ISSOURI it* BOTANICAL' SEP 1 2 1995 American Fern Journal 85(2}:37-42 (1995) MRDEN LIBRARY The Growth and Age Rate Fern Trunks of Tree in Relation Habitats to AND BiTTNER* BRECKLE S.-W. J. Germany University of Bielefeld. much known Not growth and phenology about the rates of trunks the of is some leaves in tree ferns. Conant's (1976) ecogeographical studies of Cyathea- who were by and Tanner ceae followed those of Seller (1981) (1983), investi- gated leaf turn-over rates and trunk growth in Alsophila salvlnii and Cyalhea pubescens Tryon and Tryon reported respectively. Also, (1982) different growth and some None however, rates age of tree fern species. of the studies, The growth and phenology with purpose of the correlated rates leaf habitats. was any between growth present study to see relationship existed these if and parameters habitat. Study Area known The study the Reserva Biologica Alberto Brenes, located area, as is The on the Atlantic slope of the Cordillera de Tilaran in Costa Rica. geograph- ical coordinates are 10''12' N, 84''36' W. The reserve has an elevation of 850- 1150 m. The markedly seasonal, with a dry season from the end of rainfall is mm mean December middle The annual 3300 (Spren- the of April. rainfall to is ger 1992). In the life-zone system of Holdrige (1971), this area is classified as premontane wet forest. Methods In March 1991, 233 tree ferns were marked and their height was measured. The Conant Alsophila species Alsophila erinacea (H. Karst.) D.S. (33 plants), Domin Domin (30 plants) Domin Domin and Cyatheo (Maxon) pi Christ) (13 plants), trichiata (22 were The trunks had between 20 and 490 cm. Voucher investigated. sizes ; imens of species are deposited in the National Herbarium of Costa all Museum, und (CR) and in the Botanischer Garten Botanisches in Berlin, many (B). Marked plants were located along a primitive trail system in primary 1 w and secondary open Between March 1991 and September 1993, forest. We served the plants and measured their height every 3 to 4 months. monitored the number of leaves and the production of sori. Unfortunate Hochschule, Biinteweg 17d. * Address correspondence: Botanisches Institut, Tierarztliche for 30559 Hannover, Germany. VOLUME NUMBER AMERICAN FERN JOURNAL: 85 38 2 (1995] Table Trunk growth of tree ferns in different habitats in the Reserva Biologica Alberto Brenes, Costa I. Rica. Growth Forest type (cm/year) primary 13.6 Alsophila erinacea primary 18.8 Alsopbila polystichoides primary 21.3 Cyathea delgadii primary 10.4 Cyathea pinnida Cyathea nigripes primary 17.1 Cyathea delgadii secondary 81.9 Cyathea secondary 89.7 trichiata some d months monitor growth only 23 for m monitored the 30 full com on growth and was analysis of the data plant size Statistical Wilcoxon naired-sam confidence level shown]. (analyses not Results exam C and pinnula found only in the erinacea, A. polystichoides, nigripes C. are primary Cyathea grows trichiata forest. primary and secondary in the m Although pinnula grows primary mostly occurs gaps or old C. in forest, it m We open did not any individuals of pinnula more than 2.2 find C. parts. we Within the narrow elevational range (300 m) of the study area, ob- tall. and served no correlation between elevation distribution of the species. — Table 2. Summary of trunk growth rates and estimated ages of tree fern species. Growth Estimated rate m (cm/ age of a 5 Habitat Source year) trunk (forest type) Cyathea pubescens 6.6 75 years 7 Tanner (1983) Alsophila bryophila 5.0 100 years primary Tryon and Tryon (1982) 7 Alsophila salvinii 8.3 60 years Seller (1981) Cyathea arhorea 28.6 18 years secondary Conant (1976) Alsophila erinacea 13.6 37 years primary this study 27 years primary study Alsophila polystichoides 18.8 this Cyathea delgadii 21.3 23 years primary this study Cyathea delgadii 81.9 6 years secondary this study Cyathea nigripes 17.1 29 years primary this study Cyathea pinnula 10.4 48 years primary this study secondary study Cyathea 89.7 6 years this trichata GROWTH BITTNER & BRECKLE: TREE FERN RATES 39 14 12- 10- CO 8- o 6- tic a) 4- 2- T T T T T T T T T T 9 Jun/93 Sep/93 Oct/92 Feb/9 3 Feb/9 2 Juii/9 month +— Cdelgadii C.trichiata = Average number of leaves from the secondary tree fern species Cyathea delgadii (n 37) Fig. 1. = = number and Cyathea from February 1992 to September 1993 (n of plants trichiata (n 22] sampled). month The growth of the species are various. Over the 23 or 30 period, rates cm secoundary grew three times faster than the species that occurred in forest among growth the rates primary occurred Statistical tests species that in forest. from and 490 cm. This resuU confirms simi information summarize and secoundary primary The number of leaves per plant different in the is and The secondary forest species C. delgadii C. tri- species 1-3). forest (Figs. number whole year Data showed over the (Fig. chiata a high average leaf 1). and nigripes are contrary to for the primary forest species A. polystichoides C. and May showed and erinacea a stable pinnula, A. Cyathea delgadii (primary), C. secondary than the number whole but fewer leaves in of leaves over the year, showed correlation be- The production of also a sori species forest (Fig. 3). The secondary forest tween and trunk height (aee) (Table fineries, habitat, 3). AMERICAN FERN JOURNAL: VOLUME NUMBER 40 85 2 (1995) 14 12- 10 cd 8 0) Cm O 0) 6- cd 4- 2 Feb/92 Jiiii/92 Oct/9 2 Feb/9 3 Jun/93 Sep/93 month A.polystichoides nigripes C. number Fig. 2. Average of leaves from the primary forest tree fern species Alsophila polysti- = ^ choides (n 98) and Cyathea nigripes [n -= 30) from February 1992 to September 1993 (n number of plants sampled). showed ipecies a very development of the sporophyte and fast mostly during the second year). Sori are observed in the primary about four to six years. ifter Discussion The show growth by results that the rate of tree fern trunks influenced is Those habitat. individuals that occur in secondary grow three times as forest may fast as in primary forest. This be true even individuals of the same for C shown by which species, as delgadii, occurs in both primary and secondary These forests. data support similar results found by Conant (1976) concerning the development of the habitat and the forest community. Also, the data of Tryon and Tryon (1982) support the varying growth rates that we detected for cm Important growth different habitats. is the rapid rate of nearly 90 per year by secondary forest species. This very in comparison with other species is fast, (Table 2). For problem by all calculations of age, a critical that the time required is young sporophytes to develop an erect trunk not known. After building a is GROWTH BITTNER BRECKLE: TREE FERN RATES 41 Sc 09 cd 0) o tlf) ed Sep/93 Feb/9 2 Jun/92 Oct/92 Feb/9 3 Juii/93 month erinacea Cdelgadii i C.piiinula A. Fig. Average number of leaves from the primary forest tree fern species Alsophila erinacea (n 3. = = = Cyathea and Cyathea pinnula from February 1992 September 33), delgadii (n 37] (n 13j to = 1993 number (n of plants sampled). trunk, the growth rate constant. This allows investigators to estimate the age is of individual plants. The growth secondary and primary habitat species are a differing rates of and produc- Leaf turn-over rapid sign of different life-history strategies. rates arguments concept tion of sori in the secondary forest species are for the that secondary Conant suggested these are pioneer species. (1976) also this for for- est species. Our habi- data also indicate that different tree fern species live in different primary le ic may documented be the primary forest the plants that in It J). competition from other because the pressure of open secondary Also, the the areas. in as is it growth in the secondary forest. ister open primary This species grows in parts of the . secondary and oroduction of are typical for a sori We example an of a believe that species. it is by presumably displaced other ests. Later, it is community concepts of Jacobs with the nlant i AMERICAN FERN VOLUME NUMBER JOURNAL: 42 85 2 (1995) Table Development of + = 3. sori, in relation to trunk height in tree ferns studied. sori observed; no sori lacking; data taken. Plant height (cm) 0-50 50-75 75-100 100-150 150-200 200-250 250-300 >300 Alsopliila erinacea -I- Alsophila polystichoides Cyathea delgadii (primary) 4- + Cyathea delgadii (secondary) 4- Cyathea gripes ni + + + Cyathea pinnula • + + + + Cyathea trichiata 4- Acknowledgments We are grateful to R.C. Moran (AAU) and R. Stelzer (Tierarztliche Hochschule, Hannover, Ger- many) on for advice revision of the manuscript and inspired discussion. Also thanks to M.H. Grayum Moran (MO), (AAU). Sanchez and R.C. P. V. (CR). B.Venschott (San Jose, Costa Rica), G. Zotz (BCI, Panama) for determinations, administrative assistance, and helpful discussion. critical was Part of this study financially supported by the Deutsche Forschungsgemeinschaft, Deutschen Akademischen Austausch and Dienst, Studienstiftung des Deutschen Volkes. Literature Cited CoNANT, D. S. 1976. Ecogeograhic and systematic studies in American Cyatheaceae. Ph.D. dis- sertation, Harvard University, Cambridge, MA. HoLDRiDGE, L. R., W. C. Grenke, W. H. Hatheway, Liang, and A. Tosi. 1971. Forest environ- T, J. A ment Pergamon in tropical zones: pilot study. Press, Oxford, England. life Jacobs, M. 1987. The tropical rain forest, a encounter. Springer Verlag, Heidelberg, Germany. first Seiler, R. L. 1981. Leaf turnover rates and natural history of the Central American tree fern Alsophila Amer. Fern salvinii, 71:75-81. J. Sprenger, a. 1992. Populationsokologische Untersuchungen von (Myrtaceae) im Plinia salticola pramontanen Regenwald der Corillera de Tilaran. Diplomarbeit, Universitat Bielefeld, Bie- Germany. lefeld, Tanner, E. V. 1983. Leaf demography and growth of the tree fern Cyathea pubescens in Jamaica. J. Bot. Linn. Soc. 87:213-227. J. R Tryon, R. M. and A. Tryon. 1982. Ferns and allied plants with special reference to tropical New America. Springer Verlag, York.