Performance of forest plantations in small and medium
Contents
1. Forest Ecology and Management Forest Ecology and Management 175 2003 195 204 www elsevier com locate foreco Performance of forest plantations in small and medium sized farms in the Atlantic lowlands of Costa Rica Daniel Piotto Florencia Montagnini Luis Ugalde Markku Kanninen Centro Agron mico Tropical de Investigaci n y Ense anza CATIE 7170 Turrialba Costa Rica PYale University School of Forestry and Environmental Studies 370 Prospect St New Haven CT 06511 USA Received 19 December 2001 Abstract Exotic tree species predominate in reforestation in tropical regions worldwide However some native species are suitable for plantations providing a wider variety of products Adequate government programs of incentives coupled with good technical advice to farmers are needed to stimulate reforestation especially among small and medium sized farmers with limited financial resources This project evaluates growth of native and exotic tree species on plantations in small and medium sized farms in the Atlantic humid lowlands of Costa Rica Central America A total of 210 pure plantations ranging in age from 6 to 11 years were evaluated on 123 farms that had used government incentives for reforestation and had received technical advice from local non government organizations For each species seven plantations were chosen at random for study In each plantation plots of 15 trees each were chosen systemati2. South America Tectona grandis L f Lam Verbenaceae Asia Malaysia and Indochina Dipteryx panamensis Pittier Record and Mell Fabaceae Nicaragua to Colombia Gmelina arborea Roxb Verbenaceae South Asia Jim nez and Poveda 1997 and Carpio 1992 for reforestation in the region Piotto 2001 Fig 2 shows total area planted for each species and the number of projects established between 1990 and 1995 by the local farmers with assistance from the local NGOs CACSA and FUNDECOR The majority of the farmers 60 had less than 10 ha and only 10 had farms larger than 50 ha The plantations had areas between 0 1 and 5 0 ha Table 2 shows the size and number of farms where the study areas were located The majority of the farms were used for agriculture bananas plantains heart of palm maize cassava pineapples black pepper and a few ornamentals 60 and less for cattle On 40 of the 85 Study farms the only use of the land was reforestation The principal previous land use on reforested lands was pastures 57 followed by agriculture 24 and young secondary forest 19 No new areas were deforested for the establishment of the plantations The farms were primarily on undulating terrain 57 followed by flat terrain 43 None of the farms were on steeply inclined terrain All the farmers had land titles and received govern ment incentives for plantations 22 FDF and 78 CAF Incentives were pai
3. comparison of early growth pest damage and establishment costs Commonw For Rev 74 306 314 Montagnini F Sancho F Gonz lez E Porras C Moulaert A M naco A 1997 Plantaciones forestales puras y mixtas con especies nativas para la reforestaci n de terrenos degradados en Costa Rica estudio comparativo del crecimiento da o por plagas regeneraci n natural y costos de establecimiento Biocenosis Costa Rica 12 25 34 Newbould P J 1967 Methods for Estimating the Primary Production of Forest IBP Handbook 2 Blackwell Scientific Publications Oxford UK Parrotta J A Turnbull J W Jones N 1997 Catalyzing native forest regeneration on degraded tropical lands For Ecol Manage 99 1 7 Piotto D 2001 Plantaciones forestales en Costa Rica y Nicaragua Comportamiento de las especies y preferencias de los productores Tesis M Sc CATTE Turrialba Costa Rica Roche L 1997 Official development aid policies and sustainable utilization of forest resources in developing countries Com monw For Rev 76 91 97 Schelhas J Jantzi T Kleppner C O Connor K Thatcher T 1997 Costa Rica meeting farmers needs through forest stewardship J For 95 33 38 Segura O 2000 Sustainable systems of innovation the forest sector in Central America SUDESCA Research Papers 24 Department of Business Studies Aalgorg Denmark Segura O Miranda M Mej as R 1996 Planificaci n e inversi n
4. 200 D Piotto et al Forest Ecology and Management 175 2003 195 204 Table 4 Mean annual increment in diameter MAIDBH mean annual increment in height MAIH mean annual increment of volume MATV and tree form of the nine species most used by small and medium farmers in the Atlantic lowlands of Costa Rica Species MAIDBH MAIH MAIV Straight Slightly Very Forked cm per year m per year m ha per year stem sinuous sinuous trees G arborea 2 90 0 49 a 2 24 0 42 a 31 49 14 3 a 86 2 12 2 1 6 0 8 V guatemalensis 2 59 0 29 a 1 90 0 26 b 23 51 13 0 ab 96 8 2 6 0 6 1 3 T amazonia 2 36 0 25 ab 1 97 0 31 ab 17 66 7 16 bed 96 6 3 4 0 0 7 6 T grandis 2 36 0 57 ab 1 88 0 42 b 21 39 12 7 b 78 9 17 6 3 5 8 5 C alliodora 2 09 0 38 be 1 68 0 32 be 15 67 6 36 bede 86 0 12 0 2 0 4 0 V koschnyi 1 95 0 34 be 1 41 0 37 e 11 47 7 67 cdef 100 0 0 0 0 0 0 0 H alchorneoides 1 85 0 26 bc 1 71 0 27 be 10 21 6 13 def 84 0 15 3 0 7 14 7 D panamensis 1 73 0 50 c 1 94 0 47 ab 7 90 4 39 ef 89 2 10 1 0 7 5 8 C brasiliense 1 48 0 16 c 1 29 0 19 c 5 95 3 13 f 95 1 4 9 0 0 44 Differences among means for each variable are statistically significant when the standard deviation is followed by different letters P lt 0 01 increments in height between species Table 4 G arborea and V guatemalensis were the species with greatest mean annual dbh increments with 2 90 and 2 59 cm
5. also had greater adaptability to a variety of site conditions than exotic species Use of native species helped create greater production diver sification on the plantations Also the use of medium and high quality native species in reforestation pro jects can alleviate logging pressure on natural forests The majority of native species used demonstrated high potential productivity for commercial planta tions The native species particularly V guatemalensis and T amazonia showed rapid growth high survival rates and plasticity to respond to different site con ditions Therefore these species could also be used successfully in reforestation in other regions with similar ecological conditions Programs for genetic improvement should be considered to increase pro ductivity and reduce rotation cycle length Further work to improve native species for commercial use will make them more attractive to small farmers and reduce the need for government incentives Acknowledgements This project was funded by FINNIDA Daniela Cusack translated the manuscript into English M Ashton and M Wishnie gave useful comments on this article The authors thank CACSA and FUNDE COR for their generous assistance References Bonaccorso F J Glanz W E Sandford C M 1980 Feeding assemblages of mammals at fruiting Dipteryx panamensis Papilionaceae trees in Panama seed predation dispersal and parasitism Rev Biol Trop 28 61 72 Butte
6. are located at 10 12 10 47 north latitude and 8409 8345 west longitude Fig 1 Mean annual temperature is 24 C Mean annual precipitation is 3500 5000 mm and in no month is precipitation less than 50 mm Elevation is between 30 and 200 m The overall topography is flat to undulating terrain In general soils belong to the Ultisol and Inceptisol orders There are various limitations of the soil such as slow or impeded drainage and very low to medium fertility These limitations restrict land uses to per manent crops and reforestation However projects require careful management because of the area s high susceptibility to erosion Costa Rica 1979 2 2 Characteristics of the farms used in the present research This study examines 210 pure plantations on 123 farms as part of a larger study on farmers preferences D Piotto et al Forest Ecology and Management 175 2003 195 204 Table 1 197 Species most used by small and medium farmers in the Atlantic humid lowlands of Costa Rica Species Family Natural distribution Calophyllum brasiliense Cambess Clusiaceae Mexico to N South America Vochysia guatemalensis Donn Sm Vochysiaceae Mexico to Peru Hieronyma alchorneoides Allemao Euphorbiaceae Mexico to Brazil Virola koschnyi Warb Myristicaceae Central America Cordia alliodora Ruiz and Pav n Cham Boraginaceae Mexico to South America Terminalia amazonia J Gmell Exell Combretaceae S Mexico to N
7. en el sector forestal en Costa Rica Consejo Centroamericano de Bosques y reas Protegidas Heredia Costa Rica p 32 Terborgh J Wright S J 1994 Effects of mammalian herbivores on plant recruitment in two neotropical forests Ecology 75 1829 1833 Thacher T Lee D R Schelhas J W 1997 Farmer participation in reforestation incentive programs in Costa Rica Agrofor Syst 35 269 289 Ugalde L 2000 El sistema MIRA Componente de Silvicultura Manual del usuario CATTE Turrialba Costa Rica p 82 Watson V Cervantes S Castro C Mora L Sol s M Porras LT Cornejo B 1998 Abriendo espacio para una mejor actividad forestal Estudio de Costa Rica Centro Cient fico Tropical e Institute for Environment and Development San Jos Costa Rica p 114 Wright J W 1964 Mejoramiento gen tico de los rboles forestales FAO Rome p 437
8. respectively Differences among these growth rates were highly significant P lt 0 01 when compared with other species in the study 7 amazonia and T grandis were the exceptions with similar dbh growth of 2 36 cm per year C brasiliense had the lowest mean annual dbh increment 1 48 cm This was significantly inferior P lt 0 01 to other species with the exceptions of Hieronyma alchorneoides Allemao and D panamensis with 1 85 and 1 73 cm respectively G arborea T amazonia and D panamensis had the largest mean annual increment in height with 2 24 1 97 and 1 94 m respectively G arborea and V guatemalensis had the highest mean annual incre ment in volume followed by T grandis T amazonia and C alliodora C brasiliense and D panamensis had the lowest mean annual increment in volume 3 4 Tree form V koschnyi and V guatemalensis had the highest proportion of straight stems and the lowest proportion of sinuous or bifurcated trees H alchorneoides and T grandis had the highest percentages of bifurcated stems with 14 7 and 8 5 respectively G arborea also had inferior stem form when compared with native species despite being the species with the highest growth Table 4 4 Discussion 4 1 Promising species for reforestation productivity and economic and environmental values Use of exotic species predominates in tropical timber and rural development plantations worldwide Evans 1999 However in th
9. 3 5m and 4m x 4m This design guaranteed a uni form number of observations per plot independent of initial tree spacing The use of 15 tree plots is sug gested by Wright 1964 who compared performance of 15 tree plots with 200 tree plantation plots Wright demonstrated that both plot sizes gave similarly valid estimations of tree growth relative to height and diameter Systematic plot placement was used in this inves tigation to diminish cost and time related to the investigation In the majority of the cases the sys tematic approach produces more precise results than random sampling Kleinn and P rez 2000 A random procedure was used to place the first corner of the first tree plot and the following tree plot was located 50 m from the initial tree plot Sampling intensity was four plots per hectare representing 5 4 of the area where plantations were at 3m x 3m planting dis tance and 9 6 when plantations were at 4m x 4m spacing 2 4 Data analysis In each plot dbh total height number of trees per ha tree form and spacing were evaluated Trees were placed in one of the three categories of form straight stems slightly sinuous or very sinuous stems Bifurcation in the stem at height less than 4m was also recorded The MIRA SILV software was used to analyze the field data Ugalde 2000 Tree survival basal area and volume were calculated for each plot Calculation of volume was done using a 0 5 volume factor Newbo
10. Degraded sites Incentives Native species Reforestation 1 Introduction Corresponding author Tele 1 203 436 4221 On a global scale native species are widely extracted fax 1 203 432 3929 p E mail address florencia montagnini O yale edu F Montagnini from natural forests However use of native species for Current address Rua Afonso Br s 295 Vila Nova Conceicao reforestation is minimal and exotic tree species pre Sao Paulo SP Brazil CEP 0451 011 dominate both in industrial as well as in rural devel 0378 1127 02 see front matter 2002 Elsevier Science B V All rights reserved PH S0378 1127 02 00127 5 196 D Piotto et al Forest Ecology and Management 175 2003 195 204 opment plantations Evans 1999 In humid tropical regions of Latin America forest plantations provide wood as well as various environmental services such as carbon fixation soil stabilization maintenance of biodiversity and restoration of degraded areas To ensure success of reforestation programs farmers must have access to adequate technical assistance for species and site selection In addition effective programs of government incentives to stimulate reforestation are needed especially for small and medium sized farmers with limited financial resources Segura 2000 In Costa Rica over the past 15 years the supply of wood from natural forests has diminished due to deforestation combined with the establishment of con serva
11. ant n de P rez Zeled n Costa Rica Tesis M Sc CATIE Turrialba Costa Rica p 94 Direcci n General Forestal 1987 Bolet n estad stico No 2 Direcci n General Forestal San Jos Costa Rica p 5 Espinoza M Butterfield R 1990 Adaptabilidad de 13 especies nativas bajo condiciones de plantaci n en las tierras bajas h medas de Costa Rica En Salazar R Ed Manejo y Aprovechamiento de Plantaciones Forestales con Especies de Uso M ltiple Actas Reuni n IUFRO Guatemala Abril de 1989 CATIE Turrialba Costa Rica pp 159 172 Evans J 1999 Planted forests of the wet and dry tropics their variety nature and significance New For 17 25 36 FUNDECOR 2001 Programas y su impacto reforestaci n Consulted 28 May 2001 Available in http www fundecor or cr logros programas reforestacion shtml Gonz lez E Fisher R 1994 Growth of native species planted on abandoned pastureland in Costa Rica For Ecol Manage 70 159 167 Haggar J P Briscoe C B Butterfield R P 1998 Native species a resource for the diversification of forestry production in the lowland humid tropics For Ecol Manage 106 195 203 Jim nez Q Poveda L J 1997 Lista actualizada de los rboles maderables de Costa Rica Aportes al Desarrollo Sostenible Universidad Nacional Heredia Costa Rica p 36 Kaimowitz D 1996 Livestock and deforestation Central America in the 1980s and 1990s a policy perspective CIFOR Spe
12. at the government must guarantee financial support to ensure that plantations complete a productive rotation The government must also simplify bureaucratic procedures for distribution of incentives Many studies have demonstrated that in most developing countries projects developed and maintained with incentives are not sustainable after financial support ends Roche 1997 The forestry sector needs greater emphasis on social implications of reforestation especially because incentives tend not to benefit the poorest farmers Watson et al 1998 Small scale reforestation pro jects are apparently more expensive but small projects are a better way to distribute benefits Without finan cial support forest resources on farms will continue to be managed unsustainably Farmers in the Atlantic lowlands of Costa Rica are willing to continue reforestation Piotto 2001 Forestry is commonly perceived to provide many goods and services However farms have low income limiting the establishment of plantations due to long rotations and high risk Segura 2000 Therefore programs and projects to support reforestation on small farms should be improved to satisfy social economic and environmental goals 5 Conclusions Widespread use of native species for reforestation programs in the Atlantic lowlands of Costa Rica was as the results of this study show a good decision Native species had better or equal performance than exotic species and
13. ates but high plasticity could be used on less favorable sites These species should be planted on soils that are compacted from previous land use have poor drainage low fertility and in areas where there is limited management 4 3 Farmer objectives and needs for the promotion of reforestation Previous studies indicate that many farmers throughout the tropics perceive reforestation as a way to make marginal farm areas productive both environmentally and economically D az 1995 Kor honen 2000 The primary objective of plantations in this study was to bring economic benefits to farmers and increase forest products for farm use Environ mental objectives have prevailed in importance in previous studies in Costa Rica Martinez et al 1994 Current and Scherr 1995 D az 1995 Schelhas et al 1997 Thacher et al 1997 A farmer s objective in establishing a plantation is associated to his her D Piotto et al Forest Ecology and Management 175 2003 195 204 203 economic situation and level of education Poorer farmers plant trees for economic benefit and domestic needs Current and Scherr 1995 found that economic benefit is the primary reason for the establishment of plantations in Central America where high levels of poverty predominate especially in rural areas Kaimowitz 1996 Most farmers in the region believe that the govern ment established forest policy for long term planning Piotto 2001 They believe th
14. cally for evaluation of diameter at breast height dbh total height number of trees per hectare tree form and spacing Terminalia amazonia J F Gmel Exell Hieronyma alchorneoides Allemao and Vochysia guatemalensis Donn Sm were the most frequent species found in plantations in the region of study Gmelina arborea Roxb exotic and V guatemalensis native had the highest mean annual diameter increment with 2 90 and 2 59 cm respectively Calophyllum brasiliense Cambess native had the lowest mean annual diameter increment 1 48 cm G arborea and V guatemalensis had the highest mean annual volume increment followed by Tectona grandis L f Lam exotic and T amazonia and Cordia alliodora R amp P Cham both native Although G arborea had the greatest mean annual diameter increment it had the lowest plantation density and problems with form V guatemalensis and T amazonia two native species were the most promising species for reforestation due to good growth in volume good form and adaptability to a variety of sites The poor form of exotic species was related to the low intensity management methods of small farmers Exotic species had the highest performance variability between sites while native species showed relatively high growth homogeneity Therefore native species seem more promising than exotics for general use across varying ecological conditions 2002 Elsevier Science B V All rights reserved Keywords Costa Rica
15. cial Publication Center for International Forestry Research Bogor Indonesia Keenan R J Lamb D Parrotta J Kikkawa J 1999 Ecosystem management in tropical timber plantations satisfying econom ic conservation and social objectives J Sustain For 9 117 134 Kleinn C P rez J 2000 Consideraciones metodol gicas en la experimentaci n cient fica agr cola Sub Unidad de Estad stica CATIE Turrialba Costa Rica p 28 Korhonen K 2000 The silvicultural state of planted forests in southern Costa Rica as affected by farmers motivation for reforestation evaluation of forest incentive programs Thesis University of Helsinki Finland p 71 Mart nez H H 1981 Evaluaci n de ensayos de especies forestales en Costa Rica Tesis CATIE Turrialba Costa Rica p 172 Mart nez H A Sage L F Borge C Picado W 1994 Evaluaci n t nica externa del Programa de Desarrollo Forestal DGF DECAFOR Secretar a T cnica de Apoyo Fondo de Desarrollo Forestal San Jos Costa Rica p 120 Montagnini F 2001 Plantaciones forestales con especies nativas una alternativa para la recuperaci n de reas degradadas Biocenosis Costa Rica 15 1 2 72 78 Montagnini F Mendelsohn R 1997 Managing forest fallows improving the economics of swidden agriculture Ambio 26 118 123 Montagnini F Gonz lez E Rheingans R Porras C 1995 Mixed and pure forest plantations in the humid neotropics a
16. d in cash and farmers bought supplies for their plantations individually Economic benefit from harvesting wood was the 83 area Fig 1 Map of Costa Rica showing location of study sites 198 D Piotto et al Forest Ecology and Management 175 2003 195 204 o o Number of Plantations m o o CA CB DP GAHA TA TG VG VK Species 120 100 80 60 Total Area ha 40 20 CA CB DP GA HA TA TG VG VK Species Fig 2 Number of plantations and total planted area for the species most used by farmers with the assistance of local NGOs in the Atlantic humid lowlands of Costa Rica plantations established between 1990 and 1995 CA Cordia alliodora CB Calophyllum brasiliense DP Dipteryx panamensis GA Gmelina arborea HA Hieronyma alchorneoides TA Terminalia amazonia TG Tectona grandis VG Vochysia guatemalensis VK Virola koschnyi motivation of the majority of farmers 62 Piotto 2001 Nonetheless some of the farmers reforested for environmental reasons 38 These farmers planned to keep reforested areas as permanent reserves 2 3 Methods All plantations in the region were identified and then a random subset of seven plantations was selected for study of each species 9speciesx7 plantations each 63 plantations total The number of planta tions was decided in order to obtain a 20 sampling error which is the highest acceptable error allowed in forest inventories by the Costa Rica
17. e Atlantic lowlands of Costa Rica 88 of plantations established between 1990 and 1995 used native species The high use of native species in the region is largely due to the results of tree planting projects at La Selva Biological Station as well as to the technical assistance regarding species selection provided to farmers by the local NGOs Projects at La Selva demonstrated that some native species which had not previously been used for reforestation were in fact appropriate for silviculture Butterfield 1990 Espinoza and Butterfield 1990 In addition the government subsidies provided at the time were effective in promoting reforestation with native species by small and medium farmers through out the region The results of this investigation show that the majority of plantations in the area had grown well and some advantages of using native species over exotics were apparent Although an exotic species G arborea had one of the greatest annual growth in dbh and height it had the lowest plantation density and problems with tree form This species has been studied extensively in the neotropics and similar results have previously been reported in Costa Rica D Piotto et al Forest Ecology and Management 175 2003 195 204 201 Centro Agron mico Tropical de Investigaci n and Ense anza 1991 Gonz lez and Fisher 1994 Vochysia guatemalensis and T amazonia were the most promising native species for reforestation with an
18. ia TG Tectona grandis VG Vochysia guatemalensis VK Virola koschnyi Fig 3 this study provides insight as to which species have higher performance homogeneity Exotic species had the highest performance varia bility across sites and under different management plans Exotic species had relatively higher growth in height and dbh but also had high variability between sites Fig 3 These findings indicate that these exotic species could be considered specialists 1 e site variability and management have a substantial impact on growth and development of these species None theless if the variables affecting growth could be identified the exotic species could be planted in adequate sites and managed in a way to maximize productivity Butterfield 1996 On the other hand native species had relatively high growth homogeneity across the entire study area with the exception of D panamensis Native species seem more promising than exotics for general use across varying ecological conditions For example V gua temalensis and T amazonia in addition to having similar growth rates to the exotic species and good expected volume yields at harvest displayed high plasticity in relation to site conditions These two species seem to be the best alternative for local plantations as well as for plantations in other regions with similar ecological conditions The rest of the native species which displayed relatively lower growth r
19. larged to address this problem Species like Calophyllum brasiliense Cam bess which has nearly the same number of plantations as T grandis in the region had a sampling error of 10 The species with the largest number of planta tions in the area Terminalia amazonia J Gmell Exell had the lowest sampling error Table 3 For this project a multi series sampling design was used for each species The primary units of study were the plantations chosen at random The secondary D Piotto et al Forest Ecology and Management 175 2003 195 204 199 Table 3 Survival and number of trees per hectare and sampling error on small and medium farms in Atlantic humid lowlands of Costa Rica Species Survival Number of Sampling trees ha error C brasiliense 87 1a 840 a 9 8 V guatemalensis 75 l a 647 b 10 0 H alchorneoides 72 4 ab 634 b 10 3 V koschnyi 72 4 ab 681 ab 12 9 C alliodora 71 9 ab 693 ab 15 7 T amazonia 69 0 ab 597 b 16 0 T grandis 68 0 ab 689 ab 17 0 D panamensis 66 6 ab 654 b 22 2 G arborea 59 5 b 653 b 26 8 For each variable differences among means in the same column followed by the same letter are not statistically significant P lt 0 01 units of study were temporary plots of 15 trees each The 15 tree plots were chosen systematically Plots were designed by number of trees because trees on the plantations showed homogenous spacing but with different arrangements 3m x 3 m 3 5m x
20. n government The study used the mean annual increment of diameter at breast height dbh variable for Virola koschnyi Warb using data already available for this species from FUNDECOR This variable was used because the plantations in this study are of different ages If basal area or volume had been used to study plots of Table 2 Size and number of farms where tree measurements were taken in the Atlantic humid lowlands of Costa Rica Mean area of farm sampled ha Number of farms sampled Farm size ha lt 10 25 0 98 10 50 13 1 10 gt 50 5 2 68 different ages and different spacing between trees outcomes would have lacked uniformity The following formula was used to calculate the number of plantations needed to perform this study m CV tos SE where n is the number of plantations CV the coeffi cient of variation tops the values from the Stu dent s t test at 5 probability and SE the sampling error Because of the lack of information for other species this study used a calculated size of the samples for V koschnyi and applied this value to all species How ever differences between species were expected and each species had 1ts own sampling error Table 3 The table shows that only in the G arborea and Dipteryx panamensis Pittier plantations was sampling error above 20 Because this study was meant to be an exploratory study comparing growth of different spe cies the study area was not en
21. nual growth comparable to the most commonly used exotic species Mart nez 1981 Similar results for younger trees of these species have been reported in other studies conducted in the same region Butterfield and Espinoza 1995 Gonz lez and Fisher 1994 Espinoza and Butterfield 1990 The results of this investigation are therefore in accordance with pre vious projects demonstrating the viability of using native species for timber producing reforestation in the region Although at present the total rotation times for these species are not known expected volumes at harvest are estimated as 170 m ha for T amazonia after 25 years and 250 m ha for V guatemalensis after 20 years Montagnini 2001 These yields make them attractive alternatives for farmers Fuelwood from thinnings represents an additional source of income for the farmers Montagnini and Mendelsohn 1997 The four species with best growth were two native species V guatemalensis and T amazonia and two exotics G arborea and T grandis Nonetheless when comparing tree form native species were super ior The poor form of exotic species could be related to the low intensity of management applications by small farmers Haggar et al 1998 Normally these exotic species require intensive management to guarantee productivity and high wood quality In the present research for each exotic species there is a native species that is comparable in wood quality and gro
22. ocial and environmental value D panamensis seeds are an important food source for fauna including the green macaw Ara ambigua an endangered species and some rodents like Sciurus granantensis Dasy procta punctata Agouti paca and Proechimys semi spinosus D panamensis also contributes to the establishment of other vegetation because of its inter actions with several seed dispersers and pollinators Bonaccorso et al 1980 Terborgh and Wright 1994 H alchorneoides C alliodora and V koschnyi are other native species that had relatively good growth although lower than the exotic species G arborea and T grandis and than the other more productive native species of this research such as V guatemalensis and T amazonia H alchorneoides has a relatively high percentage of bifurcated trees 14 7 and some problems with tree form However estimated revenues from harvesting H alchorneoides are high due to relatively high market prices making its planting an attractive alternative Montagnini and Mendelsohn 1997 This species requires intensive management during initial phases of a plantation development such as pruning to guarantee higher quality stems for final harvest Nonetheless for small farmers interested in high value timber these species could be used to obtain a greater variety of products to respond to market uncertainty Montagnini et al 1997 4 2 Effects of site and silvicultural practices on species perf
23. ormance The sites where the plantations were established are marginal lands for traditional agriculture because of their poor and degraded soils In these zones as in many regions of the humid tropics worldwide forestry 202 D Piotto et al Forest Ecology and Management 175 2003 195 204 activities are relatively new and are generally prac ticed by small and medium farmers 5 50 ha farms These farmers generally use low inputs give little preparation to the sites and manage the plantations with low intensity Varying site conditions and low intensity management can create a high variability in productivity of the same species on different planta tions For higher growth homogeneity across planta tions foresters should use more stable genotypes Butterfield 1996 That is genotypes that maintain a certain level of productivity across varying condi tions should be used Using dbh mean annual height increment and variance between plantations S2 0 4 0 3 0 1 0 0 1 0 1 5 2 0 2 5 3 0 MAIDBH cm 0 25 0 20 0 15 N 195 0 10 0 05 0 00 1 0 1 5 2 0 25 MAIH m Fig 3 Variance 2 versus mean annual increment in dbh MAIDBH and mean annual increment in height MATH for the nine species most used by farmers in the Atlantic humid lowlands of Costa Rica CA Cordia alliodora CB Calophyllum brasiliense DP Dipteryx panamensis GA Gmelina arborea HA Hieronyma alchorneoides TA Terminalia amazon
24. rfield R 1990 Native species for reforestation and land restoration a case study from Costa Rica In Proceedings of the 14th IUFRO World Congress Vol 2 Montreal Canada pp 3 14 Butterfield R 1996 Early species selection for tropical reforesta tion a consideration of stability For Ecol Manage 81 161 168 Butterfield R Espinoza M 1995 Screening trial of 14 tropical hardwoods with an emphasis on species native to Costa Rica fourth year results New For 9 135 145 Carpio I M 1992 Maderas de Costa Rica 150 especies forestales Universidad de Costa Rica San Jos Costa Rica p 338 Centro Agron mico Tropical de Investigaci n and Ense anza 1991 Melina Gmelina arborea especie de rbol de uso m ltiple en Am rica Central Ser T c Colecci n Gu as Silviculturales No 10 CATTE Turrialba Costa Rica p 62 Costa Rica 1979 Manual descriptivo de los criterios clases and subclases del mapa Capacidad de uso de los suelos de Costa Rica Oficina de Planificaci n Sectorial Agropecuario San Jos Costa Rica p 100 Current D Scherr S 1995 Farmer costs and benefits from agroforestry and farm forestry projects in Central America and Caribbean implications for policy Agrofor Syst 30 87 103 204 D Piotto et al Forest Ecology and Management 175 2003 195 204 D az Y V 1995 Socioeconom a y silvicultura del establecimiento de plantaciones forestales en fincas peque as del C
25. small farmers and supported by the Costa Rican Ministry of Agriculture and Livestock MAG while FUNDECOR provides technical advice to farmers in sustainable forest management and reforestation When CACSA and FUNDECOR began working on reforestation projects they recurred to the OTS for assistance in species selection Species were selected for their promising performance and rapid growth Table 1 With the work of CACSA and FUNDECOR reforestation in the region passed from a phase of pure investigation to a phase of implementation FUNDE COR 2001 By 1999 the projects were responsible for planting approximately 1500 ha in the Atlantic lowlands FUNDECOR 2001 However the investigations at the Biological Sta tion La Selva administered by OTS only covered the first phases of plantation development 3 and 4 years Information about the long term performance of the plantations is necessary to guarantee better results and diminish the investment risk for the rural farmers The objective of the present study was to evaluate the growth of native and exotic tree species in plantations ranging in age from 6 to 11 years The plantations were established by farmers using government incen tives and with the assistance of the local NGOs in the Atlantic humid lowlands of Costa Rica 2 Materials and methods 2 1 Site description The plantations were established between 1990 and 1995 on the Atlantic lowlands of Costa Rica The study sites
26. tion areas Gonz lez and Fisher 1994 In response more forest plantations have been established for timber and a number of these have been established by small and medium sized landowners through credit and government incentives Watson et al 1998 Until 1987 one native species Cordia alliodora R amp P Cham and three exotics Gmelina arborea Roxb Pinus spp and Eucalyptus spp made up 94 of the plantation production on the Atlantic lowlands of Costa Rica Direcci n General Forestal 1987 In Costa Rica studies on native species for use in plantations began in the mid 1980s with research conducted at La Selva Biological Station of the Orga nization for Tropical Studies OTS Butterfield 1990 Espinoza and Butterfield 1990 Their research shows that several native species that had not previously been used for reforestation had good growth and adapt ability to degraded soils Between 1987 and 1996 the Costa Rican govern ment promoted reforestation through economic incen tives such as the Fund for Forest Development FDF and the Forest Payment Certificate CAF Segura et al 1996 Watson et al 1998 Farmers in the Atlantic lowlands region in association with local non governmental organizations NGOs the County Agricultural Center of Sarapiqu CACSA and the Foundation for the Development of the Central Vol canic Range FUNDECOR began establishing forest plantations CACSA is an organization made up of
27. uld 1967 Analysis of variance was used to compare mean annual incre ments in dbh height and volume and survival between species Means were compared using the Turkey HSD test 3 Results 3 1 Plantation spacing Plantations with spacing of 3m x 3m 3 5m x 3 5m and 4m x 4m were found for each species The most common spacing scheme was 3m x 3 m for all species For G arborea 3m x 3m was the only spacing scheme used D panamensis was the only species with plantations in all three spacing schemes including 3 5m x 3 5m 3 2 Tree survival and number of trees per hectare Survival of species in this study reflected the per centage of trees remaining in plantations after replant ing thinning and natural mortality The species with the highest survival was C brasiliense with 87 1 of the trees initially planted still living The species with the second highest survival was V guatemalensis with 75 1 G arborea had the lowest survival with 59 5 This is a significant difference P lt 0 01 when compared with C brasiliense and V guatemalensis Table 3 The number of trees per hectare which represents the density of the stands had low variation without significant difference between species P lt 0 01 The exception to this observation was C brasiliense which had the highest density 3 3 Tree growth and productivity Significant differences were found P lt 0 01 in mean annual increments in dbh and mean annual
28. wth G arborea exotic and V gua temalensis native produce light wood with specific weight of approximately 0 34 and 0 35 g cm respec tively T grandis exotic and T amazonia native produce heavier wood with mean specific weights of 0 61 and 0 68 g cm respectively Carpio 1992 Use of native species which are better adapted to local conditions instead of exotics is one way to maintain wood production and increase the conservation value of plantations Keenan et al 1999 Parrotta et al 1997 In addition native species are better suited to low input forestry practices Haggar et al 1998 common on small and medium sized farms in tropical regions D panamensis and C brasiliense had the lowest growth in dbh and height and could be classified as slow growing species These species need long rota tion periods to produce saw timber Estimated rotation times are 35 40 years with estimated volumes at harvest of 200 m ha for C brasiliense and 300 m ha for D panamensis Montagnini 2001 C brasi liense was the slowest growing species with growth rates slightly lower than those found by Butterfield and Espinoza 1995 and by Montagnini et al 1995 in 4 year old pure plantations Nonetheless many small farmers have chosen to plant these species because of the high priced wood and their good form The high value of the wood compensates for the low annual increments in volume These species also have a high s
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