffuse distributed axial parenchyma (Pa). 20 Josef Bauch, Ligia Quiros, Guna Noldt, Petra Schmidt considerable and moreover, also varies significantly from day to day with measured minima of almost 0°C during the night (BLASER, 1987). The duration of daily sunshine differs remarkably from 7.5 hours (monthly average) in February to 3.0 hours in September (SEGURA and VENEGAS, 1999). The soil consists of a moderately fertile humus layer with a deficit in nitrogen and phosphorus (GRUBB, 1976). According to NUHN (1978) this soil type is classified as Litosole. gitudinal and ray parenchyma. The individual tracheid characteristics were determined histometrically such as radial tracheid diameter, cell wall thickness and tracheid length on sections and on macerated tissue by a digitized image analysis system (analySIS®, Olympus Hamburg), adjusted on a AX 70 microscope. Determination of annual growth increment and intra-annual growth dynamics Referring to former pinning experiences (KURODA and KIYONO, 1997; BAUCH and DÜNISCH, 2000) small pieces of razor blades were put into the cambial tissue of the selected trees monthly to verify the start of the wound response exactly to the date of treatment even after more than two years. The consistent monthly treatment allowed to determine the intra-annual growth dynamics triggered at the cambial zone. Despite of the low annual increment, the wound response caused by the pin-marks immediately led to an abrupt and drastical reduction of tracheid length and tracheid cross area as well as to an accumulation of longitudinal parenchyma at the wound spot. The structurally recognizable increment zones, the intra-annual growth dynamics and the variation of the radial cell diameter of the tracheids were also recorded with the digitized image analysis system. Results Anatomical structure of the woody tissue The structure of wood with special reference to growth increment zones (Fig. 3a) was studied on cross, radial and tangential wood sections from sapwood and heartwood from discs and cores of the five selected trees. In dry condition the brownish wood colour does not remarkably differ between sapwood and heartwood. It is striking that only weakly formed bands of radially flattened tracheids indicate wood increment zones (Fig. 3b). However, they are not continuously formed circularly within the stem which means that they do not automatically indicate the exact age of the tree. Due to relatively equal cell wall thickness (2.5-4.5 µm) of the tracheids (Fig. 3b) across the woody tissue including thin walled longitudinal and ray paren- chyma, the wood reveals a homogeneous appearance (comp. Tab. 2). The tracheid length ranges from 3.1 to 4.9 mm. However, the radial diameters of the tracheids vary considerably from cell to cell with a maximum of 61 µm and a minimum of 29 µm (unpinned sapwood), measured on macerated tracheids and confirmed by means of cross sections. But the flattened tracheids, which occur at the border of an annual increment show radial cell diameters of less than 20 µm (comp. Fig. 3b). The anatomical and histometrical results do not allow any precise conclusion with reference to annual wood increment and intra- annual growth dynamics. Consequently, pinning studies were chosen for a profound determination of wood formation. Annual wood increment By means of 26 monthly executed pins from October 16, 1998 to December 18, 2000, it could be proven that radially flattened tracheids – often only a few tangentially oriented series – are formed during Tab. 1: Mean of precipitation [mm] per month available from the neigh- bourhood of the selected forest site at the Cordillera de Talamanca for the years 1999 and 2000 (ANONYMUS, 2001). Month 1999 2000 January 9.4 26.7 February 129.8 25.6 March 25.0 14.7 April 175.8 50.6 May 450.2 368.1 June 437.4 395.4 July 94.8 186.3 August 448.8 110.8 September 377.7 572.6 October 529.5 423.8 November 264.9 162.4 December 207.1 46.0 0 100 200 300 400 500 600 J F M A M J J A S O N D Months M e a n o f p re c ip it a ti o n p e r m o n th (m m ) 0 2 4 6 8 10 12 M e a n o f te m p e ra tu re p e r m o n th ( ° C ) Fig. 2: Mean of precipitation and air temperature per month for the neighbourhood of the selected forest site at the Cordillera de Tala- manca for the years 1942-1985 (BLASER, 1987). Microscopical observations of the structural characteristics of the wood Cross-sectioned slides from the sapwood and heartwood of the discs and cores of the five selected trees, treated with safranin-astrablue, were used to determine variation in percentage of tracheids and lon- Tab. 2: Histometrical results for the adult wood of Podocarpus oleifolius var. macrostachyus Tracheids proportion [%] Axial parenchyma proportion [%] Rays proportion [%] Tracheid length [mm] wall thickness tang [µm] 91.8 - 92.9 - 94.2 1.7 - 2.2 - 2.8 4.1 - 4.9 - 5.5 3.1 - 4.0 - 4.9 2.5 - 4.5 (→6.5) Wood structure of Podocarpus oleifolius var. macrostachyus 21 November and December (Figs. 3b, 4). This is the period when the monthly amount of precipitation usually decreases. Fig. 4 illu- strates that the cells 6 and 7 were formed in November - December 2000, and the cells 28 and 29 were identified as being formed in November - December 1999. For the years 1999 and 2000 from January to March no cells were formed. The annual growth rate can be determined as 0.86 mm for both years. This means an average of only about 1.7 mm increase in wood diameter (DBH) per year based on nine months cambial cell formation. not differ in cell wall thickness from others, but some show reduced radial cell diameters (comp. Fig. 3b). Under temperate climate this special „latewood“-phenomenon is visible in species of Juniperus and Pinus strobus which obviously is strongly genetically controlled (LARSON, 1995). 50 49 Pa 1 3 2 4 Pa 5 6 7 8 9 10 11 12 13 14 16 17 15 Pa 18 19 20 21 22 Pa 23 24 25 26 27 28 29 31 30 32 33 Pa 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 0 10 20 30 40 50 60 70 0 10 20 30 40 50 Cell number R a d ia l c e ll d ia m e te r [µ m ] 1999 2000 2001 Fig. 4: Variation of radial cell diameter of an individual continuous series of radially oriented cells from April 26, 2001 (felling date) to April 1999 (Pa axial parenchyma cell). Intra-annual growth dynamics In addition to the determination of the annual wood increment, the study of the intra-annual growth dynamics might indicate to which extent environmental parameters such as monthly amount of pre- cipitation, average temperature, sharp gradients of day and night temperature and hours of sunshine will influence the quality and quantity of wood formation. The cross sections with the 26 pin-marks in total give precise information on the number and radial diameter of the monthly formed tracheids and longitudinal parenchyma cells as shown in the selected example (Fig. 4). The measurements for the years 1999 and 2000 were averaged and the data grouped in 3 months (Fig. 5). It could be demonstrated that during January to March the cambium apparently does not produce any cells. This is in accordance with the dry months with 4.2 % mm precipitation refered to the amount of the whole year (Fig. 5). The cambial activity begins at the period with a high amount of precipitation starting in April (April - June 33.9 % mm). The corresponding increment from April to June shows the highest values with 58.4 % of the radial increment of the entire year. In July and August, the amount of precipitation (Tab. 1) is retrogressive (in several years even significantly lower, comp. Fig. 2), but increases again in September and October (Tab. 1). The individual meteorological measurements for these months in 1999 and 2000 (ANONYMUS, 2001) were in accordance with the average values of 1942-1985 (BLASER, 1987). The wood increment from July to September equals 32.4 % of the entire year. Apparently from July onwards also other parameters such as limited duration of sunshine (SEGURA and VENEGAS, 1999) may contribute to a retardant cambial cell division. From October to December, the amount of precipitation (29.5 %) significantly decreases (Tab. 1). The few cell series formed from October to December correspond to an increment rate of only 9.2 % of the entire annual increment (Fig. 5), which is ecophysiologically an interesting fact. Moreover, these tracheids do Discussion This preliminary study of the wood anatomical characteristics, the annual wood increment and the intra-annual growth dynamics of Podocarpus oleifolius var. macrostachyus offers hints on wood characteristics and growth potential at high altitude conditions. The investigated trees show only faint growth ring boundaries with mostly incomplete series of radially flattened tracheids, which do not allow to determine the exact age of the tree. This finding corres- ponds to the growth characteristics of the long-lived Podocarpus neriifolius and other tropical Asian species of this genus (BUCKLEY et al., 1995) which also do not permit a dendrochronological dating. However, other species of the genus Podocarpus from outside of the tropics develop distinct annual growth boundaries, such as Podo- carpus nubigens in Chilean Patagonia (SWED and INOUE, 1987). The histometrical data reveal that Podocarpus oleifolius var. macro- stachyus is superior in qualitative aspects (such as fiber characteris- tics)to the wood of the commercially important species Podocarpus salignus from Chile and Argentina (BAUCH et al., 2006). The pinning experiments allowed investigations of the annual growth increment and the intra-annual growth dynamics triggered in the cambium as documented in detail by FRITTS (1976) and LARSON (1995) for trees grown under temperate climate. For tropical softwood species, hardly any data for annual wood increment and intra-annual growth dynamics are available (JACOBY, 1989), whereas for tropical hardwoods numerous case studies were published in recent years (e.g. BREITSPRECHER and BETHEL, 1990; WORBES, 1999; WORBES and JUNK, 1999; DÜNISCH et al., 2003). The monthly and annually determined growth rates of a dominant tree of Podocarpus oleifolius var. macrostachyus exhibit full accor- dance throughout the years 1999 and 2000. The total annual increase Fig. 5: Intra-annual growth dynamics, monthly determined by pinning examplified for one tree. Wood increment (I) illustrated as relative average values every three months for the years 1999 and 2000 in comparison to the distribution of precipation (P). 0 58.4 9.2 4.2 32.4 29.5 32.4 33.9 0 10 20 30 40 50 60 70 Jan.-March April-June July-Sept. Oct.-Dec. R e la ti v e w o o d i n c re m e n t I [% ] 0 10 20 30 40 50 60 70 R e la ti v e a m o u n t o f p re c ip it a ti o n P [ % ] I P 22 Josef Bauch, Ligia Quiros, Guna Noldt, Petra Schmidt in wood diameter is about 1.7 mm, which corresponds to some individual dendrometer measurements of the same site with about 1.9 mm total increase in diameter (DBH) per year (QUIROS, unpubl.). Comparative studies on P. oleifolius in montane forests (2,000 m a.s.l.) in Ecuador reveal an even lower annual increment (HO- MEIER, 2004). Individual dendrometer measurements in a secon- dary managed forest of Costa Rica show that under climatically more moderate conditions this softwood species can compete with commercially important native hardwoods reaching an increase of up to about 4-5 mm diameter increase per year (QUIROS, unpubl.). Nevertheless, it should be also evaluated in how far this conifer species can cope sociologically with hardwoods under mixed plantation condition. There are studies for the species Podocarpus nubigena as a shade-tolerant species (LUSK, 1996; GUTIERREZ et al., 2004). For Podocarpus oleifolius var. macrostachyus corresponding experiences do not exist. The monthly determined growth rates reveal some relationship to exogenous influences at the experimental site. The wood formation is triggered by the begin of the rainy season in April and it ends in December with the onset of dry season. In contrast to the genetically controlled relatively uniform cell wall thickness of the tracheids (comp. LARSON, 1995) throughout the entire year, the considerable variability of the lumen area from tracheid to tracheid depends obviously on short term influences, which have an direct impact on the primary cell wall phase. With adequate water supply this period of primary cell wall formation with radial tracheid enlargement lasts for Picea abies only 7-14 hours and is mainly induced during night time (DÜNISCH and BAUCH, 1994). During the night the water content in the sapwood tracheids can be increased via the fine roots and supply subsequently the cambium. Ongoing experiments under controlled conditions with temperature variation also indicate an influence of the existing air temperature during night time (DÜNISCH unpubl.). At the Cordillera de Talamanca at about 2,700 m a.s.l., the annual growth increment and the intra-annual growth dynamics will primarily depend on the distribution of the annual precipitation, but also the variation of day/night temperature has to be considered. Conclusion The preliminary investigation on wood anatomical characteristics of Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz & Gray demonstrates a tropical conifer with considerable intra-annual dy- namics in wood production, obviously controlled mainly by climatic conditions. The data of our study suggest that high altitudes are most likely not suitable for plantations due to the limited annual wood increment of the trees. However, with regard to the ecological amplitude and the potential for sociological competition this species can be recom- mended for regeneration concepts in mountainous humid regions of more moderate altitude levels (e.g. RÄBER, 1991; QUIROS unpubl.). This conclusion is underlined by some investigations of the wood properties (comp. MALAVASSI, 1995; BAUCH et al., 2006). Without doubt, this wood species can be recommended for its high-quality homogeneous raw material with reference to lumber with decorative value for furniture. Acknowledgements We are indebted to the Institute Costarricense de Electricidad, San José, Costa Rica supplying us with the meteorological data of the selected experimental site. Thanks are also directed to Dr. H. J. Saa, Costa Rica and to Dr. D. Kelch, California for taxonomic information. Dr. J. Homeier and Dr. S. Günter deserve our gratitude for supplying us with comparative samples of P. oleifolius D. Don ex Lamb, from Ecuador. For cooperation in the experimental work, we thank PD Dr. G. Koch, C. Lehringer, T. Schwarz, S. Voiß, and C. Waitkus. References ANONYMUS, 2001: Meteorological data of the site VILLA MILLS (3000 m a.s.l.). Instituto Costarricense de Electricidad, Costa Rica. ARIAS, D., DOHRENBUSCH, A., 2001: Die forstlichen Verhältnisse in Mittel- amerika – dargestellt am Beispiel Costa Rica. Forstarchiv 72, 262-266. BAUCH, J., DÜNISCH, O., 2000: Comparison of growth dynamics and wood characteristics of plantation-grown and primary forest Carapa guianensis in Central Amazonia. IAWA Journal 21, 321-333. BAUCH, J., KOCH, G., PULS, J., SCHWARZ, T., VOISS, S., 2006: Wood cha- racteristics of the tropical conifer Podocarpus oleifolius var. machro- stachyus (Parl.) Buchholz and Gray and their significance for wood utilization. Wood Sci. Technology 40, 26-38. BLASER, J., 1987: Standörtliche and waldkundliche Analyse eines Eichen- Wolkenwaldes (Quercus spp.) der Montanstufe in Costa Rica. Göttinger Beiträge zur Land- und Forstwirtschaft in den Tropen und Subtropen. Heft 26, Universität Göttingen. BLASER, J., CAMACHO, M., 1991: Estructura, composición y aspectos silvi- culturales de un bosque de robles (Quercus spp.) del piso montano en Costa Rica. Coleccion silvicultura y manejo de bosques naturales No. 1, CATIE, Turrialba Costa Rica. BREITSPRECHER, A., BETHEL, J.S., 1990: Stem-growth periodicity of trees in a tropical wet forest of Costa Rica. Ecology 71, 1156-1164. BUCHHOLZ, J.T., GRAY, N.E., 1948: A taxanomic revision of Podocarpaceae. IV. J. Arnold Arbor. 29,123-151. BUCKLEY, B.M., BARBETTI, M., WATANASA, K.M., D’ARRIGO, R., BOONCHIRD- CHOO, S., SARUTANON, S., 1995: Dendrochronological investigations in Thailand. IAWA Journal 16, 393-409. DÜNISCH, O., BAUCH J., 1994: Influence of soil substrate and drought on wood formation of spruce (Picea abies [L.] Karst.) under controlled conditions. Holzforschung 48, 447-457. DÜNISCH, O., MONTÓIA, V.R., BAUCH J., 2003: Dendroecological in- vestigations on Swietenia macrophylla King and Cedrela odorata L. (Meliaceae) in the Central Amazon. Trees 17, 244-250. FRITTS, H.C., 1976:Tree rings and climate. Academic Press London, New York, San Francisco. GRUBB, P.J., 1976: Control of forest growth and distribution on wet mountains with special references to mineral nutrition. Ann. Rev. Ecol. Syst. 8, 83- 107. GÜNTER, S., STIMM, B., WEBER, M., 2004: Silvicultural contributions towards sustainable management and conservation of forest genetic resources in Southern Ecuador. Iyonia 6, 75-91. GUTIÉRREZ, A.G., ARMESTO, J.J., ARAVENA, J.C., 2004: Disturbance and regeneration dynamics of an old-growth North Patagonian rain forest in Chiloé Island, Chile. J. Ecology 92, 598-608. HAMMEL, B.E., GRAYUM, M.H., HERRERA C., ZAMORA, N. (eds.), 2003: Manual de plantas de Costa Rica, Vol. 2: Gimnospermas y dicotyledoneas (Agavaceae – Musaceae). Monographs in systematic botany from the Missouri Botanical Garden Vol. 92. St. Louis USA. HOMEIER, J., 2004 : Baumdiversität, Waldstruktur und Wachstumsdynamik zweier tropischer Bergregenwälder in Ecuador und Costa Rica. Disser- tationes Botanicae Bd. 391. J. Cramer Berlin, Stuttgart. JACOBY, G.C., 1989: Overview of tree-ring analysis in tropical regions. IAWA Bulletin 10, 99-108. KURODA, K., KIYONO, Y., 1997: Seasonal rhythms of xylem growth measured by the wounding method and with a band-dendrometer: An instance of Chamaecyparis obtusa. IAWA Journal 18, 291-299. LARSON, P.R., 1995: The vascular cambium. Springer-Verlag, Berlin. LAUBENFELS, D.J., 1990: The Podocarpaceae of Costa Rica. Brenesia 33, Wood structure of Podocarpus oleifolius var. macrostachyus 23 119-121. LUSK, C.H., 1996: Stand dynamics of the shade-tolerant conifers Podocarpus nubigena and Saxegothaea conspicua in Chilean temperate rain forest. J. Vegetation Sci. 7, 549-558. MALAVASSI, I.M.C., 1995: Maderas de Costa Rica – 130 especies forestales. Editorial de la Universidad de Costa Rica. NUHN, H., 1978: Atlas preliminar de Costa Rica. San José, C.R., Istituto Geográfico Nacional. OROZCO, L., 1991: Estudio ecológico y de estructura horizontal de seis comunidades boscosas de la Cordillera de Talamanca, Costa Rica. Coleccion silvicultura y manejo de bosques naturales No. 2, CATIE, Turrialba Costa Rica. RÄBER, C., 1991: Regeneración natural sobre árboles muertos en un bosque nublado de Costa Rica. Coleccion silvicultura y manejo de bosques naturales No. 4, CATIE, Turrialba Costa Rica. SEGURA, M., VENEGAS, G., 1999: Tablas de volumen comercial con corteza para encino, roble y otras especies del bosque pluvial montano de la cordillera de Talamanca, Costa Rica. Colección manejo diversicado de bosques naturales No. 15, CATIE, Turrialba Costa Rica. SWEDA, T., INOUE, J., 1987: Dendrochronologies of San Rafael and Soler areas, Patagonia. Bulletin Glacier Res. 4, 125-132. WORBES, M., 1999: Annual growth rings, rainfall-dependent growth and long- term growth patterns of tropical trees from the Caparo Forest Reserve in Venezuela. J. Ecology 87, 391-403. WORBES, M., JUNK, W.J., 1999: How old are tropical trees? The persistence of a myth. IAWA Journal 20, 255-260. Address of the authors: Prof. Dr. Josef Bauch, Dr. Guna Noldt, Department of Wood Science, Hamburg University, Leuschnerstr. 91, D-21031 Hamburg. Ligia Quiros, Centro Agronômico Tropical de Investigación y Enseñanza, 7170 Turrialba, Costa Rica. Dr. Petra Schmidt, Museum of Natural Science, Erbprinzenstr. 13, D-76133 Karlsruhe. e-mail: jbauch@holz.uni-hamburg.de (corresponding author). 24 Josef Bauch, Ligia Quiros, Guna Noldt, Petra Schmidt << /ASCII85EncodePages false /AllowTransparency false /AutoPositionEPSFiles true /AutoRotatePages /All /Binding /Left /CalGrayProfile (Dot Gain 20%) /CalRGBProfile (sRGB IEC61966-2.1) /CalCMYKProfile (U.S. Web Coated \050SWOP\051 v2) /sRGBProfile (sRGB IEC61966-2.1) /CannotEmbedFontPolicy /Warning /CompatibilityLevel 1.4 /CompressObjects /Tags /CompressPages true /ConvertImagesToIndexed true /PassThroughJPEGImages true /CreateJDFFile false /CreateJobTicket false /DefaultRenderingIntent /Default /DetectBlends true /ColorConversionStrategy /LeaveColorUnchanged /DoThumbnails false /EmbedAllFonts true /EmbedJobOptions true /DSCReportingLevel 0 /EmitDSCWarnings false /EndPage -1 /ImageMemory 1048576 /LockDistillerParams false /MaxSubsetPct 100 /Optimize true /OPM 1 /ParseDSCComments true /ParseDSCCommentsForDocInfo true /PreserveCopyPage true /PreserveEPSInfo true /PreserveHalftoneInfo false /PreserveOPIComments false /PreserveOverprintSettings true /StartPage 1 /SubsetFonts true /TransferFunctionInfo /Apply /UCRandBGInfo /Preserve /UsePrologue false /ColorSettingsFile () /AlwaysEmbed [ true ] /NeverEmbed [ true ] /AntiAliasColorImages false /DownsampleColorImages true /ColorImageDownsampleType /Bicubic /ColorImageResolution 300 /ColorImageDepth -1 /ColorImageDownsampleThreshold 1.50000 /EncodeColorImages true /ColorImageFilter /DCTEncode /AutoFilterColorImages true /ColorImageAutoFilterStrategy /JPEG /ColorACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /ColorImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000ColorACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000ColorImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasGrayImages false /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /GrayImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000GrayACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000GrayImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasMonoImages false /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict << /K -1 >> /AllowPSXObjects false /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputCondition () /PDFXRegistryName (http://www.color.org) /PDFXTrapped /Unknown /Description << /FRA /ENU (Use these settings to create PDF documents with higher image resolution for improved printing quality. The PDF documents can be opened with Acrobat and Reader 5.0 and later.) /JPN /DEU /PTB /DAN /NLD /ESP /SUO /ITA /NOR /SVE >> >> setdistillerparams << /HWResolution [2400 2400] /PageSize [612.000 792.000] >> setpagedevice